Clinical and Socioeconomic Factors Associated with Early Discontinuation of Radiation Therapy

Purpose: Patients who do not complete a full course of radiation therapy (RT) are at increased risk for mortality compared with patients who completed their full course of RT (1-2). Using the National Cancer Database (NCDB), we aimed to identify the clinical and socioeconomic factors associated with RT discontinuation.

Methodology: Using the NCDB data from the year of 2018, we identified 375,143 patients treated with RT, chemoradiation (CRT), surgery with RT (Sx+RT), or surgery with CRT (Sx+CRT) that had information on radiation discontinuation. We evaluated patients with breast, CNS, GI, GU, GYN, head and neck, MSK, skin and thoracic tumors. The variables that we assessed include age (18- < 50, 50- < 70, ≥70), gender (male, female), race (White, Black, other), insurance status (private, Medicare, Medicaid/uninsured, other government), income level ( <$30,000, $30,000-$34,999, $35,000-$45,999, ≥$46,000), Charlson-Deyo Comorbidity Score (0, 1, ≥2), treatment type (RT, CRT, Sx+RT or Sx+CRT), and facility type (community, comprehensive community, academic/research or integrated cancer network). A chi-square test and a non-parametric Wilcoxon-Mann-Whitney test were used to examine differences of RT discontinuation in categorical and continuous variables, respectively. Univariable and multivariable logistic regression modeling were used to compute adjusted odds of positive RT discontinuation by clinical and socioeconomic factors.

Results: Of the 375,143 patients with information on RT discontinuation, RT was discontinued early in 14,487 (3.9%) patients. RT discontinuation rates were reported in solid tumors of the breast (1.61%), CNS (5.21%), GI (5.95%), GU (2%), GYN (4.42%), head and neck (4.83%), MSK (4.95%), skin (5.22%) and thorax (6.9%). On multivariable analysis, older age, female sex, Medicaid/uninsured status, lower income, community program, multiple comorbidities, and CRT were independently associated with RT discontinuation. The reasons for RT discontinuation were patient decision (35.7%), toxicity (19%), contraindication due to patient risk (18.4%), patient expired (15%), and family decision (3.6%).

Conclusions: This NCDB analysis showed that RT discontinuation rates correlated with clinical factors such as older age, multiple comorbidities, and chemoradiation, as well as socioeconomic factors such as Medicaid/uninsured status and lower household income. Addressing these risk factors provides a potential means to improving RT adherence.

References: 1. Chiang YY, Chou YC, Chang KP, et al. Missed radiation therapy sessions in first three weeks predict distant metastasis and less favorable outcomes in surgically treated patients with oral cavity squamous cell carcinoma. Radiat Oncol. 2020;15(1):194. doi:10.1186/s13014-020-01632-1
2. Chow R, Hasan S, Choi JI, et al. Effect of treatment interruptions on overall survival in patients with triple-negative breast cancer. J Natl Cancer Inst. 2023;115(9):1029-1035. doi:10.1093/jnci/djad127