10 Colon Cancer Red Flags

is one of the most common cancers in the United States. It is also one of the leading cause of cancer-related deaths in the country.

is sometimes called colorectal cancer (CRC) which is a term that combines and rectal cancer.

It used to be an older person’s problem, but more young adults in their 20s and 30s are being diagnosed with the disease.

60% of -related deaths can be prevented with regular screenings and early detection.

colon cancer symptoms

Understanding the colon:

The longest portion of the large intestine is called the colon. It is also referred to as the large bowel. The large intestine is a tube that about 5 to 6 feet in length and is the last part of the digestive tract.

The first 5 feet make up the colon. It is divided into four parts, the ascending, transverse, descending and the sigmoid. The colon connects to the rectum and ends with the anus.

Food reaches the colon around 3 to 8 hours after eating. By the time it gets there, the nutrients have been absorbed. What remains is a liquid waste product.

One of the colon’s function is to change the liquid waste into a solid stool. It absorbs the water in order to accomplish that. The stool can spend any time between 10 hours to several days in the colon before being expelled through the anus.

Colon Cancer:

begins when cells grow in an uncontrolled way which ends up with a tumor forming. It is a malignant or cancerous tumor that grows in the walls of the colon.

Most of colon tumors start when normal tissue in the colon wall forms an adenomatous polyp or a pre-cancerous growth. As the polyp grows larger, a tumor forms. This process can take many years, hence, there is ample time for early detection through screening tests.

Cancer can sometimes start in the small bowel (small intestine), but small bowel cancer is more uncommon than large bowel cancer.

Bowel cancer is a general term for cancer that begins in the large bowel. Depending on where cancer starts, bowel cancer is sometimes called colon or rectal cancer.


According to the American Cancer Society, men and women should begin screening for colorectal cancer at age 45.

However, the age at which such screening tests begin may depend largely upon the risk factors, especially a family history of colon and rectal cancers.

There are many screening tests available, including some non-invasive and inexpensive tests that can be done at home.

Regular colorectal screenings or examinations are very important as they help detect problems early. Colonoscopy is the best screening evaluation. Fecal occult blood tests, flexible sigmoidoscopy, barium enema and CT colonography (virtual colonoscopy) are some other screening options that a doctor can suggest to check for colon cancer.

Risk factors:

Signs and Symptoms:

is one of the most lethal cancers that can send loud warning signs to indicate that something is wrong.

Like all cancers, colon cancer is best treated when detected early. In addition to regular screenings, recognizing the signs and symptoms of colon cancer could save lives.

1. Change in bowel habits

Changes in bowel movement or habits are one of the most common symptoms of colon cancer.

It can mean changes in frequency, consistency or in the appearance of the stool. Sudden onset of constipation or diarrhea may also be experienced.

Changes in the bowels that last more than a few days may be a sign of an underlying health issue.

Occasional changes may occur due to dietary changes, viral or bacterial infection. However, if there are unexplained or new things experienced that lasts more than a couple of days, a trip to the doctor may be needed.

And while colon cancer can be a cause for these changes, many other things can do the same thing. In fact, causes other than cancer is probably more frequent. This is why having this symptom checked by a doctor is important.

2. Rectal bleeding

Rectal bleeding is the passing of blood through the anus. It is most likely due to a bleeding from the lower colon or rectum. This is a very common symptom of colon cancer.

It is called rectal bleeding because the rectum lies immediately above the anus.

Bright, red blood seen on the toilet paper or red or pink water in the toilet bowl after a bowel movement can be signs of a rectal bleeding.

Hemorrhoids are often thought to be the main cause of rectal bleeding. This more often hinders early colon cancer diagnosis.

Typically, hemorrhoids have symptoms that come and go with flare-ups, whereas rectal bleeding caused by colon cancer typically continues or worsens. It is also more likely to be accompanied by pain.

However, there are cases wherein rectal bleeding may not be painful. The bleeding also may also be occult or not visible with the human eye.

It is important to note that anyone experiencing bleeding from the rectum should see a doctor immediately. Most notably, people who are over 40 years old. If bleeding is not present but other symptoms are there, have it checked anyways. A physician will likely recommend tests such as a colonoscopy to rule out cancer.

3. Bloody and narrow stools

The appearance of blood in the stool is another serious warning symptom of colon cancer.

Sometimes the blood in the stool can be bright red, maroon or black and tarry in appearance. Black stools may signify the presence of dried blood. It may also be occult or not visible to the naked eye. The severity of this symptom depends on the advancement and the location of the disease.

A fecal occult test can detect whether there is blood in the stool, and additional examinations can help doctors determine the source of the blood and the proper course of treatment.

The appearance of narrow, pencil-thin stools is another noticeable change that may indicate colon cancer.

If the stool appearance is narrow or stringy only once in a while, it’s no big deal. But if it happens often and comes with other symptoms, it may be a sign of something more serious like colon cancer.

Obstruction of the colon is the most likely cause of these stools.

4. Abdominal pain and bloating

Together with blood in stool and changes in bowel movement, vague abdominal pain is another hallmark symptom of colon cancer.

Many people experience abdominal pain at some point in their lives. Like many other symptoms, abdominal pain is often thought of as harmless or not serious. After all, it is a common symptom of other noncancerous conditions, such as hemorrhoids and irritable bowel syndrome.

In addition, occasional cramps or bloating are common digestive issues that can occur due to an upset stomach, gas, or eating certain foods.

However, frequent severe, and unexplained cramps and bloating can be a sign of colon cancer.

Since colon cancer occurs in the large intestine, bowel habits can be greatly affected. The changes can lead to severe and frequent cramping, bloating and abdominal pain. These could be a big red flag for colon cancer.

Bloating, on the other hand, occurs when things are starting to get blocked and backed up in the colon.

If there is a constant pain in the right side of the abdomen, that may mean the disease is in the later stages and has spread to the liver.

5. Shortness of breath

This is one of the most overlooked symptom of colon cancer.

Sometimes shortness of breath can happen rapidly, and can be quite frightening. Other times, it can be mild and bothersome when doing daily activities.

Shortness of breath may include difficulty catching breath, noisy breathing or very fast and shallow breaths.

The medical term for this is dyspnea.

Cancer can drain the body of its energy. Breathing troubles are brought about by the body not getting enough oxygen because the body can’t get enough oxygen in the bloodstream.

Also, shortness of breath can be another effect of a slow internal bleeding. In the absence of aggressive bleeding or vomiting blood, the body puts more plasma in the blood without making more iron or red blood cells.

And while this prevents the body from losing blood in large volumes, it reduces the blood’s ability to carry oxygen. This results in shortness of breath.

6. Bowel doesn’t empty completely or urgent need to poop

Tenesmus or the feeling of having to defecate without having stools is another symptom of colon cancer.

This symptom makes a person feel an urgent need to use the restroom repeatedly and empty the bowels even though there is nothing left to expel.

It is further described as having pain upon defecation, a feeling of being unable to empty the large bowel of stool, cramping rectal pain, and straining harder to produce only a small amount of stool during bowel movements.

Pain can be present especially if there is cramping or other digestive symptoms. The symptoms can come and go, or they may persist long term.

A growth that tuns into a blockage in the colon may cause this symptom.

7. Weakness or fatigue

Cancer related fatigue is one of the most common symptoms reported by cancer patients.

Cancer-related fatigue (also referred to as CRF) refers to tiredness or exhaustion brought about by cancer.

It is easy to confuse fatigue with simply being tired. This type of fatigue impacts a person physically, emotionally, and mentally. It is not linked to any physical activity or exertion. CRF is also not easily alleviated by rest.

Usually, it comes on suddenly.

Colon cancer makes people feel constantly tired or weak. It is possibly due to the cancer cells using the body’s energy. In addition, the stress of bowel symptoms can further exacerbate it.

8. Unexplained weight loss

Unexplained and unintentional weight loss is the loss of 10 pounds or more within six month or less.  Colon cancer can cause this symptom in a variety of ways:

The symptoms of appetite loss, weight loss, and fatigue in patients with colon cancer are usually related.

Persistent diarrhea can also cause weight loss. Stomach pain and nausea can reduce appetite so that not enough food is consumed to maintain a healthy weight.

Cancer cells also use up a lot of the body’s energy supply.

The immune system also uses energy as it works hard to fight the disease.

In addition, cancer cells release substances into the body that change the way food is converted to energy, which can contribute to the weight loss.

Finally, when a tumor in the colon gets large enough, it could block the colon. This blockage can affect a person’s bowel habits, which can then lead to further unexplained weight loss.


is defined as the lack of red blood cells that transport oxygen to body tissues. It can also be the lack of a protein called hemoglobin which is needed by red blood cells to transport oxygen.

may be the first sign that there’s internal bleeding, even if any other colon cancer symptoms have not manifested yet.

Bleeding is believed to be the main cause of when the colon is involved. Tumors release certain chemicals that stimulate the formation of new blood vessels. As the tumor grows, these vessels burst which leads to the loss of red blood cells.

In turn, the bleeding gives rise to iron deficiency. Even if there are enough supplies of iron in the blood, the surrounding inflammation can cause iron molecules to be trapped in immune cells. The continuation of the inflammation affects the availability of iron. It becomes less and less and results in the development of iron deficiency anemia.

10. Nausea and vomiting

Nausea and vomiting are often seen as a single thing but they are separate physiological conditions.

These symptoms may indicate numerous health conditions. However, if nausea and vomiting are accompanied with other symptoms such as constipation or pain, colon cancer could be the cause.

When vomiting is a symptom of colon cancer, it is usually because a tumor is causing a bowel obstruction.

Depending on the severity of the blockage, solids, liquids and even gas may be prevented from passing through the colon. Nausea and vomiting occur when the tumor is obstructing the bowel and hinders the passage of liquid or solid waste or gas.