Occurrence of residual cancer within re-excisions in surgery of invasive breast cancer and ductal carcinoma in situ
Pahmeyer C.1, Schablack A.1, Mallmann P.2, Ratiu D.2, Grüttner B.2, Malter W.1, Eichler C.1
1Uniklinik Köln, Brustkrebszentrum Köln, Köln, Deutschland, 2Uniklinik Köln, Gynäkologie und Geburtshilfe, Köln, Deutschland

Introduction: Surgical margin status remains the most important determinant for local recurrence within invasive breast cancer and ductal carcinoma in situ. Breast conserving surgery has become a standard procedure besides subcutaneous mastectomy. We compared the number of positive margins in initial histology with rates of residual tumor in re-excision specimen depending on the operative strategy. Furthermore, we analysed cost-effectiveness of re-excisions.
Methods: 101 patients with IBC or DCIS treated with secondary surgery due to positive margins were included. Protocols of tumor-conferences were analysed regarding primary surgical strategy and its following R-situation. The first group underwent breast conserving surgery and secondary mastectomy. The second group was primarily treated with subcutaneous mastectomy followed by secondary surgery.
Results: Within the first group, 22.7% did not show residual tumor in re-excision specimen. Of the second group, primarily treated with subcutaneous mastectomy, 54.3% had no residual tumor after the second surgery. Consequentially 45,7% still needed a re-excision after subcutaneous mastectomy to achieve a tumor free margin. Cost-effectiveness was determined as secondary endpoint in this study. If a patient needs a secondary mastectomy due to R1 status the hospital gains 602,65€ in comparison to a primary breast conserving operation.
Conclusion: Patients showing positive margins after initial surgery should receive a second operation to achieve R0-status and therefore lower the risk of local recurrence of tumor. In every second patient who had first received a subcutaneous mastectomy, no tumor could be detected in the secondary operation despite a previous R1 situation.