Signs of Bowel Cancer and Who is at Risk

The bowels or intestines is classified into two distinct regions: the small intestine and the large intestine. The small intestine is the first part of gut, and it begins after the stomach. The adult small intestine is approximately 23 feet in length, and occupies majority of the abdominal space. After the small intestine ends, the large intestine begins. The large intestine (also called colon) is approximately 5 feet in length.

The term “bowel” collectively refers to both small intestine and large intestine. Cancer can affect any region of both the small and large intestines. The most common type of bowel cancer is colorectal cancer, which affects parts of colon and rectum. On the other hand, cancer of the small intestine is rare. Therefore, the term “bowel cancer” is mostly used to refer to colon or colorectal cancer. Bowel cancer is one of the deadliest forms of cancer. It is also one of the most common types of cancer in both men and women.

Do I have bowel cancer?

There are a variety of signs and symptoms that arise in bowel cancer. However, most of these signs and symptoms are not specific to bowel cancer. For example, the three main signs of bowel cancer include bloody stools, changes in bowel habits, and abdominal pain. These are very general signs that could indicate the presence of many other diseases of digestive tract, not necessarily a cancer.

Therefore, the diagnosis of bowel cancer requires further tests such as colonoscopy, biopsy, and scans. In fact, it is advisable for people who are at high risk of developing bowel cancer to have routine screenings. The following are some of the common signs and symptoms associated with bowel cancer.

Blood in stools

Blood in stool worries most people. However, a bloody stool is not a specific sign of bowel cancer. It could also arise in other conditions, such as hemorrhoids. Blood in stool may be easily visible, and may coat the stools red. Even the toilet water may turn red if bleeding is in copious amounts. However, in many cases, bleeding is not very obvious. It may only be seen as tiny red streaks in tissue wipes after a bowel motion.

Read more on bleeding in bowels.

Change in stool

Changes in the frequency of bowel movements and changes in the consistency of stools are also common signs of bowel cancer. Both diarrhea and constipation could accompany colon or colorectal cancer. However, diarrhea and constipation by themselves are not indicators of colon cancer. Only when these changes in bowel movements persist for a long period (more than 4 weeks), and are accompanied by other signs such as blood in stools, should they be investigated for the possibility of colon cancer.

Abdominal pain

Abdominal cramps or pain are also a common occurrence in colon cancer. The pain is usually localized to the lower part of the abdomen. This is because the most common form of bowel cancer is the colorectal cancer, which affects colon and rectum in the lower abdominal space.

Like other symptoms of colorectal cancer, abdominal pain is non-specific on its own. The pain may last for a short time or persist over longer periods. Presence of colorectal cancer can be investigated if abdominal pain is accompanied by other signs such as bloody stools and changes in bowel movements.

Sensation of incomplete bowel emptying

Colon cancer can also cause tenesmus. Tenesmus refers to a constant urge to defecate, even though defecation does not happen. There is a sensation of incomplete bowel emptying even after defecation.

Read more on tenesmus.

Weight loss

Unexpected weight loss, when accompanied by bloody stool, persistent change in bowel habits, lower abdominal pain and tenesmus, should be investigated for colon cancer. Unexpected and significant weight loss is a common feature in many cancers.


General weakness and fatigue is a symptom of many different diseases. When it occurs in conjunction with the above mentioned signs and symptoms, bowel cancer may be suspected. Even when other symptoms are absent, chronic and worsening fatigue should be taken seriously and medical attention must be sought.

Who is at risk?

Abdomen bowel sounds

It is difficult to conclusively identify colorectal cancer in the early stages. Initially, there are no signs and symptoms that ring the alarm bells. When the signs and symptoms do begin, they are general and not specific for colorectal cancer. However, there are certain factors that increase the risk of developing this potentially fatal disease. Doctors advise regular screening for people who have these risk factors.

The following are the main risk factors associated with development of colorectal cancer:

  • Old age: The majority of cases of colorectal cancer have been diagnosed in people over the age of 50 years. Therefore, it is advisable for people over 50 years of age to undergo regular screening for the presence of this disease. Colonoscopy is advised every year for people in this risk group. It is important to note that even though the risk of developing colon cancer is lower in the younger age groups, it is still not zero. Young people could also get colorectal cancer.
  • Genetics: Risk of getting colon cancer is also increased in people who have certain genetic mutations. A group of genetic conditions known as inherited polyposis syndromes are associated with increased risk of colorectal cancer. Examples of these genetic conditions include hereditary non-polyposis colorectal cancer, familial adenomatous polyposis, and hamartomatous polyposis syndromes. There is also an increased risk of colorectal cancer if one has close family members with the disease. Having a history of being diagnosed and treated for colorectal cancer also increases the risk of developing this malignancy again.
  • Chronic bowel disease: Chronic bowel diseases cause long-term inflammation of the gut. This chronic inflammation is thought to increase the risk of developing colorectal cancer. The most common example is inflammatory bowel disease (abbreviated as IBD), such as Crohn’s disease and ulcerative colitis. Both these conditions increase the risk of developing colorectal cancer.
  • Cigarette and alcohol: Cigarette smoking is known to increase the risk of many different types of cancers. Heavy smokers are at an increased risk for developing colon cancer. Chronic alcohol abuse is also thought to increase the risk of colon cancer.
  • Low-fiber, high-fat diet: People who chronically eat low-fiber and high-fat diets, increase their risk of developing colorectal cancer. Also, long term consumption of smoked and cured meats is also suggested to increase the risk of colorectal cancer.
  • Sedentary lifestyle: Lack of regular physical exercise and a sedentary lifestyle increases the risk of colorectal cancer. Obesity, which is commonly associated with a sedentary lifestyle, is also a risk factor for developing colorectal cancer.
  • Diabetes: People with chronic diabetes have multiple ailments. Long-term diabetes also increases the risk of developing colorectal cancer. This is believed to be due to a weak immune system in chronic diabetics.
  • Radiation: Exposure to excessive radiation is known to increase the risk of a variety of cancers. Radiation therapy of abdomen or pelvis may increase the risk of colorectal cancer.

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