Trends in Radiation Oncology Treatment Fractionation at a Single Academic Center, 2014-2020

Abstract

Recent landmark studies in radiation oncology suggest hypofractionation is appropriate for treatment of many cancers. The COVID-19 pandemic may have increased pressure to adopt hypofractionation because of concerns about disease spread at treatment centers. We know of no recent U.S. study of trends in radiation fractionation that includes comparisons of multiple disease sites and data post-COVID. Therefore, we sought to describe trends in treatment fractionation at a single academic center from 2014-2020.From our institutional database, for the years 2014-2020, we extracted the total number of patients treated, total number of fractions delivered, and mean number of fractions per treatment course for all cancers and specifically for treatment of breast cancer, prostate cancer, and bone metastases. For breast and prostate, we included only radiation courses delivered to the primary site.The dataset included 16,224 courses of radiation treatment and 257,352 treatment fractions. The mean number of fractions per treatment course overall declined steadily throughout the study period, from 18.3 in 2014 to 14.9 in 2020. For breast cancer, the mean number of fractions per treatment course was steady from 2014-2016 but began to decline more rapidly from 2017-2020. Fractionation for prostate cancer followed a similar time trend, but there was a more substantial decline from 2014 (mean 36.6 fractions per treatment course) to 2020 (mean 16.7 fractions per treatment course). For bone metastases, fractionation was relatively consistent throughout the study period. For breast patients, during the onset of COVID-19 in 2020, the monthly rate of decrease in number of fractions increased to 0.19 from a historical mean of 0.05, as the mean number of sessions dropped from 22 to 19. For bone metastases, in 2020, the mean number of sessions dropped from 6.3 to 5.3, with a monthly rate of decrease of 0.13 compared to historical mean of 0.03. COVID-19 did not spike the monthly rate of change in number of fractions for prostate which began a steady decline in 2017 with increased use of SBRT.We observed increased adoption of hypofractionation at our institution during the study period for both breast and prostate cancer. For bone metastases, hypofractionation had largely been adopted before the study period. There was evidence of an accelerated trend toward hypofractionation for some cancers during the COVID-19 pandemic.