A Midwest Tri-State Study of Overall Survival in Ovarian Cancer with Adjuvant Chemotherapy

Overall survival associated with National Comprehensive Cancer Network (NCCN) adjuvant chemotherapy treatment guideline using population-based surveillance data is limited. This study examined overall survival and compliance to the NCCN guideline for adjuvant chemotherapy.

The Midwest Ovarian Cancer Study was a collaborative project between 3 state cancer registries (Iowa, Kansas, and Missouri), Westat, and the Centers for Disease Control and Prevention. A standardized protocol was used to ascertain International Federation of Gynecology and Obstetrics (FIGO) stage-specific adjuvant chemotherapy. Primary epithelial ovarian cancers with FIGO stages IA/IB grade 3, IC, and II-IV with histologies 8000-8576 and 8930-9110 were included in this study. The Kaplan-Meier method was used to calculate survival functions. Adjusted hazard ratio (HR) was analyzed for all-cause mortality associated with NCCN compliance with adjuvant chemotherapy after adjusting for stage at diagnosis and comorbidity.

Sixtynine percent (523 of 756 eligible) were compliant with NCCN guidelines. Compliance was significantly different by age at diagnosis and insurance type (both P < .0001). The overall survival was significantly different by age group, census tract median income, histologic subtype, and tumor grade (all P < .0001). The adjusted HR of noncompliance with adjuvant chemotherapy guideline was 3.2 (95% CI, 2.600-3.911).

Better overall survival in patients who had received NCCN-recommended adjuvant chemotherapy was confirmed.

The survival benefit was 7% higher over 4 years after diagnosis when considering FIGO stage-specific chemotherapy and the corresponding number of cycles. Using the chemotherapy data field that is collected by statewide cancer registries underestimated the overall survival.