Variations in adjuvant chemotherapy and survival in women with epithelial ovarian cancer - a population-based study

Abstract

Background: To investigate whether variations in primary chemotherapy were associated with survival in a nationally complete cohort of Australian women with epithelial ovarian cancer (EOC).

Material and methods: All 1192 women diagnosed with invasive EOC in Australia in 2005 were identified through state-based cancer registries. Medical record information including details of primary chemotherapy treatment was obtained and survival data updated in 2012. Those started on standard chemotherapy (carboplatin and paclitaxel given at three-weekly intervals) after primary cytoreductive surgery were included (n = 351) and the relative dose intensity (RDI) was calculated. Time interval between surgery and start of chemotherapy was analysed in weeks. Hazard ratios [HR, 95% confidence interval (CI)] were calculated using multivariable Cox proportional hazards models.

Results: Compared to women with RDI of 91-100%, those with RDI of ≤ 70% had significantly poor survival (HRadj = 1.62, 95% CI 1.05-2.49). This association was stronger among women with advanced (FIGO stage III/IV) disease at diagnosis (HRadj = 1.90, 95% CI 1.22-2.96). The interval between primary surgery and chemotherapy was not related to survival (HRadj = 0.98, 95% CI 0.93-1.03 for every week of delay), at least up to a period of five weeks.

Conclusion: Our results suggest that RDI of 70% or less was associated with poorer survival, particularly in women with advanced stage EOC. In contrast, the interval duration between primary surgery and chemotherapy was not related to survival, irrespective of disease stage or residual disease. These results provide some reassurance that, at least up until five weeks post-surgery, timing of chemotherapy commencement has a negligible effect on survival.