Colorectal cancer, also known as bowel cancer, colon cancer or rectal cancer, is any cancer (a growth, lump, tumor) of the colon and the rectum. The World Health Organization and CDC say it is the second most common cancer worldwide, after lung cancer.
The American Cancer Society suggests that about 1 in 20 people in the US will develop colorectal cancer during their lifetime, with the risk being slightly higher for men than for women. Due to advances in screening techniques and improvements in treatments, the death rate from colorectal cancer has been dropping for over 20 years.
A colorectal cancer may be benign or malignant. Benign means the tumor will not spread, while a malignant tumor consists of cells that can spread to other parts of the body and damage them.
The colon and rectum
The large intestine is also called the colon or large bowel.
The colon and rectum belong to our body's digestive system - together they are also known as the large bowel.
The colon reabsorbs large quantities of water and nutrients from undigested food products as they pass along it.
The rectum is at the end of the colon and stores feces (stools, waste material) before being expelled from the body.
Symptoms of colorectal cancer
- Going to the toilet more often.
- A feeling that the bowel does not empty properly after a bowel movement.
- Blood in feces (stools).
- Pains in the abdomen.
- Bloating in the abdomen.
- A feeling of fullness in the abdomen (maybe even after not eating for a while).
- Fatigue (tiredness).
- Inexplicable weight loss.
- A lump in the tummy or a lump in the back passage felt by your doctor.
- Unexplained iron deficiency in men, or in women after the menopause.
As most of these symptoms may also indicate other possible conditions, it is important that the patient sees a doctor for a proper diagnosis. Anybody who experiences some of these symptoms for four weeks should see their doctor.
Causes of colorectal cancer
Experts say we are not completely sure why colorectal cancer develops in some people and not in others. However, several risk factors have been identified over the years - a risk factor is something which may increase a person's chances of developing a disease or condition.
The possible risk factors for colorectal factors are:
- Being elderly - the older you are the higher the risk is.
- A diet that is very high in animal protein.
- A diet that is very high in saturated fats.
- A diet that is very low in dietary fiber.
- A diet that is very high in calories.
- A diet that is very high in alcohol consumption.
- Women who have had breast, ovary and uterus cancers.
- A family history of colorectal cancer.
- Patients with ulcerative colitis.
- Being overweight/obese.
- Smoking. This study found that smoking is significantly associated with an increased risk for colorectal cancer and death.
- Being physically inactive.
- Presence of polyps in the colon/rectum. Untreated polyps may eventually become cancerous.
- Having Crohn's disease or Irritable Bowel Disease have a higher risk of developing colorectal cancer.
Most colon cancers develop within polyps (adenoma). These are often found inside the bowel wall.
Recent developments on colorectal cancer causes from MNT news
Men who are very overweight or obese during late adolescence may be more than twice as likely to develop colorectal cancer by middle age. This is according to a new study published in Gut - a journal of The BMJ.
Eating processed meats can cause colorectal cancer, concludes a new report from the World Health Organization, while eating red meats may also raise risk for the disease.
Sprouty2, a gene known to stop tumors spreading to other parts of the body in many types of cancer, appears to play the opposite role in some forms of colorectal cancer.
This was the finding of a study published in the journal Oncogene and led by the University of Missouri School of Medicine in Columbia, which may spur new treatments for colorectal cancer.
Scientists have revealed a biological connection between obesity and colorectal cancer, and they have identified an approved drug that might prevent the cancer from developing. The findings are published in Cancer Research.
How common is colorectal cancer?
According to WHO (World Health Organization) colorectal cancer is the second most common tumor among both men and women (after lung tumors).
Approximately 2% of over 50-year-olds will eventually develop colorectal cancer in Western Europe.
40% of people who are diagnosed with colorectal cancer are already at an advanced stage of the cancer. For these patients surgery is probably the most likely option.
Colorectal cancer tends to affect men and women equally. However, men tend to develop it at a younger age.
On the next page we look at tests and diagnosis for colorectal cancer, how it can be prevented and the available treatments for colorectal cancer.