Strengths and Limitations
cancer
ONCOLOGY, CANCER
Strengths of this study included the prospective data collection using NRG Oncology trials. Length of follow-up was relatively long, with a median follow-up of 4 years for surviving patients. Additionally, the cohort was relatively large with a relatively uncommon cancer.Study limitations included the cohort not being sufficiently large to exclude the possibility of modest, although clinically relevant, differences in survival associated with RT interruptions and duration. There was an association between RT duration and inferior LRF, DFS, and OS in some, but not all, models. Because this study was an unplanned post hoc analysis, we could not account for potential sources of bias. Enrollment in these NRG Oncology trials spanned approximately 3 decades, during which there were improvements in staging, RT planning and delivery, and supportive care. Such changes contributed to the heterogeneity of these trials, although the trial was included as a variable in the models to account for this heterogeneity. Furthermore, the trials were not associated with OS, DFS, LRF, or DF in the multivariable models.