Version July 2025
INTRODUCTION —
Ductal carcinoma in situ (DCIS) of the breast represents a heterogeneous group of neoplastic lesions confined to the breast ducts and lobules that differ in histologic appearance and biological potential. The diagnosis increased dramatically with the introduction of screening mammography [1]. The goal of therapy of DCIS is to prevent the occurrence of an invasive breast cancer.
The diagnosis, evaluation, and differential diagnosis of DCIS is discussed in this topic, while the treatment can be found elsewhere. (See "Ductal carcinoma in situ: Treatment and prognosis".)
A discussion of the pathologic criteria for DCIS is reviewed separately. (See "Pathology of breast cancer", section on 'Ductal carcinoma in situ'.)
EPIDEMIOLOGY AND RISK FACTORS
Incidence — The incidence of DCIS markedly increased from 5.8 per 100,000 women in the 1970s to 32.5 per 100,000 women in 2004 and then reached a plateau [1-3]. Approximately 25 percent of breast cancers diagnosed in the United States are DCIS, and 55,720 new cases are expected in 2023 [4,5]. This increase is attributed primarily to the utilization of breast cancer screening by mammography. (See 'Mammography' below.)
Risk factors — DCIS is less common than invasive breast cancer, but the risk factors for DCIS and invasive breast cancer are similar and include (see "Factors that modify breast cancer risk in females"):
●The risk of DCIS increases with age. DCIS is uncommon in women younger than 30 years of age. The rate of DCIS increases with age from 0.6 per 1000 screening examinations in women aged 40 to 49 years to 1.3 per 1000 screening examinations in women aged 70 to 84 years [1,6].
●Other risk factors of DCIS include a family history of breast cancer, increased breast density, obesity, and nulliparity or late age at first birth [7-11].
●DCIS is also a component of the inherited breast-ovarian cancer syndrome defined by deleterious mutations in the BRCA1 and the BRCA2 genes [12]; mutation rates are similar to those for invasive breast cancer [11]. (See "Overview of hereditary breast and ovarian cancer syndromes".)
●An association between long-term use of postmenopausal hormone replacement therapy and DCIS has not been established [10,13,14]. (See "Menopausal hormone therapy: Benefits and risks".)
CLINICAL FEATURES —
There are no specific clinical manifestations for patients with DCIS. Most patients with an abnormal mammogram suggestive of DCIS will present with no breast-related symptoms or findings on physical examination [1-3]. Prior to the use of widespread screening mammograms, DCIS presented as a palpable mass, nipple discharge, or Paget disease [15-17]. (See "Nipple discharge" and "Paget disease of the breast (PDB)".)
DIAGNOSIS —
The diagnosis of DCIS is confirmed by pathologic examination of a breast biopsy specimen, such as a core biopsy or a surgical excision, typically performed for suspicious calcifications detected by a screening mammogram. (See 'Pathology' below.)
DIAGNOSTIC EVALUATION
Imaging studies — Breast imaging of all types may over- or underestimate the disease extent of DCIS.
Mammography — More than 90 percent of all cases of DCIS are detected only on imaging studies [18]. The widespread adoption of mammographic screening in the United States, Europe, and other developed countries dramatically increased the number of cases of DCIS. (See "Screening for breast cancer: Strategies and recommendations".)
The typical change associated with DCIS is the presence of calcifications [19]. About 75 percent of women with DCIS have suspicious microcalcifications on mammography [20]. Other less common findings include a mass or other soft tissue change, such as architectural distortion or nonmass enhancement on MRI [21]. Features such as associated mass, asymmetry, architectural distortion, and a large extent of calcifications may predict an upgrade to invasive cancer at the time of surgery [22].
All patients with suspected DCIS should have diagnostic bilateral mammograms with magnification views to assess the morphology and the full extent of any calcifications. Some mammographic patterns of microcalcifications are highly suggestive of DCIS:
●Linear branching or segmental types of pleomorphic microcalcifications are frequently associated with high nuclear grade DCIS with comedo necrosis [23].
●Fine, granular calcifications are primarily associated with low-grade, micropapillary, or cribriform pattern DCIS [24].
However, most patients diagnosed with DCIS have microcalcifications of indeterminate morphology. The advent of digital mammography has led to improved detection of microcalcifications and thus increased the number of women diagnosed with DCIS [25]. (See "Breast imaging for cancer screening: Mammography and ultrasonography".)
Mammography may underestimate the number of foci in instances of multifocal disease. This underestimation increases with increasing lesion size. Historic studies have shown that DCIS can have interfoci gaps of up to 1 cm [26]. (See "Breast-conserving therapy", section on 'Margins for DCIS'.)
Magnetic resonance imaging — At present, magnetic resonance imaging (MRI) is not routinely indicated in the evaluation of newly diagnosed DCIS. The MRI examination is more useful in patients with dense breasts and suspicious calcifications, rather than those with fatty breasts, where calcifications are usually visible on mammograms.
The MRI appearance of DCIS is more frequently as a nonmass enhancement, with regional, clumped, or ductal linear types. It can also present as masses or as foci [19].
MRI estimates of the size of DCIS correlate well with the pathologic evaluation [27], with accuracy of tumor size estimation for MRI ranging from 52 to 72 percent, compared with 38 to 56 percent with mammography [28-31].
MRI appears to be no better than mammography for distinguishing DCIS from benign, atypical proliferative lesions (false positives) or microinvasion, but advanced technologies may improve this distinction in the future [32-35]. (See "Diagnostic evaluation of suspected breast cancer", section on 'Breast MRI' and "MRI of the breast and emerging technologies".)
MRI and other emerging technologies used in breast cancer detection are also discussed elsewhere. (See "MRI of the breast and emerging technologies".)
Biopsy — An abnormal lesion detected by breast imaging can be assessed preferably by a core needle biopsy or as an excisional biopsy. Fine needle aspiration cytology, which provides a sampling of cells rather than tissue, is inadequate to distinguish between invasive and in situ disease. Breast biopsy techniques are reviewed in detail separately. (See "Breast biopsy".)
Core needle biopsy — A core needle biopsy performed under stereotactic guidance is preferred for evaluation of mammographically detected microcalcifications [36-38].
●Stereotactic-guided biopsy – Most, but not all, patients with microcalcifications are candidates for stereotactic core biopsy. The thickness of the breast in compression must be adequate. Abnormalities just beneath the skin or in deep posterior locations (adjacent to the chest wall or a breast implant) may be less technically accessible. In addition, patients who are unable to lie prone are not suitable candidates for this approach. Upright stereotactic tables are an alternative and are becoming more readily available.
●Ultrasound-guided biopsy – Ultrasound-guided biopsies can be performed for evaluation of a sonographically visible mass, irrespective of the presence of calcifications, or whether the lesion is palpable or nonpalpable.
Surgical excisional biopsy — When patients are not candidates for stereotactic core biopsy procedures for the aforementioned reasons, or when the calcifications are too faint to be biopsied stereotactically, the alternative is image-guided localization and surgical excisional biopsy [39].
Pathology — DCIS is characterized by a proliferation of neoplastic epithelial cells within the mammary ductal system with no evidence of invasion into the surrounding stroma on microscopic examination [3]. DCIS is principally categorized by the nuclear grade; the presence of comedo necrosis and, to a lesser degree, the architectural pattern are also included in some classification schemes [40,41]. The extent of disease (including size, if available) should also be reported. A discussion of the pathologic criteria for DCIS is reviewed separately. (See "Pathology of breast cancer", section on 'Ductal carcinoma in situ'.)
DIFFERENTIAL DIAGNOSIS
Usual ductal hyperplasia — Usual ductal hyperplasia (UDH) is a benign proliferative lesion that may be a histologic mimic for DCIS, particularly intermediate-grade DCIS. UDH is characterized by a proliferation of epithelial cells with nuclei of variable size and shape. It is not usually an imaging target unless involving a papilloma or a complex sclerosing lesion. (See "Overview of benign breast diseases", section on 'Usual ductal hyperplasia'.)
Atypical ductal hyperplasia — Atypical ductal hyperplasia (ADH) is characterized by a proliferation of uniform epithelial cells with monomorphic round nuclei that either partially fill an involved duct or completely fill a duct but is <2 mm in extent. ADH shares the cytologic and architectural criteria of low nuclear grade DCIS [42]; if these qualitative criteria are met, the aforementioned size/extent criteria determine the diagnosis of ADH versus low-grade DCIS. (See "Atypia and lobular carcinoma in situ: High-risk lesions of the breast", section on 'Atypical ductal hyperplasia'.)
Of note, approximately 10 to 25 percent of lesions histologically interpreted as ADH are upgraded to DCIS or invasive cancer at the time of a surgical excision [39,43-48]. Consequently, surgical excision is routinely recommended for lesions showing ADH on core biopsy.
Lobular carcinoma in situ — Lobular carcinoma in situ (LCIS) is a noninvasive lesion that arises in the terminal duct lobules of the breast and was formerly categorized as a noninvasive cancer. LCIS has been removed from the current American Joint Committee on Cancer (AJCC) staging system so as not to confuse providers and patients alike [49]. LCIS is not cancer, though it is a nonobligate precursor lesion. LCIS differs from DCIS with regard to radiologic features, morphology, biologic behavior, and distribution in the breast. Classic LCIS almost always represents an incidental finding. Pleomorphic LCIS is a subset of LCIS that bears greater similarity to DCIS than classic LCIS, with regard to imaging features, pathologic features and, with limited data, in terms of clinical behavior, which leads some to treat pleomorphic LCIS as DCIS [50]. The optimal management for LCIS is evolving and is discussed elsewhere. (See "Atypia and lobular carcinoma in situ: High-risk lesions of the breast", section on 'Lobular carcinoma in situ'.)
Microinvasive carcinoma — One of the most important goals in the histologic examination of DCIS is the identification of minute foci of stromal invasion, also termed microinvasion. If microinvasive disease is found, management recommendations are changed accordingly. The management of microinvasive disease is discussed separately. (See "Microinvasive breast carcinoma".)
Invasive breast cancer — DCIS differs from invasive breast cancer in being confined within the ductal lobular system of the breast. Once the tumor breaks through the basement membrane of the duct into the parenchyma, it become invasive cancer. Approximately 10 to 20 percent of lesions interpreted as DCIS on core needle biopsy are upgraded to invasive cancer in the surgical excision specimen. (See "Pathology of breast cancer", section on 'Infiltrating ductal carcinoma'.)
POSTDIAGNOSTIC EVALUATIONS
TNM staging — According to the tumor, node, metastasis (TNM) staging system developed and maintained by the American Joint Committee on Cancer (AJCC) and the Union for International Cancer Control (UICC), DCIS is designated as Tis (DCIS) and stage 0, as it is confined within the ducts (TisN0M0). (See "Tumor, node, metastasis (TNM) staging classification for breast cancer", section on 'The eighth edition TNM staging system'.)
Risk assessment for hereditary breast cancer — Assessment of risk for hereditary breast cancer (eg, BRCA1/BRCA2) may be advised following a diagnosis of invasive breast cancer and DCIS. If the patient is at high risk (greater than 10 percent chance) for carrying a deleterious mutation as determined by published risk assessment tools, and the information gained will impact treatment planning, a referral for genetic counseling is appropriate, particularly for those with a family history of ovarian cancer [51]. (See "Genetic testing and management of individuals at risk of hereditary breast and ovarian cancer syndromes", section on 'Risk assessment models'.)
TREATMENT —
Local and systemic treatment options for patients diagnosed with DCIS are discussed in detail separately. (See "Ductal carcinoma in situ: Treatment and prognosis".)
PROGNOSIS —
Generally, patients diagnosed with DCIS have an excellent long-term breast cancer-specific survival of around 98 percent after 10 years of follow-up and a normal life expectancy [52-57]. Prognosis is discussed separately. (See "Ductal carcinoma in situ: Treatment and prognosis", section on 'Prognosis'.)
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: Ductal carcinoma in situ".)
INFORMATION FOR PATIENTS —
UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." The Basics patient education pieces are written in plain language, at the 5th to 6th grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10th to 12th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.
Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient info" and the keyword(s) of interest.)
●Basics topic (see "Patient education: Ductal carcinoma in situ (DCIS) (The Basics)")
SUMMARY AND RECOMMENDATIONS
●Ductal carcinoma in situ – Ductal carcinoma in situ (DCIS) of the breast represents a heterogeneous group of neoplastic lesions confined to the breast ducts and lobules. (See 'Introduction' above.)
●Incidence and risk factors – The diagnosis of DCIS increased dramatically with the introduction of screening mammography and now constitutes 25 percent of all breast cancers. The risk of DCIS increases with age, family history of breast cancer (including hereditary breast-ovarian syndromes), increased breast density, obesity, and nulliparity or late age at first birth. (See 'Epidemiology and risk factors' above.)
●Presentation – There are no specific clinical manifestations for patients with DCIS. Most cases of DCIS are detected only on imaging studies (most commonly by the presence of mammographic microcalcifications). (See 'Mammography' above.)
●Diagnosis – The diagnosis of DCIS is confirmed by pathologic examination of a breast biopsy specimen, such as a core biopsy or surgical excision. (See 'Diagnosis' above.)
●Imaging – The typical change associated with DCIS is the presence of calcifications on mammogram. Breast MRI may be useful in patients with dense breasts and suspicious calcifications but is not routinely indicated. (See 'Imaging studies' above.)
●Biopsy – Percutaneous core biopsy under stereotactic is preferred in the evaluation of mammographically identified microcalcifications. Fine needle aspiration biopsy is inadequate for the diagnosis of DCIS as it cannot distinguish between invasive and in situ disease. In technically challenging stereotactic cases, image-guided surgical excision may be preferable. (See 'Biopsy' above.)
●Staging and Prognosis – DCIS is designated as Tis (DCIS) and stage 0, as it is confined within the ducts (TisN0M0). The risk of cancer-related death in women with DCIS is low, estimated at 1 to 2 percent within 10 years. (See 'Epidemiology and risk factors' above.)
●Treatment – Local and systemic treatment options for patients diagnosed with DCIS are discussed in detail separately. (See "Ductal carcinoma in situ: Treatment and prognosis".)
