How to Recognize the Symptoms of Colorectal Adenomas

Colorectal adenomas are a common type of polyp that forms on the inner lining of the colon or rectum. They are composed of gland-like tissue and vary in shape and size. These polyps are classified into tubular, villous, and tubulovillous adenomas, which can only be differentiated under a microscope. Villous adenomas tend to have the highest likelihood of progressing to cancer, while tubular adenomas are the most common and generally carry a lower risk.

Adenomas are often detected during routine colonoscopies, which are recommended starting at age 45 for individuals at average risk. Because most adenomas cause no symptoms, these screenings are the best way to identify and remove them early. However, in some cases, adenomas can cause noticeable changes in bowel habits or other warning signs, which may indicate the need for medical attention.

Bleeding from a colorectal adenoma can occur gradually over time, making it difficult to detect.

As these polyps grow, they can irritate or erode nearby blood vessels, leading to small amounts of bleeding that may not be visible. Over time, bleeding may become noticeable in stool, appearing as bright red streaks or darker discoloration, depending on the polyp’s location.

Because rectal bleeding has many possible causes, including hemorrhoids, diverticulitis, and inflammatory bowel disease, it’s important to consult a doctor for an evaluation.

Even if bleeding is not visible, persistent fatigue, dizziness, or anemia could indicate hidden blood loss and should not be ignored.

Larger adenomas can disrupt normal bowel habits, leading to persistent constipation, diarrhea, or noticeable changes in stool consistency. These changes may occur when a polyp partially obstructs the bowel or affects mucus production, altering stool texture.

While occasional fluctuations in bowel movements are common due to diet, stress, or minor infections, symptoms that last for more than a few weeks without improvement may indicate an underlying issue. If bowel irregularities persist, especially when accompanied by other symptoms like rectal bleeding or abdominal discomfort, it’s important to consult a doctor to determine the cause.

As adenomas grow, they may partially obstruct the bowel, leading to cramping, bloating, or general discomfort. This pain can be intermittent or persistent, depending on the size and location of the polyp.

The discomfort occurs as the bowel works harder to move stool past the growth, which can lead to occasional sharp pains or a dull, ongoing ache.

While many conditions—such as irritable bowel syndrome, reflux, or gallstones—can cause similar symptoms, pain that persists for more than a few weeks or worsens over time warrants a visit to the doctor for further evaluation.

Slow, undetected blood loss from a colorectal adenoma can lead to iron-deficiency anemia over time. Because this bleeding is often microscopic, symptoms may develop gradually rather than appearing suddenly.

As iron levels drop, the body produces fewer red blood cells, leading to fatigue, weakness, and pale skin. Some people may also experience dizziness, shortness of breath, or cold hands and feet.

While occasional tiredness is normal, persistent fatigue—especially when paired with other symptoms—may warrant bloodwork to check for anemia. If you notice ongoing fatigue that doesn’t improve with rest, or symptoms like dizziness or pale skin, talk to your doctor.

Colorectal adenomas develop on the mucous membrane lining the intestine, and some—particularly larger adenomas—can stimulate excess mucus production. This may result in a noticeable increase in mucus within the stool or as a separate discharge.

However, mucus in the stool is not always linked to adenomas; conditions like irritable bowel syndrome, food intolerances, and infections can also cause it. If mucus is accompanied by blood, changes in bowel habits, or persists for more than a few weeks, it may be a sign of an underlying issue that requires medical evaluation.

Adenomas in the rectum can create a sensation of incomplete bowel emptying, even after a bowel movement. This occurs when the adenoma presses against the rectal wall, leading to a feeling of fullness or residual stool.

Other conditions, such as constipation and irritable bowel syndrome, can cause similar sensations, but these typically fluctuate and improve with dietary changes or hydration.

Several lifestyle and genetic factors can increase the likelihood of developing colorectal adenomas, some of which may also raise the risk of colorectal cancer.

Research has identified key risk factors, including:

• Smoking and Alcohol Consumption: Both have been linked to inflammation and cellular changes in the colon, increasing the risk of adenoma formation.
• Red Meat and High-Fat Diets: Diets high in processed and red meats may contribute to polyp growth, while high-fat diets can alter gut bacteria in ways that promote adenoma development.
• Low-Fiber Intake: Fiber helps regulate digestion and supports gut health, potentially reducing the risk of adenomas.
• Obesity and Sedentary Lifestyle: Excess body weight and lack of physical activity have been associated with higher rates of colorectal polyps and cancer.
• Age and Family History: The risk of adenomas increases with age, particularly after 45, and individuals with a family history of colorectal cancer or polyps may be at significantly higher risk.

If you have multiple risk factors, adopting a high-fiber diet, maintaining a healthy weight, and avoiding tobacco and excessive alcohol consumption may help lower your risk.

If you notice blood in your stool, experience persistent changes in bowel habits, or have unexplained abdominal pain, talk to your doctor. These symptoms can have many causes, but because colorectal adenomas can develop silently and increase the risk of cancer, early detection is key.

Due to rising colorectal cancer rates in younger adults, screenings are now recommended starting at age 45 and should be repeated at regular intervals. Those with a family history of colorectal cancer, a personal history of adenomas, or certain genetic conditions may need to begin screening earlier and undergo more frequent colonoscopies.

For people at average risk, there are non-invasive screening options available, such as stool-based tests and DNA screenings, which can detect hidden blood or genetic markers linked to colorectal cancer. While these tests can be useful for detecting abnormalities, they are generally not recommended for those at high risk, who require colonoscopies for a more thorough evaluation.

It is important to remember that many other conditions—such as irritable bowel syndrome, Crohn’s disease, or food allergies—can cause similar symptoms. The only way to determine the cause is through appropriate medical evaluation and testing. If you have concerns about your risk, speak with your doctor about the best screening plan for you.