Prior research indicates that survivors of non-Hodgkin’s lymphoma are at increased risk of secondary malignancies. However, data are lacking on long-term risk and whether such risk differs by treatment modality.

Investigators assessed standardized incidence ratios (SIR, observed-to-expected [O/E] ratio) and absolute excess risk of secondary malignancies were assessed in nearly 150,000 patients diagnosed with NHL as a first malignancy between 1975 and 2016 in the NCI’s SEER program. SMs developed in 11% of patients, more than end endemic rate (O/E, 1.29). Patients treated with any radiotherapy had similar risk of secondary malignancy as those who did not receive radiotherapy, whereas those treated with any chemotherapy had increased secondary malignancy rates when compared with those who did not receive chemotherapy. Chemotherapy alone and chemotherapy plus radiation were associated with increased risk of secondary malignancy compared with no therapy, but there was no difference in the overall risk of secondary malignancy between the chemotherapy alone and chemotherapy plus radiation groups.