Unintended weight loss is the second highest risk factor for some forms of cancer, according to the UK authors of the first “robust” research analysis to examine the link between the two.
Primary care researchers from Oxford and Exeter universities conducted the first systematic review and meta-analysis of all available evidence on the association between weight loss and cancer in primary care.
“A primary care clinician’s decision to code for weight loss is highly predictive of cancer”
Their study, which was funded by the National Institute for Health Research, found that unintended weight loss is the second highest risk factor for colorectal, lung, pancreatic and renal cancers.
The researchers looked at the findings of 25 studies, incorporating data from more than 11.5 million patients, and found that weight loss was linked with 10 types of cancer.
These were prostate, colorectal, lung, gastro-oesophageal, pancreatic, non-Hodgkin’s lymphoma, ovarian, myeloma, renal tract and biliary tree, they stated in the British Journal of General Practice.
Their analysis found that unintended weight loss in people over 60 exceeded the 3% risk threshold for urgent investigation in guidelines from the National Institute for Health and Care Excellence.
In addition, in women aged over 60, the average risk across all sites involved was estimated to be up to 6.7%, and in males up to 14.2%.
“A primary care clinician’s decision to code for weight loss is highly predictive of cancer,” said the study authors. “For such patients, urgent referral pathways are justified to investigate for cancer across multiple sites.”
“This study demonstrates beyond doubt that it is important in efforts to save lives from cancer”
Lead study author Dr Brian Nicholson, from the University of Oxford, said that “streamlined” services that allowed the investigation of non-specific symptoms like weight loss were “vitally important”.
“Our research indicates that co-ordinated investigation across multiple body sites could help to speed up cancer diagnosis in patients with weight loss,” said Dr Nicholson.
He added: “We now need to continue our research to understand the most appropriate combination of tests and to give guidance on how much weight loss GPs and patients should worry about.”
Study co-author Professor Willie Hamilton, from the University of Exeter, said: “We’ve always known that unplanned weight loss may represent cancer.
“This study pulls together all the published evidence and demonstrates beyond doubt that it is important in efforts to save lives from cancer,” he said.
He highlighted that it was particularly timely given last week’s announcement by NHS England of “one-stop” shops for cancer diagnosis.
“These units pull together all the necessary tests under one roof – making the investigation of weight loss much more speedy and convenient for the patient,” he added.