Also known as colon cancer, bowel cancer or rectal cancer, colorectal cancer is a type of cancer that develops in the colon (large intestine) and the rectum. This occurs when the normal cells lining the large intestine and rectum become abnormal and start multiplying and growing out of control.
Over a period of time, the abnormal cells start forming a tumor which can be benign, non-cancerous, or malignant. In the early stages, colorectal cancer may not present any obvious symptoms. This type of cancer is considered to be the third leading cause of cancer deaths among men, and second among women.
Types of Colorectal Cancer
There are various types of colon cancer, and these include:
Adenocarcinomas
Colon and rectal adenocarcinomas are a high-risk cause of colorectal cancer. The cells may start as polyps which form in the gastrointestinal tract spreading to the internal lining of the large intestine leading to cancer. A type of polyp called adenoma tends to grow into cancer and can be removed beforehand if the cancer is caught early during a routine procedure known as a colonoscopy.
Gastrointestinal Carcinoid Tumors
These tumors spread in the nerve cells called neuro endocrine cells where hormone production is regulated. Carcinoid tumors normally grow slowly and spread in the gastrointestinal tract, which contribute to colorectal cancer.
Colorectal Adenocarcinoma
Adenocarcinoma is a cancer that develops in the epithelial cells that line the surface of the body. Colorectal adenocarcinoma forms in the inner lining of the large intestines and extends to the outer layer. There are two genotypes of adenocarcinoma:
Signet ring cell carcinoma (SRCC) is an odd form of malignant adenocarcinoma, which extracts mucin, and its rate of cells division is very aggressive. It is characterized by its appearance under the microscope.
Mucinous adenocarcinoma contains extracellular mucin which encourages cancer cells to grow quickly and become aggressive. This contributes to the colon and rectal adenocarcinomas.
Gastrointestinal Stromal Tumors (GIST)
These is a rare type of tumor forming in the lining of the gastrointestinal tract. GIST is cancer that starts in the connective tissues such as muscle, deep skin tissues, nerves, blood vessels and fat. This then develops in the stomach or small intestine or rectum.
Primary Colorectal Lymphomas
This is a rare condition and mostly affects the older male gender and occurs in the lymphoma system in lymphocyte cells. The lymphoma may grow in the digestive tract, lymph nodes, spleen and bone marrow.
Symptoms of Colorectal Cancer
During the early stages, colorectal cancer may not present any obvious symptoms. However, an individual may experience symptoms such as:
- A feeling of fullness in the bowel even after emptying it
- Abdominal discomfort such as pain, gas and bloating
- Constipation and/or diarrhea
- Black stool due to presence of blood in it
- Bleeding from the rectum
- Fatigue
- Unexplained drastic weight loss
- Abdominal cramping
- Fatigue
- Nausea and vomiting
Causes and Risk Factors of Colorectal Cancer
There is no known cause for colorectal cancer although studies are still ongoing. However, there are risk factors which may increase the chances of one developing the disease. These include:
- Age: Studies show that the older one is, the higher the chances are of developing colorectal cancer, and this risk increases after the age of 50 years
- A history of colon polyps
- Genetic predisposition: inherited syndromes like familial adenomatous polyposis (area that normal cells inside the colon form a mass)
- Family history of colorectal cancer
- Chronic inflammatory diseases such as Crohn’s and ulcerative colitis
- Obesity
- History of bowel disease
- Sedentary lifestyle
Diagnosis of the Colorectal Cancer
Polyps tumor can be detected before they grow into cancer. Colorectal cancer if detected in its early stages can be successfully. Some of the diagnoses used to detect colorectal cancer include:
Colonoscopy
A colonoscopy is whereby the colon and rectum are fully examined using a tiny camera. If this is performed at an early stage the cancer may be avoided, if polyps are detected and removed.
CT Colonography
This is a procedure done using a CT machine which takes images of the colon. The colon is first emptied before the examination. This examination is efficient as it can find the cancer in its early stage or when it is still in the form of polyps before growing into cancerous cells.
Imaging Test
The imaging test is done using MRI scans or ultrasound which assists to indicate if the cancer has spread to other parts of the body.
Blood Stool Test
This examination is done to verify the presence of blood in the stool but cannot be accurate because the blood may not be present in all the cases.
Stool DNA-fecal Immunochemical Test
This test detects the mutation of the cells shed in stool on various genes that are linked to colon cancer. Amounts of blood in the stool is also detected.
Lower Gastrointestinal Tract Radiography (Barium enema)
This is an X-ray done by placing a contrast dye on the patient’s bowel. An enema injection is filled into the rectum via a small tube so that there is a clear image of the rectum, colon and part of small intestines.
Flexible Sigmoidoscopy
This is a procedure done using a thin flexible tube (sigmoidoscope) which is inserted into the rectum, to examine the colon.
Colorectal Cancer Treatment
Colorectal cancer treatment is usually dependent on:
- The aggressiveness of the cancer
- Type of the cancer
- Stage of the cancer
- Size and location of the tumor
- Age and overall health of the patient
- History of colorectal cancer in the family
- Gene mutation test results
Treatment options for colorectal cancer include:
Surgery
A malignant tumor in the colon and lymph nodes are usually removed surgically to prevent the multiplication of the cancer cells. Sometimes the rectum is also removed completely. Afterwards a colostomy bag is attached temporarily to enable drainage of the stools.
Chemotherapy
Involves the use of anti-cancer drugs to destroy any remaining fast-growing cancer cells in the thyroid area.
Targeted Therapy
Targeted therapy such as bevacizumab (Avastin) and ramucirumab (Cyramza) is at times used to kill the specific protein cells which cause the development of the colorectal cancer.
Radiation therapy
Radiation therapy involves high energy radiation which penetrates and destroys the cancerous cells and stop the cells from multiplying. This is sometimes done before the surgery to shrink the tumor.
Next Step
At King’s College Hospital Dubai, we focus on offering an exemplary service. From initial consultation through to final diagnosis, treatment and beyond. Our multidisciplinary team of expert doctors and nurses, and technologists led by Dr Hassan Ghazal – an American triple board-certified Consultant Medical Oncologist and a Consultant Clinical Hematologist with more than 3 decades of clinical experience, are here to offer tailored management and treatment of your condition, and to answer any questions that you may have throughout your time with us. Whatever you need us for, we’re only a phone-call away.
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