Rectal Cancer Signs and Symptoms

Rectal cancer begins in the lining of the rectum, the final several inches of the large intestine before the anus. In many cases, it develops from a polyp, a growth that forms when normal cells in the colorectal lining begin to change. Polyps are common and most are benign, but some can become cancerous over time. Because many polyps can be detected and removed during a routine colorectal cancer screening, rectal cancer can often be prevented. For this reason, it is important to follow a physician-recommended screening schedule.

Rectal cancer can affect how stool moves through the body, potentially leading to rectal bleeding, pain and changes in bowel habits. While the precise cause is not always known, risk factors can include advanced age, a personal or family history of colorectal polyps or cancer, inflammatory bowel disease (IBD) and certain inherited cancer predisposition syndromes, such as familial adenomatous polyposis (FAP) and Lynch syndrome. A sedentary lifestyle and a diet low in fruits and vegetables may also contribute.

Each year in the United States, an estimated 150,000 to 154,000 people are diagnosed with colorectal cancer. Approximately 46,000 to 47,000 of those cases are identified as rectal cancer specifically, with the remainder confirmed as colon cancer.

What are usually the first warning signs of rectal cancer?

Early-stage rectal cancer may not cause clear or lasting symptoms. When symptoms do occur, they are often mild and may be easily mistaken for a minor digestive issue or hemorrhoids. Possible warning signs include:

• Changes in bowel habits, such as diarrhea, constipation or narrow stools
• A feeling that the bowel does not empty completely
• Rectal bleeding or blood in the stool
• Mild abdominal discomfort, cramping or bloating
• Unexplained fatigue

Because these symptoms can have many causes, they should not be ignored, especially if they persist or worsen over time.

What are the symptoms of rectal cancer?

As rectal cancer progresses, the symptoms may become more frequent and noticeable. Common signs include:

• Bright red or dark blood in the stool
• Persistent changes in bowel habits
• Rectal pain or pressure
• Abdominal pain or discomfort
• Weakness or fatigue caused by anemia
• Unintentional weight loss

Rectal cancer symptoms can vary based on the size and location of the tumor and whether it has spread beyond the rectum.

What does rectal cancer look like?

Rectal cancer cannot usually be seen externally on the body. However, it may cause visible changes in bowel movements, such as blood mixed with stool or stools that appear thinner than usual. In advanced cases, a mass may be detected by a physician during a digital rectal exam (DRE) or identified through an imaging test or endoscopic procedure, such as a colonoscopy.

What does rectal cancer feel like?

Rectal cancer may cause sensations that range from mild discomfort to ongoing pain. Some patients report rectal pressure, pain during bowel movements or a persistent urge to move their bowels. Others experience abdominal cramping or discomfort that does not improve with dietary changes or over-the-counter remedies.

"When you go to the doctors, have faith in them and that they're going to do the best thing for you and have your best interests at heart. And that's exactly what every doctor here at Moffitt has done."

Melissa, Rectal Cancer Survivor

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What are the signs of advanced rectal cancer?

As rectal cancer progresses, the symptoms may become more severe and affect overall health. Signs may include:

• Persistent or heavy rectal bleeding
• Severe abdominal or rectal pain
• Significant, unexplained weight loss
• Chronic fatigue or weakness
• Bowel obstruction symptoms, such as severe constipation or vomiting
• Symptoms related to cancer spread, such as liver pain or shortness of breath

When is it important to discuss rectal cancer symptoms with a physician?

Any rectal bleeding, ongoing changes in bowel habits or other unusual changes that do not resolve within a few weeks should be discussed with a physician. An early evaluation can help determine the cause and allow for timely treatment if cancer is present.

Benefit from world-class care at Moffitt Cancer Center

Rectal cancer symptoms are not always caused by cancer. Even so, it is important to seek an early medical evaluation, since an accurate diagnosis can expand the treatment options and improve the outcome. At Moffitt, our patients are evaluated by a multispecialty team with deep expertise in gastrointestinal cancers. Working together, our specialists can identify the cause of rectal cancer symptoms and, if cancer is found, stage the tumor precisely and develop an individualized treatment plan. In addition to Moffitt’s high-volume experience, our patients benefit from advanced imaging and pathology, access to leading-edge therapies through our robust portfolio of clinical trials and coordinated supportive services that address comfort, nutrition and overall well-being throughout the continuum of care.

If you would like to learn more about rectal cancer symptoms, you can request an appointment with a specialist in our Gastrointestinal Oncology Program by calling 1-888-663-3488 or submitting a new patient registration form online. We do not require referrals.