Breast cancer. Importance of adequate surgical excision prior to radiotherapy in the local control of breast cancer in patients treated conservatively.

The extent of excision performed for mammary carcinoma prior to radiotherapy as a risk factor for local recurrence was studied in 503 patients. Three hundred twenty-three tumors (62%) were excised with a minimal rim of tissue (tumorectomy). One hundred forty-two patients (27%) had wide excision and 56 (11%) had quadrantectomy. Tumor stage, size, and radiation treatment were similar for all groups. Forty-one percent of tumorectomies had involved margins, and only 14% and 7% were involved in the wide excision and quadrantectomy groups, respectively. Local failure was 15% for tumorectomy, 7% for wide excision, and 5% for quadrantectomy. In T1 ductal carcinoma, only 4% of those with excisions greater than 5 cm had recurrences. Lesser excision had 20% recurrence. Extent of excision before radiotherapy is an important risk factor for recurrence. Failure was inversely proportional to the amount of breast tissue resected. Narrow excision should be discouraged since a larger tumor burden remains that may not be sterilized by radiation.