April 10 (UPI) -- When a person experiences an unintended weight loss, it is the second-highest predictor for some forms of cancer, according to an analysis of studies.
Researchers at the universities of Oxford and Exeter analyzed the findings of 25 studies, incorporating data from more than 11.5 million patients collected between 1994 and 2015. They found that weight loss was linked with 10 types of cancer: prostate, colorectal, lung, gastro-esophageal, pancreatic, non-Hodgkin's lymphoma, ovarian, myeloma, renal tract and biliary tree.
Their analysis was published Monday in the British Journal of General Practice.
Unintended weight loss in people older than 60 exceeded the 3 percent risk threshold for urgent investigation, according to guidelines by Britain's National Institute for Health Research.
In females older than 60 the average risk across all sites involved was estimated to be up to 6.7 percent, and in males over 60 average risk was up to 14.2 percent.
"Streamlined services that allow [doctors] to investigate non-specific symptoms like weight loss are vitally important and urgently needed if we are to catch cancer earlier and save lives," Dr. Brian Nicholson, of the University of Oxford, said in an Exeter press release. "Our research indicates that coordinated investigation across multiple body sites could help to speed up cancer diagnosis in patients with weight loss."
In the analysis, 23 of the 25 utilized primary care records. Of these, 20 defined weight loss as a physician's coding of the symptom and the rest collected data directly. Of the studies, one study was conducted in the United States and the rest in Britain.
"It is possible that non-specialist doctors do not recognize weight loss as a potential symptom of cancer and omit investigation until other symptoms occur," researchers wrote in the study.
Among patients who experience weight loss and go on to receive a cancer diagnosis, the researchers reported that those "with pancreatic cancer with weight loss as their first symptom had the longest time to diagnosis and poorest survival."
"We've always known that unplanned weight loss may represent cancer," co-author Dr. Willie Hamilton, of the University of Exeter, said. "This study pulls together all the published evidence and demonstrates beyond doubt that it is important in efforts to save lives from cancer."
Researchers said the studies didn't say how many pounds could be considered as unexplained weight loss.
Nicholson said further research is needed, specifically to find the most appropriate combination of tests for doctors to order and to provide proper guidance on how much weight loss doctors and patients should be concerned about.
Already ahead of the game, NHS England announced last week that "one-stop shops" aimed at speeding up cancer diagnosis are being introduced across the country. The agency said people with vague symptoms, including unexplained weight loss, can be referred repeatedly for different tests for different cancers.