Spatial location of local recurrences after mastectomy: a systematic review

Purpose: We performed a systematic review to document the spatial location of local recurrences (LR) after mastectomy. Methods: A PubMed search was conducted in August 2019 for the following terms: breast [Title/Abstract] AND cancer [Title/Abstract] AND recurrence [Title/Abstract] AND mastectomy [Title/Abstract]. The search was filtered for English language. Exclusion criteria included studies that did not specify the LR location or studies reporting LR associated with inflammatory breast cancer, or other breast cancers such as phyllodes tumours, lymphoma or associated with sarcoma/angiosarcoma. Results: A total of 3922 titles were identified, of which 21 publications were eligible for inclusion in the final analysis. A total of 6901 mastectomy patients were included (range 25–1694). The mean LR proportion was 3.5%. Among the total of 351 LR lesions, 81.8% were in the subcutaneous tissue and the skin, while 16% were pectoral muscle recurrences. Conclusion: Local recurrences are mostly located within the subcutaneous tissue and the skin, assumed to result from unrecognized/subclinical tumour foci left behind after mastectomy, surgical implantation of tumour cells in the wound/scar and/or tumour emboli within the subcutaneous lymphatics. Pectoral muscle recurrences are less frequent and may be attributed to residual disease along the posterior surgical margin and/or lymphatic involvement.