Ductal carcinoma in situ (DCIS) is a non-invasive breast cancer. In DCIS, abnormal cells are contained in the milk ducts. It is called “in situ” (which means “in place”) because the cells have not left the milk ducts to invade nearby breast tissue. DCIS is also be intraductal (within the milk ducts) carcinoma, when it is larger but still not invasice. Without treatment, the abnormal cells could turn into invasive cancer over time. Some physicians however, argue that DCIS is a marker of cancer and not cancer in itself, and that prophylactic systemic therapy should be used when DCIS is present. Left untreated, about 20 to 30 percent of patients with low grade DCIS will progress to invasive breast cancer.
An update of the two NSABP studies was recently published by Wapnir et al. The goal of the update was to evaluate long-term invasive ipsilateral in-breast recurrence outcomes in the two studies. The update confirmed previous findings: mortality from DCIS is low regardless of treatment, and recurrence risk is highest in patients who do not receive radiation therapy or tamoxifen.
Standard treatment for DCIS includes breast-conserving surgery, often involving wire or radioactive seed localization; whole-breast radiation therapy; and tamoxifen for localized DCIS. Simple mastectomy and sentinel node biopsy are recommended for extensive or multicentric DCIS and for women in whom adequate cosmesis cannot be achieved because of breast size.
When DCIS accompanies invasive disease, it is called muticentric or multifocal and how to treat such patients is controversial. The consensus remains that mastectomy is standard of care, although more recent retrospective studies suggests that conservative treatment with breast preservation may be adequate (B. Fisher, 2011). There also remains a controversy whether MRI should be used to identify DCIS and make surgical decisions accordingly.
While a lumpectomy is not inappropriate, it should not be performed without a discussion with the patient and advising her of the need for radiation and the risk of finding multicentric disease, that would require additional resections or a completion mastectomy.
Cuzick J, Sestak I, Pinder SE, et al. Effect of tamoxifen and radiotherapy in women with locally excised ductal carcinoma in situ: long-term results from the UK/ANZ DCIS trial. Lancet Oncol. 12(1):21-9, 2011.
Wapnir IL, Dignam JJ, Fisher B, et al. Long-term outcomes of invasive ipsilateral breast tumor recurrences after lumpectomy in NSABP B-17 and B-24 randomized clinical trials for DCIS. J Natl Cancer Inst. 103(6):478-88, 2011.
Bernard Fisher Role of Science in the Treatment of Breast Cancer When Tumor Multicentricity is Present J Natl Cancer Inst. 2011;103(17):1292-1298
Kane RL, Virnig BA, Shamliyan T, Wang SY, Tuttle TM, Wilt TJ. The impact of surgery, radiation, and systemic treatment on outcomes in patients with ductal carcinoma in situ. J Natl Cancer Inst Monogr. 2010(41):130-3, 2010.
Swati Kulkarni Management of DCIS—A Work in Progress ONCOLOGY. Vol. 25 No. 9, 2011