Risk factors for relapse after conservative treatment in T1-T2 breast cancer with one to three positive axillary nodes: results of an observational study.

Background: As few data are available on irradiation of the draining nodes after conservative surgery (CS), this study was designed to identify patients with T1–T2 breast cancer and one to three positive axillary nodes who needed regional radiotherapy (RT). Patients and methods: Five hundred seventy-five patients were treated between 1988 and 2001 with CS and RT to the breast. All but three received adjuvant chemotherapy and/or hormone therapy. Risk factors for and the relationships between local, nodal and distant relapses were analyzed. Results: At a median follow-up of 7.3 years, the 10-year probability of survival free of local relapse, nodal relapse and distant metastases were 92.8%, 94.0% and 84.9%, respectively. Independent predictors of local relapse were the positive/excised node ratio, margin status and age. Predictors of nodal relapse were tumor grade, hormone receptor and margin status. Significant risk factors for distant metastases were tumor stage, grade, hormone receptor and margin status. Local and nodal relapses were related significantly with distant metastases. Only local and distant relapses were linked by temporal sequence (P = 0.03). Conclusions: Overall relapse rates were low in these patients and different mechanisms appeared to underlie local, nodal or distant relapse.