Female breast cancer treatment and survival in South Australia: Results from linked health data.

Five-year disease-specific survival increased to 91% for 2010-2014. Most women had breast surgery (90%), systemic therapy (72%) and radiotherapy (60%). Less treatment applied for ages 80+ vs <50 years (aOR 0.10, 95% CI 0.05-0.20) and TNM stage IV vs stage I (aOR 0.13, 95% CI 0.08-0.22). Surgical treatment increased during the study period and strongly predicted higher survival. Compared with no surgery, aSHRs were 0.31 (95% CI 0.26-0.36) for women having breast-conserving surgery, 0.49 (95% CI 0.41-0.57) for mastectomy and 0.42 (95% CI 0.33-0.52) when both surgery types were received. Patients aged 80+ years had lower survival and less treatment. More trial evidence is needed to optimise trade-offs between benefits and harms in these older women. Survival differences were not found by residential remoteness and were marginal by socioeconomic status.