Ipsilateral breast tumour recurrence in hereditary breast cancer following breast-conserving therapy

The overall rate of an ipsilateral breast tumour recurrence (IBTR) after breast-conserving therapy (BCT) ranges from 1% to 2% per year. Risk factors include young age but data on the impact of BRCA1/2 mutations or a definite positive family history for breast cancer are scarce. We investigated IBTR after BCT in patients with hereditary breast cancer (HBC). Through our family cancer clinic we identified 87 HBC patients, including 26 BRCA1/2 carriers, who underwent BCT between 1980 and 1995 (cases). They were compared to 174 patients with sporadic breast cancer (controls) also treated with BCT, matched for age and year of diagnosis. Median follow up was 6.1 years for the cases and 6.0 years for controls. Patient and tumour characteristics were similar in both groups. An IBTR was observed in 19 (21.8%) hereditary and 21 (12.1%) sporadic patients. In the hereditary patients more recurrences occurred elsewhere in the breast (21% versus 9.5%), suggestive of new primaries. Overall, the actuarial IBTR rate was similar at 2 years, but higher in hereditary as compared to sporadic patients at 5 years (14% versus 7%) and at 10 years (30% versus 16%) (P=0.05). Post-relapse and overall survival was not different between hereditary and sporadic cases. Hereditary breast cancer was therefore associated with a higher frequency of early (2-5 years) and late (>5 years) local recurrences following BCT. These data suggest an indication for long-term follow up in HBC and should be taken into account when additional 'risk-reducing' surgery after primary BCT is eventually considered.