Local failure is responsible for the decrease in survival for patients with breast cancer treated with conservative surgery and postoperative radiotherapy

Purpose: The aim of the present study was to evaluate the role of local fai lure (LF) in the survival of patients treated with lumpectomy and postopera tive radiotherapy and to investigate whether LF is nat only a marker for di stant metastasis (DM) but also a cause, Methods: Charts of patients treated with breast conservative surgery betwee n 1969 and 1991 were reviewed retrospectively. There were 2,030 patients av ailable for analysis. The median duration of follow-vp was 6 years. A Cox r egression multivariate analysis was performed using LF as a time-dependent covariate, Results: Local control(LC) was 87% at 10 years. Local failure led to poorer survival at 10 years than local control (55% v 75%, P < .00). In a Cox mod el, local failure was a powerful predictor of mortality. The relative risk associated with LF was 3.6 for mortality and 5.1 for DM (P < .00). In patie nts with LF, the rate of DM peaked at 5 to 6 years, whereas it peaked at 2 years for patients with LC. The mean time between surgery and DM was 1,050 days for patients without LF and 1,650 days for patients with LF (P < .00). Conclusion: Our results show that local failure is associated with an incre ase in mortality. The difference in the time distribution of distant metast asis for LF and LC could imply distinct mechanisms of dissemination. Local failure should be considered not only as a marker of occult circulating dis tant metastases but also as a source for new distant metastases and subsequ ent mortality. J Clin Oncol 17:107-109. (C) 1999 by American Society of Clinical Oncology.