L. Rigacci, B. Puccini, A. Broccoli, A. Evangelista, D. Gioia, M. Dona, S. Kovalchuk, A. Santoro, M. Bonfichi, A. Re, C. Pagani, L. Mannelli, F. Zaja, U. Vitolo, M. Spina, A. Pulsoni, L. Nassi, C. Stelitano, F. Salvi, C. Rusconi, M. Tani, R. Freilone, E. Borsatti, P. L. Zinzani
On behalf of Fondazione Italiana Linfomi
Purpose: The clinical impact of positron emission tomography (PET) performed early during therapy in patients with advanced-stage Hodgkin lymphoma has confirmed its impact in progression free survival. It is disappointing the observation of a group of patients with negative interim-PET (i-PET) but with a positive PET at the end of induction therapy (e-PET). These patients underline that i-PET is not a perfect instrument and it could be very important to analyze their clinical or biological characteristics to identify them.
Patients and Methods: The phase II part of the multicenter HD0801 study involved 519 patients with advanced-stage de novo Hodgkin lymphoma who received an initial treatment with ABVD and underwent a i-PET. Patients with positive i-PET shifted to a salvage therapy and those with negative i-PET continued with standard treatment. Patients with negative i-PET were evaluated for response and patients with a positive e-PET were moved to a salvage therapy. The aim of this study was to evaluate clinical and biological characteristics of these patients.
Results: In all 409 were i-PET negative. Among them 16 interrupted the therapy for different causes, therefore 393 patients were evaluated with e-PET, 354 were negative and 39 were positive. Sixteen out 39 were submitted to a diagnostic biopsy and 15 were confirmed as HD; 23 did not performed biopsy due to technical difficulties or decision of the clinicians. Seventeen out 39 e-PET were reviewed according Deauville Score and in sixteen it was confirmed positive (10 DS 5, 6 DS 4) in 1 case was unvaluable. With the exception of LDH value at diagnosis no clinical characteristics were significantly different in comparison with e-PET negative patients. The survival of e-PET positive patients was very disappointing 78% at 36 months in comparison either with negative e-PET or with positive i-PET.
Conclusion: Positive e-PET represents a very bad prognostic event even in comparison with i-PET positive patients salvaged with intensified therapy. We must consider carefully this little group of patients in which despite negative i-PET we observe an early progression. These group of patients do not have specific clinical characteristics at diagnosis, probably biological and pathological markers could be associated with i-PET to increase the predictive power and in particular to reduce the false negative or, finally, more sensitive PET evaluation with MTV and GTV evaluation could reduce the false negative i-PET.