Overview
Colon cancer, also known as colorectal cancer, is a growth of cells that begins in a part of the large intestine called the colon. It typically affects older adults but can occur at any age. Colon cancer usually starts as small clumps of cells called polyps, which are usually non-cancerous but can turn into cancer over time. Symptoms of colon cancer may include changes in bowel habits, rectal bleeding, abdominal discomfort, a feeling that the bowel doesn't empty completely, weakness or tiredness, and unexplained weight loss. Regular screening tests are recommended to detect and remove polyps, which can prevent colon cancer. Treatments for colon cancer include surgery, radiation therapy, and various medications, such as chemotherapy, targeted therapy, and immunotherapy.
Understanding the disease
Symptoms
The symptoms of colon cancer may include:
- A change in bowel habits, such as more frequent diarrhea or constipation.
- Rectal bleeding or blood in the stool.
- Ongoing discomfort in the belly area, such as cramps, gas or pain.
- A feeling that the bowel doesn't empty all the way during a bowel movement.
- Weakness or tiredness.
- Losing weight without trying. If you notice lasting symptoms that worry you, it's best to make an appointment with a health care professional.
Risk Factors
Risk factors for developing colon cancer include having a family history of colon cancer, consuming a low-fiber, high-fat diet, being overweight or obese, smoking, and having a personal history of colorectal cancer or polyps. Other risk factors include inflammatory bowel diseases, inherited syndromes that increase colon cancer risk, advanced age, black race, and excessive alcohol consumption or radiation therapy for cancer. Regular exercise and maintaining a healthy diet high in vegetables can potentially help lower the risk.
Development
Colon cancer develops when cells in the colon undergo changes in their DNA. These changes tell the cells to multiply quickly and continue living when healthy cells die as part of their natural lifecycle. This leads to the accumulation of too many cells, which can form a mass or tumor. Over time, these cells can invade and destroy healthy body tissue, and eventually break away and spread to other parts of the body. The specific cause of these DNA changes is not clear, but certain risk factors can increase the likelihood of developing colon cancer. In some cases, inherited gene mutations can also play a role in the development of colon and rectal cancer.
Assessment and Diagnosis
Triage
You should see a doctor if you experience symptoms such as a change in your bowel habits that lasts longer than a week, abdominal pain, or blood in your stool, as these may indicate colon cancer. Additionally, if you are 50 years or older or have risk factors such as a family history of colon cancer, you should be screened regularly for polyps that could potentially turn into colon cancer.
Diagnosis
To diagnose colon cancer, a combination of tests and procedures is used. These may include:
- Colonoscopy: A long, flexible tube with a camera attached is inserted into the rectum to examine the inside of the colon and rectum. If any suspicious areas are found, tissue samples can be taken for analysis.
- Biopsy: A procedure to remove a tissue sample for testing in a lab. This is often done during a colonoscopy, but sometimes surgery is necessary to obtain the sample.
- Upper endoscopy: A tiny camera is used to examine the inside of the stomach, which can help detect signs of cancer.
- CT scan: A computed tomography scan can be used to create detailed images of the inside of the body, which may help detect the presence of colon cancer. It is important to undergo regular screening tests for colon cancer to identify polyps before they become cancerous or detect colon cancer in its early stages. Common screening methods include colonoscopy and virtual colonoscopy.
Management and Treatment
Complications
Possible complications of colon cancer include:
- Severe bleeding
- Severe dehydration
- A rapidly swelling colon, also called a toxic megacolon
- A hole in the colon, also called a perforated colon
- Increased risk of blood clots in veins and arteries
- Inflammation of the skin, joints, and eyes
- An increased risk of colon cancer (This is actually a risk factor rather than a complication, but I included it here for completeness.)
Prevention
Colon cancer can be prevented to a certain extent through regular screenings, lifestyle changes, and medications for individuals at high risk. Regular screenings help in detecting and removing polyps before they turn cancerous. Adopting a healthy lifestyle by consuming a diet rich in fruits, vegetables, and whole grains, limiting alcohol intake, quitting smoking, and staying physically active can also reduce the risk of colon cancer. For people with a high risk of colon cancer, certain medications, such as aspirin or aspirin-like medicines, may be recommended by their healthcare provider. However, it is important to consult with your healthcare provider to determine the best prevention strategies based on your individual risk factors.
Treatment
Treatments for colon cancer include surgery, radiation therapy, and medications such as chemotherapy, targeted therapy, and immunotherapy.
Preparing for medical consultation
To prepare for an appointment for colon cancer, you should:
- Make an appointment with your primary care doctor or family doctor if you have signs and symptoms that concern you. If your doctor suspects colon cancer, you may be referred to a gastroenterologist, oncologist, or surgeon.
- Be aware of any pre-appointment restrictions. Ask if there's anything you need to do in advance, such as restricting your diet.
- Write down any symptoms you're experiencing, including those that may seem unrelated to colon cancer.
- Make a list of all your medications, vitamins, and supplements.
- Write down your key medical information, including other conditions.
- Write down key personal information, including any major stresses or recent life changes.
- Ask a relative or friend to accompany you to help you remember what the health care provider says.
- Write down questions to ask your provider, such as:
- What's the most likely cause of my symptoms?
- What kinds of tests do I need? Do these tests require any special preparation?
- What treatments are available?
- What are the chances these polyps are malignant?
- Is it possible that I have a genetic condition leading to colon polyps?
- What kind of follow-up testing do I need?
- Should I remove or add any foods to my diet?
- How can I best manage other health conditions together with my colon cancer treatment? Remember to also ask any other questions that come up during your appointment.