Real-World Utilization of Radiation Therapy (RT) in Multiple Myeloma (MM): An Analysis of the Connect® MM Registry

Abstract

<h3>Purpose/Objective(s)</h3> RT is an important therapeutic modality utilized at various stages along the treatment continuum in MM. However, there has been no national study of RT utilization and data on the factors that influence use are lacking due to its palliative nature and the fact that RT can be used multiple times over the course of MM treatment. The Connect® MM Registry is a largely community-based registry that provides a unique opportunity to evaluate real-world use and factors that influence RT use in MM treatment. <h3>Materials/Methods</h3> The Connect MM Registry is a large, US, multicenter, prospective observational cohort study of patients (pts) aged ≥ 18 y with newly diagnosed MM from 250 community, academic, and government sites. This analysis investigated Registry pts who received RT. RT utilization was captured quarterly over the entire course of pt treatment, in the first 6 months from study enrollment and in the last 6 months prior to death. Data from 9/28/2009 — 2/4/2021 were used in this analysis. <h3>Results</h3> The Connect MM Registry included 3011 pts of whom 903 (30%) received RT at any time. Twenty-one percent (636/3011) received RT within the first 6 months of study enrollment and 16% (241/1526) within the last 6 months before death (among all death pts). Overall, pts were predominantly white (83%), male (57%), with a median age of 67 y (range 24 – 94) and received a triplet anti-MM regimen (55%). At baseline, most common indications for RT were pain (65%), impending fracture (13%), or neurologic compression (12%). On multivariable analysis, overall RT use was significantly less common in pts with Eastern Cooperative Oncology Group performance status (ECOG PS) of 0 – 1 vs 2+ (odds ratio [OR], 0.58; <i>P</i> = 0.0014) and more common in ISS stage I + II vs III pts (OR, 1.61; <i>P</i> = 0.0009). We observed no statistically significant difference regarding pt age, sex, race/ethnicity, insurance status, geographic region, intent to transplant, or use of novel anti-MM agents in first line of treatment. In the first 6 months after study enrollment, there was more than double the odds of RT use in pts with ISS I+II vs III (OR, 2.07; <i>P</i> < 0.001) and in pts with ECOG PS 0–1 vs 2+ (OR, 0.46; <i>P</i> < 0.001). No other sociodemographic or clinical factors studied were significant. In the 6 months before death, the only factor associated with increased RT use was increasing lines of MM therapy (OR, 1.19; <i>P</i> < 0.001). <h3>Conclusion</h3> These results from the CONNECT MM Registry, representative of real-world practice, show that even in the era of novel anti-MM agents, RT is used frequently for pt care. RT use is dictated by clinical factors, including PS and disease stage, rather than sociodemographic factors. Earlier in MM diagnosis, RT may be used as an adjunct to palliate symptoms (poor PS) or to delay systemic therapy (early stage). Toward the end of life, RT is more frequently used for palliation, with limited systemic options after multiple lines of therapy.