Stable use of radiotherapy in lymphoma patients over time - A comprehensive national overview of radiotherapy use in Sweden with focus on older patients.

BACKGROUND AND PURPOSE: The role of radiotherapy (RT) in lymphoma is constantly refined with the advent of novel treatments. However, RT is still an effective treatment and tolerability is high. Therefore, we aimed to describe the use of RT in primary treatment of lymphoma over calendar time, with a specific focus on older patients (age ≥ 70 years) with non-Hodgkin lymphoma (NHL) subtypes.

MATERIALS & METHODS: All adult patients diagnosed with lymphoma from 2007 to 2018 in Sweden were included and followed for survival until end of 2020. Patient characteristics and relative survival (RS) were described for patients with NHL by subtype and RT use.

RESULTS: In the cohort of lymphoma patients aged ≥ 70 years (n = 12,698) 11 % received RT as part of primary treatment. No decline in use of RT over calendar period was seen. Use of RT as monotherapy was associated with stage I-II disease and older age among patients with stage III-IV disease. Patients with indolent lymphomas aged ≥ 70 years who were selected for treatment with RT as monotherapy with a dose of ≥ 20 Gy had 2-year RS rate of 100 % which remained similar at five years. For patients with DLBCL, RT as monotherapy with a dose of ≥ 20 Gy was mostly administered to patients aged ≥ 85 years with a 2-year RS rate of 68 %.

CONCLUSION: The use of RT in first-line lymphoma treatment was stable over calendar time. RT monotherapy is associated with encouraging outcomes among patients with NHL aged ≥ 70 years who were selected to receive this.