Different Role of PET-CT Evaluation in Newly Diagnosed Follicular Lymphoma Upon Rituximab-Based Chemotherapy and Chemo-Free Immunotherapy.

Newly diagnosed follicular lymphoma (FL) patients usually received first-line rituximab-based immunochemotherapy (R-chemo). Recently, rituximab plus lenalidomide (R2) emerged as an alternative chemo-free immunotherapy. We performed a comparative analysis of positron emission tomography/computed tomography (PET/CT) in FL undergoing R-chemo or R2. With data of sequential PET/CT at the baseline, interim, and end-of-induction, treatment responses and survival outcomes were analyzed using Deauville scores at the interim and end-of-induction. Additionally, correlations between interim Deauville scores and baseline PET/CT parameters were explored. Conclusively, we revealed that Deauville 1-3 at the interim and end-of-induction showed lower disease progression within 24 months (POD24) and superior progression-free survival (PFS) in R-chemo and R2 cohorts. Also, patients with interim Deauville 1-3 exhibited reduced POD24 and favorable PFS as compared to those with interim Deauville 4-5/end-of-induction Deauville 1-3. Furthermore, total lesion glycolysis of baseline PET-CT surpassed standardized uptake value and total metabolic tumor volume in predicting interim Deauville 1-3, with different optimal cutoffs of 2600 and 600 mL in the R-chemo and R2 cohort. These findings underscored the potential of PET-CT-adapted strategies to achieve durable remission in FL undergoing rituximab-based immunochemotherapy or immunotherapy.