Introduction Infradiaphragmatic Hodgkin Lymphoma (IDHL) accounts for 3-11% of adult cases of stage I-II Hodgkin Lymphoma. While the treatment strategy of most clinical subsets of HL has been improved and standardized along the last decades, it remains more heterogeneous in IDHL. Moreover, previous studies considered IDHL, patients on the basis of CT-scan staging which could underestimated advanced disease compared to the more sensitive PET-CT staging currently widely available. Thus, this study aimed to evaluate the characteristics of PET-staged IDHL patients compared to patients with an IDHL disease defined on the basis of CT scan assessment, and to analyse the outcome of patients with PET-defined disease.
Methods The baseline clinical, biological data, and the outcome of patients with a first diagnosis of stage I-II of IDHL treated with ABVD +/- radiotherapy were retrospectively collected in 8 french departments of hematology. Patients with a positive HIV serology and those treated with radiotherapy alone were excluded. .
Results From 1986 to 2014, 99 patients were included whose 65 (66%) of them were staged with PET-CT. PET-CT staged patients were older (53 years vs 47 years, p=0.043), had lower ESR (27 vs 58 mm, p= 0.022), higher haemoglobin level (13.6 vs 12.8g/dL, p=0.015), less frequent Ann Arbor stage II (74% vs 91%) and less frequently central adenopathy involvement (60% vs 80%, p=0.024). The median follow-up of 99 patients was 3.8 years. For the PET-CT staged patients, at five years, PFS was 78% (IC95% 0.64-0.87) and OS was 88% (IC95% 0.73-0.95). Thirteen relapses occurred (20%) whose eleven (16%) within the five-years after diagnosis, and five patients died (8%), 3 from HL progression and 2 from toxicity of chemotherapy. In univariate analysis, patients with crural adenopathy involvement and treated with chemotherapy alone (p=0.026) had a poorer PFS. The treatment modality retained significance (p=0.036) in the modelisation analysis and also performans status (0.045) and crural involvement (0.005).
Conclusion This multicenter study of IDHL shows that CT-scan defined IDHL patients have more unfavorable characteristics than PET-CT staged patients which might be related in some cases to more advanced diseases specifically in younger patients. So, PET-CT is required for better defining IDHL diseases. The present study suggests that chemo-radiotherapy combined modality provides a better PFS than chemotherapy alone in these patients.