Methods
This retrospective cohort study evaluated pediatrics patients diagnosed with HL, ages 4-20 years old at diagnosis, between 1999 and 2018 at Children’s Hospital Los Angeles (CHLA). Patients were identified by reviewing an already-existing database of patients maintained for the purposes of providing direct patient care. All patients who received ABVD and/or ABVE-PC as initial treatment for newly diagnosed HL were included. Patients were excluded due to either receiving a different therapy (e.g. bleomycin, etoposide, doxorubicin, cyclophosphamide, vincristine, procarbazine and prednisone {BEACOPP}), incomplete therapy, receiving therapy at an outside institution of CHLA with incomplete data including pathology reports, treatment documentation and disease response evaluations.
Demographic information collected included: age at diagnosis as well as self-reported gender, race, and ethnicity. Prognostic variables abstracted from the medical record included Ann Arbor staging, presence of B-symptoms (unexplained weight loss > 10% in the preceding 6 months, unexplained recurrent fever ≥ 38°C in the preceding month or recurrent drenching sweats in the preceding month), presence of splenic involvement, presence of extra-nodal disease, erythrocyte sedimentation rate at diagnosis, peripheral blood leukocyte count at diagnosis, and hemoglobin concentration at diagnosis. All chemotherapy regimens, including changes and deviations, were recorded. Results of positron emission tomography/computed tomography (PET/CT) were recorded where available. Total anthracycline doses were recorded in doxorubicin-equivalent units and reported as mg/m2. Echocardiogram and pulmonary function testing results were recorded where available. OS was defined as the time from diagnosis to death of any cause. EFS was defined as the time from diagnosis to death, relapse/progression of disease, or diagnosis of a secondary malignancy.
Descriptive analyses were performed using the Student’s t-test or Fisher’s exact test for continuous or dichotomous variables, respectively. Survival analysis was performed using the Kaplan-Meier life table method. All analyses followed an intention-to-treat principle, guided by the initial therapy chosen. Late effects were analyzed and including secondary malignancy, pulmonary toxicity and cardiomyopathy determined by shortening fraction <29%. We assessed treatment response from the available radiology reports, which included CT and PET/CT. Disease response was assessed by change in maximum SUV, change in the size of lymph nodes, and, if available, the Deauville score. All analyses were carried out on the R Project for Statistical Computing version 3.
All study protocols were carried out under supervision of the IRB and in compliance with the Declaration of Helsinki.