IPSILATERAL BREAST-TUMOR RECURRENCE POSTLUMPECTOMY IS PREDICTIVE OF SUBSEQUENT MORTALITY - RESULTS FROM A RANDOMIZED TRIAL

Purpose: To determine whether ipsilateral breast tumor recurrence (IBT R) postlumpectomy was independently predictive of distant relapse and mortality in women with node negative breast cancer. Methods and Mater ials: A randomized trial was conducted in Ontario between 1984 and 198 9, in which 837 women with node negative disease who had undergone lum pectomy and axillary dissection were randomized to either postoperativ e radiation (40 Gy in 16 fractions to the whole breast, followed by a boost of 12.5 Gy in five fractions to the primary site), or no further treatment. A Cox proportional hazards regression analysis was perform ed for the endpoints mortality and distant relapse using the fixed cov ariates, treatment, age, tumour size, estrogen receptor status, proges terone receptor status, and nuclear grade; and the time dependent vari able IBTR. Results: The analysis was based on 799 patients for which a ll fixed covariate data was available. Median follow-up was 66 months. The cumulative rate of IBTR at 5 years was significantly greater for the no treatment group compared to the radiation group; 30% vs. 8% res pectively (p < 0.0001). No difference was detected in overall survival between the treatment groups (p = 0.45). Significant independent pred ictors for mortality were nuclear grade, high vs. medium or low (relat ive risk (RR) = 2.28, p = 0.0001); and tumor size greater than or equa l to 2 cm. vs. (2 cm. (RR = 1.64, p = 0.01). In addition, IBTR predict ed increased mortality (RR = 2.18, p = 0.0006). Similar results were o bserved for distant relapse. An IBTR within 1 year of surgery was asso ciated with a higher risk of distant relapse and mortality. Conclusion : Local breast recurrence following lumpectomy is associated with an i ncreased risk of distant relapse and death.