Use of Adjuvant Breast Hypofractionation Radiation Treatment at a Cancer Center in Ontario From 2011 to 2018

BACKGROUND: The adoption of hypofractionated radiotherapy (HFRT) into clinical practice varies widely despite randomized trials and guidelines supporting its equivalence to conventional fractionated radiotherapy (CFRT) for certain patient populations. We assessed the use of HFRT at a single institution from 2011 to 2018, as well as time-savings calculations. PATIENTS AND METHODS: A retrospective cohort study was conducted for patients with breast cancer receiving adjuvant radiotherapy by HFRT or CFRT. Trends in HFRT use (≤ 16 fractions) were stratified according to 4 subgroups: tangential breast RT, locoregional breast RT, tangential chest wall RT, and locoregional chest wall RT. Treatment time savings were approximated using the institutional median treatment time. RESULTS: A total of 5190 patients were included. HFRT use in all subgroups increased from 2011 to 2018. Tangential breast HFRT alone increased from 62.2% in 2011 to 96.9% in 2018. Locoregional breast HFRT and tangential chest wall HFRT use increased from less than 10% in 2011 to 76.2% and 76.9% in 2018. In locoregional chest wall RT, HFRT use of 44.9% was observed in 2018. Increased use of locoregional HFRT was mainly due to institutional policy changes. Time-savings calculations showed that 4002 hours of treatment or an additional 1402 HFRT courses could have been administered if all patients received HFRT. CONCLUSION: The use of HFRT at our center increased in all patient subgroups. More evidence and guidelines for patients receiving chest wall or locoregional HFRT are required because the use of HFRT remains low in these patient cohorts.