INTRODUCTION — Surgery is the cornerstone of curative therapy for rectal adenocarcinoma [1]. Depending upon the clinical stage, size, and location of the primary tumor, a rectal cancer can be treated with either local or radical excision. A local excision is usually performed transanally. A radical excision is performed transabdominally with either a sphincter-sparing procedure such as low anterior resection or an abdominoperineal resection. Rectal cancers that have invaded adjacent organs may require a multivisceral resection.
In this topic, we provide an overview of various surgical techniques that are used to treat rectal cancer. Specific techniques are discussed in other dedicated topics:
●(See "Transanal endoscopic surgery (TES)".)
●(See "Radical resection of rectal cancer".)
●(See "Abdominal perineal resection (APR): Open technique".)
●(See "Minimally invasive techniques: Left/sigmoid colectomy and proctectomy".)
Diagnosis, staging, and nonsurgical treatment of rectal cancer can be found elsewhere:
●(See "Clinical presentation, diagnosis, and staging of colorectal cancer".)
●(See "Pretreatment local staging evaluation for rectal cancer".)
●(See "Overview of the management of rectal adenocarcinoma".)
SELECTING A SURGICAL TREATMENT — For patients with rectal cancer, the choice of a surgical treatment must take into consideration the following factors [2]:
●The distance of the cancer from the anal verge (ie, low, mid-, or upper rectal cancer) (figure 1) as well as the distance from the lower border of the tumor to the top of the anorectal ring (which informs surgical decision making for sphincter preservation)
●Presence of invasion into the lateral pelvic walls and/or other intra-abdominal organs
●Size of the cancer
●Presence of regional lymph node metastases
●Patient's pelvic anatomy
●Patient's presurgical anorectal sphincter function
●Whether or not the patient can tolerate transabdominal surgery
A stepwise approach to selecting the appropriate surgical technique based upon the pretreatment clinical disease stage and patient factors is outlined in the accompanying algorithms (algorithm 1 and algorithm 2 and algorithm 3)and described in detail in another topic. (See "Overview of the management of rectal adenocarcinoma", section on 'Management according to initial clinical stage'.)
The eligibility criteria for each surgical technique are described in detail in the respective sections below.
LOCAL EXCISION — Performed transanally, local excision removes both the tumor and adjoining rectal tissue in one specimen (ie, full-thickness excision) without tumor fragmentation, which permits pathologic assessment of inked margins, histologic differentiation, vascular involvement, and depth of invasion. However, it does not excise or stage mesorectal lymph nodes and therefore can miss nodal metastasis or tumor cell deposits in the mesorectum.
Thus, local excision is only appropriate for early-stage rectal cancer (cT0 or cT1) without high-risk features with which the risk of lymph node metastasis is low, and for those with more advanced diseases but who are medically unfit for radical surgery (algorithm 1 and algorithm 2).
Criteria for local excision — Patients with an early rectal cancer that meets all of the criteria below are eligible for local excision (algorithm 1) [2-7]:
●Superficial T0 or T1 rectal cancer (table 1)
●Tumor less than 3 cm in diameter
●Tumor involves <30 percent of the bowel lumen circumference
●Tumor is mobile and nonfixed
●Able to achieve clear margins with local excision
●Favorable histologic features based upon biopsy (ie, well- to moderately differentiated cancer, no lymphovascular or perineural invasion)
●No radiographic evidence of metastatic disease to regional nodes (N0)
●Patient compliant with aggressive postoperative surveillance
Before attempting local excision on a low polyp, one should consider if the procedure will impact future total mesorectal excision (TME) procedures if one is required. A local excision can disrupt tissue planes in the low rectum near the sphincter such that abdominoperineal resection (APR) is required instead of sphincter-saving procedures such as low anterior resection (LAR).
Patients with more advanced diseases (eg, cT2 or higher) may also be treated with local excision after sufficient counselling if they (algorithm 2) [8,9]:
●Have medical comorbidities that preclude any transabdominal surgery
●Refuse any transabdominal surgery
●Have a short life expectancy due to metastatic disease
Patients with more advanced disease (T2 or greater) may benefit from neoadjuvant therapy prior to local excision and may require further surgery or adjuvant treatment after local excision, depending upon the final pathologic staging. (See "Overview of the management of rectal adenocarcinoma", section on 'Clinical T2N0 and cT1N0 not amenable to local excision'.)
Techniques of local excision — Technically, local excision involves full-thickness excision, ideally with a ≥10 mm grossly normal circumferential margin with a depth down to perirectal fat providing a minimum of a 2-mm-deep margin [10].
●Lesions in the very distal rectum (<5 cm from anal verge) are best excised with conventional transanal excision (TAE) because they may be obscured by the transanal endoscopic surgery (TES) platform.
●TES is ideal for local excision of lesions in the mid- to proximal rectum up to 15 cm from the anal verge. (See "Transanal endoscopic surgery (TES)".)
●Rectal cancers in the mid or upper rectum that were unreachable by TAE were historically excised with one of the posterior techniques (eg, the transsphincteric [York-Mason] procedure [11] or the transsacral [Kraske] procedure [12]). However, these techniques have largely been supplanted by TES because of higher morbidity [13,14]. They remain a salvage option for treating local recurrences in the presacral space following an APR or for treating fistulas arising after an LAR or prostatectomy [15].
Outcomes of local excision — Outcomes for local excision are dependent upon the T stage of the rectal cancer. As an example, in a meta-analysis of 73 studies and over 4600 patients, there was a substantial risk of local recurrence in patients who received no additional treatment after local excision, especially those with high-risk pT1 (13.6 percent) and pT2 rectal cancer (28.9 percent) [16]. The lowest recurrence risk was provided by completion total mesorectal excision (TME; 4 percent for both pT1 and pT2); adjuvant chemoradiotherapy had outcomes comparable to those of completion TME for high-risk pT1 tumors (3.9 percent) but showed a higher risk for pT2 tumors (14.7 percent).
●The rate of local recurrence following local excision varies from 7 to 21 percent for T1 lesions and is consistently higher than that after radical resection [17-19]. Subsequent radical resection with TME is typically recommended if pathologic examination of the local excision specimen reveals significant risk factors like deeper T stage, inadequate margins, poor differentiation, submucosal invasion depth >1 mm or deep submucosal (SM3) invasion, tumor budding, or lymphovascular or perineural invasion [20]. (See 'Low anterior resection' below.)
●In general, local excision alone is not an oncologically adequate treatment for cT2 lesions, because of high local recurrence rates (26 to 47 percent) and an elevated risk for occult nodal metastasis [21]. Radical resection with TME is typically recommended under these circumstances. The use of local excision in combination with either neoadjuvant or adjuvant chemoradiation therapy for distal T2 lesions is currently being investigated [22,23]. (See "Neoadjuvant therapy for rectal adenocarcinoma", section on 'T1-2N0 tumors'.)
If radical resection is indicated based on pathology of the local excision, but the patient refuses or is unfit for radical resection, such patients should be considered for adjuvant chemoradiation, followed by surveillance for a potentially salvageable recurrence [24,25]. The performance of local excision after neoadjuvant chemoradiation has been studied for select T1/T2 lesions [8,23,26,27] but is complicated by high morbidities (eg, rectal pain, suture line dehiscence) [28,29].
LOW ANTERIOR RESECTION — Patients with invasive rectal adenocarcinomas who are not candidates for local excision should undergo radical transabdominal surgery (algorithm 2 and algorithm 3). A sphincter-sparing resection such as low anterior resection (LAR) is preferred if a negative distal margin can be achieved. An abdominoperineal resection (APR) is required if an adequate distal margin cannot be obtained. (See "Overview of the management of rectal adenocarcinoma", section on 'Clinical T3-4, N0-2 or T2, N1-2' and "Radical resection of rectal cancer".)
Criteria for low anterior resection — Patients with a rectal cancer that meets all of the criteria below should undergo a sphincter-sparing resection:
●Invasive rectal cancer cT2-4 (table 1).
●A negative distal margin can be achieved. (See "Radical resection of rectal cancer", section on 'Distal margin'.)
●Adequate presurgical anorectal sphincter function.
Techniques of low anterior resection — An LAR entails partial or total resection of the rectum followed by a colorectal or coloanal anastomosis to reestablish intestinal continuity.
For transabdominal radical resections, both LAR and APR, it is also crucial to perform a total mesorectal excision (TME) and an adequate lymph node dissection. Whenever feasible, the patient's intestinal continuity should be reestablished to preserve their anorectal function (ie, fecal continence). Such surgical principles are discussed in another topic. (See "Radical resection of rectal cancer", section on 'Principles of radical resection'.)
The techniques of laparoscopic and robotic proctectomy are also discussed in another topic. (See "Minimally invasive techniques: Left/sigmoid colectomy and proctectomy", section on 'Laparoscopic/robotic proctectomy'.)
An example of the laparoscopic approach to a sigmoid colectomy and LAR can be found in the Society of American Gastrointestinal and Endoscopic Surgeons (SAGES) video library.
An example of the laparoscopic nerve-sparing proctectomy with mesorectal excision for rectal cancer can also be found in the SAGES video library.
An example of the laparoscopic approach to an LAR and transanal mucosectomy with construction of a J-pouch can be found in the SAGES video library.
An example of the laparoscopic approach to a TME with intersphincteric dissection and coloanal anastomosis in ultra-low rectal cancer can be found in the SAGES video library.
Outcomes of low anterior resection — In contemporary series, sphincter-sparing procedures and APR have similar local recurrence rates of less than 10 percent [30-32]. Lower recurrence rates are generally associated with the use of meticulous surgical techniques (eg, achieving adequate margins, performing TME) and/or adjuvant chemoradiation therapy. (See "Radical resection of rectal cancer", section on 'Principles of radical resection' and "Neoadjuvant therapy for rectal adenocarcinoma" and "Adjuvant therapy for resected rectal adenocarcinoma in patients not receiving neoadjuvant therapy".)
ABDOMINOPERINEAL RESECTION — Traditionally, abdominoperineal resection (APR) was the gold standard for treating low-lying rectal cancers against which sphincter-sparing procedures and local excision were compared. With the advent of better surgical techniques and equipment (eg, staplers) as well as neoadjuvant therapy, APR has been gradually supplanted by sphincter-sparing procedures. However, patients with disease involvement of the anal sphincter musculature or rectovaginal septum, as well as those with poor preoperative continence or diarrheal disorders, are still best treated with an APR. (See "Overview of the management of rectal adenocarcinoma", section on 'Clinical T4, N2 disease, or other high-risk features' and "Overview of the management of rectal adenocarcinoma", section on 'Management of locally recurrent disease'.)
Criteria for abdominoperineal resection — Patients with an invasive, cT2-4 rectal cancer (table 1) who also meet one of the criteria below should be treated with an APR [33]:
●A negative distal margin of 1 cm cannot be achieved with any of the sphincter-sparing procedures. (See 'Low anterior resection' above.)
●Locally advanced low-lying rectal cancer.
●Locally recurrent low-lying rectal cancer (as a salvage procedure).
●Poor presurgical anorectal function.
Techniques of abdominoperineal resection — An APR entails en bloc resection of the sigmoid colon, rectum, and anus, followed by construction of a permanent colostomy. The techniques of APR are discussed elsewhere. (See "Abdominal perineal resection (APR): Open technique".)
Outcomes of abdominoperineal resection — Progressively lower surgical anastomoses are associated with commensurate decline in anorectal function, characterized by increased stool frequency, more incontinence and perianal irritation, decreased stool and flatus discrimination, more incomplete evacuations, and decreased rectal compliance [34]. Poor anorectal function results in poor quality of life (QOL). In one prospective study of QOL after rectal cancer surgery, patients who had an anastomosis within 5 cm of the anal verge had significantly worse QOL compared with those who underwent an APR [35].
According to several studies, long-term QOL after APR was similar to QOL after sphincter-sparing procedures [35-40]. QOL was not adversely affected by adjuvant radiation therapy after an APR [41].
MULTIVISCERAL RESECTION — A multivisceral resection includes the resection of the rectum along with one or more adjacent organs invaded by the rectal cancer. It is required for curative resection of T4 rectal cancers. (See "Overview of the management of rectal adenocarcinoma", section on 'Clinical T4, N2 disease, or other high-risk features' and "Overview of the management of rectal adenocarcinoma", section on 'Management of locally recurrent disease'.)
Criteria for multivisceral resection — Multivisceral resection is a potentially morbid procedure that is only used when a less radical procedure would not suffice in one of two scenarios [2,42,43]:
●Locally advanced rectal cancer involving adjacent organs or bony structures (T4) (table 1)
●Locally recurrent rectal cancer (as a salvage procedure)
In the modern era, approximately 6 to 10 percent of patients with rectal cancer have locally advanced disease without metastasis at the time of diagnosis and may be eligible for multivisceral resection [44].
Techniques of multivisceral resection — A multivisceral resection involves resection of the rectum with one or more of the adjacent pelvic organs or bony structures. It can be performed as a total or partial (modified) pelvic exenteration depending upon the extent of the disease.
A total pelvic exenteration removes all of the pelvic organs, including the rectum, bladder, and internal reproductive organs (ie, prostate and seminal vesicles in males or uterus, ovaries, and vagina in females) [45,46]. A partial pelvic exenteration can be anterior, posterior, supralevator, or composite, depending upon the organs or structures resected. A multivisceral resection for rectal cancer most often requires a posterior or a supralevator partial pelvic exenteration.
The techniques of multivisceral resection are discussed in detail elsewhere. (See "Exenteration for gynecologic cancer", section on 'Operative technique'.)
Outcomes of multivisceral resection — In specialized centers, pelvic exenterative surgery can provide long-term survival in patients with locally advanced rectal cancer, provided that negative resection margins are attained. Nodal status was also a determinant of overall survival.
In an international collaborative study of 1291 pelvic exenterative procedures performed for locally advanced primary rectal cancer, the median overall survival following R0, R1, and R2 resection was 43, 21, and 10 months with a three-year survival rate of 56.4, 29.6, and 8.1 percent, respectively [44].
In another retrospective review of 1741 patients with T4M0 rectal cancer, patients treated with a multivisceral resection had a better overall five-year survival than those treated with a standard colorectal resection (35 versus 28 percent) [47]. Other studies also showed that multivisceral resection can be performed with low mortality (range 0 to 8 percent) but high morbidity (range 26 to 61 percent) and high reoperation rates (20 to 30 percent) [44,45,48-56].
Compared with patients undergoing multivisceral resection for recurrences, patients undergoing multivisceral resection for locally advanced primary rectal cancer have better disease control (89 versus 38 percent) and survival (43 to 66 percent versus 1 to 8 percent) [45,46,50,51].
Multivisceral resection is typically used as a part of multimodality therapy for treating locally advanced or recurrent rectal cancer. Adjuvant therapy for treating locally advanced or recurrent rectal cancer is discussed separately. (See "Neoadjuvant therapy for rectal adenocarcinoma" and "Adjuvant therapy for resected rectal adenocarcinoma in patients not receiving neoadjuvant therapy".)
TUMOR-RELATED EMERGENCIES AND SURGICAL PALLIATION — Up to 20 percent of patients with colorectal cancer present as emergencies. Despite competing treatment priorities, the management of patients with rectal cancer presenting with tumor-related emergencies should follow oncologic principles whenever possible. Tumor-related emergencies related to rectal cancer typically include bleeding, obstruction, and perforation.
Bleeding — Radiation therapy can effectively palliate 87 to 100 percent of tumor-related rectal bleeding and is considered the first-line approach [57,58]. Alternatively, bleeding can also be managed endoscopically, by interventional radiology, or topically [59]. Emergency resection can typically be avoided in this situation.
Perforation — The main priority of managing perforation is to obtain source control. Once that is achieved, oncologic resection with or without anastomosis can then be performed as much as the patient's clinical condition allows. If the perforation occurs proximal to the tumor, an extended resection encompassing both pathologies may be required.
Obstruction — For those with potentially curable obstructing rectal cancer, decompression via stenting or stoma allows for staging and appropriate multimodality therapy before resection. The timing and method of decompression should be individualized. (See "Large bowel obstruction", section on 'Malignant obstruction'.)
●For proximal rectal cancers that are potentially curable, an endoluminal expanding stent can act as a "bridge" to allow decompression and bowel preparation before definitive surgery. Stenting should not be performed for distal rectal cancer, because stents deployed in the low rectum can cause tenesmus and pain [60]. Stenting is also not recommended for patients being treated with antiangiogenic chemotherapeutic agents, because of a higher risk of stent-related perforation [61]. The techniques of endoluminal stenting are discussed elsewhere. (See "Enteral stents for the management of malignant colorectal obstruction".)
●Proximal diversion is performed to relieve intestinal obstruction in patients whose rectal cancer is not amenable to endoluminal stenting. A loop ostomy with a distal limb is preferred in those with complete obstruction to permit retrograde distal decompression [62]. The techniques of proximal diversion are discussed elsewhere. (See "Overview of surgical ostomy for fecal diversion".)
Surgical palliation — For patients who present with a recurrent or metastatic rectal cancer that is unresectable, or when patients are not a surgical candidate, the goal of surgery is to relieve symptoms, rather than to cure cancer. Although some studies showed that resecting the primary cancer in the presence of unresectable metastatic disease may prolong survival, such practice is not the standard of care. (See "Locoregional methods for management and palliation in patients who present with stage IV colorectal cancer", section on 'Management of the primary cancer'.)
Despite modern chemotherapy, up to one-third of patients with metastatic rectal cancer experience primary tumor-related complications [63]. Most of such complications require surgical intervention, which usually results in the creation of a stoma. Thus, patients with an in situ primary tumor require follow-up to assess the tumor's response to systemic therapy. If the primary tumor progresses despite systemic therapy, a tumor-directed intervention should be offered electively or preemptively before complications occur. The occurrence of primary tumor-related complications can negatively impact the patient's survival and quality of life.
For patients with stage IV rectal cancer, surgical palliation can be achieved by endoluminal stenting, proximal diversion, external radiation, or one of the nonresectional procedures such as fulguration or endocavitary radiation [64,65]. However, fulguration and endocavitary radiation are rarely performed in modern practice.
SPECIAL CONSIDERATIONS DURING THE COVID-19 PANDEMIC — The COVID-19 pandemic has increased the complexity of cancer care. Important issues include balancing the risk from delaying cancer treatment versus harm from COVID-19, minimizing the number of clinic and hospital visits to reduce exposure whenever possible, mitigating the negative impacts of social distancing on delivery of care, and appropriately and fairly allocating limited healthcare resources. Specific guidance for decision-making for cancer surgery on a disease-by-disease basis is available from the American College of Surgeons, from the Society for Surgical Oncology, and from others. These and other recommendations for cancer care during active phases of the COVID-19 pandemic are discussed separately. (See "COVID-19: Considerations in patients with cancer".)
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: Colorectal cancer" and "Society guideline links: Colorectal surgery for cancer".)
SUMMARY AND RECOMMENDATIONS
●Local resection – For most patients who have early-stage rectal cancer (≤cT1) without high-risk features, we suggest local excision rather than radical transabdominal resection (Grade 2C). Local excision may also be offered to those who have more advanced diseases (≥cT2) but who are medically unfit for radical transabdominal surgery after sufficient counselling. Local excision is typically performed with transanal endoscopic surgery or, less frequently, with transanal excision. (See 'Local excision' above.)
●Radical resection – Patients with invasive rectal cancer who are not candidates for local excision require radical transabdominal resection. For patients undergoing radical transabdominal resection, we suggest a sphincter-preserving procedure such as low anterior resection (LAR) if a negative distal margin can be achieved (Grade 2C). An abdominoperineal resection (APR) is required if an adequate distal margin cannot be obtained or if the patient has poor presurgical anorectal function. (See 'Low anterior resection' above and 'Abdominoperineal resection' above.)
●Multivisceral resection – A multivisceral resection is required for patients with T4 rectal cancer that invades adjacent organs or bony structures or as a salvage procedure for locally recurrent rectal cancer. A total or partial pelvic exenteration is required to achieve a curative resection in such patients. (See 'Multivisceral resection' above.)
●Tumor-related emergencies – The management of tumor-related emergencies should follow oncologic principles whenever possible.
•Bleeding – Bleeding is typically managed with radiation therapy. (See 'Bleeding' above.)
•Perforation – The main priority of managing perforation is to obtain source control. Once that is achieved, oncologic resection with or without anastomosis can then be performed as much as the patient's clinical condition allows. (See 'Perforation' above.)
•Obstruction – For those with potentially curable obstructing rectal cancer, decompression via stenting or stoma allows for staging and appropriate multimodality therapy before resection. Stenting is not recommended for distal rectal cancer or for patients receiving antiangiogenic agents. Stenting is preferred for incurable patients with obstruction. (See 'Obstruction' above and 'Surgical palliation' above.)
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