Medical and surgical postoperative complications after breast conservation versus mastectomy in older women with breast cancer: Swedish population-based register study of 34 139 women

Abstract Background Mastectomy rates in breast cancer are higher in older patients. The aim was to compare postoperative complication rates after breast-conserving surgery (BCS) to mastectomy in women aged 70–79 and older than 80 years versus those aged 50–69 years, and to evaluate survival effects. Methods This population-based cohort included women aged 50 years and older with invasive breast cancer T1–3 N0–3 M0 operated on in Sweden 2008–2017. Major surgical and medical 30-day postoperative complications were assessed in adjusted logistic regression models. Overall survival was assessed in Cox models adjusted for clinical confounders, socio-economics, and comorbidity. Results Of 34 139 women, 8372 (24.5 per cent) were aged 70–79 years, 3928 (11.5 per cent) were 80 years of age or older, and 21 839 (64.0 per cent) were aged 50–69 years. Major surgical postoperative complications did not differ between age groups receiving equivalent surgery (BCS: 2.1 per cent and 2.0 per cent versus 2.1 per cent (P = 0.90); mastectomy: 4.6 per cent and 5.1 per cent versus 4.6 per cent (P = 0.49)). Major medical postoperative complications were higher in women aged >70 years than in women aged 50–69 years (BCS: 1.0 per cent and 2.3 per cent versus 0.4 per cent (P < 0.001); mastectomy: 3.1 per cent and 6.2 per cent versus 1.1 per cent (P < 0.001)), which persisted after adjustments. In women treated by mastectomy, major medical and surgical postoperative complications were associated with worse overall survival in all but the middle age group. Conclusion Mastectomy has higher medical and surgical postoperative complication rates than BCS. Major medical postoperative complications increase significantly with age. Major postoperative complications are associated with worse survival after mastectomy, which should be used with caution in older women.