Identifying disparities in brachytherapy delivery for locally advanced cervical cancer.

Introduction: The standard of care for locally advanced cervical cancer is concurrent chemotherapy and external beam radiation therapy (EBRT) followed by a brachytherapy boost. Some studies show a decreased usage of brachytherapy in cervical cancer patients despite the standard of care and known survival advantage. This study aims to characterize the utilization of brachytherapy in Oregon and identify where disparities in treatment may exist.

Methods: The Oregon State Cancer Registry database was used to identify patients diagnosed with FIGO Stage IB2-IVB cervical cancer between 2007 and 2016. Patients who received initial EBRT were categorized by whether they received brachytherapy boost or not. Age at diagnosis, county of patient residence, rural-urban status of the county, race/ethnicity, and insurance payer were studied using multivariable logistic regression to identify possible underserved populations. Survival data was compared using a Cox proportional hazard survival model.

Results: 401 patients who received primary EBRT for FIGO stage IB2-IVB cervical cancer were identified in the 10-year span. Breakdown by stage is: 16% stage IB2, 23.9% stage II, 37.4% stage III, and 22.7% stage IV. Of those, 154 (38.4%) received brachytherapy boost treatment, 75 (18.7%) received a different boost modality, and 42.9% received no boost. Stage IV (p = 0.001) and uninsured patients (p = 0.04) were significantly less likely to receive brachytherapy. Older age was also associated with decreased brachytherapy usage, as each additional year of life decreased brachytherapy receipt by 1.8% (p = 0.04). Native American and Pacific Islander patients were the only group significantly more likely to receive brachytherapy (p=0.003). There was no significant difference in the rate of brachytherapy boost identified based on urban/rural status of the county (p = 0.63 to 0.69), other racial/ethnic categories (p = 0.66 to 0.80), or among the other stages (p=0.45 to 0.63). In Cox proportional hazard survival analysis, patients that received brachytherapy showed a 42% reduction in risk of cancer specific mortality, though this did not reach the predetermined level of statistical significance (p = 0.057).

Conclusions: The brachytherapy boost rate among locally advanced cervical cancer patients was 38.4%. The data also indicated a likely reduction in cancer specific mortality in patients receiving brachytherapy. Older patients, stage IV patients, and uninsured patients were less likely to receive brachytherapy. Given the low overall brachytherapy usage, these data indicate access and delivery of brachytherapy care needs to be improved across the state. The increased brachytherapy use in the American Indian and Pacific Islander patient population should be further studied to identify facilitators to treatment completion and potentially extrapolate to other groups.