Has Time to Chemotherapy from Primary Debulking Surgery in Advanced Ovarian Cancer an Impact on Survival? - A Population-based Nationwide SweGCG Study

Objective: The aim of the study was to investigate if time to start chemotherapy (TTC) after primary debulking surgery (PDS) impacted relative survival (RS) in advanced epithelial ovarian/fallopian tube/primary peritoneal cancer (EOC).

Methods: Nationwide population-based study of women with EOC FIGO stages IIIC-IV, registered 2008-2018 in the Swedish Quality Register for Gynecologic Cancer, treated with PDS and chemotherapy. TTC was categorized into; ≤21 days, 22-28 days, 29-35 days, 36-42 days and > 42 days. Relative survival (RS) was estimated using the Pohar-Perme estimate of net survival. Multivariable analyses of excess mortality rate ratios (EMRRs) were estimated by Poisson regression models.

Results: In total, 1694 women were included. The median age was 65.0 years. Older age and no residual disease were more common in TTC >42 days than 0-21 days. The RS at 5-years was 37.9% and did not differ between TTC groups. In the R0 (no residual disease) cohort (n = 806), 2-year RS was higher in TTC ≤21 days (91.6%) and 22-28 days (91.4%) than TTC >42 days (79.1%). TTC >42 days (EMRR 2.33, p = 0.026), FIGO stage IV (EMRR 1.83, p = 0.007) and non-serous histology (EMRR 4.20, p < 0.001) were associated with 2-year worse excess mortality compared to TTC 0-21 days, in the R0 cohort. TTC was associated with 2-year survival in the R0 cohort in FIGO stage IV but not in stage IIIC. TTC was not associated with RS in patients with residual disease.

Conclusions: For the entire cohort, stage IV, non-serous morphology and residual disease, but not TTC, influenced 5-year relative survival. However, longer TTC was associated with a poorer 2-year survival for those without residual disease after PDS.