Pretransplatation PET as Major Prognostic Discriminant in IGEV (ifosfamide, gemcitabine, vinorelbine and prednisone) Treated Patients with Relapsed/Refractory Hodgkin's Lymphoma (HL).

response to salvage chemotherapy prior to high–dose therapy (HDT) is of major prognostic concern in relapsed/refractory HL. FDG-PET is able to distinguish between persistent disease and fibrosis/necrosis and has thus become the mainstay to define clinical response in this setting (Cheson et al, JCO 2007). The value of FDG-PET in this subset of patient is less well established. IGEV chemotherapy has shown very encouraging results as induction therapy in refractory/relapsed HL (Santoro et al, Haematologica 2007).

to retrospectively evaluate the predictive value of PET in pts with relapsed/refractory HL receiving IGEV and HDT.

seventy-two multicentric cases with refractory/relapsed HL who had completed IGEV x 4 courses and HDT between 01/98 and 05/07 were reviewed. FDG-PET evaluation was performed before HDT and, according to revised Cheson criteria, complete remission (CR) was defined as negative FDG-PET, independently from the presence of residual masses at CT scan.

Univariate analysis was performed considering FDG-PET as well as other usually evaluated prognostic factors.

patient characteristics: M/F 30/42, median age 33 (range 16-71), Nodular sclerosis 61 (85%), refractory 28 (39%), relapsed 44 (61%), one previous regimen 60 (83%), B symptoms 18 (25%), bulky disease 7 (10%), extranodal disease 32 (44%), previous radiotherapy 39 (54%). After induction, 36 pts (50%) received single (with BEAM as conditioning regimen ), and 36 (50%) tandem HDT (with melphalan as first and BEAM as second conditioning). After IGEV, on the basis of PET 47 pts (65%) were classified as complete remission (CR), 21 (29%) as partial remission (PR) and 4 (6%) did not respond.

Ten of the 47 PET negative pts, and 18 of the 25 PET positive pts relapsed. With a median follow up 48 months, the 3-year PFS was 80% vs 25% for patient with negative vs positive PET respectively (HR 5.7 no CR vs CR - CI 95%: 2.6-12.4). The 3-year overall survival (OS) was 91% vs 56 % for patient with negative vs positive PET respectively (HR 7.8 no CR vs CR CI 95%: 2.6-23.7).

In univariate analysis, factors influencing the probability of achieving CR to IGEV were disease status (refractory vs relapse) (p.096) and bulky disease at IGEV (p .088). Factor significantly associated with PFS and OS are reported in table.

In multivariate analysis only response to therapy, as defined by pre-transplant PET result, maintained significance as prognostic indicator for both PFS (HR 5.7) and OS (HR 7.8).

these data in homogeneously treated pts with refractory/relapsed HL underline the crucial prognostic relevance of pre-transplant FDG-PET, even overwhelming the impact of disease status at progression. FDG-PET driven trials are highly recommended in this subset of patients.

No relevant conflicts of interest to declare.