Impact of baseline suvmax in untreated high-tumor-burden follicular lymphoma

Abstract Background: Positron emission tomography is considered the reference imaging technique for the initial staging and therapeutic assessment of follicular lymphoma (FL). Among the quantitative parameters investigated, the standardized uptake value (SUV, g/mL) has emerged as a potential prognostic indicator, with an observed association between an elevated baseline maximum SUV (SUVmax) at diagnosis and a more aggressive disease course. However, there is insufficient evidence to establish specific therapeutic strategies for patients with a high baseline SUVmax in the absence of confirmed histologic transformation. Furthermore, the prognostic significance of an elevated baseline SUVmax in patients with high-tumor-burden FL remains uncertain, particularly in the context of contemporary immunochemotherapy regimens. This study aimed to evaluate the influence of a high baseline SUVmax on clinical outcomes in treatment-naïve FL patients who had received first-line immunochemotherapy. Patients and Methods This retrospective single-center study included 196 consecutive patients who had received first-line immunochemotherapy between 2007 and 2025 for untreated high-tumor-burden FL. The selection of the immunochemotherapy regimen was determined by the treating physician, and all patients subsequently received maintenance therapy. Progression-free survival (PFS) and overall survival (OS) were defined as the durations from treatment initiation to progression, relapse, or death, respectively. The SUVmax at baseline was categorized according to the median value. Kaplan Meier survival curves and multivariable Cox models were employed to evaluate outcomes. The primary endpoint was to ascertain the impact of the baseline SUVmax on survival outcomes (PFS and OS). Results The median age at diagnosis was 62 years (range, 29-86) and 52.6% of the patients were male (n=103). Eighty-seven percent (n=171) of the patients presented with Ann Arbor stage III/IV disease, 82.7% (n=162) exhibited normal lactate dehydrogenase levels, and 22.5% (n=44) manifested B symptoms at diagnosis. The FLIPI (Follicular Lymphoma International Prognostic Index) score was 0-2 for 71.4% (n=140) of the patients and 3-5 for 28.6% (n=56). The immunochemotherapy regimens administered were Rituximab-CHOP (n=65, 33.2%), Rituximab-Bendamustine (n=74, 37.7%), Obinutuzumab-CHOP (n=19, 9.7%), and Obinutuzumab-Bendamustine (n=38, 19.4%). Baseline SUVmax was available for 145 (74.0%) patients, with a median of 12.0 (range, 4.8-43.0). At a median follow-up of 52 months (range, 2-211 months), the PFS and OS rates at 60 months were 57.4% (95% CI 49.0-65.0) and 77.3% (95% CI 69.7-83.2), respectively. In univariate analyses, patients with elevated lactate dehydrogenase levels and a FLIPI score of 3-5 demonstrated significantly lower PFS (P=0.017 and P=0.003, respectively) and OS (P<0.001 and P<0.001, respectively). Age at treatment initiation, Ann Arbor stage, and immunochemotherapy regimen did not affect the outcomes. Higher baseline SUVmax was not associated with PFS (hazard ratio [HR]=0.85, 95% CI 0.49-1.48) or OS (HR=0.89, 95%CI 0.39-2.06) in univariate and multivariate analyses. Conclusions In this single-center retrospective study, no correlation was observed between elevated baseline SUVmax and adverse clinical outcomes in patients with high-tumor-burden FL who received first-line immunochemotherapy. Given the inherent limitations of retrospective analyses and potential biases in treatment selection, these findings do not support the utilization of SUVmax as a determinant for first-line treatment decisions in this patient population.