Impact of Risk Factors and Long Term Survival Analysis of Patients With Primary Refractory Hodgkin Lymphoma Who Underwent High Dose Chemotherapy and Autologous Stem Cell Transplant

Abstract

Patients with primary refractory Hodgkin lymphoma (ref-HL) can still be salvaged with high-dose chemotherapy (HDC) and autologous stem cell transplantation (auto-SCT). Outcomes of patients with ref-HL is poorer than those with relapsed HL, but most studies have included patients with both relapsed and refractory diseases, and separate analyses or studies on patients with ref-HL are limited. This study aimed to evaluate the outcomes of HDC auto-SCT and impact of various prognostic factors in patients with ref-HL at the time of primary treatment failure and subsequent survival at the time of failure post-HDC auto-SCT. This retrospective single-institution cohort analysis using an HDC and auto-SCT database was approved by the Institutional Research Advisory Counsel and Ethics Committee for identifying patients. We used the Fine and Gray competing risk analysis method, a regression model for outcome analysis, and the Kaplan-Meier (KM) method for survival analysis. The study cohort comprised 200 consecutive ref-HL patients who underwent HDC auto-SCT between 1996 and 2019. The median patient age was 22.75 years, and median follow-up was 106 months. Post-auto-SCT disease status was complete remission (CR) in 122 patients (61%), partial remission in 22 (11%), and progressive disease in 47 (23.5%). KM median progression-free survival (PFS) after auto-SCT was 43.9 months (5 years, 49.3%; 10 years, 45.5%). Median overall survival (OS) was 168.6 months (5 years, 61.2%: 10 years, 56.2%). Eighty-five patients (44.5%) died, 69 (34.5%) due to disease. Multivariate analysis identified similar adverse factors for both PFS and OS. For PFS, these adverse factors included stage III-IV at relapse (hazard ratio [HR], 1.65; P = .045), mediastinal involvement (HR, 2.01; P = .009), and absence of CR after salvage chemotherapy (HR, 2.2; P = .001). PFS with 0 or 1 adverse factors (not reached), 2 adverse factors (40.8 months), and 3 adverse factors (5.4 months) was significant (P < .001). For OS, significant adverse factors included stage III-IV at relapse (HR, 1.68; P = .045), mediastinal involvement (HR, 2.52; P = .007), and no CR after salvage chemotherapy (HR, 2.15; P = .004) were significant. OS with 0 or 1 adverse factors (not reached), 2 adverse factors (148.5 months), and 3 adverse factors (34.4 months) was significant (P < .001). The median OS after auto-SCT failure was 23.6 months; patients received post auto-SCT brentuximab/second SCT (not reached), other treatments (22.5 months), and supportive care (8.4 months) (P < .001). OS with 5 risk factors present at HDC auto-SCT failure- stage III-IV, failure at <12 months, tumor >5 cm, B symptoms, and low serum albumin-was 152 months for 0 or 1 risk factors, 30.9 months with 2 risk factors, and 9.45 months with 3 to 5 risk factors (P < .001). Ref-HL patients have encouraging survival after HDC auto-SCT and can even be salvaged after auto-SCT failure. Based on prognostic factors, survival prediction is possible. Patients who fail to respond to HDC auto-SCT may benefit from newer treatments strategies and may qualify for enrollment in clinical trials.

Keywords: Adolescent and young adults; Autologous stem cell transplantation; Hodgkin lymphoma; Prognostic model; Refractory Hodgkin lymphoma.