Spatial analysis of adherence to treatment guidelines for advanced-stage ovarian cancer and the impact of race and socioeconomic status

Abstract

Objective: To determine the impact of geographic location on advanced-stage ovarian cancer care adherence to the National Comprehensive Cancer Network (NCCN) guidelines in relation to race and socioeconomic status (SES).

Methods: Patients diagnosed with stage IIIC/IV epithelial ovarian cancer (1/1/96-12/31/06) were identified from the California Cancer Registry. Generalized additive models were created to assess the effect of spatial distributions of geographic location, proximity to a high-volume hospital (≥20 cases/year), distance traveled to receive care, race, and SES on adherence to NCCN guidelines, with simultaneous smoothing of geographic location and adjustment for confounding variables. Disparities in geographic predictors of treatment adherence were analyzed with the x(2) test for equality of proportions.

Results: Of the 11,770 patients identified, 45.4% were treated according to NCCN guidelines. Black race (OR=1.49, 95%CI=1.21-1.83), low-SES (OR=1.46, 95%CI=1.24-1.72), and geographic location ≥80 km/50 mi from a high-volume hospital (OR=1.88, 95%CI=1.61-2.19) were independently associated with an increased risk of non-adherent care, while high-volume hospital treatment (OR=0.59, 95%CI=0.53-0.66) and travel distance to receive care ≥32 km/20 mi (OR=0.80, 95%CI=0.69-0.92) were independently protective. SES was inversely associated with location ≥80 km/50 mi from a high-volume hospital, ranging from 6.3% (high-SES) to 33.0% (low-SES) (p<0.0001). White patients were significantly more likely to travel ≥32 km/20 mi to receive care (21.8%) compared to Blacks (14.4%), Hispanics (15.9%), and Asian/Pacific Islanders (15.5%) (p<0.0001).

Conclusion: Geographic proximity to a high-volume hospital and travel distance to receive treatment are independently associated with NCCN guideline adherent care for advanced-stage ovarian cancer. Geographic barriers to standard ovarian cancer treatment disproportionately affect racial minorities and women of low-SES.

Keywords: Geographic location; Ovarian cancer; Treatment guidelines.