Combined prognostic role of TARC and interim 18F-FDG PET/CT in patients with Hodgkin lymphoma-real world observational study

OBJECTIVEAlthough the majority of patients with Hodgkin lymphoma (HL) has recently become long-term survivors, 20%-30% of HL patients have primary refractory disease or relapse. It is essential to identify patients at risk of treatment failure during first-line therapy. To objective of the present study was to investigate the combined prognostic role of fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) imaging and thymus and activation-regulated chemokine (TARC) levels in Hodgkin lymphoma. SUBJECTS AND METHODSBetween 01/01/2013 and 01/03/2019 77 HL patients were enrolled in this study where serum TARC levels were measured by an immunoassay and 18F-FDG PET/CT scans were performed at baseline, after the second cycle of ABVD treatment (interim) and at the end of first-line therapy. RESULTSTwenty-six patients (34%) had early-stage HL, while 51 patients presented with advanced-stage disease. Fifteen patients had primary refractory HL, while 1 patient relapsed after first-line therapy. Optimal TARC cut-off value for progression-free survival (PFS) was 700pg/mL based on receiver operating characteristic (ROC) curve analysis. With Cox regression analysis, 18F-FDG PET/CT with Deauville scores of 3, 4, or 5 and TARC levels above 700pg/mL predicted treatment failure at interim assessment. Inclusion of HL patients with a Deauville score of 3 to the high-risk population resulted in a 7-fold increase in the estimated risk of relapse compared to patients with Deauville score 4-5 with TARC levels above 700pg/mL. Patients with interim 18F-FDG PET/CT Deauville scores 3-5 had a significant survival benefit if their TARC levels were 700pg/mL. Positive predictive value (PPV) of interim 18F-FDG PET/CT scans with a Deauville score 3-5 was 47.8%, while combined PPV of a similar 18F-FDGPET/CT assessment and elevated TARC levels was 88.8%. CONCLUSIONInterim 18F-FDG PET/CT and TARC analyzed together accurately identify HL patients who do not respond sufficiently to treatment and who need an early change of therapy.