Intensification treatment based on early FDG-PET in patients with high-risk diffuse large B-cell lymphoma: a phase II GELTAMO trial.

We conducted a multicentre, phase II study of interim positron emission tomography (PET) as a guide to risk-adapted therapy in high-risk patients with newly diagnosed diffuse large B-cell lymphoma (DLBCL). Patients achieving negative fluorodeoxyglucose (FDG)-PET after three courses of R-MegaCHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, prednisone) received three additional courses, whereas PET-positive patients received two courses of R-IFE (rituximab, ifosfamide, etoposide) followed by BEAM (BCNU, etoposide, cytarabine, melphalan) and autologous stem-cell transplantation. The primary endpoint was progression-free survival (PFS). 71 patients (median age 55years, range 25-69) were enrolled. With a median follow-up of 428months (range 72-584), the estimated 4-year PFS and overall survival (OS) were 67% and 78%, respectively, for the global series. Patients in complete remission after interim PET (N=36) had significantly better 3-year PFS than those with partial response (N=30) [81% vs. 57%, Hazard ratio (HR)=26, 95% confidence interval (CI)=102-665] but not a statistically significant longer OS. A retrospective PET central review was done for 51 patients. According to semiquantitative analysis, 3-year PFS (81% vs. 33%; HR=69, 95% CI=235-206) and OS (95% vs. 33%, HR=194, 95% CI=389-970) were significantly better for negative than for positive interim PET patients. Early PET assessment is valuable for risk stratification in DLBCL; for this purpose semiquantitative evaluation is a better predictor than visual criteria.