Determining the effect of frailty on survival in advanced ovarian cancer: study protocol for a prospective multicentre national cohort study (FOLERO).

Background and purpose: There is an urgent need to improve patient-selection to surgical treatment in advanced ovarian cancer as our results showed that cytoreductive surgery was without effect or even detrimental in a yet unknown subgroup of women. With an ageing population, 30% of women with advanced ovarian cancer in Sweden are >75 years. Nevertheless, there are no recommendations on patient-selection, albeit treating an unselected population in a public and centralized health care setting. Little attention has been placed on frailty assessments in oncology, despite their potential to stratify the risk of adverse outcome and mortality. Consequently, we hypothesize that frailty is a predictor of poor survival.

Patients and methods: In this Swedish multi-centre prospective cohort study, where the exposure is frailty, consecutive women with advanced ovarian cancer scheduled for surgery with curative intent are eligible for inclusion. Three different frailty instruments are evaluated preoperatively, blinded to the caregiver. The primary outcome is 2-year overall survival. With a fixed sample size of 450 patients, a two-sided α of 0.05 and β of 0.20, the study is powered to detect a difference in 2-year survival of 12.5% by frailty, assuming a 20% prevalence of frailty. The result of the study will have a direct impact on clinical management and patient-selection as the results are expected to have a high external validity. Total study-time is 5 years, with 3 years of accrual. All participating centres started accrual by September 2024. Presentation of data on primary outcome is expected 2029.

Study registration: ClinicalTrials.gov NCT06298877.