The word cancer can bear heavily on almost everyone, but what is important is to look beyond this fear and learn more about the disease so one can make informed decisions about treatment and management for a better future.
Cancer in the colon or rectum, the last sections of the large intestine, is called colorectal cancer. Most of these cancers start as a small clump of abnormally growing cells called polyp on the inner lining of the wall of the intestine. Mostly harmless, these polyps are potential precursors to colon cancer. No symptoms may show at this initial stage. When a polyp becomes cancerous, the cells multiply and grow through the various layers of the wall of the colon or rectum (stages 0 to I), and may affect the blood and lymph vessels (stage II to III), which serves as a medium for the spread of cancer to other parts of the body (stage IV). With the progression of the cancer, one or more these symptoms may be experienced:
- Changes in bowel movements (constipation, diarrhea or narrowing of stools)
- A feeling of having a bowel movement, which does not get relieved even after having one
- Rectal bleeding and bloody stools
- Abdominal pain
- Weakness and fatigue
- Unintended weight loss
- Excess blood loss due to bleeding in the digestive tract
If you have any of these symptoms, it is highly advisable to visit your doctor immediately.
So what causes colorectal cancer? As with most cancers, the exact cause of colorectal cancer is not very clear. There are various factors that increase the risk of colorectal cancer and may include obesity, physical inactivity, smoking, heavy use of alcohol, and diets rich in red meats, processed meats and meats cooked at very high temperatures. These are things that you can change in your lifestyle to avoid colorectal cancer. However, there are other risk factors such as age (after the age of 50), history of inflammatory bowel disease or diabetes, being African-American, or a family history of colorectal cancer or polyps, that one cannot change.
Colorectal cancer is considered the third most common cancer (apart from skin cancer) in the United States and third leading cause of death due to cancer. With estimates of new cases of colon cancer for the year 2016 are 95,270 of colon cancer and 39,220 of rectal cancer, the death toll for the year is estimated to be 49,190 in the US alone. However alarming these numbers may seem, there has been a constant drop in the number of cases of colorectal cancer due to early screening and removal of the cancer at its initial stage.1
It has been suggested that regular screening is the most effect means of preventing colorectal cancer if you have a predisposition to developing it. A harmless polyp can take 10 to 15 years to develop into cancer, which is a large window period within which one can get tested and treated effectively. Treating colorectal cancer at an early stage can offer a 90% 5-year relative survival rate. Sadly only a little over half of high-risk patients get tested.
Treatment of colorectal cancer is decided based on the stage of cancer (stages 0 to IV), which is the extent to which the cancer has progressed. The main treatment modalities include:
- Surgery: Cancer cells are removed surgically.
- Radiation therapy: High-frequency radiation is directed onto the body to kill the cancer cells.
- Chemotherapy: Medications are administered to kill the cancer cells.
- Targeted therapy: This involves the administration of drugs that interfere with specific changes that take place for a cell to become cancerous.
- Ablation: Radiofrequency, alcohol or cryosurgery (freezing temperature) are used to destroy the cancer cells.
- Embolization: The blood flow to the cancer cells are either blocked or reduced so that they do not receive nourishment for survival.
Success of treatment and 5-year relative survival rates are higher for early stage cancer as shown below:
|Colon cancer||Rectal cancer|
|Stage I: ~92%||Stage I: ~87%|
|Stage II: 63 to 87%||Stage II: 49 to 80%|
|Stage III: 53 to 89%||Stage III: 58 to 84%|
|Stage IV: 11%||Stage IV: 12%|
These numbers clearly depict the importance of early identification, prevention and intervention. Apart from this, research is ongoing to find the exact cause of colorectal cancer and better ways to treat this cancer.
At Greater Houston Gastroenterology, we provide specialized services and treatments for a wide range of gastrointestinal conditions. Our dedicated clinical staff and physician assistants are available to assist in delivering high-quality treatment and expert care. As the largest GI group in the greater Houston area, we offer 17 locations for your convenience.