Risk of second primary cancers in nodal non-Hodgkin lymphoma patients by primary lymph node location: a retrospective cohort population-based study.

Background: Non-Hodgkin lymphoma (NHL) is a diverse group of blood cancers with increasing incidence and survival rates due to advancements in treatment and early detection. However, NHL survivors are at significant risk of developing second primary cancers, which can adversely impact their long-term survival. Methods: This retrospective population-based cohort study utilized data from the Surveillance, Epidemiology, and End Results database, covering 17 geographic areas in the United States from 2000 to 2021. The authors included patients diagnosed with nodal NHL as a first primary cancer and excluded those diagnosed at autopsy or via death certificate only. Standardized Incidence Ratios, Absolute Excess Risks, and Person-Years at Risk were calculated to evaluate the risk of developing SPCs according to the primary lymph node site and stratified by latency periods following the initial NHL diagnosis. Results: The cohort included 54 012 NHL patients. The authors' results showed that for most SPCs, the risk of development was different for different primary NHL lymph node locations. The highest risks were observed for thyroid cancer, acute myeloid leukemia, and Hodgkin lymphoma. Notably, the risk for thyroid cancer was highest in the first year post-diagnosis, while hematological malignancies such as acute myeloid leukemia and Hodgkin lymphoma showed elevated risks in the intermediate and late latency periods. Conclusion: NHL survivors are at an increased risk of developing SPCs, influenced by the primary lymph node site and latency period. These findings highlight the need for tailored surveillance strategies and preventive measures to mitigate the long-term risks of SPCs in NHL survivors. Further research is necessary to elucidate the underlying mechanisms and to develop targeted interventions for this high-risk population.