Colorectal cancer is any cancer that affects the colon and the rectum, also known as bowel cancer, colon cancer, or rectal cancer.
The American Cancer Society reports that in the United States about 1 in 21 men and 1 in 23 women will develop colorectal cancer during their lifetime.
It’s the second leading cause of death from cancer in women, and the third leading cause for men. However, the death rate from colorectal cancer has been declining due to advancements in screening methods and changes in therapies.
Colorectal cancer may be either benign, non-cancer, or malignant. A malignant cancer can spread and cause damage to other parts of the body.
Symptoms of colorectal cancer include:
- changes in bowel habits
- diarrhea or constipation
- a feeling that the bowel does not empty properly after a bowel movement
- blood in feces that makes stools look black
- bright red blood coming from the rectum
- pain and bloating in the abdomen
- a feeling of fullness in the abdomen, even after not eating for a while.
- fatigue or tiredness
- unexplained weight loss
- a lump in the abdomen or the back passage felt by your doctor
- unexplained iron deficiency in men, or in women after menopause
Most of these signs can indicate other potential conditions as well. If the symptoms continue for 4 weeks or more it is necessary to see a doctor.
Treatment may rely on many factors, including cancer size , location and level, whether it is recurring or not, and the patient’s current overall state of health.
Surgery for colorectal cancer
It is the treatment which is most common. To minimize the risk of cancer spreading, the affected malignant tumors and any associated lymph nodes should be removed.
The intestine is normally stitched back together but often the rectum is entirely removed and a colostomy bag is inserted for drainage. The stools are stored in the colostomy bag. This is generally a temporary measure, but it may be permanent unless the ends of the bowel can be joined.
If the cancer is diagnosed early enough, this can be successfully removed by surgery. When surgery doesn’t stop the cancer, the symptoms will ease.
Targeted therapy is a kind of chemotherapy that targets precisely the proteins that facilitate the growth of some cancers. They may have fewer side-effects than other chemotherapy types. Bevacizumab (Avastin) and ramucirumab (Cyramza) are medicines which can be used for colorectal cancer.
A research found that patients with advanced colon cancer who undergo chemotherapy and who have a colorectal cancer family history have a substantially lower risk of recurrence and death from cancer.
Radiation therapy uses rays of high energy radiation to kill and prevent the cancer cells from spreading. This is most widely used in treating rectal cancer. This can be used in an effort to shrink the tumor before surgery.
Following surgery, both radiation therapy and chemotherapy can be given to help reduce recurrence chances.
Ablation may make a tumor removed without destroying it. It can be achieved with radiofrequency, ethanol, or cryosurgery. These are delivered using an ultrasonic or CT scanning technology guided probe or needle.
Malignant tumors will spread if left untreated, to other parts of the body. The chances of a complete cure significantly rely on how early the cancer is diagnosed and treated.
The recovery of a patient depends on the following factors:
- the stage when diagnosis was made
- whether the cancer created a hole or blockage in the colon
- the patient’s general state of health
In some cases, the cancer may return.
Possible risk factors include:
- older age
- a diet that is high in animal protein, saturated fats, and calories
- a diet that is low in fiber
- high alcohol consumption
- having had breast, ovary, or uterine cancer
- a family history of colorectal cancer
- having ulcerative colitis, Crohn’s disease, or irritable bowel disease (IBD)
- overweight and obesity
- a lack of physical activity
- the presence of polyps in the colon or rectum, as these may eventually become cancerous.
Many colon cancers (adenoma) arise within polyps. They are also located within the lining of the bowel.
Eating red or processed meats will add to the risk.
Individuals with a tumor suppressor gene known as Sprouty2 may be at higher risk for some colorectal cancers.
Colorectal cancer is the second most common tumor in both men and women, after lung tumors, according to WHO (World Health Organization).
Throughout Western Europe, around 2 per cent of people over 50 years of age will potentially develop colorectal cancer.
It is not clear exactly why colorectal cancer develops in some people and not in others.
A cancer stage determines only how far it has spread. Determining the stage assists in selecting the most appropriate therapy.
A widely used method gives a number from 0 to 4 for the phases. Colon cancer stage is:
- Stage 0: This is the earliest stage, when the cancer is still in the colon or rectum’s mucosa, or inner layer. This is also known as in situ carcinoma.
- Stage 1: The cancer has progressed through the inner colon or rectum layer but has not yet spread beyond the rectum or colon wall.
- Stage 2: The cancer has spread through or through the colon or rectum wall, but has still not entered nearby lymph nodes.
- Stage 3: The cancer has reached surrounding lymph nodes, but other areas of the body have not been affected yet.
- Step 4: The cancer has spread to other areas of the body, including other organs such as the liver, the abdominal cavity lining membrane, the lung, or the ovaries.
- Recurrent: After surgery the cancer has returned. This may come back, impacting the rectum, colon, or other body part.
In 40 percent of cases, diagnosis occurs at an advanced stage, when surgery is likely the best option.
Screening can detect polyps until they become cancerous, as well as detect colon cancer when the chances of a cure are much higher during the early stages.
The following are the most common Colorectal Cancer screening and diagnostic procedures.
Fecal occult blood test (blood stool test)
It tests for the presence of blood to a sample of the patient’s stool (feces). It can be done in the doctor’s office, or at home with a kit. The sample is returned to the Physician’s office and sent to a laboratory.
A blood stool check is not 100 % effective, because not all tumors cause blood loss, or they do not bleed all the time. The test may therefore yield a false negative result. Blood can also be present due to certain diseases or disorders, such as hemorrhoids. Some foods may indicate blood in the colon, when there was in fact none.
Stool DNA test
The examination analyzes multiple markers of DNA which are shed into the stool by colon cancers or precancerous polyps. A kit with instructions on how to extract a stool sample at home can be given to patients. That has to be taken back to the office of the doctor. This is then sent to a laboratory.
This test is more effective than polyps for detecting colon cancer, but it can not identify all of the DNA mutations that suggest a tumor is present.
To view the patient’s rectum and sigmoid, the doctor uses a sigmoidoscope, a flexible, narrow, and lighted tube. The sigmoid column is the colon’s last part, before the rectum.
The examination takes a couple of minutes and is not painful but can be uncomfortable. There is a tiny chance of colon wall perforation.
When polyps or colon cancer are identified by the doctor, then a colonoscopy can be used to inspect the entire colon and remove any polyps present. All are to be examined under a microscope.
A sigmoidoscopy can find only polyps or cancer in the colon and the rectum in the end section. In no other part of the digestive tract does it detect an problem.
Barium enema X-ray
Barium is an enema-shaped contrast dye that is stored in the patient’s bowel, and it appears on an X-ray. As well, air is inserted in a double-contrast barium enema.
The barium covers and coats the bowel lining, providing a simple picture of the rectum, colon, and even a small section of the small intestine of the patient.
A flexible sigmoidoscopy can be performed to detect any tiny polyps that the X-ray barium enema can miss. If anything abnormal is detected by the barium enema X-ray, the doctor can prescribe a colonoscopy.
A colonoscope is more than just a sigmoidoscope. It is a slim, thin , flexible tube, attached to a video camera and monitor. The physician can see the whole colon and the rectum. Some polyps found during this test can be removed during the process and tissue samples, or biopsies, are often taken instead.
A colonoscopy is painless but to calm them down some patients are given a mild sedative. They can be given laxative fluid before the test to clean out the colon. In rare cases an enema is used. Colon wall bleeding and perforation are potential complications, but extremely rare.
Upon clearing the colon, a CT-machine takes pictures of the colon. When something suspicious is found, it can require traditional colonoscopy. This procedure can give patients with increased risk of colorectal cancer a less-invasive, better-tolerated, and good diagnostic accuracy alternative to colonoscopy.
Ultrasound or MRI scans can help to show whether the cancer has spread to another body part.
Daily screening for people aged 50 to 75 is recommended by the Centers for Disease Control and Prevention ( CDC). Duration depends on test form.
A number of lifestyle measures may reduce the risk of developing colorectal cancer:
- Regular screenings: People who have had colorectal cancer before, who are over 50 years of age, who have a family history of this type of cancer, or who have Crohn’s disease, Lynch syndrome, or adenomatous polyposis should have regular screenings.
- Nutrition: Follow a diet with plenty of fiber, fruit, vegetables, and good quality carbohydrates and a minimum of red and processed meats. Switch from saturated fats to good quality fats, such as avocado, olive oil, fish oils, and nuts.
- Exercise: Moderate, regular exercise has been shown to have a significant impact on lowering a person’s risk of developing colorectal cancer.
- Bodyweight: Being overweight or obese raises the risk of many cancers, including colorectal cancer.
A gene linked to the recurrence of bowel cancer and reduced survival may help predict outcomes for patients with the mutation – and take scientists a step closer to creating tailored therapies, research in the Gut journal reveals.