RESULTS OF CONSERVATIVE SURGERY AND RADIATION FOR MAMMOGRAPHICALLY DETECTED DUCTAL CARCINOMA IN-SITU (DCIS)

Purpose: The role of conservative surgery and radiation for mammograph ically detected ductal carcinoma in situ (DCIS) is controversial. In p articular, there is little data for outcome with radiation in a group of patients comparable to those treated with local excision and survei llance (mammographic calcifications less than or equal to 2.5 cm, nega tive resection margins, negative postbiopsy mammogram). This study rep orts outcome of conservative surgery and radiation for mammographicall y detected DCIS with an emphasis on results in patients considered can didates for excision alone. Methods and Materials: From 1983 to 1992, 110 women with mammographically detected DCIS (77% calcifications +/- mass) and no prior history of breast cancer underwent needle localizat ion and biopsy with (55%) or without a reexcision and radiation. Final margins of resection mere negative in 62%, positive 7%, close 11%, an d unknown 20%. The median patient age was 56 years. The most common hi stologic subtype was comedo (54%, followed by cribriform (22%). The me dian pathologic tumor size was 8 mm (range 2 mm to 5 cm). Forty-seven percent of patients with calcifications only had a negative postbiopsy mammogram prior to radiation. Radiation consisted of treatment to the entire breast (median 50.00 Gy) and a boost to the primary site (97%) for a median total dose of 60.40 Gy. Results: With a median follow-up of 5.3 years, three patients developed a recurrence in the treated br east, The median interval to recurrence was 8.8 gears and all were inv asive cancers. Two (67%) occurred outside the initial quadrant. The 5- and 10-year actuarial rates of recurrence were 1 and 15%. Cause-speci fic survival was 100% at 5 and 10 years. Contralateral breast cancer d eveloped in two patients. There were too few failures for statistical significance to be achieved with any of the following factors: patient age, family history, race, mammographic findings, location primary, p athologic size, histologic subtype, reexcision, or final margin status . However, young age, positive or close margins, and the presence of a mass without calcifications had a trend for an increased risk of recu rrence. There were no recurrences in the subset of 16 patients who wou ld be candidates for surveillance by Lagios' criteria. Conclusion: For selected patients, conservative surgery and radiation for mammographi cally detected DCIS results in a low risk of recurrence in the treated breast and 100% 5- and 10-year cause-specific survival. Improved mamm ographic and pathologic evaluation results in better patient selection and reduces the risk of the subsequent appearance of DCIS in the biop sy site. The identification of risk factors for an ipsilateral invasiv e breast recurrence is evolving. (C) 1997 Elsevier Science Inc.