It is the abnormal growth of cells within the large intestine/colon and rectum, and can be commonly called bowel cancer. In the initial stages this condition develops as little outgrowths on the inner lining of the colon and rectum called polyps. And gradually, if it goes undetected they turn into invasive cancer, which can spread to the adjacent tissue as well as to other part of the body. Depending on the region of the intestine that is affected, it is either called colon cancer or rectal cancer.
Bowel cancer remains one of the leading causes of morbidity and mortality worldwide, with the incidence of bowel cancer accounting for 9% of all diagnosed cancers each year. An estimated 394,000 deaths occur annually due to colorectal cancer. The five year survival rate for those diagnosed with colon and rectal cancer is about 69%.
What Are the Symptoms of colon and rectal Cancer?
Symptoms which should give you a warning that you may be having bowel cancer include:
- Altered bowel habits with alternating episodes of constipation and diarrhea
- Feeling of incomplete evacuation/emptying
- Bleeding per rectum
- Passage of bloody stools
- Abdominal or rectal pain
- Abdominal distention
- A lump in the anus
- Easy fatigability and weight loss
- Anemia which cannot be explained, indicating that you might be having concealed bleeding internally
If you have developed any of these symptoms and you are worried, then you should definitely see your doctor at the earliest.
What causes colon and rectal cancer?
Although an exact cause for the development of colon and rectal cancer cannot be pointed out, there have been several risk factors associated with increased chances of developing bowel cancer. These include:
- Having pre-existing bowel conditions such as Inflammatory bowel disease
- Genetic predisposition with a strong family history
- Previous diagnosis of polyps in the bowel
- Smoking
- Consumption of alcohol
- Being overweight or obese
- Consumption of a diet rich in red meat, especially processed meat
What tests are used to diagnose colon and rectal cancer?
Colon and rectal cancers are diagnosed by doctors using a physical examination and various investigation. During the physical examination your doctor will try to feel for abdominal distention or the presence of hard masses within the abdomen, as well as do a digital rectal examination to feel the presence of any lumps inside the rectum. Investigations which help with confirming the diagnosis of bowel cancer include:
- Blood test – which will indicate if you have a low hemoglobin level and give an indication towards internal bleeding
- Ultrasound scan – is another imaging test which is done by running a probe over your abdomen. It is pain free and helps to detect the presence of any hard masses such as a tumor inside the abdomen, because the ultrasound waves will bounce of these dense tissues.
- Colonoscopy – is the gold standard for diagnosing bowel cancer, which is done by passing a thin, flexible tube fitted with a camera at one end, through your anus into you rectum and colon in order to visualize the lining of these areas, to detect any areas of abnormality. And it also allows your doctor to obtain a sample of tissue from the areas which look abnormal, so that it can be viewed under a microscope to detect the presence of cancer cells.
- CT and MRI scan – is done to visualize the abdomen in cross-sectional views. It gives an idea about the size of the tumor and also helps assess the spread to other parts of the body.
- PET scan - is a test where a radioactive substance is injected into your body and is then taken up by the cancer cells, in order to image them.
What is the treatment for colon and rectal cancer?
The type of treatment you will receive depends on the staging of the disease. For this your doctor will use the TNM system, which will be determined using the size of the tumor and the extent of spread of the tumor.
Treatment of colon and rectal cancer has to be individualized according to each patient depending on the stage of the disease. Therefore you need a specialized team of professionals to care for a patient diagnosed with bowel cancer and this includes a GP, Gastroenterologist, Colorectal Surgeon, Medical Oncologist, Radiation Oncologist, Cancer Nurses, as well as other healthcare workers such as dietician, occupational therapists and social worker.
The treatment modalities available for bowel cancer include:
- Surgery – depending on the position and extent of the tumor, your doctor will decide if a part or the whole of your colon has to be removed, which is known as a colectomy.
- Radiotherapy – makes use of high intensity radiation to destroy the cancer cells, and it can be used before surgery in order to shrink the tumor together with chemotherapy.
- Chemotherapy – is recommended in patients who have undergone bowel resection surgery for removal of the tumor. The anti-cancer medication given during chemotherapy helps to prevent recurrence of cancer.
- Systemic treatment – consists of chemotherapy and targeted therapy which is directed against specific mutated genes present within the cancer cells, in order to destroy them. This form of treatment is used in the case of advanced disease.
Palliative care is aimed at symptom relief and slowing down the spread of the cancer, when nothing else can be done to completely cure the condition. Keeping the patient as comfortable as possible with pain relief is an important factor. Palliative care also makes use of chemotherapy, radiotherapy and various other drugs to achieve this.
What is the Prognosis of colon and rectal cancer?
The outcome of bowel cancer is dependent on many factors such as the stage of the cancer and the exact location of it. The general health condition of the patient such as age, level of fitness and medical history also play a role in determining the outcome of the disease.
Screening for and prevention of colon and rectal cancer
For people who have a low risk of bowel cancer, they can undergo what is known as a fecal occult blood test at home in order to determine the presence of even small amounts of blood in their stools. This might help detect the presence of any abnormality within your bowel early on.
The risk of developing bowel cancer can be reduced by reducing alcohol consumption, weight reduction, consumption of a healthy diet and quitting tobacco smoking.