The impact of histologic grade on the outcome of high-dose therapy and autologous stem cell transplantation for follicular lymphoma

The impact of the follicular lymphoma (FL) histologic grade on outcomes after high-dose therapy (HDT) and autologous stem cell transplantation (ASCT) is unknown. We evaluated 219 consecutive patients with grades 1-3 FL who underwent HDT and ASCT at our center. Overall survival (OS), progression-free survival (PFS), relapse and non-relapse mortality (NRM) was estimated for each grade after controlling for other predictive factors. The number of patients with grades 1, 2 and 3 FL was 106 (48%), 75 (34%) and 38 (17%), respectively. Five-year outcome estimates for the entire cohort included 60% OS, 39% PFS and 46% relapse (median follow-up = 7.8 years). PFS and relapse were nearly identical among patients with grade 3 FL versus grades 1-2 FL after adjusting for other contributing factors (hazard ratio (HR) = 0.90, P = 0.68; HR = 1.07, P = 0.80, respectively). The hazard for mortality (HR = 0.70, P = 0.23) and NRM (HR = 0.33, P = 0.07) was non-significantly lower among patients with grade 3 FL compared to patients with grades 1-2 disease. Factors associated with inferior PFS included elevated lactate dehydrogenase (HR = 1.52, P = 0.03), chemoresistance (HR =1.82, P = 0.02), ≥2 prior therapies (HR = 1.8, P = 0.03) and prior radiation (HR = 1.99, P = 0.003). These data suggest that the histologic grade of FL does not impact PFS or relapse following HDT and ASCT.