High Basal Maximal Standardized Uptake Value (SUV(max)) in Follicular Lymphoma Identifies Patients with a Low Risk of Long-Term Relapse

SIMPLE SUMMARY: A simple and easily available parameter, such as SUV(max), could represent a useful tool in clinical practice to evaluate at diagnosis the risk of late relapse in Follicular Lymphoma. A higher basal FDG uptake (>6) was associated with a lower long-term relapse probability only in the absence of other risk factors (bone marrow involvement, B-symptoms, extra-nodal disease, elevated LDH, and/or b2-microglobulin), which can overwhelm the favourable effects of a high SUV. A low basal SUV(max) reflects an indolent behaviour with a higher rate of late relapse, thus, requiring a prolonged follow-up. ABSTRACT: Background: Despite that the unfavorable prognostic role of a high Total Metabolic Tumor Volume (TMTV) in Follicular Lymphoma has been demonstrated, the role of SUV(max) alone at baseline PET/CT could have a different prognostic role. Patients and Methods: We performed a retrospective observational monocentric cohort study. All patients affected by FL who underwent a basal PET/CT were included. Two subgroups were identified and compared in terms of PFS and OS: (A) Basal SUV(max) ≤ 6; and (B) Basal SUV(max) > 6. Results: Ninety-four patients were included, 34 in group A (36.2%) and 60 in group B (63.8%). The PFS at two years was comparable in the two groups (97%). The five-year PFS was 73.5% for group A and 95% for group B (p 0.005). The five-year PFS in the whole cohort was 87.5%. A clear advantage was confirmed in group A in the absence of other risk factors. Patients with SUV(max) ≤ 6 and no risk factors showed a 5-year PFS of 73% against 83% for patients with SUV(max) > 6 and at least two risk factors. Conclusion: A high FDG uptake favorably correlated with PFS. A low basal SUV(max) reflected a higher rate of late relapse requiring a prolonged follow-up. The basal SUV(max) is an approachable parameter with prognostic implications.