Results of re-excisional biopsy of the primary tumor in preparation for definitive irradiation of patients with early stage breast cancer.

From December 1977 through November 1984, 251 patients underwent a re-excisional biopsy procedure in preparation for definitive radiation therapy because of uncertainty in the extent of the initial biopsy procedure. Analysis of the cases was limited to patients with AJC Clinical Stages I or II breast cancer and whose initial biopsy procedure demonstrated invasive carcinoma. Sixty-three percent (158/251) of the 251 re-excisions were positive for residual tumor, and 37% (93/251) did not show any residual tumor. Of the positive re-excisions, 85% (134/158) revealed an invasive component of tumor; 15% (24/158) revealed only non-invasive disease. For patients whose initial biopsy was described as incisional only, 97% (64/66) had residual tumor; 51% (94/185) of patients with an initial excisional biopsy had residual tumor. Because of the extremely high rate of positive re-excision in patients with an initial incisional biopsy, these cases were excluded from the remainder of the analysis. When the pathologic margin of the initial biopsy specimen was described as positive, 60% (15/25) had residual tumor on re-excision and 49% (79/160) when the pathology margin was unknown. Of the clinical T1 lesions, 45% (57/126) had positive re-excision, and of the clinical T2 lesions, 63% (37/59) were positive. When a post-biopsy mammogram (i.e. following initial biopsy procedure but before re-excision) showed residual microcalcifications, 86% (12/14) had residual tumor found in the re-excision specimen. Based on these findings, indications for re-excisional biopsy of the primary tumor are: initial incisional biopsy, positive or unknown pathologic margin on an initial excisional biopsy specimen, or residual microcalcifications on post-biopsy mammogram. When inked margins were negative on pathological examination of an initial excisional biopsy specimen, re-excision of the primary tumor bed was not recommended. These results suggest that a re-excisional biopsy procedure may be an important component of the overall treatment approach to assure removal of all tumor, and should continue to be used when indicated prior to definitive irradiation of the breast for early stage breast cancer.