Prognostic value of interim FDG-PET after two or three cycles of chemotherapy in Hodgkin lymphoma

Background: Long-term survival from Hodgkin lymphoma (HL) is 80-90%, but the treatment has serious late adverse effects. Modern risk-adapted treatment requires accurate assessment of the patient's prognosis. This investigation assessed the value of positron emission tomography (PET) with 2-[F-18]fluoro-2-deoxy-D-glucose (FDG-PET) after two or three cycles of chemotherapy for prediction of progression-free survival (PFS) and overall survival (OS). Patients and methods: A total of 85 patients with HL underwent FDG-PET after two or three cycles of chemotherapy. Median follow-up was 3.3 years. FDG-PET results were related to PFS and OS using Kaplan-Meier analysis. Regression analyses were employed to test for independence of established pretreatment prognostic factors. Results: After two or three cycles of chemotherapy, 63 patients had negative FDG-PET scans, nine patients had minimal residual uptake (MRU) and 13 patients had positive scans. Three PET-negative patients and one patient from the MRU group relapsed. In the PET-positive group, nine patients progressed and two died. Survival analyses showed highly significant associations between early interim FDG-PET and PFS (P < 0.0007) and OS (P < 0.03). All advanced-stage patients with positive interim FDG-PET relapsed within 2 years. Conclusion: Early interim FDG-PET is an accurate and independent predictor of PFS and OS in HL. A positive interim FDG-PET is highly predictive of relapse in advanced-stage disease.