Volume of resection in patients treated with breast conservation for ductal carcinoma in situ

Background: The optimal treatment of ductal carcinoma in situ (DCIS) is one of the most controversial issues in the management of breast cancer. Identification of factors that affect the risk of local recurrence is very important as the incidence of DCIS increases and the use of breast conservation becomes more widespread. Because the extent of resection may affect the relapse rate, we hypothesized that larger volumes of resection (VR) may account for the lower local recurrence rates we have previously found in elderly patients.Methods: Between 1978 and 1990, 173 cases of histologically confirmed DCIS were treated at MSKCC with breast conservation therapy. Of these, complete VR data were available for 126 cases. The VRs thus obtained were divided into two groups, <60 cm³ and 60 cm³, and were evaluated for correlating factors. The patients were divided into three groups by age at diagnosis: younger than 40 years, 40 to 69 years, and 70 years or older.Results: The eldest group had a significantly greater proportion of large VRs (30%) as compared to the middle group (11%) and the youngest group (9%) (P=.03, x²). Although not statistically significant, the large VR group had a lower 6-year actuarial local recurrence rate (5.6%) than did the small VR group (21.3%) (P=.16, log-rank test). This trend was observed even though adjuvant radiotherapy was used less often in patients who had large VRs.Conclusion: Breast conservation surgery for DCIS in elderly patients is more likely to employ a large VR. This may explain, at least in part, the observation that elderly patients have a lower local recurrence rate.Presented at the 50th Annual Cancer Symposium of The Society of Surgical Oncology, Chicago, Illinois, March 20–23, 1997.