2602 - Policy vs. Pandemic: Effects on Utilization of Shorter Radiation Regimens for Palliating Osseous Metastases

Y. Shi¹, R. P. McDougall², C. Morrison³, L. Wang Jr³, C. C. Hsu³, and J. R. Robbins⁴; ¹University of Arizona Cancer Center, Tucson, AZ, ²University of Arizona, Tucson, AZ, ³University of Arizona - Department of Radiation Oncology, Tucson, AZ, ⁴University of Arizona, College of Medicine-Tucson, Department of Radiation Oncology, Tucson, AZ

Purpose/Objective(s): Despite countless trials showing equipoise for single vs multifaction radiation regimens for palliating bone metastases, the majority are treated with long courses. In 2013, ASTRO promoted the “Choose Wisely” campaign (CW) to limit the use of extended fractionation (11+ fractions). The global COVID-19 pandemic (CP) provided opportunities to limit exposure by reducing treatment duration. The goal of this study is to evaluate the utilized radiation schemas before and after these events with the hypothesis that the CP would have a more profound impact. Materials/

Methods: The National Cancer Database was queried to identify all patients with radiation treated osseous metastases. The cohort consisted of two groups: 2011-2015 CW (n=36,812) and 2018-2021 CP (n=41,713), and common fractionation regimens were evaluated. Treatment parameters were compared. The following definitions were used: extended fractionation (EF) was 11+fx, hypofractionation (HF) was = 5fx and single fraction (SF) was 8 Gy in 1 fx. Year-to-Year Relative Percent change was calculated to evaluate the impact of each event.
Results: Overall, a significant trend toward fewer fractions, less EF, and increased HF and SF were observed in both groups (see table). The largest reduction in EF was seen in 2014 (-24.4%), the year after the CW kickoff. Although the utilization of SF and HF were relatively low compared to 30 Gy/10 fx, which was 55-60% of all cases, the frequency increased in both groups with the largest gains observed in 2013 and 2014, the first 2 years of CW (HF:+15.9%, +20.3%; SF +23.1%, 21.9%) and 2020, the first year of the CP (HF +21%, SF +31.6%). These large relative gains in SF use represented only minor absolute gains of (1.4-2.4%). During CW, the frequency of 30 Gy/10 fx increased, while it dropped in 2020 by 8.5%, even though the rate was still >50%. The trends in adopting SF and HF regimens during 2020 reversed in 2021, when the relative rates of both declined (SF -12%, HF -1.2%).
Conclusion: Both CW and CP impacted palliative regimens by decreasing EF and increasing SF/HF, but ultimately 30 Gy/10 fx was delivered in >50%, blunting the overall impact of shorter courses and prolonging treatment, even amidst a global pandemic. Any incentive to limit COVID exposure in 2020 tapered off in 2021. Neither policy nor pandemic sustainably or substantially reduced the number of patients receiving a two-week course of palliative RT.

	Choose Wisely Group					Covid Pandemic group
	2011	2012	2013	2014	2015	2018	2019	2020	2021
Mean # fx	9.63	9.51	9.12	8.71	8.49	8.25	8.00	7.58	7.57
Y2Y Rel%	-	-4.5%	-4.1%	-4.5%	-2.5%	-	-3.0%	-5.3%	-.01%
30 Gy/10fx	54.9%	56.6%	57.8%	59.3%	59.9%	60.4%	59.0%	54.0%	55.0%
Y2Y Rel%	-	3.1%	2.1%	3.5%	0.2%	-	-2.3%	-8.5%	1.9%
EF	29.1%	26.4	22.5%	17.0%	14.0%	12.1%	10.2%	8.8%	7.7%
Y2Y Rel%	-	-9.3%	-14.8%	-24.4%	-17.7%	-	-15.7%	-13.7%	-12.5%
HF	16.0%	17.0%	19.7%	23.7%	26.1%	24.8%	27.8%	33.8%	33.4%
Y2Y Rel%	-	6.3%	15.9%	20.3%	10.1%	-	12.1%	21.6%	-1.2%
SF	4.6%	5.2%	6.4%	7.8%	7.9%	6.9%	7.6%	10%	8.8%
Y2Y Rel%	-	13.0%	23.1%	21.9%	1.3%	-	10.1%	31.6%	-12.0%