Testing The Siblings of Newborn Cancer Variant Carriers Could Save Lives

Testing The Siblings of Newborn Cancer Variant Carriers Could Save Lives
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Carrying out genetic testing on siblings of infants found to be carriers of cancer-associated gene variants can save lives and costs later on, suggest the results of a new study.

Led by Ann Chen Wu, an associate professor in the Department of Population Medicine at Harvard Medical School, the study found that carrying out sibling ‘cascade’ testing had the potential to prevent early deaths due to cancer in about half the siblings identified to be at risk. It was also highly cost effective.

Earlier research by the same group showed that screening newborns for cancer risk mutations could reduce pediatric cancer deaths, while also being cost effective. This study, published in JAMA Network Open, modeled whether testing siblings of infants found to have variants of concern, so called ‘cascade’ testing, could also be beneficial.

“Economic studies of cascade testing have focused on adults, although evidence suggests that cost-effectiveness improves for some cancer syndromes when surveillance is initiated in younger individuals,” write Wu and co-authors.

“Our objective was to estimate the benefits and costs of cascade testing of siblings of newborns with cancer susceptibility gene variants.”

Using a virtual cohort of 3.7 million newborns, the model estimated that based on currently available data and predictions approximately 1584 newborns and 792 siblings would carry variants that could increase their risk for cancer.

Of the siblings in the cancer risk variant group in the model, 116 were estimated to go on to develop cancer before the age of 20 years. If these children were identified at an early stage and underwent regular surveillance, the researchers estimate that 15 cancer deaths could be prevented, which would correspond to an estimated 52% reduction compared to individuals not offered testing.

The incremental cost-effectiveness ratio (ICER) is a common statistic used to assess how beneficial a medical test, treatment or other intervention may be given how much it costs the provider. The researchers estimated that testing siblings for cancer risk variants would be highly cost effective with an average ICER of $16,910 per life year gained.

Wu and team note that testing for some gene variants is more cost effective than others based on how much of an impact carriage of a specific variant has on risk, but there was a significant benefit shown across the different known variants.

For sequencing and initial visits to a specialist the ICER ranged from $16,650-$17,160 per life year gained and for subsequent surveillance costs to $10,040-$24,380 per life year gained.

“Results align with adult studies that find relatives’ genetic testing cost effective compared with standard screening,” write the authors.

They acknowledge that the model has some omissions, eg. that only variants in 11 genes were included, but add that it demonstrates “how sibling cascade testing would enhance newborn screening efforts and how targeted screening approaches may be more efficient than universal screening to achieve population-level benefits.”