What is rectal cancer?
Cancer of the rectum (rectal cancer) and colon (colon cancer) is often called “colorectal cancer.” The rectum is the last few inches of the large intestine. It begins at the end of the last section of your colon and ends when it reaches the small, narrow path that leads to the anus.
Although rectal and colon cancers are similar in many ways, their treatments are very different. This is because the rectum is in a confined space and cannot be separated from other organs and structures. Surgery may be done to remove the narrow-space rectal cancer complex.
In the past, long-term survival was rare for people with colorectal cancer, even after long-term treatment. Thanks to advances in treatment over the past few decades, colorectal cancer survival rates have vastly improved.
Types of rectal cancer
Most people with colorectal cancer have a type called adenocarcinoma. There are also other types of rare tumors. These other types of rectal cancer can be treated differently from adenocarcinoma. The section of this guide on the diagnosis and treatment of this cancer is primarily concerned with adenocarcinoma.
Learn more about the types:
- Adenocarcinoma: It is a cancer of the cells that line the inner surface of the rectum.
- Carcinoid tumors: Carcinoid tumors begin in the hormone-producing cells of the intestine.
- Gastrointestinal stromal tumors: Gastrointestinal stromal tumors are a type of soft tissue sarcoma that is found anywhere in the gastrointestinal tract, but it is very rare in the rectum. These tumors can also be other types of sarcoma that begin in the blood vessels or connective tissue of the colon.
- Lymphoma: Lymphoma is a cancer of the immune system. It usually begins in the lymph nodes, but begins in the rectum.
- Hereditary rectal cancer: 5 to 10 per cent of people develop colorectal cancer because, specific mutations in genes are passed down from parent to child, known as inheritance. MSK experts can provide you with a genetic test to find out if your genes have a genetic mutation that increases your risk of cancer. Having this test assesses your personal risk. Learn more about genetic testing for colorectal cancer and the inherited conditions that cause the disease.
Causes of rectal cancer
There are an estimated 44,180 new cases of colorectal cancer each year in the United States. It occurs more often in men than in women. Colon cancers are often together and have the same risk factors. The average age of diagnosis is 66 years and the risk increases with age.
People with a personal or family history of colorectal cancer or polyps are more likely to have inherited colorectal cancer syndromes (that is, familial adenomatous polyposis (FAP) and hereditary nonpolyposis colorectal cancer (HNPCC) or ulcerative colitis.
Screening may be necessary) earlier than the general population A person with a first-degree relative (parents, siblings, or children) with colon cancer is 2 to 3 times more likely to develop cancer, but this does not mean that people without a family history are at risk 80% of new cases of colorectal cancer Many are diagnosed in people who are not identified as “high risk.”
Colorectal cancer case studies have found that certain lifestyle factors increase a person’s risk. These factors are:
- A diet is rich in fat and red meat.
- A diet low in fruits and vegetables.
- High caloric intake.
- Less physical activity.
- Ob arrears.
- Also, smoking and excessive alcohol consumption influence the development of colorectal cancer.
Although all of these factors are avoided, some people still develop colon cancer. With screening and early detection, these patients can be cured in most cases.
Symptoms & signs of rectal cancer
Signs and Symptoms may include:
- A change in bowel habits such as diarrhoea, constipation, or increased bowel movements
- Dark maroon or bright red blood in the stool
- Narrow stool
- The feeling that your bowel is not empty
- Abdominal pain
- Unexplained weight loss
- Weakness or fatigue
- Most cancers occur after age 50 (except for family history or hereditary cause of the disease). However, in recent years, rates of colorectal cancer among people in their 20s and 30s have been on the rise.
- Learn more about colorectal cancer before age 50.
- Family history of Lynch syndrome or familial adenomatous polyposis
- Some inherited disorders can dramatically increase the risk of colorectal cancer. These include Lynch syndrome and familial adenomatous polyposis. Learn more about the risk of colorectal cancer and these and other inherited conditions that affect our genetic testing services.
- Cancer history
- If you already have colon cancer, you are at risk of developing it again.
- History of inflammatory bowel disease
- Inflammatory bowel diseases, such as ulcerative colitis and Crohn’s colitis, increase the risk of this colon cancer.
- Family history of cancer
You are at risk for colorectal cancer:
- A close family member, such as parents or siblings, was diagnosed with colorectal cancer 50 years ago.
- Many blood relatives have cancer.
- There is a familiar pattern to some other cancers, including endometrial, ovarian, gastric, urinary tract, brain, and pancreas cancers.
The colorectal cancer screening test can detect rectal cancer. Or suspect based on your symptoms. Tests and procedures used to confirm the diagnosis:
- Using an endoscope to examine the inside of your colon and rectum (colonoscopy): A colonoscopy uses a long, flexible tube (colonoscope) connected to a video camera and monitor to view your colon and rectum. If cancer is found in your rectum, your doctor may recommend examining your colon for additional suspicious areas.
- Removing a sample of tissue for examination (biopsy): If suspicious areas are found, your doctor can send tissue samples (biopsies) for analysis and surgical instruments through a colonoscopy to remove the polyps.
- The tissue samples are sent to the laboratory for analysis by doctors who specialize in analyzing blood and body tissues (pathologists): The tests can determine if the cells are cancerous if they are aggressive, and which genes are abnormal in the cancer cells. Your doctor will use this information to help her understand your diagnosis and determine your treatment options.
Rectal cancer treatment
When possible, surgery is used to kill cancer cells. Other treatments, such as chemotherapy and radiation therapy, may be used to kill cancer cells that remain after surgery and reduce the risk of cancer recurrence.
your doctor may recommend a combination of chemotherapy and radiation therapy as initial treatment. These combination therapies can shrink cancer and make it easier to remove during surgery.
Which operation is best for you depends on your specific condition, such as the location and stage of your cancer, how aggressive the cancer cells are, your general health, and your preferences.
Operations used to treat rectal cancer
Removal of very small cancers from inside the rectum:
Most small bowel cancers can be removed with a colonoscopy or other special scope inserted through the anus (transanal local excision). Surgical instruments can be sent through the endoscope to cut through cancer and some of the healthy tissue around it.
This procedure may be an option if your cancer is small and unlikely to spread to nearby lymph nodes. If a lab test finds that your cancer cells are aggressive or may be spreading to the lymph nodes, your doctor may recommend additional surgery.
Total or partial removal of the rectum:
Large rectal cancers that are too far from the anal canal can be removed in one or the entire rectal procedure (less anterior dissection). Nearby lymph nodes and tissues are also removed. This procedure protects the anus so that waste leaves the body normally.
The way this procedure is done depends on the location of cancer. If cancer affects the upper part of the rectum, that part of the rectum is removed and the colon is then attached to the rest of the rectum (colorectal anastomosis). If the cancer is in the lower rectum, the entire rectum is removed. The colon then forms like a pouch and is attached to the anus (coloanal anastomosis).
Removal of the rectum and anus:
For rectal cancers near the anus, it is not possible to completely remove cancer without damaging the muscles that control bowel movements.
The surgeon creates an opening in the abdomen and fixes the rest of the colon (colostomy). Waste leaves your body through the opening and collects in a bag that is attached to your abdomen.