In Vivo Treatment Sensitivity Testing With Positron Emission Tomography/Computed Tomography After One Cycle of Chemotherapy for Hodgkin Lymphoma

Abstract

Purpose Negative [18F]fluorodeoxyglucose (FDG) –positron emission tomography (PET)/computed tomography (CT) after two cycles of chemotherapy indicates a favorable prognosis in Hodgkin lymphoma (HL). We hypothesized that the negative predictive value would be even higher in patients responding rapidly enough to be PET negative after one cycle. This prospective study aimed to assess the prognostic value of PET after one cycle of chemotherapy in HL and to assess the dynamics of FDG uptake after one cycle (PET1) and after two cycles (PET2). Patients and Methods All PET scans were read by two blinded, independent reviewers in different countries, according to the Deauville five-point scale. The main end point was progression-free survival (PFS) after 2 years. Results A total of 126 patients were included, and all had PET1; 89 patients had both PET1 and PET2. The prognostic value of PET1 was statistically significant with respect to both PFS and overall survival. Two-year PFS for PET1-negative and PET1-positive patients was 94.1% and 40.8%, respectively. Among those with both PET1 and PET2, 2-year PFS was 98.3% and 38.5% for PET1-negative and PET1-positive patients and 90.2% and 23.1% for PET2-negative and PET2-positive patients, respectively. No PET1-negative patient was PET2 positive. Conclusion PET after one cycle of chemotherapy is highly prognostic in HL. No other prognostic tool identifies a group of patients with HL with a more favorable outcome than those patients with a negative PET1. In the absence of precise pretherapeutic predictive markers, PET1 is the best method for response-adapted strategies designed to select patients for less intensive treatment.