Overall survival in patients with a re-excision following breast conserving surgery compared to those without in a...

To investigate the overall survival of invasive breast cancer patients with primary breast conserving surgery (BCS) followed by re-excision compared to those with primary BCS only. The Dutch re-excision indications are less stringent compared to other European and Northern American countries (Society of Surgical Oncology-American Society for Radiation Oncology (SSO/ASTRO) guideline).

Retrospective analyses in women <75years with breast cancer stage pT1-T3 treated by BCS and radiotherapy between 1999 and 2012 from a population-based database. The national guideline recommends to reserve re-excision for invasive tumours showing 'more than focally positive' margin since 2002. Patients were divided into 'primary BCS only', 're-excision by BCS', and 're-excision by mastectomy'. Multivariable Cox regression analysis was adjusted for patient and systemic treatment characteristics.

A total of 11,695 patients were included of which 2156 (18.4%) underwent re-excision. Median time of follow-up was 61months (interquartile range (IQR) 26-101). The 5-year overall survival rates in the 'primary BCS only', 're-excision by BCS' and 're-excision by mastectomy' group were 92%, 95% and 91%, respectively. The 10-year overall survival rates were 81%, 82% and 79%, respectively (P=0.20). After multivariable analyses no significant association was observed between use of and type of re-excision and overall survival.

The overall survival of breast cancer patients with a re-excision did not significantly differ from the survival of women who underwent primary BCS only. Advising re-excision only for those tumours showing 'more than focally positive' resection margin appears safe, supposing the long-term safety of the recent SSO/ASTRO guideline that more cautiously recommended re-excision for tumours showing 'ink on tumour'.