A recent study has analyzed data from over 400,000 individuals aged 30 and above in the UK who sought medical attention for stomach pain, alongside more than 50,000 others reporting bloating.
According to the findings of this research led by UCL researchers, routine blood test results could potentially accelerate the identification of cancer in individuals experiencing stomach pain or bloating.
Typically, when patients report these issues to their general practitioner (GP), they are often sent for blood tests. However, it remains unclear how effective these tests, which evaluate various health issues, are in predicting the risk of cancer.
The study, published in PLOS Medicine, reviewed data involving over 400,000 UK residents over the age of 30 who visited a GP regarding stomach pain, and over 50,000 with bloating. Approximately two-thirds of these individuals underwent blood tests following their consultation.
The researchers discovered that in 19 frequently utilized blood tests, abnormal outcomes correlated with an increased likelihood of being diagnosed with cancer within a year. They estimated that accounting for these abnormal findings would lead to a 16% rise in the number of cases of undiagnosed cancer receiving urgent referrals—beyond those evaluated based solely on symptoms, age, and gender.
This equates to an additional six urgent referrals for undiagnosed cancer per 1,000 patients who visited their GP with stomach pain or bloating, in addition to the 40 people already referred for urgent assessment, without considering blood test results.*
Dr. Meena Rafiq, who spearheaded the study at the UCL Department of Behavioural Science & Health, commented: “Our findings indicate that we can enhance cancer detection using readily available blood tests that are routinely administered to individuals with ambiguous symptoms. This approach could provide a cost-effective and efficient strategy to facilitate early cancer diagnosis and, in some cases, improve treatment outcomes.”
“Given that it may be challenging for GPs to analyze a range of blood test data, our research highlights the necessity for an automated tool that could assess cancer risk based on multiple factors.”
The researchers utilized anonymized patient information from the Clinical Practice Research Datalink (CPRD), compiled from GP practices across the UK between 2007 and 2016.
The study revealed that one in 50 (2.2%) individuals who sought medical attention for stomach pain received a cancer diagnosis within the next year. The same percentage (2.2%) applied to those reporting bloating.
According to guidelines from the National Institute for Health and Care Excellence (NICE) in the UK, urgent cancer referrals should be made when a person’s cancer risk exceeds 3%.
The researchers identified that individuals aged 60 or older, who visited their GP due to stomach pain or bloating, had a sufficiently elevated risk to merit an urgent cancer referral (risk above 3%), irrespective of their blood test outcomes. Currently, in the UK, individuals over 60 exhibiting these symptoms are only referred for cancer assessment if they show additional signs, such as weight loss.
The cancer risk was estimated to be 3.1% for men in their 60s reporting stomach pain, escalating to 8.6% for those in their 80s with the same symptom. For women in these age brackets, the risk started at 3.1% and increased to 6.1% for the older group.
The researchers cautioned that cancer occurrence in their study sample may be higher than in a larger population of individuals with stomach pain or bloating who do not seek GP visits or undergo blood tests.
In this UK study population, the researchers found that among those aged 30 to 59 years presenting with abdominal pain or bloating, indicators such as anaemia, low albumin, elevated platelets, abnormal ferritin, and heightened inflammatory markers significantly predicted the risk of undiagnosed cancer.
For instance, in women aged 50 to 59 with abdominal bloating, the pre-test cancer risk of 1.6% surged to 10% with increased ferritin, 9% with low albumin, 8% with elevated platelets, 6% with raised inflammatory markers, and 4% with anaemia.
At present, only raised platelets and anaemia are included in cancer referral guidelines. The researchers noted that these guidelines mainly emphasize the existence of ‘alarm’ symptoms and the risk of cancer for a single organ, lacking broad guidance for vague symptoms that could indicate cancer in multiple organs.
Dr. Rafiq added: “Many patients with undetected cancer initially present with vague symptoms that can pose a diagnostic challenge. Numerous patients are evaluated in primary care using widely administered blood tests that could aid in identifying those at the highest risk of underlying cancer, prioritizing them for referral.”
This study shows that utilizing these common tests can significantly enhance the assessment of cancer risk.
Additionally, the research highlighted which types of cancer were prevalent among individuals with the symptoms and how this prevalence varied with age and gender. Overall, bowel cancer emerged as the most common, followed by prostate and pancreatic cancers in men, while in women, bowel cancer was followed by breast and ovarian cancers.
The researchers cautioned that the results regarding blood tests and cancer prediction could not be generalized to other healthcare systems with different rates of blood test usage.
The study received financial support from the International Alliance for Cancer Early Detection (ACED), a coalition comprising UCL, Cancer Research UK (CRUK), Canary Center at Stanford University, the University of Cambridge, OHSU Knight Cancer Institute, and the University of Manchester. Additional funding was provided by CRUK and the National Institute of Health Research (NIHR).
*Patients who had one or more blood tests indicating an elevated risk above 3% (and who would not have met the referral criteria based solely on age, gender, and symptoms) were included as additional urgent referrals.
