Background: Stage III follicular lymphoma (FL) is currently still considered incurable after RCHOP (rituximab, cyclophosphamide, doxorubicin, vincristine and prednisone) chemotherapy and rituximab maintenance. Radiotherapy plays a vital role in early-stage FL, but the value remains unclear in stage III FL. Here, we reported the results of invasive field radiotherapy (IFRT) combined with rituximab maintenance versus rituximab maintenance alone in patients with stage III FL who achieved complete remission (CR) or partial response (PR) after induction chemotherapy.

Methods: From January 2015 and January 2020, patients aged 18-70 years with CR or PR after induction chemotherapy in stage III FL, grade 1, 2 or 3a and CD20 positive in immunohistochemical feature were randomly assigned (1:1) to receive IFRT combined rituximab maintenance or rituximab maintenance alone after induction chemotherapy in multicenter. The primary endpoint was progression-free survival at 5 years. This study is registered with Chinese ClinicalTrials.gov, number ChiCTR2000032550.

Results: 63 patients were randomly assigned to IFRT combined rituximab maintenance (IFRT+R arm) and 66 patients to rituximab maintenance alone (R arm) after induction chemotherapy. The dose of IFRT was 30Gy. After a medium follow-up of 48 months (range 7-72 months), the 5-year progression free survival (PFS) were significantly improved in patients with IFRT +R, with 87.8% versus 67.1% (HR, 0.32; 95% CI, 0.14-0.72, P=0.006). Patients with IFRT +R also have a better overall survival (OS), OS was 96.6% versus 80% (HR, 0.28; 95% CI, 0.09-0.92, P=0.036). Thirty-six (57%) patients in IFRT+R arm and twenty-four (36%) patients in R arm suffered toxic effects (P=0.02). Grade 3 and 4 adverse events were recorded in 17 patients (27%) in IFRT+R arm and 11 (16%) in R arm (P=0.200).

Conclusion: On the basis of rituximab maintenance, IFRT demonstrated promising efficacy and manageable toxicity in stage III FL, with longer PFS and OS compared with rituximab alone.

Figure 1
Figure 1.
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Disclosures

No relevant conflicts of interest to declare.

© 2021 by The American Society of Hematology
2021
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