Ductal Carcinoma In Situ (DCIS) Diagnosis and Management

Definition and Epidemiology

Ductal carcinoma in situ (DCIS) represents a heterogeneous group of neoplastic lesions in the breast ducts that have not invaded beyond the ductal basement membrane, as defined by the National Comprehensive Cancer Network (NCCN) 3, 4
Before widespread mammography screening, DCIS was uncommon, accounting for only 2-3% of palpable breast cancers, according to the American College of Radiology 1
Currently, DCIS accounts for approximately 20% of breast cancers diagnosed in the United States, as reported by the American College of Radiology 1, 2
The American Cancer Society estimates that 55,720 new cases of DCIS will be diagnosed, based on data from the Journal of the American College of Radiology 2
Incidence is highest among non-Hispanic White (26.6 per 100,000) and Black (26.5 per 100,000) people, according to the American College of Radiology 1

DCIS most commonly presents as a mammographically detected clinically occult disease, as described by the American College of Radiology 1
The most common mammographic presentation is microcalcifications (90-98% of cases), according to Ca-A Cancer Journal for Clinicians 5, 6
Calcifications in DCIS typically are pleomorphic, varying in size, form, and density, often in linear or segmental arrangements, as reported by Ca-A Cancer Journal for Clinicians 5
About 10% of mammographically evident DCIS presents as an uncalcified mass, according to Ca-A Cancer Journal for Clinicians 7
Definitive diagnosis requires pathologic evaluation of tissue specimen, as imaging cannot determine whether basement membrane invasion has occurred, as stated by Ca-A Cancer Journal for Clinicians 7

DCIS has an excellent prognosis with a 10-year overall survival rate of 97.2% to 98.6%, as reported by the American College of Radiology 1
Following breast-conservation therapy, about 50% of recurrences are invasive cancer and 50% are DCIS, according to the American College of Radiology 1

Larger DCIS lesion size is a risk factor for progression, as reported by the American College of Radiology 2
Younger age is a risk factor for progression, according to the American College of Radiology 2
HER2 overexpression is a risk factor for progression, as stated by the American College of Radiology 2

Breast-conserving surgery (BCS) or total mastectomy are both appropriate treatment options, as recommended by the National Comprehensive Cancer Network (NCCN) and Ca-A Cancer Journal for Clinicians 3, 5
There is no difference in overall survival between mastectomy and BCS for DCIS, as reported by the American College of Radiology 1
The current National Comprehensive Cancer Network (NCCN) guidelines for DCIS recommend BCS without lymph node sampling, according to the American College of Radiology 2
Randomized trials evaluating radiotherapy after BCS for DCIS have demonstrated a reduction in ipsilateral breast tumor recurrence rates by 50% to 70%, as reported by the American College of Radiology 2
Tamoxifen provides risk reduction in both the ipsilateral breast treated with BCS and in the contralateral breast with estrogen receptor-positive tumors, according to the American College of Radiology 2

Underestimating the risk of occult invasive disease: A meta-analysis reported an overall DCIS upstaging rate to invasive cancer of 25.9% at surgical excision, as stated by the American College of Radiology 1
Unnecessary axillary lymph node dissection: The cumulative incidence of axillary node metastasis in patients diagnosed preoperatively with DCIS is low (0%-14%), according to the American College of Radiology 1

Regular clinical examinations and mammography are recommended for post-treatment surveillance, as suggested by Praxis Medical Insights: Practical Summaries of Clinical Guidelines, but an alternative source is preferred, however, the American College of Radiology also recommends regular follow-up 1
Long-term follow-up is essential as recurrences can occur even after 5 years, however, this fact is from Praxis Medical Insights: Practical Summaries of Clinical Guidelines, an alternative source is preferred, but the American College of Radiology also emphasizes the importance of long-term follow-up 1