Hyperthermic intraperitoneal chemotherapy after upfront cytoreductive surgery for stage III epithelial ovarian cancer: Follow-up of long-term survival

Introduction

The survival benefit of hyperthermic intraperitoneal chemotherapy (HIPEC) has been well defined at the time of interval cytoreductive surgery, but the role of HIPEC remains uncertain for patients with newly diagnosed advanced ovarian cancer in the upfront setting. The present study aimed to report the updated long-term survival outcomes after 5 years of follow-up from our previous multicenter retrospective cohort study to compare primary cytoreductive surgery (PCS) plus HIPEC with PCS alone among women with stage III epithelial ovarian cancer.

Material and Methods

This study was conducted at five high-volume gynecological medical centers in China from January 2010 to May 2017. Eligible patients with complete data were treated with either PCS combined with HIPEC or PCS alone. The 5-year overall survival (OS) rate was updated to compare PCS plus HIPEC with PCS alone. The inverse probability of treatment weighting (IPTW) method based on a propensity score model for each patient was used to control the confounding factors and evaluate the effect of HIPEC.

Results

Data from 789 patients, a total of 584 eligible stage III epithelial ovarian cancer patients were ultimately included in the analysis (PCS-plus-HIPEC group, n = 425; PCS-alone group, n = 159). After IPTW adjustment, the median OS was 44.5 (95% CI, 40.1–49.1) months in the PCS-plus-HIPEC group and 32.4 (95% CI, 28.8–40.3) months in the PCS-alone group (weighted hazard ratio, 0.74; 95% CI, 0.59–0.93; p = 0.006). At 5 years, the OS rates were 37.9% (95% CI, 33.0%–42.8%) in the PCS-plus-HIPEC group and 26.4% (95% CI, 18.9%–34.6%) in the PCS-alone group (p = 0.007). After stratification into optimal and suboptimal cytoreduction subgroups, patients in the PCS-plus-HIPEC group maintained a greater association with improved OS than those in the PCS-alone group. Among the women who underwent optimal cytoreduction in the PCS-plus-HIPEC group and PCS-alone group, the median OS was 49.9 (95% CI, 45.2–58.4) months and 37.8 (95% CI, 30.5–53.0) months (p = 0.042) while the 5-year OS rate was 43.7% (95% CI, 37.7%–49.6%) and 33.2% (95% CI, 23.3%–43.5%), respectively (p = 0.040). Meanwhile, for those treated with suboptimal cytoreduction subgroup in the PCS-plus-HIPEC and PCS-alone groups, the median OS was 28.4 (95% CI, 22.2–39.9) months and 20.6 (95% CI, 10.6–32.4) months (p = 0.099) while the 5-year OS rate was 22.4% (95% CI, 15.1%–30.5%) and 12.2% (95% CI, 4.4%–24.2%), respectively (p = 0.060). The median follow-up period was 87.2 (95% CI, 85.1–92.7) months.

Conclusions

The updated results indicate that the addition of HIPEC is associated with improved long-term survival outcomes beyond 5 years for patients with stage III epithelial ovarian cancer in the upfront setting.