Rectal Cancer Symptoms

What are the symptoms of rectal cancer?

A few common symptoms of rectal cancer are bowel habit changes, rectal bleeding and blood in the stool. But often, colorectal cancer—including rectal cancer—doesn’t cause symptoms in the early stages.

Most of the time, rectal cancer starts with pre-cancerous rectal polyps. If these polyps are caught and removed early, you can prevent rectal cancer from developing. That’s why it’s so important to have routine rectal cancer screenings, such as a colonoscopy, even when you don’t have any signs or symptoms of the condition.

Early symptoms of rectal cancer

Especially early on, rectal cancer may not cause any symptoms at all. When symptoms start to appear, some of the most common early signs are changes in bowel habits, narrowing of the stool, rectal bleeding or blood in the stool, and abdominal pain.

It may be hard to tell the difference between symptoms caused by early rectal cancer and those caused by other digestive conditions. Occasional digestive upset is common for most people. Ongoing digestive symptoms could be a sign of not only rectal cancer but also irritable bowel syndrome, infections, inflammatory bowel diseases, hemorrhoids, and more.

When you have these common digestive symptoms, it’s likely that rectal cancer isn’t the cause. However, you should still talk to your doctor and be proactive about caring for your digestive health.

Changes in bowel habits

Changes in bowel habits

While temporary changes in bowel habits happen from time to time, rectal cancer may cause persistent changes. These include increased mucus discharge with the bowel movement, diarrhea, constipation, a feeling that your bowel doesn’t empty completely or changes in the frequency of going to the bathroom.
Bloody stools

Bloody stools

Early signs of rectal cancer include ongoing rectal bleeding, blood in your stool (from a bright red to dark red color) and blood when you wipe. Sometimes, rectal cancer will also cause blood in your stool that you don’t see at all. In that case, you might find blood in the stool through a fecal occult blood test.
Narrow or thin stools

Narrow or thin stools

Cancer developing in the rectum might cause a change in the shape or size of the stool. The most common change is narrow or thin stools. Some people describe the appearance as ribbon-like or stringy.
Persistent abdominal pain or cramping

Persistent abdominal pain or cramping

Abdominal discomfort, such as aches, pains or feeling bloated, could be symptoms of rectal cancer. As a tumor grows, it can cause pressure and inflammation in the digestive tract, which leads to persistent pain or cramping.

Changes in bowel habits

While temporary changes in bowel habits happen from time to time, rectal cancer may cause persistent changes. These include increased mucus discharge with the bowel movement, diarrhea, constipation, a feeling that your bowel doesn’t empty completely or changes in the frequency of going to the bathroom.

Bloody stools

Early signs of rectal cancer include ongoing rectal bleeding, blood in your stool (from a bright red to dark red color) and blood when you wipe. Sometimes, rectal cancer will also cause blood in your stool that you don’t see at all. In that case, you might find blood in the stool through a fecal occult blood test.

Narrow or thin stools

Cancer developing in the rectum might cause a change in the shape or size of the stool. The most common change is narrow or thin stools. Some people describe the appearance as ribbon-like or stringy.

Persistent abdominal pain or cramping

Abdominal discomfort, such as aches, pains or feeling bloated, could be symptoms of rectal cancer. As a tumor grows, it can cause pressure and inflammation in the digestive tract, which leads to persistent pain or cramping.

Systemic rectal cancer symptoms

Systemic rectal cancer symptoms happen when rectal cancer affects other areas in your body beyond just the digestive system. These symptoms are more common as cancer progresses past the earliest stages and is no longer contained in the rectum. Many systemic rectal cancer symptoms are similar to symptoms you might have with other types of cancer.

When cancer spreads in the body, it might affect how you digest food and use nutrients, change the levels of certain hormones or increase inflammation. As these changes occur, you may experience symptoms that affect your entire body, such as weight loss, weakness or fatigue.

Advanced-stage rectal cancer symptoms

When rectal cancer spreads to distant body areas, you could begin to have advanced-stage rectal cancer symptoms. These symptoms often develop along with previous digestive-related signs or systemic symptoms. During advanced rectal cancer stages, such as stage 4, cancer cells begin to affect other organs and their ability to function correctly.

The exact advanced-stage rectal cancer symptoms you have depend on which organs or areas of the body are affected by cancer. However, some common locations where symptoms develop with advanced rectal cancer are in the bones, liver or lungs.

Swollen abdomen

Swollen abdomen

Inflammation and growing areas of cancer in the abdominal lining may lead to swelling and pain. If rectal cancer has spread to the liver, a swollen abdomen could also be caused by a fluid buildup.
Bone pain

Bone pain

One sign that rectal cancer has spread—or metastasized—in the bones is persistent, intense bone pain. Areas of cancer in the bones also make them more likely to fracture.
Difficulty breathing

Difficulty breathing

Symptoms like difficulty breathing, wheezing or coughing may happen in advanced stages of rectal cancer. These symptoms are most common when the cancer has spread to the lungs.

Swollen abdomen

Inflammation and growing areas of cancer in the abdominal lining may lead to swelling and pain. If rectal cancer has spread to the liver, a swollen abdomen could also be caused by a fluid buildup.

Bone pain

One sign that rectal cancer has spread—or metastasized—in the bones is persistent, intense bone pain. Areas of cancer in the bones also make them more likely to fracture.

Difficulty breathing

Symptoms like difficulty breathing, wheezing or coughing may happen in advanced stages of rectal cancer. These symptoms are most common when the cancer has spread to the lungs.

Rectal cancer vs. hemorrhoids

Hemorrhoids are a common rectal condition that happens when veins in the rectum become swollen and irritated. Both rectal cancer and hemorrhoids share a common symptom—rectal bleeding. Because rectal cancer doesn’t cause many symptoms in its earliest stages, it might be hard to know when bleeding is caused by hemorrhoids or something more serious like cancer.

While hemorrhoids are more commonly the cause of rectal bleeding than rectal cancer, you should always let your doctor know if you’re bleeding or notice any blood in the stool. This is especially true if you have other symptoms in addition to rectal bleeding.

Frequently asked questions

How is rectal cancer diagnosed?

Rectal cancer is usually diagnosed using a colonoscopy, either as a screening test or to check on symptoms. If an area of concern is found during a colonoscopy, your doctor may take a tissue sample, called a biopsy, to confirm a rectal cancer diagnosis.
How long does rectal cancer take to develop?

Rectal cancer may take up to 10-15 years to develop. Most of the time, rectal cancer starts as a rectal polyp, and these may be slow to progress to cancer. Once cancer develops, the rate at which it grows depends on several factors.
Can rectal cancer cause back pain?

Yes. While it isn’t the most common symptom, rectal cancer may lead to back pain, especially in advanced stages. As rectal cancer spreads, it could create pressure on the nerves in the lower back, leading to pain that doesn’t change or worsens when you move.
Can rectal cancer cause urinary problems?

Yes. Rectal cancer can affect the bladder or spread to it, causing urinary changes. According to one study, urinary problems like incontinence, trouble emptying the bladder or the urgent need to go to the bathroom were common one year after a rectal cancer diagnosis.
Can rectal cancer cause constipation?

Yes. Constipation and feeling like you still need to go after a bowel movement are common symptoms of rectal cancer. A tumor blocking or restricting the rectum may make it hard to pass stool.

What are the symptoms of rectal cancer?