The following is a summary of “Survival outcomes of primary vs interval cytoreductive surgery for International Federation of Gynecology and Obstetrics stage IV ovarian cancer: a nationwide population-based target trial emulation,” published in the February 2025 issue of American Journal of Obstetrics & Gynecology by Jochum et al. 

The comparison between primary and interval cytoreductive surgery for stage IV ovarian cancer outcomes is unclear and might be influenced by the stage and location of extraperitoneal metastasis, with causal assessment and propensity score adjustment becoming key methods for evaluating interventions using observational data.  

Researchers conducted a retrospective study to estimate the effect of primary vs interval cytoreductive surgery on progression-free and overall survival (OS) in patients with International Federation of Gynecology and Obstetrics stage IV ovarian cancer using target trial emulation.  

They used the French national health insurance database to emulate a target trial (Surgery for Ovarian cancer FIGO 4: SOFI-4) to evaluate the causal effects of primary vs interval cytoreductive surgery on stage IV ovarian cancer prognosis. The clone method with inverse probability of censoring weighting adjusted for informative censoring and balanced baseline characteristics between the groups. Subgroup analyses were performed based on stage and extraperitoneal metastasis location. Patients under 75 years, in good health, and diagnosed with stage IV ovarian cancer between January 1, 2014, and December 31, 2022, were included. Primary and secondary outcomes were 5-year progression-free survival and 7-year OS, respectively.  

The results showed that among 2,772 patients, 948 (34.2%) had stage IVA ovarian cancer and 1,824 (65.8%) had stage IVB. Primary cytoreductive surgery was executed in 1,182 patients (42.6%), and interval cytoreductive surgery in 1,590 (57.4%). Median progression-free survival was 19.7 months (interquartile range, 19.3–20.1) for primary cytoreductive surgery and 15.7 months (IQR, 15.7–16.1) for interval surgery. Median OS was 63.1 months (IQR, 61.7–65.4) for primary surgery and 55.6 months (IQR, 53.8–56.3) for interval surgery. Primary cytoreductive surgery was linked with a 5.0-month increase in 5-year progression-free survival (95% confidence interval [CI], 3.8–6.2) and a 3.9-month increase in 7-year OS (95% CI, 1.9–6.2). These survival benefits were observed in both stage IVA and IVB subgroups and in patients with pleural, supradiaphragmatic, or extra-abdominal lymph node metastasis.  

Investigators concluded that primary cytoreductive surgery offered benefits over interval cytoreductive surgery for patients with stage IV ovarian cancer. 

Source: ajog.org/article/S0002-9378(24)00818-4/fulltext