Diagnosis and management of ductal carcinoma in situ

Abstract

Ductal carcinoma in situ (DCIS) is a preinvasive form of breast cancer that has increased in incidence over the past 25 years, primarily as a result of mammographically detected microcalcifications. Inadequately treated DCIS carries a risk for evolving into the malignant phenotype; however, the magnitude and timeline for this risk are poorly defined. Treatment options include lumpectomy with or without breast irradiation and mastectomy. The overall survival rate is 96% to 98% with any of these strategies, but the risk of local recurrence (LR) is highest after lumpectomy alone. Breast irradiation can reduce this risk from levels in excess of 40% to 10% over a 10-year follow-up period. Approximately 50% of all LR from DCIS are invasive lesions. Therefore, the occurrence of a LR after breast-conserving therapy is a potentially greater threat to the patient with DCIS compared to the patient diagnosed with invasive cancer. In patients diagnosed with invasive cancer, the risk of micrometastatic disease is present from the time of initial diagnosis. In patients with DCIS, the expectation is that a potentially 100% cure rate should be achieved with local therapy alone. Although most DCIS cases complicated by LR will be successfully salvaged with prolonged overall survival, it is critically important to take every precaution that will minimize the risk of locally recurrent disease. Therefore, radiation therapy as an adjunct to lumpectomy is essential. A subset of patients with DCIS with low-volume low-grade disease who can be safely treated by lumpectomy alone has not yet been clearly defined. Prospective studies designed to identify this category are ongoing. Inadequate margin control is the most consistent risk factor for LR that has been reported thus far, but there is no universally accepted definition for what constitutes an optimal negative margin distance. Young age at diagnosis, high nuclear grade, and comedonecrosis are other factors that have been implicated as increasing the risk for LR. Tamoxifen can further decrease the rate of new in-breast events on the affected side and in the contralateral breast. Ongoing trials will also define the role of aromatase inhibitors as a risk-reducing strategy.

Management of ductal carcinoma in situ according to Van Nuys Prognostic Index in Australia and New Zealand

“…However, radiotherapy was omitted in 358 patients in VNPI group 2, including 32 with involved margins and 267 with margins less than 10 mm. Margin width is indicative of the completeness of disease resection and is generally accepted to be the most important determinant of local recurrence following BCS for DCIS, 33 with three times the power of tumour grade in predicting local recurrence 27 . A number of reports have questioned the value of adjuvant radiotherapy in patients with widely excised lesions, regardless of the pathological tumour grade 34,35 .…”

Carbohydrate antigens in nipple aspirate fluid predict the presence of atypia and cancer in women requiring diagnostic breast biopsy

“…These agents are especially effective in the prevention of breast cancer among women who have AH. The highest TF and Tn values were observed in women with DCIS, in whom cure rates approach 100% with proper treatment [11]. …”

Risk of subsequent invasive breast carcinoma after in situ breast carcinoma in a population covered by national mammographic screening

“…The proportion of women receiving conservative surgery increased from 7% in 1980 to 51% in 1996 (Lindqvist et al, 2002). Inadequately treated in situ breast carcinoma, for example, insufficient margin control, may have contributed to the observed risk increase (Yau et al, 2002;Fredriksson et al, 2003;Kerlikowske et al, 2003;Khan and Newman, 2004).…”