Radiotherapy for Stage I/II Follicular Lymphoma (Fl): is It Time for a Reappraisal?

Aim: Almost 30% of FL presents with stage I-II disease. The standard of care consists of involved-field radiation therapy (IFRT). Nevertheless, relapses occur in almost half of patients and usually outside the primary irradiation field, leading to death in a substantial number of cases. Systemic immunotherapy with rituximab (R) with or without IFRT could reduce distant recurrences leading to a better outcome. Therefore, we compared the efficacy of IFRT alone or in association with R (R + IFRT) versus R alone in stage I/II FL (grade 1-3A). Methods: From 1995 to September 2012, 108 consecutive patients affected by FL were retrospectively assessed at the Medical University of Innsbruck and at the University Hospital “G. Martino” in Messina. Treatment response was evaluated 6-12 weeks after the end of treatment and consisted of a physical examination, blood testing and CT scan. Results: 36 patients underwent IFRT (24–40Gy), 38 R alone (4-8 doses at 375mg/m2) and 34 R + IFRT (24–30Gy). Overall, median age at time of diagnosis was 60 years (range 31 - 88 years). In patients who underwent R or R + IFRT the percentage of adverse prognostic factors (B-symptoms, LDH, B2-Microglobulin, FLIPI score) was significantly higher. Among all three treatment groups no grade 3/4 toxicities were registered. Complete response rate was 84% in the IFRT-group, 87% in the R group and 97% in the R + IFRT-group (p = 0.1). Overall, median follow-up was 8 years (range, 1-20). Progression free survival (PFS) and time to next treatment (TTNT) were significantly higher in both rituximab arms compared to IFRT alone: median PFS was 5 and 6 years in the R and R + IFRT groups vs. 2.3 years in the IFRT one (p Conclusions: In conclusion, patients who underwent R or R + IFRT had a clearly better long-term control of the disease despite a significantly poorer prognostic profile at time of diagnosis. In the R + IFRT group results were even better than in the R group. Longer follow-up is needed to evaluate the impact on OS. Disclosure: All authors have declared no conflicts of interest.