Pre-transplant FDG-PET-based survival model in relapsed and refractory Hodgkin's lymphoma: outcome after high-dose chemotherapy and auto-SCT

Hodgkin's lymphoma (HL) patients with positive F-18-fluorodeoxyglucose positron emission tomography (FDG-PET) post salvage chemotherapy or before high-dose chemotherapy and auto-SCT (HDC ASCT) have inferior outcomes. We reviewed 21 prognostic factors before salvage chemotherapy (at relapse/progression) and integrated post salvage FDG-PET results to develop a prognostic model for post HDC ASCT outcome. We used Fine and Gray method for competing risk analysis and regression model for risks assessment and outcome. One hundred and forty-one patients had post salvage FDG-PET before HDC ASCT (median age 25.5 years); male/female 55%: 45%, relapsed/refractory 43%: 57%, median follow-up 33 months. Multivariate analysis identified HL International Prognostic Score >= 3 (P = 0.001; hazard ratio (HR): 3.7 (1.6-8.3)) and post salvage positive FDG-PET (P = 0.011; HR: 3.4 (1.3-8.9)) with higher hazard of disease-specific death (model P = 0.0001). Cumulative incidence of disease-specific death with 0, 1, 2 risk factors was 7%: 29%: 52%, respectively (P = 0.00003). For disease-specific event (persistent, progressive or relapsed disease), mediastinal involvement (P = 0.024; HR: 2.7 (1.14-6.5)), B symptoms (P = 0.027; HR: 2.1 (1.09-4.2)) and positive post salvage FDG-PET (P = 0.001; HR: 3.3 (1.7-6.7)) were significant (model P = <0.00001). Cumulative incidence of disease-specific event with 0, 1, 2, 3 risk factors was 8%:31%:50%:75%, respectively (P = 0.0000006). Patients with higher scores have higher risk of treatment failure. They are potential candidates for newer therapies along with HDC ASCT.