A recent population-based study has highlighted the potential risks associated with childhood obesity in cancer outcomes. Published in CANCER, a peer-reviewed journal of the American Cancer Society, the study examined data from the Cancer in Young People in Canada (CYP-C) database, which includes information on children aged 2 to 18 diagnosed with cancer in Canada between 2001 and 2020. Obesity was defined as a body mass index (BMI) at or above the 95th percentile adjusted for age and sex.
Out of 11,291 children with cancer, 10.5% were classified as obese at the time of diagnosis. The study focused on both event-free survival (EFS)—survival without cancer relapse—and overall survival (OS). Findings revealed that children with obesity at diagnosis had poorer outcomes compared to those with a healthy weight. Specifically, those with obesity had lower 5-year EFS (77.5% vs. 79.6%) and OS (83.0% vs. 85.9%).
After adjusting for various factors such as age, sex, ethnicity, neighborhood income, treatment era, and cancer types, obesity was found to be associated with a 16% higher risk of cancer relapse and a 29% greater risk of death. The effect was especially significant in children with acute lymphoblastic leukemia (ALL) and brain tumors.
The study underscores the impact of obesity on the prognosis of childhood cancer and stresses the importance of addressing childhood obesity to reduce future health risks. “Our research highlights the urgent need to explore strategies to counteract the adverse effects of obesity on cancer outcomes,” said Dr. Thai Hoa Tran, a co-senior author from the Centre Hospitalier Universitaire Sainte-Justine in Montreal. He also noted the broader health risks associated with childhood obesity, including diabetes, sleep apnea, and hypertension.
While obesity’s impact on childhood cancer prognosis has been recognized, the specific mechanisms remain unclear, and past studies have been inconsistent due to variations in cancer types and research methodologies. This study aimed to provide a clearer understanding by using a comprehensive, population-based dataset.
The cohort of 11,291 patients included those diagnosed between the ages of 2 and 17, with a median age of 7.6 years. Cancer types were categorized as leukemia (37.1%), lymphoma (14.5%), central nervous system (CNS) tumors (21.8%), and non-CNS solid tumors (26.6%). Of the 10.5% obese patients, obesity prevalence varied by cancer type, with leukemia patients showing the highest rate at 11.3%, followed by lymphoma at 11.4%, CNS tumors at 9.7%, and non-CNS solid tumors at 9.4%.
The study found that patients with obesity at diagnosis were older than their non-obese counterparts, with a median age of 8.6 years versus 7.5 years. The analysis also revealed that obesity significantly affected EFS and OS, especially for ALL and CNS tumor patients. In those with ALL, obesity was linked to lower 5-year EFS (84.5% vs. 89.8%) and OS (89.8% vs. 94.4%). Similarly, in CNS tumor patients, obesity was associated with reduced 5-year EFS (68.1% vs. 74.2%) and OS (73.1% vs. 79.3%).
Despite the study’s valuable insights, the researchers acknowledged some limitations, such as the exclusion of 13.6% of the cohort due to missing weight and height data. These gaps could introduce selection bias, but the study’s findings still suggest areas for further exploration.
The authors concluded that more research is needed to understand the biological mechanisms behind obesity’s impact on pediatric cancer survival. They also emphasized the importance of investigating whether weight normalization during treatment could improve cancer outcomes, which could inform future clinical trials and supportive care strategies.
