The diagnosis of bowel cancer in patients with inflammatory bowel disease (IBD) and other serious illnesses is often significantly delayed compared to patients without pre-existing illness. This delayed diagnosis could negatively affect treatment outcomes, according to a study published in the British Journal of Cancer.

Among several conditions that delayed bowel cancer diagnosis, including heart disease and mental health issues, IBD was found to cause the longest delays, of up to 26 days.

“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,” said William Hamilton, the study’s senior author from the University of Exeter, in the U.K. “This really matters — as the complications may kill.” 

For patients with multiple health issues, this diagnosis delay can exceed one month, researchers said.

The study, “Comorbid conditions delay diagnosis of colorectal cancer: a cohort study using electronic primary care records,” examined medical records of more than 4,500 bowel cancer patients to reach its conclusions.

“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,” said Jose Valderas, the study’s co-author from the University of Exeter’s Medical School.

“It’s vital that doctors realize 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,” he added.

Deborah Alsina, MBE, chief executive of Bowel Cancer UK, said that once symptoms of bowel cancer appear, the disease already is in a later stage, making early diagnosis crucial.

She said that about half of all bowel cancer patients are diagnosed in later stages, and 20% of patients are diagnosed with bowel cancer as an emergency, when treatment is difficult and outcomes are generally poor.

One possible explanation for IBD’s link to delayed diagnosis are the similarities in symptoms between IBD and bowel cancer, researchers said.

“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,” Alsina said.

“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,” she added.