Detection of residual disease following breast-conserving surgery

Assessment of completeness of tumour excision has become an integral part of breast-conserving surgery, but the accuracy of margin analysis has been questioned. This study compared the results of resection margin analysis with an examination of tumour bed biopsies and of the excised cavity wall.

One hundred and forty-four patients underwent breast-conserving surgery for T1-2 N0-1 breast cancer. Following wide local excision, four bed biopsies were taken from the cavity wall which was then completely excised. The presence of invasive and in situ disease at the inked resection margin (IRM) and in the adjacent bed biopsies and cavity wall was recorded.

Positive margins and/or residual disease in either the bed biopsies or cavity wall was found in 62 (43 per cent) of 144 cases. Residual disease (invasive or in situ) was present at the IRM in 39 specimens (27 per cent) and was present in 25 bed biopsy (17 per cent) and 39 cavity wall (27 per cent) specimens. These comprised different but overlapping groups of patients.

Margin analysis of wide local excision specimens is a poor predictor of completeness of excision. Routine resection and examination of the entire cavity wall increases the detection of residual disease compared with examination of bed biopsies alone and is a useful adjuvant to conventional margin evaluation.