Patients will receive R2 induction therapy consisting of rituximab and lenalidomide. Patients who achieve complete response or partial response after induction will undergo observation without maintenance anti-lymphoma therapy.

Duration of response is defined as the time from the first documented complete response or partial response to disease progression, relapse, or death from any cause, whichever occurs first.

Overall survival is defined as the time from randomization to death from any cause.

Event-free survival is defined as the time from randomization to disease progression, relapse, initiation of new systemic anti-lymphoma therapy, or death from any cause, whichever occurs first.

Disease-free survival is defined as the time from the first documented complete response to disease relapse, progression, or death from any cause, whichever occurs first.

POD24 is defined as the proportion of patients who experience disease progression, relapse, or death from any cause within 24 months from the start of frontline induction therapy.

Patient-reported outcomes will be assessed using the EORTC QLQ-C30 questionnaire.

The incidence and severity of adverse events and serious adverse events will be assessed according to the National Cancer Institute Common Terminology Criteria for Adverse Events version 5.0.