The importance of margins status after breast conservative surgery and radiotherapy in node positive patients: a follow-up of 10–15 years

BACKGROUND: Margin status is the main factor determining local recurrence (LR) after wide excision and radiotherapy for breast cancer. The aim of the study is to evaluate if positive margins are as great a risk factor for LR in node-positive as in node-negative patients, since the major risk in the former group is dissemination and whether there is a correlation between nodal status and margins in relation to prognosis. METHODS: 773 patients underwent WLE and radiotherapy between 1988 and 1992 and were followed-up (> 10 years) to determine LR rates according to margin and nodal status. Margins were assessed by cavity-shave biopsies and the axilla was staged by sampling or clearance. RESULTS: 461 patients were node negative and 312 node positive. In the node-negative group 415 patients had negative margins and 46 positive: LR after > 10 years was 12 % and 28 % respectively. Among the 312 patients in the node positive group, 267 were margin negative and 45 positive; the LR rate was 12 % and 18 % respectively. In the node negative-group there was a statistically significant difference between the positive and the negative margins with higher relapse rate and lower overall survival (p < 0.001), whereas in the node-positive group the equivalent comparison didn't show any statistical difference. CONCLUSION: Although re-excision should be always recommended, in node-negative patients positive margins are associated with a statistically higher LR rate and lower overall survival while in node-positive disease margins might be of less importance in determining prognosis as dissemination is more likely to occur.