Positron emission tomography (PET) after induction therapy in follicular lymphoma (FL) is predictive of survival in clinical trials. We describe use of PET and computed tomography (CT) after rituximab-based induction therapy in FL patients followed by the National LymphoCare Study and explore the association between imaging response assessment and survival. Among 1289 patients, imaging consisted of: PET ± CT (35%), CT alone (42%), other/no imaging (24%). Median follow-up was 7.6 years. In unadjusted analyses, positive PET ± CT and CT were prognostic of inferior OS (HR 1.78; 95% CI: 1.16-2.72 and HR 1.61, 95% CI: 1.13-2.29, respectively) and PFS (HR 1.63, 95% CI: 1.21-2.20 and HR 1.45, 95% CI: 1.12-1.89, respectively). Adjusting for FL International Prognostic Index, PET remained predictive of OS (HR 1.54, 95% CI: 1.01-2.36) and PFS (HR 1.54, 95% CI: 1.14-2.07). Residual disease via PET in FL is prognostic of survival in clinical practice.
