Infradiaphragmatic Hodgkin lymphoma: a large series of patients staged with PET-CT

Infradiaphragmatic Hodgkin Lymphoma (IDHL) accounts for 3-11% of adult cases of stage I-II Hodgkin Lymphoma and the treatment strategy in IDHL is still heterogeneous. All previous published studies were conducted before the PET-CT era. PET may provide a more accurate evaluation of IDHL stage. The aim of this study was to analyze the clinical and biological characteristics of IDHL patients staged by CT scan or PET-CT in eight French hematology departments and their impact on outcomes in these patients. Baseline clinical and biological data and outcomes in patients with a first diagnosis of stage I-II IDHL treated with ABVD +/- radiotherapy were retrospectively collected. Among the 99 patients included, 65 (66%) were staged with PET-CT. These patients were older (53 years vs 46 years, p=0.043), had lower ESR (27 vs 58mm, p=0.022), higher hemoglobin level (13.6 vs 12.8g/dL, p=0.015), less frequent Ann Arbor stage II (74% vs 91%) and less central adenopathy involvement (60% vs 82%, p=0.024). Treatment was chemotherapy alone in 55% of patients and the remaining patients received chemo-radiotherapy (CRT). Five-year PFS and OS rates in PET-CT-staged patients were 78% (95% CI 64-87) and 88% (95% CI 73-95), respectively, compared with 65% (p=0.225) and 82% (p=0.352) in CT-staged patients. The CRT strategy was associated with fewer relapses (p=0.027). This study showed that the characteristics of CT-staged IDHL patients were less favorable than those of PET-CT-staged patients and indicated that CRT provided better PFS than did chemotherapy alone.