A rectal cancer is a cancer that is developed in the rectum which is the lower part of the colon that connects the large intestine to the anus. It stores the formed stool that needs to be eliminated. Rectal cancer is more likely to develop in men when compared to women. The most common type of rectal cancer is adenocarcinoma, which develops from the glands.
The symptoms of rectal cancer may be similar to bowel diseases, like Crohn's disease. It may even be similar to colon cancer. There are no early signs of cancer, however, when cancer develops, the symptoms become persistent and severe. The severity of the symptoms increases when cancer spreads throughout the rectum and to other parts of the body like the colon. Rectal cancer also changes the frequency of bowel movements. The color of the stool may appear dark if the person experiences bloody stool.
A few symptoms that are mentioned below are:
- Inability to empty the bowel
- Change in the shape and size of the faecal matter
- Bloody stool
- Bowel obstruction
- Pain in the rectum
- Cramps in the stomach
- Bloated feeling
- Rectal bleeding
- Abdominal pain and discomfort
- Unexplained weight loss
Every individual is different and therefore these signs and symptoms may vary from one person to another.
Causes and Risk Factors
Rectal cancer is a slow growing cancer. It first forms as a precancerous growth called the polyp and later forms a tumour. Cancer is caused when a few cells in the rectum develop mutations in the DNA. These mutated cells divide and grow rapidly which lead to the formation of a tumour. The cancerous cells damage the organ and invade, by spreading the disease to the other parts of the body.
The exact cause of the disease is not known, however, a few risk factors are mentioned which increase the risk of developing the disease.
- A family history of cancer may increase the risk of developing rectal cancer. An inherited gene in the body may increase the probability of developing the disease in a person’s lifetime.
- Age is one of the most significant causes of developing the disease. As a person ages, the body and the immune cells becomes weak and so the body may be affected with various diseases, even rectal cancer. Rectal cancer usually develops in people above the age of 55 years.
- Smoking also increases the risk of developing rectal cancer.
- Inflammatory bowel disease may lead to the development of rectal cancer.
If the person experiences any of the above mentioned symptoms, the doctor recommends a few diagnostic tests to check for the presence of a tumour or any abnormal changes in the rectum. The following diagnostic tests are:
- Rectal examination is performed by the doctor to check for the changes in the rectum. He inserts two fingers into the rectum to feel for polyps or other abnormal changes.
- Faecal occult blood test (FOBT) is a stool test to check for the traces of blood in the stool. This test also detects the presence of tiny polyps.
- Faecal immunochemical test is a test performed at home. It is done to check for the presence of blood proteins in the faecal matter of the patient
- Endoscopic tests are performed to get a clear picture of the condition inside the rectum. A few endoscopic tests are:
- Proctoscopy is a method in which a thin tube is inserted into the rectum. It provides a proper view of the rectum. Abnormal tissues can be removed and sent as a biopsy sample for examination.
- Sigmoidoscopy is a method which uses a flexible plastic tube with a camera fixed at one end. It is inserted into the rectum. It helps the doctor view the rectum and the lower part of the colon. Any abnormal changes can be removed and sent for examination.
- Colonoscopy is a method in which a tube is sent into the colon to get a view of the inside of the colon. This tube is slightly longer than the tube in sigmoidoscopy. Colonoscopy helps the doctor get an entire view of the colon.
- Endoscopic ultrasound (EUS) is performed to get a picture of the organ from inside. An endoscope is inserted into the body with a probe at one end of the tube that creates sound waves to create a picture of the internal organ. This method is also called as endosonography.
- Imaging tests
- CT scan
- MRI scan
- PET scan
- Double contrast barium enema
Once the diagnosis confirms the presence of a tumour in the rectum, one or more of the following treatments are performed.
Chemotherapy is a treatment that uses drugs to stop the spread of cancer to other parts of the body and also kills the cancer-causing cells. This medication travels through the body and kills the cancerous cells in the body. These drugs are called as cytotoxic medicines.
Radiotherapy uses radiation beams to kill the cancer-causing cells. It is usually given after the surgery or along with chemotherapy to remove any leftover cancer cells in the body.
Surgery is performed to remove a part of the tissue or the entire organ. The aim of the surgery is to remove cancer from the body.
Immunotherapy is also performed to treat the person suffering from cancer. Vaccines and medications are given to the patient to help the patient get rid of cancer.