Prognostic value of [F]FDG PET/CT in follicular lymphoma.

[OBJECTIVE] To determine the prognostic value of [F]FDG PET/CT in follicular lymphoma (FL) patients in our routine clinical practice.

[MATERIAL AND METHODS] Retrospective study of FL patients assessed with PET/CT in our centre from 01/06/2008 to 01/06/2020. This study aimed to investigate the prognostic value of quantitative parameters (MTV, TLG, ΔSUV max) and qualitative criteria (Lugano classification), and its relationships with progression-free survival (PFS) and overall survival (OS).

[RESULTS] Among patients with available staging PET/CT, the 5-year OS was 90.4% for those with lower MTV and 89.7% for those with higher MTV (p = 0.3). The PFS was 77.6% for those with lower MTV and 53.2% for those with higher MTV (p = 0.001). TLG yielded statistically similar results. A ΔSUV max ≥ 66% was associated with higher OS and PFS at 5 years, at both interim and final PET/CT studies (iPET and fPET). The 5-year OS for patients with complete metabolic response was 86.3% in iPET and 89.0% in fPET, compared to 84.1% and 79.0%, respectively, for those positive in iPET (p = 0.3) and fPET (p = 0.1). The 5-year PFS for patients with complete metabolic response was 76.9% in iPET and 73.1% in fPET, compared to 58.7% and 62.2%, respectively, for those positive in iPET (p = 0.04) and fPET (p = 0.09).

[CONCLUSIONS] PET/CT is valuable as a prognostic factor in FL, both during staging (providing parameters with independent prognostic value such as MTV and TLG) and during and after treatment (as it correlates with survival).