Relationship between initial margin status for invasive breast cancer and residual carcinoma after re-excision

Little data exists addressing the relationship between initial margin status in a specimen from an excisional biopsy and the presence of residual carcinoma in a subsequent specimen from lumpectomy or mastectomy. We sought to determine the relationship between initial margin status and the presence of residual invasive cancer, and to identify any relationship to other variables. This study was a retrospective review of pathology reports of 582 early-stage invasive duct carcinomas with open excisional biopsies. The initial specimen was classified into one of six margin categories: multiply focally positive (n = 174), focally positive (n = 132), margins < 1 mm (n = 98), margins 1 to 2 mm (n = 20), margins > 2 mm (n = 46), and margins undetermined (n = 90). All patients had a subsequent definitive second procedure. Pathology reports from the second procedure revealed the presence of residual invasive cancer by initial margin status as follows: in 30 per cent of the initial procedures with multiply focally positive margins, in 22 per cent with focally positive margins, in 8 per cent, 15 per cent, and 4 per cent with margins of < 1 mm, 1 to 2 mm, and > 2 mm, respectively, and in 28 per cent with undetermined margins. Women with palpable tumors, larger tumor size, and positive axillary nodes were more likely to have multiply focal and focally positive margins. Multiply focally positive and focally positive margins had similar residual invasive carcinoma rates and should be re-excised. All clear margins were equivalent; thus, re-excision was not necessary.