Ductal carcinoma in situ of the breast: a systematic review of incidence, treatment, and outcomes.
BACKGROUND: The National Institutes of Health Office of Medical Applications of Research commissioned a structured literature review on the incidence, treatment, and outcomes of ductal carcinoma in situ (DCIS) as a background article for the State of the Science Conference on Diagnosis and Management of DCIS. METHODS: Published studies were identified and abstracted from MEDLINE and other sources. We include articles published between 1965 and January 31, 2009; 374 publications were identified that addressed DCIS incidence, staging, treatment, and outcomes in adult women. RESULTS: In the United States, DCIS incidence rose from 1.87 per 100 000 in 1973-1975 to 32.5 in 2004. Incidence increased in all ages but more so in women older than 50 years. Increased use of mammography explains some but not all of the increased incidence. Risk factors for incident DCIS include older age and family history. Although tamoxifen treatment prevented both invasive breast cancer and DCIS, raloxifene treatment decreased incidence of invasive breast cancer but not DCIS. Among patients with DCIS, magnetic resonance imaging was more sensitive than mammography for detecting multicentric disease and estimating tumor size. Because about 15% of patients with DCIS identified on core needle biopsy are diagnosed with invasive breast cancer after excision or mastectomy, the accuracy of sentinel lymph node biopsy after excision is relevant to surgical management of DCIS. Most studies demonstrated that sentinel lymph node biopsy is feasible after breast-conserving surgery (BCS). Younger age, positive surgical margins, tumor size and grade, and comedo necrosis were consistently related to DCIS recurrence. DCIS outcomes after either mastectomy or BCS plus radiation therapy were superior to BCS alone. Tamoxifen treatment after DCIS diagnosis reduced risk of recurrent disease. CONCLUSIONS: Scientific questions deserving further investigation include the relationship between mammography use and DCIS incidence and whether imaging technologies and treatment guidelines can be modified to focus on lesions that are most likely to become clinically problematic.