Clinical characteristics and prognostic factors of primary extranodal classical Hodgkin lymphoma: a retrospective study.

To analyze the clinical characteristics and prognosis of primary extranodal classical Hodgkin lymphoma (PE-cHL). Clinical features and outcomes of 22 PE-cHL patients who received initial chemotherapy January 2008 to January 2018 were analyzed retrospectively, and compared with 274 primary nodal Hodgkin lymphoma (PN-cHL) patients treated in the same period. With a median follow-up period of 42 months, compared with 274 PN-cHL patients, no significant difference of overall response rate (ORR) or complete remission (CR) rate was found, but the PE-cHL patients showed a higher recurrence rate (36.4% vs. 13.1%, p = .003) and poorer survival [(5-year overall survival (OS) rate: 64.6% vs. 97.7%, p = .001; 5-year progression-free survival (PFS) rate: 42.4% vs. 82.2%, p < .001)]. To minimize the effects of confounding factors, PE-cHL patients were matched with PN-cHL patients at a ratio of 1:1 according to age, gender, histological types and stage. Compared with 22 matched PN-cHL cases, PE-cHL was still associated with poor PFS (5-year PFS: 42.4% vs. 79.9%, p = .004). As to 22 PE-cHL patients, univariate analysis showed elevated serum lactate dehydrogenase (LDH) and elevated platelet (PLT) were associated with poor PFS (p < .05). Compared with PN-cHLs, PE-cHLs showed a considerable shorter duration of remission, higher recurrence tendency and poorer survival, indicating that more intensive therapy may be needed. The prognosis of PE-cHL is unfavorable. Elevated LDH and PLT are poor prognostic factors for PE-cHL.