Evaluating the Short-Term Environmental and Clinical Effects of a Radiation Oncology Department's Response to the COVID-19 Pandemic (STEER COVID-19)

PURPOSE/OBJECTIVE(S): During the COVID-19 pandemic, hypofractionated regimens and virtual care was adopted by our institution to preserve hospital capacity and reduce foot traffic. This study's primary objective was to assess the collective environmental impact of these strategic changes by identifying sources of carbon dioxide equivalents (CO(2)e). As sustainable healthcare is only justifiable if the quality of the care is maintained, we also evaluated the rate of radiation-related acute adverse event. MATERIALS/METHODS: All patients treated with external beam radiation therapy from April 1, 2019 to March 31, 2021 at our single institution were identified (n=10,175) along with their radiotherapy visits (176,423 fractions), and visits to the radiation nursing clinic (RNC) or emergency (ER) department. A treatment regimen was considered hypofractionated if the dose per fraction was ≥ 240 cGy. If the dose per fraction was ≥ 600 cGy and the total dose of the treatment regimen was > 2000 cGy, then the treatment regimen was classified as SBRT. Out-patient hospital and virtual visits (n=75,853) during this same period were also analyzed. Environmental impact measures, including linear accelerator power usage, patient travel distances, and personal protection equipment (PPE) consumption were all converted into CO(2)e. A waiver of individual patient consent was granted for this study by our institution's Research Ethics Board (REB). RESULTS: The use of curative hypofractionated regimens increased from 17% to 27% during the pandemic year. Twelve out of 15 cancer sites increased their use of hypofractionated regimens. Carbon footprint was reduced by 39% during the pandemic year (1,332,388 kg CO(2)e) as compared to the pre-pandemic year (2,024,823 kg CO(2)e). For comparison, the 744 tonnes of CO(2)e saved during the pandemic year equates to the CO(2)e produced by the annual energy consumption of 182 Canadian households or the CO(2)e sequestered by 12,000 seedling trees planted and grown for 10 years. On average 121 kg CO(2)e and 100 kg CO(2)e were emitted per radiation regimen delivered during the pre-pandemic and pandemic year, respectively. Comparing patients in the pre-pandemic vs. pandemic year, there was a significant reduction in the proportion of hypofractionated patients who needed a visit to either the RNC (39% vs. 25%; p<0.001) or ER (6% vs. 2%; p<0.001) during and within 90 days of radiotherapy. CONCLUSION: This study demonstrated the environmental benefits of increased use of hypofractionated regimens and virtual care, while assuring that there was no added acute radiation-related adverse event. Our findings support their continued use as one of many long-term strategies to reduce the environmental footprint of healthcare delivery. Treatment efficacy and side-effects will need to be assessed in subsequent years to further support the sustainability of these strategies.