Incidence and Outcome of Breast Sarcomas in England (2013-2018): An analysis from the National Cancer Registration and Analysis Service.

BACKGROUND:Breast sarcomas (BS) are rare cancers originating from mesenchymal breast tissue with a paucity of national population level data detailing their incidence and outcomes. METHODS:We performed an analysis of data collected by National Cancer Registration and Analysis Service (NCRAS) for patients diagnosed with BS between 2013 and 2018. Chi-square test was used to compare groups. Overall survival (OS) was calculated by Kaplan-Meier. Specialist sarcoma centres (SSC) were defined as centres with a sarcoma multidisciplinary team (MDT). RESULTS:There were 684 patients with BS (357 malignant phyllodes tumours [PTs], 238 vascular tumours, 93 other morphology) with a median age of 64 (range 14-96); 187 (27%) had received breast radiotherapy for a prior malignancy; 633 (92%) had resection of the tumour within 12 months of diagnosis. Five-year OS was 82%, 54% and 48% in patients with PT, vascular tumours and other sarcomas, respectively, and 55% for those with radiation-induced BS. Patients managed within SSC more frequently had a biopsy prior to surgery 83% versus 72%, p < 0.05) and were less likely to require multiple operations (26% versus 41%, p < 0.05). Tumour stage and grade data were not available. CONCLUSION:This is the first population series evaluating incidence and outcomes for BS. Patients treated at non-specialist sarcoma centres (NSSCs) are less likely to have a biopsy prior to surgery and more likely to require multiple operations. Based on these observational data, we would recommend all BS are discussed at a sarcoma MDT meeting early in their pathway and surgery to be considered at SSC where possible.