Limited surgical management for primary breast cancer: A commentary on the NSABP reports

This report presents an overview of findings from 2 interrelated studies carried out during the past 15 years by the National Surgical Adjuvant Breast and Bowel Project to determine the efficacy of alternative local and regional treatments of primary breast cancer. Findings from the first clinical trial, begun in 1971 involving 1,665 women, indicate that after 10 years of follow-up there are no significant differences in disease-free survival, distant disease-free survival, or survival among patients treated by radical mastectomy or total mastectomy with and without radiation. The findings also indicate that radiation of internal mammary nodes in patients with inner quadrant lesions does not improve survival and that results obtained at 5 years accurately predict the outcome through 10 years. The second clinical trial, implemented in 1976 and accruing 1,843 women, demonstrates that after 5 years, treatment by segmental mastectomy (lumpectomy) with or without radiation results in disease-free, distant disease-free, and overall survival at least equivalent to, and in certain aspects better than, that achieved after total breast removal. Whereas 92% of those treated with radiation remained free of breast tumor at 5 years, when breast radiation was not employed, 72% (p<0.001) were without tumor reoccurrence. In positive-node patients, 98% of those radiated remained tumor free, whereas only 64% of those receiving no radiation were free of tumor although both groups received chemotherapy. While the clinical significance of these findings is obvious, their biological importance has received less attention. When considered in conjunction with other laboratory and clinical investigations, they lend no support for the anatomic and mechanistic precepts that have dictated thinking relative to metastasis production and have influenced surgical thinking. Clinical issues have arisen as a consequence of the 2 studies, particularly the second. Should a mastectomy be performed when lumpectomy specimen margins are involved with tumor? How should tumor reoccurrence in the ipsilateral breast following lumpectomy be managed? Can lumpectomy be employed for subareolar tumors or for tumors ≥4 cm? How extensive need radiation therapy be following lumpectomy? We have commented on all of these issues and have presented our current thinking regarding the management of patients in whom they arise.