Infradiaphragmatic versus supradiaphragmatic Hodgkin lymphoma: a retrospective review of 1,114 patients.

Infradiaphragmatic Hodgkin lymphoma (IDH) accounts for 4-13% of cases of stage I-II Hodgkin lymphoma (HD). It has been associated with distinct pre-treatment characteristics and outcomes when compared with supradiaphragmatic HD (SDH). The comparison of IDH vs SDH can only be made in early and intermediate stages (I-II), such a comparison is not possible for advanced stages (III-IV). This study retrospectively compared two groups of 1013 patients with stage I-II SDH and 101 patients with IDH (10%). These two sub-groups of patients were treated in 1988-1993 in 2 prospective randomized clinical trials in Germany for early and intermediate stages of Hodgkin lymphoma. IDH-patients were older (median 39 vs 31 years; p < 0.001), predominantly male (73% vs 52%; p < 0.001) and more often had involvement of 3 lymph node areas (LNA) (80% vs 55%; p < 0.001). Histology in IDH was more likely to be mixed cellularity (46.5% vs 23.6%, p < 0.001) or lymphocyte predominant (20 vs 10%, p = 0.003) and less likely nodular sclerosis (25% vs 63%, p < 0.001). In early-stage unfavorable disease, IDH was associated with a higher treatment failure rate (unadjusted hazard ratio 2, 95% CI, 1.3-3.4; p = 0.003). After controlling for age, sex, stage, histology, B-symptoms and involvement of 3 LNA, the adjusted hazard ratio was 1.25 (95% CI, 0.65-2.4; p = 0.51) so that IDH was no longer associated with a statistically significant treatment failure rate. Poorer outcomes with IDH as compared to SDH are attributable to its association with known adverse prognostic risk factors, but IDH, in itself, is not an independent adverse prognostic factor for treatment failure or survival.