Importance of Routine Cavity Sampling in Breast Conservation Surgery

Background: The role of cavity biopsy (CB) at the time of wide local excision (WLE) for primary breast

cancer has not been evaluated fully. This study compared four groups of patients to determine the

significance of margins and CB histology on tumour characteristics and outcome.

Methods: This was a retrospective study of patients undergoing WLE and CB in one institution

over 21 years. Demographic data, tumour characteristics and survival information were obtained. Four

subgroups of patients were compared according to their margin and cavity status (positive or negative).

Results: A total of 957 patients had WLE. The median 10-year survival was 85·6 per cent and breast

cancer-specific survival was 92·4 per cent. Tumour size, grade, node and oestrogen receptor status

were independent predictors of survival. There was poor concordance between positivity of resection

margins and CB (32·0 per cent); a negative margin carried a 10·8 per cent risk of demonstrable residual

disease. A positive CB, but not a positive margin, was associated with reduced overall survival and breast

cancer-specific survival.

Conclusion: Cavity status wasmore significant with regard to survival than margin status.CB is important

in identifying residual and multifocal disease, as margin and cavity positivity are often not concordant.