Breast-conservative surgery with and without radiotherapy in patients aged 55-75 years with early-stage breast cancer: a prospective, randomized, multicenter trial analysis after 108 months of median follow-up.

Objectives: Breast-conserving therapy (BCT), including postoperative whole breast irradiation (WBI), is generally accepted as the treatment of choice for most patients with early-stage breast cancer. The question whether WBI is mandatory in all patients remains one of the most controversial issues in BCT. To answer this question, a randomized, prospective, multicentre study was launched in January 2001. Primary endpoints of the study were to assess the cumulative incidence of in-breast-recurrences (IBR) and overall survival (OAS) after conservative surgery (BCS) with or without WBI.

Methods: From January 2001 until December 2005, 749 patients with unifocal infiltrating breast cancer up to 25 mm, 0-3 positive axillary lymph nodes, no extensive intraductal component or lymphvascular invasion from 11 centres in Italy, were randomly assigned to BCS+WBI (arm 1:373 patients) or BCS alone (arm 2:376 patients). Treatment arms were well balanced in terms of baseline characteristics. Systemic adjuvant therapy was administered according to the institutional policies. Kaplan-Meier method was used for survival analysis and log-rank test to evaluate the difference between the two arms. RESULTS (Last analysis 31.12.2012): After median follow-up of 108 months, 12 (3.4%) IBR were observed in arm 1 and 16 (4.4%) in arm 2. OAS was 81.4% in arm 1 and 83.7% in arm 2. There was no statistically significant difference regarding IBR and death in the two treatment groups.

Conclusions: These data are promising and suggest that WBI after BCS can be omitted in selected patients with early stage breast cancer without exposing them to an increased risk of local recurrence and death. Longer follow-up is needed to further consolidate these results.