Scientists find obese children diagnosed with cancer face worse health outcomes

Children with obesity who are diagnosed with cancer may have poorer health outcomes including a higher risk of death, according to a new study. 

Researchers from Canada analysed the data of more than 11,000 cancer patients aged between 2 and 19, of which 10.5 per cent were obese at the time of diagnosis.

The conditions ranged from leukaemia, a cancer of the bone marrow, and lymphoma, a group of blood cancers, to other tumours.

Obesity was linked to worse outcomes “across the entire cohort,” researchers said in their findings published in the journal Cancer.

Obese children had a 16 per cent increase in the risk of relapse and a 29 per cent increase in the risk of death after adjusting for factors such as age, sex or ethnicity.

Relapse and survival were calculated within five years of diagnosis.

“Our study highlights the negative impact of obesity among all types of childhood cancers. It provides the rationale to evaluate different strategies to mitigate the adverse risk of obesity on cancer outcomes in future trials,” Thai Hoa Tran, paediatric haematologist and oncologist at the University Hospital Centre Sainte-Justine in Montreal, Canada and one of the study’s authors, said in a statement.

“It also reinforces the urgent need to reduce the epidemic of childhood obesity as it can result in significant health consequences,” he added.

The impact of obesity on health outcomes was particularly strong for patients with acute lymphoblastic leukaemia, a type of cancer of the blood and bone marrow, and for those with brain tumours.

Previous studies have shown “that adipose [fat] tissue cells play an active role in promoting tumour development, metastases, or treatment resistance,” researchers wrote in their paper. 

They added that “potential undertreatment and inappropriate dosing of chemotherapeutic agents remain important concerns for obese patients”.

The study has some limitations including the use of body mass index (BMI) to determine excess weight and obesity. 

“BMI remains a crude and imperfect measure that does not accurately represent body composition, nutritional status, or nutritional intake,” the authors wrote.

This week, a group of researchers called for a new approach to diagnosing obesity, saying that relying on BMI means the condition is likely overdiagnosed.