Version May 2024
INTRODUCTION — Pelvic and paraaortic lymph node evaluation is a major component of the surgical staging procedure for several gynecologic malignancies, including endometrial and ovarian carcinoma [1]. Historically, cervical cancer was staged based on clinical findings alone; however, in 2018, surgical and radiologic evaluation were added to the staging system.
The surgical and oncologic goals of the lymph node dissection are to define the extent of disease and, thereby, to guide further treatment. Lymphadenectomy may also have a therapeutic goal in conditions in which removing nodes harboring metastatic disease improves survival [2-5].
The role of the pelvic and paraaortic lymph node dissection for patients diagnosed with a gynecologic malignancy has evolved since the 1990s. For each tumor site, there is controversy about the extent of dissection (complete lymphadenectomy versus lymph node sampling) and the anatomic level of dissection that is required (ie, pelvic with or without paraaortic nodes).
Techniques for pelvic and paraaortic lymphadenectomy in gynecologic malignancies are reviewed here. Staging of individual tumor sites is discussed separately. (See "Invasive cervical cancer: Staging and evaluation of lymph nodes" and "Endometrial carcinoma: Staging and surgical treatment" and "Epithelial carcinoma of the ovary, fallopian tube, and peritoneum: Surgical staging".)
ANATOMY
Retroperitoneal space — The retroperitoneal space is a potential space that is accessed via a transperitoneal incision, or directly via an extraperitoneal approach (figure 1). The kidneys, ureters, bladder, great vessels, lymphatic channels, lymph nodes, nerves, and muscles lie underneath the peritoneum and are enveloped in loose areolar connective tissue. Knowledge of the anatomy of the retroperitoneum and the surgical ability to dissect and develop these potential spaces greatly facilitates radical gynecologic surgery and pelvic and paraaortic lymph node dissection. The pararectal and paravesical pelvic spaces and the retroperitoneum of the lower abdomen are developed by the surgeon in order to define the boundaries of the lymph nodes and facilitate the surgical dissection.
Lymphatic system — The lymphatic system transports excess intracellular fluid that will be recirculated or excreted. It is able to drain larger-sized debris compared with the vascular system. Small lymphatic capillaries drain organs and merge into larger vessels that eventually drain into lymph nodes. The ultimate destination of this drainage and filtration system is the thoracic duct, which empties into the venous system.
Malignant tumors can invade the lymphatic endothelium, creating emboli that may be transported to regional or distant lymph nodes [6]. The lymph nodes of interest in a pelvic and paraaortic dissection lie along, upon, or in between the great vessels of the pelvis and abdomen (figure 2). Lymph nodes are divided into regions based upon arbitrary anatomic boundaries for the purpose of staging of cancers and for defining the boundaries of surgical dissection.
Lymphatic drainage from the pelvic viscera may proceed in a stepwise fashion from the pelvic to the lower and then upper aortic lymph nodes; however, lymphatic channels from the ovaries, fallopian tubes, and uterus may also drain directly into the lower and upper paraaortic nodes.
Pelvic lymph nodes — The pelvic lymph nodes include the lower portion of the common iliac, external and internal iliac, obturator, sacral, and pararectal nodes (figure 3). It is uncommon for the sacral and pararectal nodes to be included in a routine lymph node dissection for a gynecologic malignancy. However, with the increased use of sentinel lymph node mapping, two studies have shown that approximately 8 to 17 percent of the sentinel lymph nodes lie outside the usual dissection areas [7,8].
According to the Gynecologic Oncology Group Surgical Procedures Manual, pelvic node dissection includes bilateral removal of nodal tissue from the distal one-half of each common iliac artery, the anterior and medial aspect of the proximal half of the external iliac artery and vein, and the distal half of the obturator fat pad anterior to the obturator nerve [9]. Most of the pelvic lymph nodes lie anterior, medially, and posteriorly to the external and internal iliac vessels and the obturator nerve. There are a few nodes that lie lateral to these structures, between the vessels and the pelvic sidewall, and these are generally removed in a complete dissection [10].
Paraaortic lymph nodes — According to the Gynecologic Oncology Group Surgical Procedures Manual, paraaortic node dissection consists of resection of nodal tissue over the distal vena cava from the level of the inferior mesenteric artery (IMA) to the mid right common iliac artery and between the aorta and the left ureter from the IMA to the left mid common iliac artery (figure 4) [9].
By convention, many staging protocols limit the superior extent of dissection for gynecologic malignancies to the level of the IMA. However, uterine fundal, fallopian tube, and ovarian lymphatics can drain directly to the paraaortic nodes above the level of the IMA. The lymphatic drainage from pelvic viscera to the paraaortic nodes is complex and involves both ipsilateral and contralateral connections in addition to direct lymphatic channels that may bypass the pelvic drainage basin.
It is not uncommon for the surgeon to encounter anatomic vascular anomalies of the arteries and veins during a paraaortic lymphadenectomy. Accessory renal arteries are likely the most common arterial anomaly, and many types of venous abnormalities exist [11-13].
Extent of lymph node evaluation — A lymph node dissection (also referred to as lymphadenectomy) is intended to clear all lymph nodes from a specified area defined by anatomic boundaries and is the most accurate technique for defining the surgical stage in a patient with a gynecologic malignancy.
Selective or random sampling of nodes from the pelvis and/or the paraaortic region has been described and is less thorough or complete compared with a lymph node dissection (lymphadenectomy). If selective node sampling is performed, nodes are typically visualized and palpated and sampled if they are suspicious for metastatic disease (eg, enlarged to >1 cm, rounded instead of oval, hard, fall apart when dissected). Selective or random sampling is generally of little value except when performed as part of a formal sentinel node identification procedure or if the selected node is suspicious for malignancy.
In the staging of gynecologic cancers, the extent of lymphadenectomy varies by type of cancer and node chain (pelvic or paraaortic). The approach to evaluation of lymph nodes for each tumor site is discussed in detail separately. (See "Invasive cervical cancer: Staging and evaluation of lymph nodes" and "Endometrial carcinoma: Staging and surgical treatment" and "Epithelial carcinoma of the ovary, fallopian tube, and peritoneum: Surgical staging".)
TUMOR SITES — The use of pelvic and paraaortic lymphadenectomy in gynecologic malignancies is summarized here briefly. The evaluation of lymph node status for each tumor site is discussed in detail separately. (See "Invasive cervical cancer: Staging and evaluation of lymph nodes" and "Endometrial carcinoma: Staging and surgical treatment" and "Epithelial carcinoma of the ovary, fallopian tube, and peritoneum: Surgical staging".)
Cervical cancer — Cervical cancer is staged based on clinical, radiologic, and surgical findings (table 1). Evaluation for pelvic and paraaortic lymph node metastases impacts prognosis and treatment decisions and is now part of International Federation of Gynecology and Obstetrics staging. Thus, pelvic and/or paraaortic lymph node dissection is regularly incorporated into the management of patients with early-stage disease and in selected patients with locally advanced-stage disease [2,14].
In early-stage cervical cancer, information regarding lymph node involvement helps to guide whether the primary therapy will be radical hysterectomy or chemoradiation and if adjuvant chemoradiation should be given. In addition, the information impacts the anatomic level chosen for volume-directed radiation therapy in both early- and advanced-stage disease.
It is controversial whether debulking grossly enlarged positive lymph nodes is therapeutic in cervical cancer [2-4], but some centers routinely remove bulky nodes in patients with advanced cervical cancer prior to definitive treatment with radiation and concurrent chemotherapy. Lymph nodes >2 to 3 cm are considered less likely to be sterilized with the use of chemoradiation only.
Lymph node evaluation in cervical cancer is discussed in detail separately. (See "Invasive cervical cancer: Staging and evaluation of lymph nodes", section on 'Surgical evaluation of lymph nodes' and "Management of early-stage cervical cancer", section on 'Primary therapy' and "Management of locally advanced cervical cancer", section on 'Treatment of para-aortic nodes'.)
Endometrial cancer — Endometrial cancer is surgically staged (table 2 and table 3). One of the most important prognostic factors for endometrial carcinoma is the presence of extrauterine disease, particularly pelvic and paraaortic lymph node metastases. Evaluation of pelvic and paraaortic lymph nodes is required as part of staging, but there is ongoing controversy about the mode of evaluation, particularly in patients presumed to have early-stage disease. Possible approaches include pelvic and paraaortic node palpation and sampling, selective lymphadenectomy based on frozen section criteria (grade, tumor size, and depth of invasion), complete lymphadenectomy, or sentinel node evaluation. The extent of lymph node dissection (ie, whether paraaortic lymphadenectomy should be performed and to what anatomic level) is also a topic of debate. Endometrial cancer remains the least uniformly managed gynecologic malignancy, even among gynecologic oncologists [15].
The presence of pelvic and/or paraaortic lymph node metastases determines whether chemotherapy with or without radiation is indicated and to what level the radiation may possibly be given. (See "Endometrial carcinoma: Staging and surgical treatment" and "Overview of resectable endometrial carcinoma", section on 'Lymphovascular space invasion'.)
Ovarian cancer — Ovarian cancer is surgically staged (table 4). Unfortunately, 75 percent of patients diagnosed with epithelial ovarian cancer present with stage II or higher disease [16]. In those patients, a lymph node dissection is less useful prognostically and to guide treatment decisions than for the patient diagnosed with disease confined to the ovaries. However, it is important to remove suspicious or grossly enlarged nodes in patients with advanced disease undergoing tumor debulking with the goal of optimal cytoreductive surgery [17,18]. For patients who have no apparent disease outside the ovaries, 15 to 20 percent will have lymph node involvement, with histologic grade being the most significant risk factor [19,20].
Chemotherapy is indicated for patients with stage IC or higher disease, so lymph node metastases are not the sole indication for postoperative therapy. However, the absence of lymph node involvement is clinically significant for subsets of patients with surgically staged low-risk epithelial, germ cell, and stromal ovarian malignancies, who may be candidates for observation without adjuvant chemotherapy [17,18]. Some data suggest that lymph node dissection is therapeutic in a portion of patients with obvious advanced-stage disease [21-24]. However, a randomized phase III trial suggested no additional benefit of lymphadenectomy in the absence of suspicious lymph nodes and otherwise completely resected advanced ovarian cancer [25,26]. (See "Adjuvant therapy of early-stage (stage I and II) epithelial ovarian, fallopian tube, or peritoneal cancer" and "First-line chemotherapy for advanced (stage III or IV) epithelial ovarian, fallopian tube, and peritoneal cancer".)
PREOPERATIVE PREPARATION
Preoperative evaluation — Preoperative preparation for pelvic or paraaortic lymphadenectomy as a standalone procedure should include appropriate evaluation based on tumor site, medical comorbidities, and performance status. General principles of preoperative evaluation and preparation and specific requirements for patients with cervical, endometrial, or ovarian cancer are discussed in detail separately. (See "Overview of preoperative evaluation and preparation for gynecologic surgery" and "Invasive cervical cancer: Staging and evaluation of lymph nodes" and "Endometrial carcinoma: Staging and surgical treatment" and "Epithelial carcinoma of the ovary, fallopian tube, and peritoneum: Surgical staging".)
Prophylactic antibiotics — There are no guidelines or data regarding whether antibiotic prophylaxis to prevent surgical site infection is indicated for pelvic or paraaortic lymphadenectomy when performed as a standalone procedure. In our experience, many surgeons do give antibiotics for these procedures to cover for skin flora, but as a clean procedure, antibiotics are not indicated.
Thromboprophylaxis — Patients with gynecologic malignancy and those undergoing procedures that are >45 minutes in duration have at least a moderate risk of venous thromboembolism, and many patients are at high risk and should receive prophylactic pharmacologic anticoagulation (table 5). (See "Prevention of venous thromboembolic disease in adult nonorthopedic surgical patients", section on 'Assess risk for thrombosis'.)
LYMPHADENECTOMY PROCEDURE
Surgical access — The surgical approach used for a lymphadenectomy procedure in gynecologic oncology is typically determined by the best approach for the total procedure since procedures for endometrial and ovarian, fallopian tube, and peritoneal cancer include full surgical staging with hysterectomy, bilateral salpingo-oophorectomy, and cytoreduction.
For patients with locally advanced cervical cancer (stages IB2 to IVA) who undergo pelvic and paraaortic lymphadenectomy for evaluation prior to primary chemoradiation, the lymphadenectomy procedure is often performed as a standalone procedure. For these patients, in our practice, we use a robotic transperitoneal approach, although others prefer the extraperitoneal or transperitoneal laparoscopic approach.
Laparoscopy — Most laparoscopic gynecologic oncology procedures are performed using robotic surgery.
Robotic laparoscopy — The port site setup for robotic surgery is different than for conventional laparoscopic procedures as ports are generally placed above the umbilicus (figure 5) [27,28]. Most gynecologic oncologists will use four 8 mm robotic ports and two additional laparoscopic ports to be controlled by the bedside assistant. This port setup and surgical approach is effective for most situations requiring hysterectomy with pelvic and paraaortic lymph node dissection up to the level of the inferior mesenteric artery (IMA). Adequate exposure to the paraaortic nodes is more likely with the robotic technique compared with laparoscopic; however, obesity and surgeon experience are still potential limiting factors, especially if the goal is dissection of nodes above the level of the IMA.
Surgical techniques have been described to improve the ability to dissect the higher-level paraaortic lymph nodes [29-31]. Using such techniques, surgical ports are placed below the level of the umbilicus and the robot is docked from the head of the table [30]. This technique likely improves access to the higher paraaortic nodes but does not allow access to the pelvis. Therefore, these techniques are best in patients where the goals of the surgery are limited to information related to the paraaortic nodes, such as surgical staging for advanced cervical cancer.
Conventional laparoscopy — The precise location of laparoscopic ports is not standardized and is highly dependent on the procedure, anatomic level of the paraaortic lymph node dissection, surgeon, and whether the laparoscopic approach is transperitoneal or extraperitoneal [32-34]. The most common port setup is a "diamond-like" pattern with the camera port at the umbilicus and three operative ports placed suprapubically and laterally in the left and right lower quadrants (picture 1) [35,36]. Additional ports are often added to retract bowel and enhance exposure.
Laparotomy — Historically, all gynecologic oncology procedures were performed via laparotomy. In current practice, full staging procedures (including hysterectomy, bilateral salpingo-oophorectomy, cytoreduction) may be performed using either laparotomy or laparoscopy. Pelvic or paraaortic lymphadenectomy as a standalone procedure is typically performed via a minimally invasive approach (robotic or conventional laparoscopic).
If pelvic lymphadenectomy is performed via laparotomy, either a vertical midline or a variety of transverse incisions (eg, Pfannenstiel, Maylard) can be utilized. A midline incision that extends above the level of the umbilicus is the most reliable for exposure to the paraaortic nodes, especially if a node dissection above the level of the IMA is planned or needed. (See "Incisions for open abdominal surgery".)
Transperitoneal versus extraperitoneal — Pelvic and/or paraaortic lymphadenectomy for gynecologic oncology procedures is typically done as part of a complete staging procedure, as noted above. In terms of access to the nodes, these are performed via laparotomy or laparoscopy and thus are transperitoneal procedures; that is, the peritoneal is incised at the abdominal incision and then again posteriorly to access the nodes in the retroperitoneum.
The main exception to this is for patients with cervical cancer, in whom lymph node dissection is performed as a standalone procedure, however, there are several options for surgical access to the retroperitoneum [2-4,33]. In our practice, we perform these procedures with a robotic, transperitoneal approach, if feasible. If this is not feasible, we perform a laparotomy. Based on the available evidence, for an open procedure, we suggest an extraperitoneal rather than a transperitoneal approach.
The two minimally invasive (laparoscopic or robotic) approaches to the retroperitoneum each have advantages and disadvantages:
●A transperitoneal approach gives excellent access to the pelvic nodes and variable access to the paraaortic nodes. Access to the paraaortic nodes is primarily dependent on the patient's body mass index and the experience of the surgeon. Paraaortic lymphadenectomy is more difficult in patients with obesity because the bowel and omentum store a great deal of fat. These structures need to be mobilized and retracted out of the field of dissection to access the paraaortic nodes.
●An extraperitoneal approach provides excellent exposure to the paraaortic nodes, even in patients with obesity. A pelvic lymph node dissection below the level of the common iliac nodes is not possible, however, unless additional port sites are placed.
Transperitoneal laparotomy for lymph node dissection prior to radiation therapy in this patient population appears to result in a higher frequency of some postirradiation regional enteric complications, presumably secondary to adhesion formation. The data regarding this are mainly based on one retrospective study, a Gynecologic Oncology Group study of 284 patients [37]. This is discussed in detail separately. (See "Invasive cervical cancer: Staging and evaluation of lymph nodes", section on 'Lymph node dissection'.)
When a laparoscopic approach is planned, the factors differ from laparotomy regarding the choice of a transperitoneal versus extraperitoneal approach. There is less risk of adhesion formation, so this is a less important factor. Extraperitoneal laparotomy was designed as an alternative to transperitoneal laparotomy to avoid intraperitoneal adhesions prior to definitive radiation therapy for advanced cervical cancer. However, transperitoneal laparoscopy is associated with a lower risk of intraperitoneal adhesions than transperitoneal laparotomy. Blinded studies in animal models reveal a similar rate and severity of adhesions between transperitoneal laparoscopic lymph node dissection and extraperitoneal laparotomy; however, transperitoneal laparoscopic lymphadenectomy is associated with significantly fewer adhesions compared with transperitoneal laparotomy [38,39].
A systematic review of robotic extraperitoneal paraaortic lymphadenectomy included five studies and 88 patients (72 percent with cervical cancer) and found that the mean number of paraaortic node yielded was 15.4 (standard deviation ±4.7) nodes [40]. Blood transfusion and intraoperative complication rates were 2 and 6 percent, respectively. Six and four percent of patients had conversion to another minimally invasive procedure and open surgery, respectively.
The procedure for an extraperitoneal approach to paraaortic lymphadenectomy is detailed below. (See 'Extraperitoneal laparoscopic access' below.)
Pelvic lymphadenectomy — Transperitoneal pelvic lymph node dissection is performed via a retroperitoneal incision, regardless of the surgical approach (ie, open versus minimally invasive). The steps of the procedure include:
●The retroperitoneum is accessed by incising the peritoneum along the psoas muscle lateral to the level of the pelvic vessels (figure 1 and picture 2). On the left side, any adhesions of the sigmoid colon are divided sharply.
●The round ligaments are transected; this usually allows for improved exposure of the obturator fossa and the distal external iliac vessels.
●The pararectal and paravesical spaces are then developed with a combination of sharp and blunt dissection. A useful landmark is the obliterated umbilical artery, which is usually visualized as a discrete fold on either side of the bladder. Developing the area between the obliterated umbilical artery and the external iliac vessels exposes the paravesical space medially and the obturator fossa laterally.
●The ureter is identified along the medial peritoneal fold. This is typically retracted medially during the entire procedure.
●The pararectal space can be developed in the area between the ureter medially and the origin of the hypogastric vessels laterally.
●The pelvic lymph node dissection is then initiated by dissecting the lateral nodal tissue away from the psoas muscle. Care is taken to identify and isolate the genitofemoral nerve, which can easily be misidentified as a lymphatic channel. The external iliac vessels can be gently retracted medially; the space between the vessels and the psoas muscle is developed. As the dissection is carried caudad, the assistant places an instrument into the paravesical space for medial retraction. The dissection continues until the circumflex iliac vein is clearly visualized.
●At this point, the fibrofatty tissue surrounding the external iliac vessels is elevated. The fibrous sheath overlying the external iliac artery is incised in order to mobilize the specimen. The surgeon then grasps the specimen and retracts it medially.
●Any adhesions to the medial portion of the external iliac artery can then be incised. The space between the external iliac artery and vein is sharply and bluntly developed. Next, the tissue adherent to the external iliac vein is gently dissected free.
●The surgeon then dissects within the obturator fossa. The fibrofatty tissue of the lymph node bundle is retracted medially, and a plane is created underneath the external iliac vein. Sharp and blunt dissection is performed within the fossa until the obturator nerve is visualized; this nerve can be isolated along its entire course within the obturator fossa. Accessory vessels in this space often arise from the undersurface of the external iliac vein; these can be clipped or cauterized only after the obturator nerve is clearly delineated and the ureter is safely retracted out of the field of dissection. Particular care must be taken at the proximal aspect of the fossa, where the bifurcation of the common iliac artery is found and the lymph nodes may be more adherent to the hypogastric vessels.
Paraaortic lymphadenectomy — Paraaortic lymphadenectomy may be performed using either a transperitoneal or extraperitoneal approach.
Extraperitoneal laparoscopic access — Extraperitoneal paraaortic lymphadenectomy is performed laparoscopically, either by conventional or robotic laparoscopy [29,30,33,34,41,42].
In terms of patient setup, for the robotic approach, the bed is placed at a different angle for the paraaortic lymphadenectomy procedure than for the hysterectomy and pelvic lymphadenectomy procedure, so the bed will need to be rotated (or the robot redocked).
Briefly, a small incision is made in the left flank of the mid abdomen. The fascia is transected, taking care not to enter the peritoneal space. The retroperitoneal space is developed using blunt finger dissection until the psoas muscle is palpated. The laparoscopic port is placed, and the space is then insufflated with carbon dioxide gas (10 to 15 mmHg). Two additional ports are then placed (figure 6) [30,33,34,43]. On the left side, the areolar tissues are transected to separate the mesentery from the lymph node bundle, and the left common iliac artery and aorta are identified. A laparoscopic retractor may be used to hold up the peritoneal sac that forms the roof of the extraperitoneal space, as needed. The ureter is identified in the mesentery (lifted up by the insufflation), and the gonadal vein is followed to its entry into the left renal vein. The lymph nodes to the left of the aorta are then dissected using a sharp and blunt dissection.
To remove the right paraaortic nodes, the dissection is continued laterally over the aorta to reach the right aortic lymph nodes covering the inferior vena cava. The right ureter is identified, and the lymph node bundle over the inferior vena cava is then carefully dissected.
For laparoscopic pelvic lymph nodes, the ports are advanced from extraperitoneally (for the aortic lymph nodes) to intraperitoneally (for the pelvic lymph nodes), and the steps are as described above.
Setup and positioning for laparoscopic surgery is discussed in detail separately. (See "Abdominal access techniques used in laparoscopic surgery" and "Nerve injury associated with pelvic surgery", section on 'Prevention of nerve injury'.)
Procedure — The procedure for paraaortic lymphadenectomy regardless of the technique used to access the retroperitoneum is as follows:
Left side — The procedure for left-side paraaortic lymphadenectomy is as follows:
●An incision is made in the peritoneum over the right common iliac artery and is extended cephalad along the aorta to the level of the duodenum.
●Next, the bifurcation of the aorta is identified, and the peritoneum over the left common iliac artery is incised.
●The mesentery of the sigmoid colon is retracted anteriorly. The areolar tissue between the left common iliac artery (and aorta) and the mesentery of the sigmoid colon is opened with a combination of blunt and sharp dissection until the left psoas muscle is identified.
●The left ureter is also identified and retracted laterally so that it is safely out of the field of dissection. The degree of difficulty in obtaining this critical exposure is dependent on the ability to "pack" the small bowel into the upper abdomen above the level of the IMA and to avoid redundancy of the sigmoid colon. It is very important to identify the IMA prior to starting the lymph node dissection to avoid cutting into the mesentery of the sigmoid colon.
●Once adequate exposure has been achieved, the surgeon grasps the nodal bundle adjacent to either the aorta or proximal left common iliac artery and lifts anteriorly while dissecting the plane between the great vessels and the lymph nodes that lie adjacent to them. The dissection is then extended in a cephalad direction with blunt and sharp dissection and with electrosurgery and with scissors as needed.
●The nodal chain is then transected at the cephalad end near the IMA. The cephalad border of dissection is usually the IMA, unless there are suspicious nodes above this or a higher dissection is indicated.
Right side — The procedure for right-side paraaortic lymphadenectomy is as follows:
●To obtain exposure for the right-sided paraaortic lymph node dissection, the assistant lifts the previously incised peritoneum overlying the vena cava and the right common iliac artery. Elevation of this peritoneal window permits lateral retraction of the ureter out of the operative field and visualization of the vena cava and aorta.
●The surgeon sharply dissects within the areolar plane between the lymph nodes and the peritoneum.
●The right-side paraaortic lymphadenectomy is then performed with the use of monopolar cautery and/or hemoclips for hemostasis and sealing of lymphatic channels. The dissection is begun over the aorta and proceeds in a medial to lateral direction. Thin pedicles are created prior to transection so that perforating veins can be identified.
Infrarenal nodes — The infrarenal nodes are the nodes between the IMA and the renal vessels. These are superior paraaortic nodes and are removed if indicated; however, exposure is more difficult to obtain in this region.
The procedure for infrarenal lymphadenectomy is as follows:
●The peritoneum between the IMA and along the duodenum is incised. This incision may be carried out toward the left along the mesentery of the descending colon, often until encountering the inferior mesenteric vein.
●After adequate cephalad exposure is obtained, the nodal dissection may begin.
●On the left side, the plane of dissection is over the anterior surface of the aorta. It is important to identify the left renal and ovarian veins as well as the ovarian artery. Exposure is facilitated by dissecting the areolar tissue beneath the duodenum and then gently retracting it cephalad. The ureter is retracted laterally by the assistant. The left ovarian artery is often sacrificed to improve access to the nodes. The left nodal bundle is transected near the level of the left renal vein.
●On the right side, exposure is not as difficult and the lower paraaortic dissection is carried up to the level between the ovarian vein and the right renal vein. The right renal vein is often not visualized.
SENTINEL NODE EVALUATION — A sentinel lymph node (SLN) is defined as a lymph node that has a direct connection to the primary tumor through a lymphatic channel and represents the lymph node(s) most likely to first receive metastases from the primary tumor. SLN detection is becoming more common in the treatment of both endometrial and cervical cancer and has been endorsed in guidelines from the Society of Gynecologic Oncology [44] and the National Comprehensive Cancer Network [45]. Many retrospective and prospective studies have demonstrated feasibility and safety of SLN with low false-negative rates [46-48]. Although no randomized trials of SLN mapping versus complete lymphadenectomy have been completed to date that focused on survival, the SENTICOL-II trial reported improved postoperative lymphatic morbidity in patients who underwent SLN biopsy (SLNB) compared with SLNB plus complete lymphadenectomy [49]. This study was not powered for survival outcomes; however, disease-free survival at four years was similar between groups. SENTICOL-III is a randomized trial to assess survival outcomes and is currently still enrolling [50]. Several retrospective studies found no difference in survival outcomes in patients with deeply myoinvasive endometrial cancer or high-grade histologies [51,52]. Furthermore, other studies have suggested that pelvic sidewall recurrence may be reduced after the addition of SLN mapping [7,53]. SLN mapping may also be more cost-effective than routine or selective lymphadenectomy [54].
The rationale for SLN mapping is to identify patients with lymph node metastases and avoid the morbidity of a full lymphadenectomy in patients with negative SLNs. In addition, SLN mapping may also be considered a technique that may identify occult metastatic disease not otherwise identified by a standard lymphadenectomy. This may occur if the node lies outside of the usual boundaries of pelvic or paraaortic lymph node dissection. Also, the SLN evaluation process typically includes serial sectioning (or ultrastaging) of the SLN and immunohistochemical staining, which may be more sensitive than the traditional hematoxylin and eosin evaluation, although the clinical significance of low-volume metastases (isolated tumor cells) is unclear [55].
The most common technique for identification of SLNs is the injection of vital blue dyes (eg, isosulfan blue [ISB]), indocyanine green (detectable with near infrared immunofluorescent light), and/or a radioisotope (eg, technetium-99) around the tumor or in the cervix. These techniques are relatively well established for patients diagnosed with vulvar and cervical carcinoma. This injection can be performed intraoperatively with or without preoperative lymphoscintigraphy, and handheld and laparoscopic instruments (gamma probe) are available. While the initial studies mostly used technetium-99 or ISB, most surgeons use indocyanine green dye for improved detection and visibility in patients with endometrial or cervical cancer [56,57].
SLN evaluation for specific gynecologic tumor sites is discussed in detail separately. (See "Invasive cervical cancer: Staging and evaluation of lymph nodes", section on 'Sentinel lymph node biopsy' and "Endometrial carcinoma: Staging and surgical treatment" and "Squamous cell carcinoma of the vulva: Staging and surgical treatment", section on 'Sentinel lymph node biopsy'.)
POSTOPERATIVE CARE — There are no postoperative management issues unique to the pelvic or paraaortic lymphadenectomy. Patients undergoing pelvic and paraaortic lymphadenectomy are managed based on the type of surgical approach (laparotomy, laparoscopy) and extent of surgery (eg, lymph node dissection alone or full surgical staging) [58,59].
Leaving a drain in place to drain the lymph node dissection basin has fallen out of favor and is not indicated [60].
COMPLICATIONS — Surgical complications in patients undergoing a pelvic and paraaortic lymph node dissection are multifactorial and usually related to the patient age, existing patient comorbidities, surgical approach, operative duration, and concurrent surgical procedures. Laparoscopic procedures in general result in less morbidity than laparotomy, including pain and wound complications [61-63].
The incidence of major organ and vessel injury related to lymphadenectomy is low [64,65].
Patients undergoing lymphadenectomy for gynecologic malignancy are at least at a moderate risk of venous thromboembolism. It is not clear that the risk of deep vein thrombosis is higher with or without lymph node dissection. The incidence of thromboembolic disease has been reported in 2 to 5 percent of cases among all patients undergoing lymph node dissection for endometrial cancer staging [65-67].
Lymph node drainage issues — Complications related to lymphatic drainage are specific to the lymph node dissection.
Lymphedema is the most common complication of pelvic and paraaortic lymphadenectomy, reported in 1.5 to 45.0 percent of patients [68-70]. Postoperative irradiation and a greater extent of lymph node dissection increase the risk of this complication. A prospective cohort study found a lymphedema incidence of 11 to 34 percent, depending on the extent of limb volume change [71]. Presentation of lymphedema can be quite variable. Some patients only notice some increased ankle swelling, but edema can extend from the feet to the abdominal wall as well as in more atypical places such as the mons pubis and upper thighs only, and a fluctuating course is not uncommon. Sixty percent of patients reported it affected their daily activities and noted exacerbating factors such as prolonged standing, heat, and walking [72]. Physical and mental quality of life was lower in patients with lower leg swelling compared with those without lower leg swelling [73,74]. Early recognition is paramount for control of the disease. Patients with lymphedema are recommended to wear compression stockings as much as possible and should be referred to a physical therapist who specializes in lymphedema therapy. Another option includes elevation of the legs, and there are some early data on lymphatic venous anastomosis [75,76]. (See "Clinical features and diagnosis of peripheral lymphedema" and "Clinical staging and conservative management of peripheral lymphedema".)
Another potential complication is lymphocele. In a prospective study of 800 patients who underwent solo pelvic and/or paraaortic lymphadenectomy for gynecologic cancer, the rate of lymphocele was 20 percent, and the rate of symptomatic lymphocele was 6 percent [77]. The most common location was the left pelvic sidewall. In another series of 138 patients with endometrial cancer, lymphocele was reported in 1 percent of patients after laparoscopy and in 15 percent after laparotomy [78]. Lymphoceles are often asymptomatic but can present as pelvic pressure or pain, may cause hydronephrosis secondary to external compression of the ureter, and often will be palpable as a rounded smooth mass that can be slightly compressed along the pelvic sidewall. They may resolve spontaneously over time, but if there are secondary consequences (pain, lymphedema, hydronephrosis, infection), they may require image-guided drainage. If drain output continues to be high after several weeks (>50 to 100 mL/day), sclerotherapy with instillation of alcohol, iodine, doxycycline, or talc directly into the cystic collection can be considered [79]. Alternatively, a laparoscopic marsupialization is another option [80].
Many patients may have drainage of lymphatic fluid (lymphorrhea) from the vagina in the immediate postoperative period. This typically resolves within a few weeks [66]. If there is no improvement in drainage, a vesicovaginal or ureterovaginal fistula should be considered.
The risk of lymphatic fistula and chylous ascites has been reported but is quite uncommon [81-88]. Chylous ascites after gynecologic surgery mostly occur after paraaortic lymph node dissection. Often it will resolve with conservative management, but drain placement, median chain fatty acid diet, somatostatin analogues, or surgical correction may be required.
SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Treatment of cervical cancer".)
SUMMARY AND RECOMMENDATIONS
●Clinical significance – Pelvic and paraaortic lymph node dissection is a key part of surgical staging for patients with cervical, uterine, or ovarian, fallopian tube, or peritoneal cancers. (See 'Introduction' above.)
●Pelvic node dissection – The pelvic lymph nodes include the lower portion of the common iliac, external and internal iliac, obturator, sacral, and pararectal nodes (figure 3). Pelvic node dissection includes bilateral removal of nodal tissue from the distal one-half of each common iliac artery, the anterior and medial aspect of the proximal half of the external iliac artery and vein, and the distal half of the obturator fat pad anterior to the obturator nerve. (See 'Pelvic lymph nodes' above.)
●Paraaortic node dissection – Paraaortic node dissection consists of resection of nodal tissue over the distal vena cava from the level of the inferior mesenteric artery to the mid right common iliac artery and between the aorta and the left ureter from the inferior mesenteric artery to the left mid common iliac artery (figure 4). (See 'Paraaortic lymph nodes' above.)
●Surgical access – The surgical approach used for a lymphadenectomy procedure in gynecologic oncology is typically determined by the best approach for the total procedure since procedures for endometrial and ovarian, fallopian tube, and peritoneal cancer include full surgical staging with hysterectomy, bilateral salpingo-oophorectomy, and cytoreduction. (See 'Surgical access' above.)
•For patients with locally advanced cervical cancer (stages IB2 to IVA) who undergo pelvic and paraaortic lymphadenectomy for evaluation prior to primary chemoradiation, the lymphadenectomy procedure is often performed as a standalone procedure. (See 'Surgical access' above.)
•For such patients, we use a robotic approach if feasible and use transperitoneal access. For patients in whom the standalone procedure is performed via laparotomy, we suggest an extraperitoneal rather than a transperitoneal approach (Grade 2C). (See 'Transperitoneal versus extraperitoneal' above.)
●Lymphedema – Lymphedema is the most common complication of pelvic and paraaortic lymphadenectomy, reported in 1.5 to 28 percent of patients. This is likely lower than the actual incidence since this complication is likely to be underreported in retrospective reports. Postoperative irradiation and a greater extent of lymph node dissection increase the risk of this complication. Early recognition is paramount for control of the disease. Patients with lymphedema are recommended to wear compression stockings as much as possible and should be referred to a physical therapist specialized in lymphedema therapy. (See 'Lymph node drainage issues' above.)
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