3625 - Modern Radiotherapy Does Not Increase the Risk of Second Primary Malignancies in Survivors of Hodgkin Lymphoma
Presenter(s)
A. C. Gober1, E. Urias2, D. K. Gaffney2, A. Maity2, J. D. Tward2, F. M. Cruz3, and G. Nelson2; 1University of Utah, Salt Lake City, UT, 2Department of Radiation Oncology, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT, 3University of Alabama at Birmingham, Birmingham, AL
Purpose/Objective(s): Previous studies have shown an overall increased risk of second primary malignancies (SPMs) in survivors of Hodgkin’s Lymphoma (HL), especially in patients treated with radiation therapy. Our study aims to quantify the risk of SPMs in these patients treated with modern radiation techniques.
Materials/Methods: Using the National Cancer Institute’s Surveillance, Epidemiology, and End Results Program, patients with primary HL from 1975 to 2021 were identified. Patients with primary disease outside of the mediastinum or locoregional lymph nodes were excluded, and the standardized incidence ratio and absolute excess risk of SPMs were assessed. Subgroup analyses were performed by treatment era, with the modern treatment era defined as 2000-2021. Accounting for death as a competing risk, propensity score-adjusted cumulative incidence functions were generated by treatment modality, including chemotherapy (CT) and chemoradiation (CRT
Results: In total, 8,187 patients with Hodgkin Lymphoma were identified with a mean follow up of 195 months. Eleven percent of patients developed an SPM with a standardized incidence ratio of 1.99 (95% CI: 1.87-2.11). Temporal patterns showed an increasing risk of solid malignancies over time, while hematologic malignancies most commonly presented within the first five years of treatment. When stratified by treatment era, patients treated prior to the year 2000 had a significant increase in SPM risk when treated with CRT versus CT (SHR 1.82, p < 0.01). Conversely, the cumulative incidence of SPMs was not increased with CRT versus CT in patients treated with modern radiation techniques (SHR = 1.41, CI: 1.18-2.81, p=0.2).
Conclusion: In this population-based study, we demonstrate SPM risk patterns in patients treated with CRT versus CT for primary HL. Treatment with modern radiation techniques does not result in a significantly increased cumulative incidence of SPM in this cohort. Abstract Figures may be found online.