Colorectal cancer occurs when cells or growths called polyps in the colon or rectum become cancerous. According to the National Cancer Institute, colorectal cancer is the fourth most common cancer diagnosis in the United States and second leading cause of cancer deaths. In 2023, it’s estimated that more than 153,00 American men and women will be diagnosed, and an estimated 52,550 people will die of this disease.
Colon cancer begins in the large intestine at the lower part of the digestive tract. Rectal cancer occurs in the rectum, which is between the colon and anus.
Generally, men are a little more likely than women to develop colorectal cancer and African Americans are at higher risk. Adults above 50 years old are more likely to be diagnosed with colorectal cancer, although trends are showing that colorectal cancer has been affecting people as young as their 20s.
Colorectal cancer is not a contagious disease and cannot be spread from person to person. Researchers aren’t sure what causes colorectal cancer; however, there are some risk factors including:
- Eating a low-fiber diet
- Chronic inflammatory disease
- Family history of the disease
Screening for colorectal cancer has proven to be an effective tool in preventing the disease from developing in most cases. Early discovery of precancerous polyps in the colon or rectum allows for them to be removed before becoming cancerous.
In addition to screenings, there are lifestyle choices that may help reduce the risk of developing colorectal cancer including:
- Eating a high-fiber diet including fruits and vegetables
- Maintaining a healthy weight
- Limiting alcohol
- Avoiding smoking
Screening makes it possible to diagnose colorectal cancer early before it has a chance to spread and when it may be easier to treat, leading to better outcomes.
A diagnosis of colorectal cancer can be made using high-sensitivity fecal occult blood testing, sigmoidoscopy or colonoscopy beginning at age 45 years. For individuals at high risk, screening may be recommended sooner and performed more often than for people at average risk. Those with increased risk are individuals:
- Who have a close relative diagnosed with colorectal polyps or colorectal cancer
- Who have inflammatory bowel disease
- Who have genetic syndromes such as familial adenomatous polyposis (FAP) or hereditary non-polyposis colorectal cancer
- Who are African American
After colorectal cancer has been detected, a diagnostic colonoscopy will be performed to look inside the colon and rectum and a small piece of tissue can be biopsied. The doctor can also remove polyps during this procedure.
To determine treatment, the doctor will perform additional tests to stage the colorectal cancer as follows:
- Stage 1 and 2 – in the colon wall
- Stage 3 – spread to nearby lymph nodes
- Stage 4 – spread to other organs
Surgery is generally the treatment for colorectal cancer, which can be combined with chemotherapy and radio therapy.