PROGNOSIS FOR BREAST-CANCER SURGERY AND RADIATION-THERAPY COMPARED WITH MASTECTOMY ALONE - A RETROSPECTIVE ANALYSIS OF 759 PATIENTS WITH STAGE-I STAGE-II BREAST-CANCER

Seven hundred fifty-nine patients with Stage I/II breast cancer who were treated with mastectomy alone (558 patients) or breast-conserving surgery and tangential irradiation (201 patients) were evaluated. Median follow-up time was 34 months. Axillary node status showed differences between treatment groups. Seventy-two percent of patients undergoing lumpectomy and radiation therapy (Lx) versus 35% of patients in the mastectomy group were pathologically node-negative, 18% Lx versus 30% mastectomy alone had one to three nodes positive, and four or more positive axillary nodes were seen in 35% of mastectomy alone patients. Reflecting this trend, overall survival (P < 0.007), time to locoregional failure (P < 0.0005), and time to any failure (P < 0.0001) favored Lx patients. Correcting for axillary node status, significant differences persisted only for node-negative patients. Median actuarial survival time was 73 months for the mastectomy alone group (196 patients) versus 120 months for the Lx group (144 patients) (P < 0.02), with significant differences also noted in time to local failure (P < 0.003) and time to any failure (P < 0.001). Stratification according to primary tumor size in patients who were node-negative yielded marked differences in time to locoregional failure in T1 (< 2 cm) (P < 0.0006) presentations, with analysis approaching significance for T2 (2 to 5 cm) lesions (P < 0.06). Disease-free interval was greater in node-negative Lx patients for both T1 (P < 0.007) and T2 (P < 0.05) presentations. Overall survival was not significantly different in node-negative Lx patients when primary tumor size was considered. Improved prognosis was identified in node-negative patients undergoing breast-conserving surgery and radiation therapy over mastectomy alone. Theoretical considerations included eradication of occult microscopic disease within the chest wall by tangential irradiation.