Diverticulitis is a common condition where small pouches (diverticula) in the colon wall become inflamed or infected. While many individuals with diverticula (diverticulosis) experience no symptoms, inflammation can cause discomfort. A frequent concern is diverticulitis’s potential connection to colorectal cancer. This article clarifies the relationship between these two distinct health issues.
Understanding the Relationship Between Diverticulitis and Cancer
Current research indicates diverticulitis does not directly “turn into” colorectal cancer. Diverticulitis is an inflammatory condition, while colorectal cancer originates from abnormal cell growth, often from polyps. However, these two conditions can coexist, and some lifestyle factors, such as a low-fiber diet, are associated with an increased risk for both.
Observational studies suggest a slightly increased risk of colorectal cancer diagnosed shortly after a diverticulitis episode. For example, one study found individuals with diverticulitis had a 2.1% risk of colon cancer compared to 1.9% in a control group, with increased risk noted within six months. This short-term association may be due to increased diagnostic scrutiny, as patients often undergo imaging and colonoscopies that can uncover previously undetected cancers.
Complicated diverticulitis, involving issues like abscesses or perforations, may show a higher prevalence of colorectal cancer compared to uncomplicated cases. A review reported a 1.9% prevalence of colorectal cancer in acute diverticulitis, rising to 7.9% in complicated cases. Some studies also suggest a reduced long-term cancer risk for diverticulitis patients, possibly due to the protective effect of increased screening.
Why Symptoms Can Overlap
Diverticulitis and colorectal cancer can present with similar signs due to overlapping symptoms. Both conditions affect the colon. Common shared symptoms include abdominal pain, often in the lower left side for diverticulitis.
Changes in bowel habits, such as constipation or diarrhea, are also frequently reported. Rectal bleeding can occur in either condition, contributing to diagnostic confusion. Unexplained fatigue and a feeling of fullness or bloating can also be present.
Diagnostic Approaches to Distinguish Conditions
Distinguishing between diverticulitis and colorectal cancer involves a combination of medical assessments. Healthcare providers use medical history, physical examination, and diagnostic tests. Imaging techniques, such as CT scans, frequently diagnose acute diverticulitis and its complications, identifying inflammation, abscesses, or perforations.
However, CT scans have limitations in differentiating benign from malignant tumors, as cancer can cause inflammation that mimics diverticulitis. What appears to be diverticulitis on a CT scan is sometimes later identified as colon cancer. This highlights the importance of further investigation, particularly colonoscopy, which is the definitive tool for diagnosing both conditions.
Colonoscopy allows direct visualization of the colon lining, enabling polyp removal and biopsy of suspicious lesions. While typically not performed during an acute diverticulitis flare, it is often recommended several weeks after inflammation subsides. This follow-up colonoscopy helps confirm the diagnosis and exclude underlying malignancy, especially in complicated cases or with persistent symptoms.
General Colorectal Cancer Risk Factors
Understanding colorectal cancer risk factors, independent of diverticulitis, is important. Age is a prominent risk factor, with risk increasing significantly as individuals get older. Most cases are diagnosed in people over 50.
A personal or family history of colorectal cancer or polyps also elevates risk. Genetic syndromes, such as familial adenomatous polyposis (FAP) or Lynch syndrome, significantly increase susceptibility. Inflammatory bowel diseases, like Crohn’s disease or ulcerative colitis, are also associated with a higher risk due to chronic inflammation.
Lifestyle factors contribute to colorectal cancer risk. These include a lack of regular physical activity, a diet low in fruits and vegetables, and a diet high in processed meats and low in fiber. Obesity, excessive alcohol consumption, and long-term tobacco use are additional factors that increase the likelihood of developing colorectal cancer.