Efficacy and safety of Involved Field (IF) radiotherapy in combination for anti-CD20 antibody Rituximab (MabThera) and Involved field Radiotherapy for early-stage Diffuse Large Cell lymphoma (DLBCL) in a prospective, single-arm multicenter study.

Forty-five stage I–II FL patients received 8 cycles of Rituximab (375  mg/m2) and IF irradiation (30/40 Gy). Progression-Free Survival (PFS) 1-year from treatment start is the primary endpoint. Secondary endpoints were complete response rates, toxicity, quality of life with protocol defined visits up to month 15.

For the primary endpoint, PFS at 1-year was 85% for the intention-to-treat set. Long-term data were captured in selected sites and evaluated as post hoc analysis in the Per Protocol (PP) set: PFS was 78% at 1-year with a median follow-up of 15 months, respectively. There were 17/45 recurrences in the PP set, of which 14 were outside the radiation volume only. There were 9 serious adverse events (3 related to the therapy) during the first 15 months.

IF radiotherapy combined with Rituximab is well tolerated and highly efficient with low rates of recurrence in the first years in early-stage DLBCL. The efficacy is comparable with more aggressive therapy approaches without compromising the quality of life and maintains for an extended follow-up of more than 3 years.