Trends in the Use of Stereotactic Body Radiotherapy for Treatment of Prostate Cancer in the United States

Abstract

Importance: Stereotactic body radiotherapy is a hypofractionated, cost-effective treatment option for localized prostate cancer.

Objective: To characterize US national trends and the clinical and socioeconomic factors associated with the use of stereotactic body radiotherapy in prostate cancer.

Design, setting, and participants: This retrospective cohort study used data collected by the National Cancer Database to assess the clinical and socioeconomic factors among 106 926 men diagnosed as having prostate cancer from 2010 to 2015 who underwent definitive radiotherapy and the trends in the use of this therapy. The initial analysis was performed between January and February 2018, with final updates performed August 2019.

Exposure: Stereotactic body radiotherapy, defined as 5 fractions of radiotherapy.

Main outcomes and measures: Temporal trends and clinical and sociodemographic factors associated with stereotactic body radiotherapy use.

Results: In total, 106 926 patients diagnosed as having localized prostate cancer between 2010 and 2015 and receiving definitive radiotherapy were identified. White patients composed 77.3% of this cohort, whereas black patients composed 18.7%. Government-issued insurance was used by 61.2% of patients. More than 80% of patients had a Charlson-Deyo Comorbidity Index score of 0 (range, 0 to ≥3, with lower numbers indicating fewer comorbidities). In the study population, 25.7% had low-risk disease; 26.3%, favorable intermediate-risk disease; 23.3%, unfavorable intermediate-risk disease; and 24.7%, high-risk disease. The proportion of patients who underwent radiotherapy and received stereotactic body radiotherapy (a total of 5395 patients) increased from 3.1% in 2010 to 7.2% in 2015 (odds ratio, 0.36; 95% CI, 0.33-0.40; P < .001). Among the entire cohort, patients received a median dose of 36.25 Gy (range, 30.00-50.00 Gy). Androgen deprivation therapy use increased significantly as disease risk level increased among all patients receiving radiotherapy (9.5% with low risk to 76.6% with high risk; P = .02) and among those receiving stereotactic body radiotherapy (4.1% with low risk to 33.2% with high risk; P = .04) or not receiving stereotactic body radiotherapy (9.9% with low risk to 77.6% with high risk; P = .04). Patients treated at an academic center, living in an urban area, or possessing higher incomes and those who were healthier, white individuals, or were diagnosed as having lower-risk prostate cancer had higher odds of receiving stereotactic body radiotherapy.

Conclusions and relevance: This study found that stereotactic body radiotherapy use in prostate cancer more than doubled from 2010 to 2015 but accounted for less than 10% of all patients undergoing radiotherapy. Androgen deprivation therapy use increased with disease risk among patients overall, regardless of receiving stereotactic body radiotherapy. Socioeconomic and clinical determinants of stereotactic body radiotherapy included risk category, Charlson-Deyo Comorbidity Index score, facility type and location, income, race/ethnicity, and year of diagnosis. These results are hypothesis generating; further studies evaluating potential disparities in stereotactic body radiotherapy use in localized prostate cancer are warranted.