Posted: Tuesday, November 8, 2022
Omran Saifi, MD, of the Mayo Clinic, Jacksonville, Florida, and colleagues aimed to better define the role of salvage radiotherapy after CD19-directed chimeric antigen receptor (CAR) T-cell therapy in relapsed or refractory B-cell non-Hodgkin lymphoma (NHL). Presented during the 2022 American Society for Radiation Oncology (ASTRO) Annual Meeting (Abstract 198), the results of this study indicated this strategy may be viable for this patient population.
“Post CAR T-cell therapy comprehensive salvage radiotherapy for relapsed/refractory B-cell NHL is a reasonable salvage intervention for patients with limited relapsed disease and is associated with better freedom from subsequent [disease] progression, freedom from subsequent event, and overall survival compared to focal salvage radiotherapy,” concluded the investigators.
The data for 48 patients with resistant B-cell NHL who underwent salvage radiotherapy after CAR T-cell therapy were retrospectively reviewed. Participant demographics such as local control rate, freedom from subsequent disease progression and events, and overall survival were defined from the initiation of salvage radiotherapy.
The median time from CAR T-cell infusion to salvage radiotherapy was 103 days, with the most common comprehensive and focal radiotherapies consisting of 36 Gy in 12 fractions and 20 Gy in 5 fractions, respectively. Of the 65 irradiated sites, in-field recurrence was observed in 21 lesions among 16 patients; the 1-year local recurrence rate was 62%.
A multivariate analysis showed that the maximum standardized uptake value and a high lactate dehydrogenase level retained a significant association with in-field recurrence. Among 37 patients with limited disease and 11 with extensive disease, the 1-year overall survival rates were 39% and 0%, respectively (P < .001). Of note, 26 individuals with limited disease underwent comprehensive salvage radiotherapy and 11 received focal salvage radiotherapy. With a median follow-up of 20 months, participants with limited disease who underwent comprehensive radiotherapy had a significantly higher 1-year freedom from subsequent disease progression (P < .001) and events (P = .01), as well as a higher 1-year overall survival (P = .028) compared with focal radiotherapy.
Disclosure: Dr. Saifi reported no conflicts of interest.