Classic Hodgkin lymphoma in Guatemalan children of age less than six years: analysis of immune regulatory pathways and the tumor microenvironment.

Classic Hodgkin lymphoma (cHL) in young children (ages 0-6) is rare in high income countries (HICs) but is more prevalent in low- and middle-income countries (LMICs) like Guatemala. Given that the majority of cHL studies have evaluated adolescent/adults, and the immune system changes with age, we sought to characterize Epstein-Barr virus (EBV) expression, immune regulatory pathway markers and the tumor microenvironment in 42 children ages 0-6 with cHL from Guatemala. We found a very high frequency of EBV expression (97.5%). Hodgkin cells showed increased expression of PD1 ligands and CD137, indicative of shared immune regulatory mechanisms with adult cHL. Pediatric cHL also showed an increase in CD8+ tumor infiltrating lymphocytes and tumor associated macrophages within the tumor microenvironment. Despite 25 having high risk disease, only 4 patients died from progressive disease, relapse or infection.

A chemotherapy only therapeutic approach to pediatric Hodgkin lymphoma: AHOPCA LH 1999.

BACKGROUND: AHOPCA is a collaborative group that designs uniform treatment regimens (protocols) for children diagnosed with cancer in Central America. Based on a preliminary report from one of the AHOPCA centers, AHOPCA adopted a treatment regimen to maintain a good event-free survival (EFS) as well as eliminate radiation therapy from the treatment of children with Hodgkin lymphoma. PROCEDURE: Newly diagnosed patients with histologically proven Hodgkin lymphoma were staged according to the Ann Arbor classification and divided into favorable (stage I, stage IIA, and IIIA) and unfavorable (stage IIB, IIIB, and IV) groups. Subjects classified as group 1 (favorable) were treated with six 28-day cycles of chemotherapy (COPP/COPP ± ABV). Subjects classified as group 2 (unfavorable) were treated with eight 28-day cycles of COPP/ABV chemotherapy. RESULTS: Of 269 patients registered, 216 were eligible for evaluation. The mean age at diagnosis was 7.5 years with a male to female ratio of 3.7-1. The predominant histology was nodular sclerosis (44%) but with a relatively high proportion of mixed cellularity (35.2%) The EFS at 5 and 10 years was 71% and 68%, respectively. There was a 14% rate of abandonment of therapy. CONCLUSION: This treatment regimen for children with Hodgkin lymphoma, when applied as a multi-institutional regimen, had poorer outcome than our previously reported preliminary data and was inferior to the EFS reported in high-income countries. The major contributor adversely affecting EFS in this report is abandonment of therapy. Given these results, AHOPCA initiated a concerted effort to decrease abandonment of therapy.