Introduction/Background While R0 resection is defined as ‘no tumour on ink’ in primary surgery of Breast carcinoma (BC), the optimal definition of R0 after neoadjuvant chemotherapy (NAC) is not well established. There are insufficient data which demonstrate that surgery within new margins in cases of a pathological complete response (pCR) is safe. We therefore investigated the influence of different margins and pCR on local recurrence and survival rates after NAC in BC.

Methodology A retrospective cohort of 75 patients with clinical and pathological data from 2017 to 2018 were included in this study. Clinical and pathologic features, including age, histological type, biomarker status, treatment, response, recurrence, survival etc, were obtained from medical records. H&E Slides were reviewed by breast pathologists to evaluate the status of resection margins in relation to fibrotic tumor bed. The prognosis for each case was classified as well (disease-free for >=5 years), local recurrence, metastasis, death or lost-to-follow-up.

Results Between January 2017 and December 2018, a total of 75 tumorectomies status post NAC were retrieved (median age 52-year old, range 29–75 years). Twenty-five (33,3%) cases had pCR, including 10 (40%) cases with positive fibrotic bed margin and 15 (60%) cases with negative margins. Thirty-four (45,3%) cases had partial pathologic response. Twenty of the specimens were found to be positive for fibrotic tumor bed at resection margins (58%) and 14 were negative (42%). Carcinomas were classified as triple negative in 41 cases and HER 2 in 34 cases. The margin status for the fibrotic tumor bed did not show any correlation with the biomarker status or the prognosis of the tumor.

Conclusion Margins positive for fibrotic tumor bed do not cause significant difference in recurrence or overall 5-year survival in patients with BC status post NAC. The re-excision is not necessary.

Disclosures Authors declare that they have no relevant or material financial interests that relate to the research described in this paper.