Impact of surgeon type and rurality on treatment and survival of ovarian cancer patients

Objectives: We aimed to determine if rurality impacts type of surgeon and estimate if the interaction between rurality and type of surgeon impacts cytoreductive surgery, chemotherapy initiation, and survival. Methods: Our population-based cohort of Iowan (N=675) ovarian cancer patients included women diagnosed with histologically confirmed stages IB-IV cancer in 2010-2016 at the ages of 18-89 years old and who received cancer-directed surgery in Iowa. Multivariable logistic regression analysis was used to determine the independent impact of rurality on type of surgeon, and the interaction between rurality and type of surgeon on cytoreductive surgery and chemotherapy initiation. Cox proportional hazards models were used to assess if the interaction between rurality and type of surgeon impacted 3-year all-cause and cause-specific mortality. Results: 83% (N=563) of Iowans who received in-state surgical care had a gynecologic oncologist surgeon. Rural patients had lower odds of having a gynecologic oncologist (adjusted odds ratio (aOR) 0.48; 95% confidence interval (CI) 0.30-0.78). Compared to rural patients with a non-gynecologic oncologist, rural and urban patients with a gynecologic oncologist surgeon were more likely to receive guideline-recommended cytoreduction (aOR 2.84, 2.58; 95% CI 1.31-6.14, 1.29-5.16, respectively) and chemotherapy (aORs 4.22, 7.94; 95% CI 1.82-9.78, 3.64-17.3, respectively). Compared to urban patients with a non-gynecologic oncologist, rural and urban patients with a gynecologic oncologist were more likely to receive cytoreduction (aORs 4.60, 4.19; 95% CI 2.13-9.94, 2.11-8.33, respectively) and urban patients with a gynecologic oncologist were more likely to receive chemotherapy (aOR 4.03; 95% CI 1.73-9.37). Rural patients with a non-gynecologic oncologist had the lowest 3-year cause-specific survival estimates controlling for patient/tumor factors. Urban patients with a non-gynecologic oncologist had higher 3-year cause-specific survival estimates than urban patients with a gynecologic oncologist. These differences became non-significant when controlling for treatment covariates. Conclusions: Rural patients were less likely to receive surgery from a gynecologic oncologist. Patients with non-gynecologic oncologist surgeons had lower odds of chemotherapy initiation and cytoreductive surgery. Gynecologic oncologist-provided surgery conferred a 3-year cause-specific survival advantage among rural patients and a survival disadvantage among urban patients in the model without treatment covariates. The significance dissipated when treatment variables were added to the model. The variation in the gynecologic oncologist survival advantage may be due to treatment differences, referral differences and/or differences in non-gynecologic oncologist volume or specialty by rurality. This is the first study to investigate the ovarian cancer survival advantage of having a gynecologic oncologist surgeon by rurality. Interventions are needed to determine the cause of variation by rurality and to ensure rurality does not impact treatment or survival.