The researchers from the University of Exeter analysed clinical data from over 4,500 patients across the UK who were later diagnosed with bowel cancer. In a study published in the British Journal of Cancer, they looked at whether pre-existing illness affected the time it took them to get a cancer diagnosis, making it one of the first studies to investigate this.
They found that if you have a single serious illness or mental health issue unrelated to cancer, such as depression or heart disease, your bowel cancer is diagnosed on average 10 days later than usual , a 13% increase from the usual time taken for a diagnosis. This could go up to over one month when patients had multiple illnesses. These illnesses may take up a lot of time in visits to the GP and leave not enough time available to investigate symptoms or signs linked to cancer.
A bowel cancer sign or symptom which can be explained by a pre-existing condition, such as stomach pains, delayed cancer diagnosis by 9 days on average, a 12% increase from the usual time taken for a diagnosis. These cancer signs and symptom can be explained by the additional illness that the patient has so doctors are 'led astray', making it more difficult to arrive at a cancer diagnosis.
They also found that if you have Inflammatory Bowel Disease (IBD), it can delay a bowel cancer diagnosis by 26 days.
Professor Jose Valderas, one of the lead researchers from the University of Exeter Medical School, said: "When you're trying to diagnose cancer, other illnesses can be a distraction either because they also require attention or because they can mask what would otherwise be flagged as a possible sign of cancer.
"It's vital that doctors realise that existing illnesses make a diagnosis of cancer more difficult and stay alert to recognize signs and symptoms of cancer as such. It's also important that patients flag symptoms with their doctor as early as possible, whether it's unexplained weight loss or changes to your bowel habits."
Professor Willie Hamilton, one of the lead researchers from the University of Exeter, said: "A ten day delay may not sound much but it may be the difference between a well-planned admission and an emergency admission with a complication. This really matters - as the complications may kill."
The study, 'Comorbid conditions delay diagnosis of colorectal cancer: a cohort study using electronic primary care records' is published in the British Journal of Cancer. Authors are Luke TA Mounce, Sarah Price, Jose M Valderas, and Willie Hamilton.
Commenting on the study, Deborah Alsina MBE, Chief Executive of Bowel Cancer UK, said: "As symptoms of bowel cancer can relate to later stage of disease it is important that delays in diagnosis are minimised. While the delays highlighted in this study are relatively small, if they add onto delays in patients presenting to their GP with symptoms, or in a diagnostic appointment, they become more serious. Currently around 20% of people are diagnosed with bowel cancer as an emergency when outcomes are generally poorer and almost 50% in later stages of the disease when it is harder to treat. "This interesting study highlights another aspect of the complexity of diagnosing bowel cancer as the majority of patients have multiple conditions. Therefore finding quicker, more effective ways to identify and diagnose these patients is crucial to help GPs and other clinicians identify or rule out bowel cancer quickly to give people the very best opportunity for successful treatment. Bowel cancer is after all, treatable and curable especially if diagnosed early."