We aim to describe trends in net survival (NS) and to assess the prognostic factors among women with de novo metastatic breast cancer (MBC) according to human epidermal growth factor receptor 2 (HER2) and hormone receptor (HR) status. Data on women suffering from de novo MBC and diagnosed from 1998 to 2009 were provided by the Côte-d'Or breast cancer registry. NS was described using the Pohar Perme estimator and prognostic factors were investigated in a generalised linear model. We identified 232 patients (mean age = 64.7). Median NS was 29.2 months, 1- and 5-year NS were 76% and 26% respectively. The survival trend in patients with HER2-positive tumours who did not receive trastuzumab was similar to that in women with triple-negative tumours. A higher relative excess risk of death by cancer was observed for high-grade tumours [RER, relative excess rates = 1.76 (95% CI, confidence intervals: 1.17-2.62) for Scarff Bloom Richardson grade 3 vs. 1 + 2], while a lower risk was observed for luminal tumours [RER = 0.49 (95% CI: 0.27-0.89)] and HER2-positive tumours treated with trastuzumab [RER = 0.28 (95% CI: 0.14-0.59)], both compared with triple-negative tumours. Surgery of the primary tumour was associated with better survival [RER = 0.43 (95% CI: 0.28-0.68)]. With half of the women dead before 29 months, stage IV breast cancer still has a bleak outlook. Progress should continue with new target therapies for both HR and HER2 receptors.
Keywords: HER2 receptors; hormone receptors; metastatic breast cancer; net survival; population-based; register.
© 2015 John Wiley & Sons Ltd.