Background: Breast cancer treatment is guided by diagnostic subtyping, yet cancer registries do not routinely capture this information, and real-world studies reporting subtype-specific incidence and survival do not reflect contemporary clinical management.
Methods: We analysed breast cancer incidence and survival using Queensland cancer registry data (2017-2019), stratifying by hormone receptor (HR) and HER2 status.
Results: Subtype-specific, age-standardised incidence rates were: 125.6 HR+/HER2- cases/100,000 women (76.0% of all diagnoses), followed by 17.7/100,000 for triple-negative (TNBC; 10.3%), 15.0/100,000 for HR+/HER2+ (8.7%), and 8.6/100,000 for HR-/HER2+ (5.0%). Compared to HR+/HER2-, all other subtypes had poorer breast cancer-specific survival (BCSS) and overall survival (OS; except HR+/HER2+ for OS) at 2-years, with OS associations attenuated but still significant for TNBC at 4-years. Stratifying by stage at diagnosis, TNBC had consistently poorer 2-year BCSS in those with stage I-III TNBC (HRadj>7), and marginally poorer in those with stage IV.
Conclusions: HR+/HER2- breast cancer is the most common subtype and has the best short-term prognosis. TNBC has markedly poorer short-term survival, even when diagnosed at an early stage. This study provides real-world data for benchmarking breast cancer incidence and survival, and highlights the importance of capturing receptor status and stage for cancer surveillance.
Policy summary: Routinely capturing breast cancer subtypes and stages in cancer registries needs to be prioritised to assess the real-world efficacy of evolving targeted therapies and to inform tailored surveillance for high-risk subtypes.