Outcomes and factors impacting local recurrence of ductal carcinoma in situ

BACKGROUND: The optimal management of ductal carcinoma in situ (DCIS) remains controversial. Investigators have focused on identifying patients who are eligible for treatment by excision alone. A retrospective analysis of patients with DCIS treated by various modalities was conducted to compare outcomes and determine factors significant for local recurrence (LR). METHODS: Between 1985-1992, 88 consecutive diagnoses of DCIS were identified in 85 patients. Seventy-four percent were detected mammographically. The most common histologic subtypes were comedo (54%) and cribriform (23%). Tumor sizes were < 2.5 cm (49%), > 2.5-5 cm (26%), > 5 cm (23%), and unknown (2%). Final resection margins were tumor free (75%), close/positive (23%), and unknown (2%). Treatment methods included mastectomy (30%), localized surgery and radiation therapy (LSR) (43%), or wide localized surgery alone (LS) (27%). Radiation therapy (RT) was comprised of 50 grays to the breast, and 53% of treated patients received local "boost" irradiation. RESULTS: The median follow up was 8.3 years. The overall recurrence rate was 13. 6%, whereas the median time to LR was 27.8 months. Recurrence rates according to treatment modality were: LS: 25%; LSR: 13%; and mastectomy: 4%. However, if surgical margins were tumor free, LSR had a LR rate of 3.4%. After RT, no LR occurred prior to 15 months, and 4 of 5 tumors were noninvasive. Nine patients treated by excision alone conformed to the criteria of Lagios et al. criteria and LR occurred in three of nine tumors. Of the factors analyzed, margin status was found to be the best predictor for LR (P = 0.05). CONCLUSIONS: If surgical margins are tumor free, the LSR regimen is equivalent to mastectomy for local tumor control. Annual mammograms may be adequate for the follow-up of patients with irradiated breasts, but biannual studies still are recommended for patients treated with excision alone.