Positron emission tomography with 2-[18F]-fluoro-2-desoxy-D-glucose after two cycles of R-CHOP predicts event free survival in diffuse large B-cell lymphoma: Partial results from multi-center IAEA-sponsored study

Objectives To assess the prognostic value of interim FDG-PET after two cycles of chemotherapy using R-CHOP in overall patients with Diffuse Large B-Cell Lymphoma. (DLBCL).

Methods A total of 73 patients with newly diagnosed DLBCL were prospectively included in this multicenter study including patients from Brazil and Chile. All submitted to standard R-CHOP therapy followed by consolidation radiotherapy in case of bulky disease. After two cycles of R-CHOP patients were evaluated with interim PET (PET2). Prognostic analysis compared three-year event free survival (EFS) rate to PET2 results, clinical data and R-International Prognostic index (RIPI).

Results Of the 73 evaluated patients, 61 achieved complete remission after first-line therapy. In a median follow-up of 9.2 (±5.7) months, death, relapse or disease progression was seen in 16 patients. Treatment failure was seen in eight of the 16 PET2-positve patients and in only 8 of the 57 PET2-negative patients. PET2 was the only significant prognostic factor in univariate analysis. Eighteen months EFS for PET2-positive patients was 19.8% and 70.4% for PET2-negative ones (P: 0.002). When patients were divided in low and high IPS risk and early and advanced stage disease, PET2 was also significantly associated with treatment outcome.

Conclusions PET2 is an accurate and independent predictor of EFS in DLBC. A negative interim FDG-PET is highly predictive of treatment success in overall DLBC patients independent of RIPI risk.

Research Support The International Atomic Energy Agency (IAEA) sponsored and coordinated the study