C. Casulo, B. Day, K.L. Dawson, X. Zhou, C.R. Flowers, C.M. Farber, J.D. Hainsworth, J.R. Cerhan, B.K. Link, A.D. Zelenetz, J.W. Friedberg

Follicular lymphoma (FL) is the most common indolent non-Hodgkin lymphoma, with median age at diagnosis in the seventh decade. FL in young adults (YA), defined as diagnosis at≤40 years, is uncommon. No standard approaches exist guiding treatment of YA FL, and little is known about their disease characteristics and outcomes. To gain further insight into YA FL, we analyzed the National LymphoCare Study (NLCS) to describe characteristics, initial treatments, and outcomes in this population versus patients aged>40 years. Using the NLCS database, we stratified FL patients by age: 18-40 (YA), 41-60, 61-70, 71-80, and>80 years. Survival probability was estimated using Kaplan-Meier methodology. We examined associations between age and survival using hazard ratios and 95% confidence intervals (CI) from multivariable Cox models. Of 2652 eligible FL patients in the NLCS, 164 (6%) were YA. Of YA patients, 69% had advanced disease, 80% had low-grade histology, 50% had good-risk disease according to the Follicular Lymphoma International Prognostic Index (FLIPI). Nineteen percent underwent observation, 12% received rituximab monotherapy, 46% received chemo-immunotherapy (in 59% of these: R-CHOP [rituximab plus cyclophosphamide, doxorubicin, vincristine and prednisone]). With median follow-up of 8 years, overall survival (OS) at 2, 5, and 8 years was 98% (95% CI 93-99), 94% (95% CI 89-97), and 90% (95% CI 83-94), respectively. Median progression-free survival (PFS) was 7.3 years (95% CI 5.6-not reached). In one of the largest cohorts of YA FL patients treated in the rituximab era, disease characteristics and outcomes were similar to patients aged 41-60 years; with favorable OS and PFS in YA. Longer-term outcomes and YA-specific survivorship concerns should be considered when defining management. These data may not support the need for more aggressive therapies in YA FL.