Predictive role of Early Interim FDG-PET in Hodgkin Lymphoma.

Hodgkin lymphoma (HL) is a curable malignancy with a long-term survival of around 80%. FDG-PET is a noninvasive imaging modality widely used in lymphoma patients. Early PET assessment of response to therapy is a routine part of management in HL patients, and an independent, strong predictor of progression-free survival.

178 patients, with a diagnosis of HL, underwent to an early PET evaluation during their course of chemotherapy and were considered eligible for the study. 85 patients (48%) were male and 93 (52%) female; the median age at diagnosis was 33 (13-78) years. 6 patients (3%) had stage I disease; 106 patients (60%) stage II; 34 (19%) stage III and 32 (18%) stage IV (bone marrow involvement in 5 cases).

B-symptoms were detected in 81 patients (46%). A mediastinal bulk was detected in 54 cases (30%). The majority of patients (173, 97%) underwent to ABVD as first line therapy; 5 received BEACOPP chemotherapy (3%). Early PET evaluation was performed after the second course of therapy. Results were classified into complete response (CR), partial response (PR), stable disease (SD) or progressive disease (PD) according to International Workshop standardized response criteria. PET scan was performed again at the end of the first-line treatment. 44 patients have been addressed to a second-line therapy, in presence of PR, PD or relapsing disease; in particular, 39 patients received an autologous stem-cells transplantation (ASCT), and 3 an allogeneic bone marrow transplantation (ABMT).

At a median follow up of 41,85 (5,23-141,77) months, 152 patients are alive and in CR; 7 in PR; 3 alive with SD and 7 present a PD. 9 patients have died. 150 patients presented with a negative PET after 2 cycles, and 28 with a positive one (26 in PR, 1 with SD and 1 with PD). More specifically, of the 178 initial patients, 150 (84%) had a negative early PET and 28 (16%) a positive early PET. Of those with a negative PET, 135 (90%) experienced a continuous CR, while among those with a positive early PET, none obtained at least a stable CR. Of this unfavourable group of patients, 9 (32%) reached, and still maintain, a CR after ASCT.

Our experience indeed confirms the highly predictive value of a negative early PET during the therapy for HL. Moreover we may suggest the potential role of ASCT in inducing a CR in around one-third of those unfavorable patients with a positive early interim PET.

No relevant conflicts of interest to declare.