Disparities in radiation treatment modality for prostate cancer

Stereotactic Body Radiation Therapy (SBRT) and Intensity Modulated Radiation Therapy (IMRT) are 2 common radiation treatment options used for prostate cancer therapy. SBRT has increased in use over the past decade. Factors associated with the uptake of this relatively novel therapy in prostate cancer patients are poorly understood. We attempted to characterize the choice of radiation therapy to help elucidate factors contributing to different treatment decisions.

We studied 1,624 prostate cancer patients diagnosed between 2008 and 2017 in the SEER-Medicare dataset who were treated with SBRT or IMRT at networks offering SBRT. Our analysis focused on White or Black patients with localized prostate cancer. We analyzed patient demographics and compared median times from diagnosis to treatment using the Wilcoxon rank-sum test.

We identified clinical and demographic factors associated with SBRT use compared to IMRT. On multivariable logistic regression, Black race was associated with decreased odds of receiving SBRT compared to White race (OR: 0.4; 95% CI: 0.2-0.7). Hispanic compared to non-Hispanic ethnicity was associated with decreased odds of receiving SBRT (OR: 0.4; 95% CI: 0.2-0.9). Patients living in a county with a population less than 250,000 people were more likely to receive SBRT compared to patients living in populous counties (OR: 3.6; 95% CI: 1.7-7.7).

Among patients from the SEER-Medicare dataset from 2008 to 2017 treated with radiation for clinically localized prostate cancer, disparities exist in the choice of treatment modality. Understanding differences in treatment patterns is an important area to guide intervention as SBRT becomes available nationwide.