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 55 years, range 25-69) were enrolled. With a median follow-up of 42·8 months (range 7·2-58·4), 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) = 2·6, 95% confidence interval (CI) = 1·02-6·65] 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 = 6·9, 95% CI = 2·35-20·6) and OS (95% vs. 33%, HR = 19·4, 95% CI = 3·89-97·0) 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.
Keywords: autologous stem cell transplantation; fluorodeoxyglucose positron emission tomography; lymphoma.
© 2014 John Wiley & Sons Ltd.