The Role of Bone Marrow Examination in the Initial Evaluation of Pediatric Hodgkin’ Disease: The Canadian Perspective.
Authors: Simpson David C. , Gao Jun , Fernandez Conrad V. , Yhap Margaret , Price Victoria E. , Berman Jason N. 
Published: April 2020

Abstract
Hodgkin’s Disease (HD) is the most common lymphoma affecting young adults and teenagers. Bone marrow involvement is rare but if present, infers Stage IV disease and an inferior outcome. Adult studies have suggested that bone marrow examination (BME) may not be necessary unless certain risk factors are present. However, some pediatric centers continue to perform BME routinely on all children with HD. BME is invasive and generally performed under conscious sedation in children. We validated and administered an internet-based survey to examine the practice of all Canadian pediatric oncologists regarding BME in children with HD. We also retrospectively evaluated the impact of routine BME on the HD patients treated at our institution over the past 27 years. Forty-three percent of eligible physicians (n=93) completed the survey and 16 of a total of 17 Canadian pediatric oncology centers were represented. BME universally consisted of bilateral bone marrow aspirates and trephine biopsies. Routine BME for Stage III and IV disease was consistently practised nationally (by 92% and 97% of respondents, respectively). By contrast, 54% and 70% of respondents reported performing routine BME in low stage (Stage I and II) disease, respectively. Respondents were more likely to report performing routine BME in low stage patients, if their pediatric hematology/oncology training was entirely outside Canada (p=0.04 for Stage I and p=0.07 for Stage II) and if they practiced at smaller centers (p=0.05 for Stage I and p=0.03 for Stage II). There were no differences in practice regarding BME associated with the number of years in practice or the number of patients seen annually by the respondent. If not part of routine staging for all patients, BME was more likely performed if there were “B” symptoms, cytopenias, and/or bulky disease. Most respondents (95%) would proceed with BME following a positive PET scan. In the review of local institutional practice, 62 patients with HD and BME were eligible for analysis. Only 4 patients (6.5%) had a positive BME. No patient with otherwise low stage disease was found to have bone marrow involvement. Two patients, who would have been assigned as Stage III disease, were upstaged to Stage IV due to their BME. Comparison of staging with and without BME demonstrated no significant difference. Hemoglobin level was found to be the to be the only significant risk factor for marrow involvement based on univariate analysis(put in statisticp=0.006). Age, gender, histologic subtype, presence of “B” symptoms, and other blood parameters (white count, platelets, ESR and transaminases) were not significant factors. Practice regarding BME in children with low stage HD is highly variable across Canada. Bone marrow examination in pediatric patients with low stage HD should be abandoned, unless there is a specific indication to do so (for example positive PET scan or unexplained anemia). Moreover, BME does not appear to add any additional therapeutic direction for higher stage patients.