Prognostic Role of PET-FDG Before Autologous Stem Cell Transplantation in Advanced Hodgkin's Lymphoma.

Abstract 1548

Poster Board I-571

PET-FDG (PET) has assumed in recent years a relevant role in the management of patients with Hodgkin Lymphoma (HL). In advanced stage HL, PET performed after two courses of ABVD chemotherapy has demonstrated a very high negative predictive value (NPV) and positive predictive value (PPV), and is presently considered the most relevant available prognostic factor in correlation with outcome.

The aim of our study was to investigate the prognostic role of PET performed before autologous stem cell transplantation (ASCT) in resistant or relapsed HL.

From June 2002 to December 2008, 32 patients with resistant or relapsed HL underwent a salvage chemotherapy program consisting of 3 or 4 courses of IEV or IGEV chemotherapy with peripheral blood stem cell collection followed by BEAM conditioned ASCT. Eight patients were consolidated with the BEACOPP regimen (2 to 4 courses) before transplantation. Median age was 30.4 years (range 21.6 – 61.4); 19 were males. At the time of enrolment, B symptoms were present in 4 patients and bulky and/or extranodal disease was recorded in 7 patients; the International Prognostic Score (IPS) was ≥2 in 15 patients. Sixteen patients were resistant to first-line chemotherapy, 13 were in first relapse (in 6 cases occurred earlier than 12 months), 3 were in second or subsequent relapse.

Pre-transplant PET evaluation was negative in 21 cases: of these, 16 are currently in continuous complete remission (CCR) after a median follow-up of 30 months (range 7.0 – 59.0), while 5 have relapsed after a median of 10 months from transplant (range 3.0 – 11.0). Among the 11 patients autografted after a positive PET, 9 have relapsed after a median of 8.3 months (range 3.3 – 18.6). In the figure is shown the progression free survival of the patients stratified by pre-transplant PET. On the entire population the negative predictive value (NPV) of pre-transplant PET was 76.2%, while the positive predictive value (PPV) was 81.8%. Analyzing separately patients enrolled with a primary resistant disease, the NPV was 62.5% and the PPV was 75.0%. In the group of patients enrolled in relapse NPV was 84.6% and PPV was 100%. The prognostic value of the following parameters at the time of enrolment was evaluated: presence of bulky and/or extranodal disease, number of previous chemotherapy lines, chemoresistance/chemosensitivity to pre-transplant therapy evaluated by CT scan: no statistically significant correlation with the outcome was recorded.

In conclusion, our preliminary results show a relevant prognostic role of pre-transplant PET in patients with advanced phase HL: 76% of patients with a negative pre-transplant PET obtained a CCR compared to only 18% of those with a positive pre-transplant PET (p = 0.003). The predictive role of pre-transplant PET is superior in patients undergoing the transplant program for a relapsed disease with respect to those with a primary resistant disease. Other prognostic factors need to be considered, although none of those so far examined showed a statistically significant role. These data need to be conclusively confirmed on a larger number of patients and a longer follow-up.