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Scientists have developed a simple and affordable blood test to help spot cancer cases in low- and middle-income countries, marking the latest move to boost disease prevention among ageing populations.
The method can detect multiple diseases within minutes and could slash missed diagnosis rates for colorectal, gastric and pancreatic cancers, according to the Shanghai-based researchers.
The hunt for reliable but cheap cancer diagnostics is intensifying as longer global life expectancies increase the prevalence of the chronic disease outside wealthier nations.
“[The] approach is practical and can achieve a high level of diagnostic accuracy, even when carried out by local health workers in resource-limited clinical settings,” the Shanghai scientists write in the paper published by Nature Sustainability on Monday. “This work provides insight into delivering metabolic diagnosis with maximum health gains using available resources.”
Low- and middle-income countries already account for about 70 per cent of cancer deaths worldwide, but often lack the diagnostic capabilities that are available in richer nations, the paper says. Fewer than 30 per cent of low-income countries have such facilities generally available, meaning that the rate of undetected disease is high, according to the World Health Organization.
The tool developed by the researchers uses dried spots of serum that can be transported to central facilities for analysis, reducing the need for specialised facilities and refrigerated storage used in traditional cancer blood testing.
Experiments suggested that use of the technique in less developed regions could reduce the estimated proportion of undiagnosed cases of gastric cancer from 77.57 per cent to 57.22 per cent, colorectal cancer from 84.30 per cent to 29.20 per cent, and pancreatic cancer from 34.56 per cent to 9.30 per cent, the researchers said.
The diagnostic method should cost less than traditional approaches as the chemicals needed are inexpensive, they add.
The focus on diagnosing diseases that are more common among older people is increasing as global demographics change. Research published this month forecast that a near-doubling of prostate cancer deaths in 20 years would be concentrated in low- and middle-income states, mainly because men in these countries were living longer than before.
The Shanghai paper highlighted a “significant need” in cancer diagnostics but it was “very early” to say how much impact the work would have, said Hector Keun, professor of biochemistry at Imperial College London.
“Further ‘real-world’ tests of the approach are needed to understand how well it will cope with all the variability in the general population, including the presence of other conditions which can affect metabolic health,” he said. “There are costs — human and economic — associated with overtreatment as well and one needs to consider the diagnostic pathway as a whole.”
Improvements in diagnostic capabilities would need to be matched by increased treatment capacity, analysts said. If treatment facilities are unavailable or unaffordable, the diagnosis may be of limited benefit — and may add to the psychological burden on patients.
“Early diagnosis needs to be connected to treatment or it is pointless,” said Nick James, professor at the UK Institute of Cancer Research and leader of the work on prostate cancer. “Also, if diagnosis is done at scale it will change the case mix and treatment needs.”
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