International journal of radiation oncology, biology, physics | 2021
Trends in Receipt of Shorter Regimens of Radiation Therapy and Treatment Noncompletion Disparities Among Breast and Prostate Cancer Patients in the United States.
Abstract
PURPOSE/OBJECTIVE(S)\nAlthough racial and sociodemographic disparities exist in the rates of treatment noncompletion for patients receiving breast and prostate radiotherapy, shorter regimens may be associated with lower rates of treatment noncompletion. We assessed predictors of treatment noncompletion and racial disparities in access to shorter regimens for patients with prostate cancer (PCa) and breast cancer (BCa).\n\n\nMATERIALS/METHODS\nUsing the 2004-2017 National Cancer Database, men with localized PCa were defined as receiving conventional fractionation if they received 180cGY/fraction (noncompletion: < 41 fractions) or 200cGY/fraction (noncompletion: < 37 fractions). Stereotactic body radiotherapy (SBRT) was defined as five to eight fractions of 600-800cGY/fraction (non-completion: < 5 fractions). Women with non-metastatic BCa who received surgery with radiotherapy were included. Patients receiving 180cGY or 200cGY/fraction were defined as receiving conventional fractionation (noncompletion: < 25 fractions); patients receiving 266cGY, 267cGY, or 270cGY per fraction (noncompletion: < 15 fractions) were defined as receiving hypofractionated regimens. Multivariable logistic regressions assessed predictors of treatment noncompletion and racial disparities in access to shorter regimens.\n\n\nRESULTS\n166,436 men with complete data met inclusion criteria (median age 70 years [IQR 64-75]; 19.6% low-risk, 47.3% intermediate-risk; 33.1% high-risk; 17.5% Black; 82.5% white). Black men had higher rates of treatment noncompletion compared with white men (13.5% vs. 12.3%, OR 1.07, 95% CI 1.03-1.12, P < 0.001). SBRT was associated with lower odds of treatment non-completion compared with conventional EBRT (SBRT 1.3% vs. EBRT 13.2%; OR 0.08, 95% CI 0.07-0.1, P < 0.001). Although use of SBRT increased from 0.07% in 2004 to 13.03% in 2017, Black patients were less likely to receive SBRT (5.3% vs. 6.1%, OR 0.77, 95% CI 0.71-0.83, P < 0.001). 306,846 women met inclusion criteria (median age 61 years [IQR 52-69]; 17.4% in situ; 43.0% stage 1; 26.5% stage 2; 13.2% stage 3; 12.3% were Black and 87.7% were white). Treatment noncompletion did not differ significantly for Black (2.8%) vs. White (2.0%) women. Women who received hypofractionated EBRT had lower rates of treatment noncompletion compared to women who received conventional regimens (1.0% vs. 2.3%; OR 0.39, 95% CI 0.35-0.44, P < 0.001). Although rates of hypofractionated EBRT for breast cancer significantly increased from 0.8% in 2004 to 35.6% in 2017, Black patients were significantly less likely to receive hypofractionated EBRT (10.4% vs. 15.3%, OR 0.78, 95% CI 0.75-0.81, P < 0.001).\n\n\nCONCLUSION\nAlthough shorter treatment regimens of radiation therapy were associated with lower rates of treatment noncompletion, disparities persisted in receipt of shorter regimens. Our findings underscore the need to identify barriers to treatment completion and racial bias and inequities in access to treatment regimens that are more likely to be completed.