Leukaemia remains the most common cancer among children, with those younger than five at the greatest risk of the blood disorder, says the South African National Cancer Registry.

In its first report on childhood cancers in SA, the registry showed that about 1,000 children are diagnosed with cancer each year, with more boys affected than girls.

The report noted that 975 cancers were diagnosed in children aged 0-14 in 2018 — equating to about 60 cases per million children. The most common cancer group diagnosed in children was leukaemia, accounting for 19%, followed by lymphoma which made up almost 18% of cases. Almost half of all the cases that were diagnosed were children aged 0-4 years old.

Lymphomas were common in the 10-14 age group, with Hodgkin lymphomas the most common type. Only 18 cases of hepatic tumours were diagnosed, making them the least commonly diagnosed cancers in children in 2018. About 54% of cancers were diagnosed in boys and 46% in girls. Lymphomas were more commonly diagnosed in boys, accounting for 69%, compared with 31% in girls, whereas germ cell tumours (cancers of reproductive organs) were more commonly diagnosed in girls (about 73% compared with 27% in boys).

While the rate of childhood cancers in SA is comparable to global trends, the authors of the report argue the diagnosis of childhood cancers in middle- to lower-income nations in Africa remains challenging because of inadequate diagnostic abilities in resource-poor settings. This is compounded by the fact that childhood cancers at times mimicked infectious diseases, which are prevalent in SA and other parts of the continent.

Due to resource constraints, survival of cancer remains low in the continent at about 20%, compared with high-income countries where survival rates are about 80%. This was recently highlighted in the global initiative for childhood cancer of the World Health Organization which was launched a few years ago with the aim of reaching at least a 60% survival rate for children with cancer by 2030, thereby saving an additional million lives. 

The report’s authors, including Elvira Singh, the head of department at the cancer registry, senior epidemiologist Dr Mazvita Muchengeti and colleagues, said though there is no stand-alone childhood cancer policy in SA, cancers of childhood, adolescence and young adulthood, have been identified as a national priority and work is under way to draft a “Childhood Cancer Strategic Framework”.

“This highlights the need for the cancer registry to produce annual childhood cancer reports and provide accurate incidence rates to guide policymakers nationally and globally.”

The latest report shows that renal tumours were most prevalent in the 0-4 years age group, comparable with global trends. The lowest rates were in the 10-14 group (47.2 per million).

They noted the latest incidence of cancers in children of about 60 per million is higher than the previously reported 45.7 per million children from 2000-2006 and 45.2 per million from 1987-2007 by the SA Children’s Tumour Registry.

“The higher incidence rate is likely a result of a comprehensive national data set created by linking the various data sources. As there is a lack of unique identifiers in the SA healthcare system, this is the first time data sources have been linked using probabilistic record linkage to achieve a more complete estimate of childhood cancers,” said authors.

Renal tumours, predominantly nephroblastomas, were the fifth most common childhood cancer.

The report authors noted that childhood cancer remains underreported in SA. Annual reports are therefore the first step towards improving reporting and raising awareness about the incidence of childhood cancers. “Misdiagnosis and delay in diagnosis of childhood cancers are major barriers in improving outcomes. There is a need for increased index of suspicion for childhood cancers by clinicians as childhood cancers may mimic other infection-related diseases within the South African context.”

“This is much-needed to guide both clinicians and policymakers to improve childhood cancer awareness, screening, diagnosis, treatment and outcomes,” the authors noted.

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