Adjuvant Chemotherapy for Stage I Ovarian Clear Cell Carcinoma

OBJECTIVE: To assess the association between postoperative chemotherapy and the prognosis of patients with stage I ovarian clear cell carcinoma. METHODS: This was a retrospective cohort study of patients with stage I ovarian clear cell carcinoma who underwent surgery, including hysterectomy and bilateral salpingo-oophorectomy, between 2005 and 2019 at 11 affiliated institutions. Patients with preoperative lymph node enlargement, and those who underwent fertility-sparing surgery were excluded. The primary outcome was disease-free survival and overall survival, and was investigated as a secondary outcome. We used propensity score overlap weighting to adjust for confounding factors and estimated the adjusted hazard ratios (HRs) and 95% CIs for the disease-free and overall survival of patients in the control group that did not receive chemotherapy and in the platinum-based multiagent chemotherapy group during the follow-up period. RESULTS: In total, 283 patients (64 in the control group and 219 in the chemotherapy group) were included. Five-year disease-free survival was 0.77 (95% CI, 0.66–0.89) in the control group and 0.86 (95% CI, 0.81–0.91) in the chemotherapy group. The unadjusted HR was 0.69 (95% CI, 0.36–1.32; P =.26). After adjustment, patients who received chemotherapy had a significantly lower risk of recurrence than those in the control group (weighted HR for disease-free survival: 0.43; 95% CI, 0.20–0.90; P =.026). There was no difference in overall survival (weighted HR 0.68; 95% CI, 0.27–1.69; P =.40). CONCLUSION: Postoperative platinum-based multiagent chemotherapy was associated with improved disease-free survival. These findings provide crucial information for shared decision-making regarding whether to undergo adjuvant chemotherapy.