Common blood tests can aid in early cancer detection and guide referral strategies.

Early detection of cancer is crucial for effective treatment. However, undiagnosed cancer patients often visit primary care providers with non-specific symptoms, such as abdominal pain or bloating, which can also result from benign conditions.

This makes it challenging to identify patients who require further diagnostic testing or specialist referrals. 

Current guidelines typically focus on ‘alarm’ symptoms specific to particular cancer types, leaving limited guidance for non-specific symptoms that could indicate various cancer types.

A recent study analysed over 470,000 patients aged 30 and older who presented with abdominal symptoms like pain or bloating. 

Within a year, around 9,000 patients with abdominal pain and 1,000 patients with bloating were diagnosed with cancer. 

Researchers examined 19 abnormal blood test results taken during the initial primary care visit to determine their predictive value for cancer diagnosis.

Several blood abnormalities were found to be strong predictors of cancer risk across different age and sex groups. 

For instance, in patients aged 30-59 with abdominal symptoms, abnormalities such as anaemia, low albumin, raised platelets, abnormal ferritin, and increased inflammatory markers were significant indicators of cancer risk. 

In patients aged 60 and above, the mere presence of abdominal pain or bloating warranted a cancer referral.

The study also detailed the types of cancers most commonly associated with specific blood test abnormalities based on patient age and sex. 

For example, women aged 50-59 with anaemia and abdominal bloating were most commonly diagnosed with bowel or ovarian cancer. 

Experts say this detailed information can help healthcare providers prioritise diagnostic strategies for their patients.

The findings suggest that routine blood tests can provide valuable context in assessing cancer risk among patients with non-specific abdominal symptoms, potentially leading to earlier diagnosis and more timely referrals to specialists.

“Using existing blood tests can be an effective and affordable way to improve early diagnosis of cancer in people who see their GP with vague symptoms,” the study says.  

“Our study identified several commonly used GP blood tests where abnormal results increase a patient's risk of having cancer and these can be used to diagnose cancer earlier.”