Prognostic value of baseline SUVmax in patients with advanced stage follicular lymphoma receiving frontline rituximab-based therapy.

Abstract

7540 Background: Positron emission tomography (PET) is recommended in follicular lymphoma (FL) for initial staging, evaluation of potential transformation, and response assessment. The prognostic value of pre-treatment PET scan has not been adequately explored. Methods: We performed a single-institution retrospective analysis of patients with advanced stage FL, without histological evidence of transformation, treated with frontline rituximab-based therapy, and analyzed the prognostic significance of baseline maximum standardized uptake value (SUVmax). Results: The median follow-up for the cohort was 94 months. Of 346 patients, 151 (44%) received R-CHOP and 195 (56%) received non-R-CHOP regimens. Among multiple single unit increments of SUVmax, a value of >18 showed the strongest association with progression-free survival (PFS) (hazard ratio [HR] 1.5, 95% confidence interval (CI) 0.95-2.3, p=0.08), and was selected as cut-off for further analysis. Fifty-two (15%) patients had a SUVmax > 18. On univariate analysis, factors associated with SUVmax > 18 were male sex (67% vs 52%, p=0.05), elevated β2-microglobulin (65% vs 47%, p=0.02), elevated LDH (37% vs 13%, p<0.001), presence of B symptoms (35% vs 14%, p=0.01), and largest lymph node ≥ 6 cm (64% vs 30%, p<0.001). On multivariate analysis, largest lymph node ≥ 6 cm was the only factor maintaining its association with SUVmax > 18 (odds ratio [OR] 2.7, 95% CI 1.3-5.3, p=0.006). SUVmax > 18 significantly associated with a lower CR rate among patients treated with non-R-CHOP regimens (45% vs 92%) (p<0.001) but not among patients treated with R-CHOP (p=1). SUVmax > 18 associated with significantly shorter PFS among patients treated with non-R-CHOP regimens (77 months vs not reached, p=0.02), but not among patients treated with R-CHOP (p=0.73). SUVmax > 18 associated with shorter overall survival (OS) both in patients treated with R-CHOP (15 year OS 70% vs 75%, p=0.02) and non-R-CHOP regimens (15 year OS 50% vs 75%, p=0.001). Conclusions: In conclusion, baseline SUVmax has prognostic value in patients with advanced stage FL receiving rituximab-based therapies. Evaluation in prospective studies is needed to further confirm these findings.