A SINGLE INSTITUTION RETROSPECTIVE STUDY OF PALLIATIVE RADIOTHERAPY FOR BONE METASTASES: COMPARING THE FIRST SIX MONTHS OF THE 2020 COVID-19 PANDEMIC WITH THE SAME CALENDAR PERIOD DURING 2019

ABSTRACT

Purpose: To compare treatment courses received by patients with bone metastases during the first six months of the 2020 COVID-19 pandemic with those received during the same calendar period during 2019. Materials and Methods: Our radiotherapy information system was searched for palliative-intent treatment courses prescribed during the six-month period beginning March 14, 2020, the day that COVID-19 measures were operationalized at our institution. The same period during 2019 was similarly searched. Bone metastases cases were identified by reviewing stored images of radiotherapy plans for all treatment courses returned in the search. Descriptive statistics were used to analyze the cohorts. Results: From 1399 courses returned in the search, 1242 were confirmed as bone metastases cases. From 2019 to 2020 the number of patients treated for bone metastases fell from 398 to 377 (5% decline) and the number of courses they received fell from 633 to 609 (4% decline). Of all courses received in 2019 and 2020 respectively, the proportion of 1-fraction courses rose from 51% (234 of 633) to 59% (359 of 609) and the proportion of 2-fraction courses rose from 3% (18 of 633) to 11% (65 of 609). The proportion of 5-fraction courses fell from 42% (266 of 633) to 28% (172 of 609) and the proportion of 6 or more fraction courses fell from 2% (10 of 633) to 0.2% (1 of 609). The three most common dose fractionation schedules received in 2019 were 8Gy/1 (49% [309 of 633]), 20Gy/5 (31% [197 of 633]) and 15Gy/5 (6% [37 of 633]), and those received in 2020 were 8Gy/1 (54% [329 of 609]), 20Gy/5 (20% [122 of 609]) and 16Gy/2 (9% [56 of 609]). Conclusions: Compared to the same calendar period in 2019, during the first six months of the 2020 COVID-19 pandemic the number of patients treated with bone metastases and the total number of radiotherapy courses they received decreased modestly. The proportions of 1-fraction and 2-fraction courses increased noticeably, while the proportions of 5-fraction and 6 or more fraction courses decreased. An in-depth radiographic analysis is ongoing that will describe the morphologic characteristics of all treated bone metastases;data will be presented.