It can be tough to know whether or not you have colon cancer based on the symptoms. It's best to go for a checkup from a doctor as soon as possible if you notice any of these symptoms.
- rectal bleeding
- black stool (melaena)
- vomiting blood (hematemesis)
- bloody diarrhea (dysentery)
- abdominal cramping or pain
If you wonder whether or not you might have colon cancer, here are some things that could help:
• Look at your poop. Not everyone has a bowel movement daily, but changes in what comes out may point to something going on inside your body. A change in the type of feces (for example, it becomes dark and sticky), straining when you go number two, or having frequent diarrhea (loose, watery bowel movements) is concerning and should be checked out by a doctor. You should see a doctor even if there is blood in your stool, even if it isn't bright red.
• Look at your stomach. If you put on weight quickly, especially around your waistline, this could also point to colon cancer or another condition such as irritable bowel syndrome (IBS).
• Take a good look at any lumps or bumps you find on your body. Early signs of colorectal cancer include polyps in the colon and rectum that can turn into cancer with time — sometimes 15-20 years. Polyps in the anus (the last part of the rectum before exiting out of your body), in particular, can be very dangerous when ignored because they spread so quickly if not detected early. As you go through your day, be on the lookout for any new lumps or bumps that have appeared out of nowhere, especially if they are painless.
• Be wary of dark patches in your skin. Any changes in color to your skin could be a sign of colon cancer. If you find any large areas of dark brown or black discoloration anywhere on your body (for instance, under your arm), this could mean that there is bleeding near the surface of the skin, which itself often points to colon cancer.
• See a doctor if you're having abdominal pain. It can be challenging to know what's causing this type of pain, but it points to something serious like colon cancer, especially if it persists past a day.
• Notice any lumps or masses in your groin area. The lymph nodes near your colon can get larger when there's trouble going on inside your body, so if you feel anything new and unusual around these glands, this could point to cancer.
• Keep track of blood in your urine. If you notice a change from a standard color of urine to a darker shade that is sometimes accompanied by pain or fever, it might be worth seeing a doctor.
• Look out for changes in the color of your stool. Your feces should be brownish-orange at worst. Any other colors may indicate bleeding inside the digestive tract (therefore, colon cancer or other conditions should be checked out).
• Get to know your body. Check yourself for any new lumps or bumps. If you get a chance, check out the area underneath your arms and around your groin to see any changes from the norm in these areas.
• Be aware of fatigue, which can indicate many different things, including colon cancer. Persistent tiredness could mean that something is going on inside your body.
How do you test for colon cancer?
These tests are an option when the doctor is not readily available, and you want to know immediately if something is wrong with your health.
The first test, called a guaiac fecal occult blood test (gFOBT), works by checking your stool for hidden blood that cannot be seen or felt. Hidden blood in the feces often happens because of cancer in the large intestine like the colon. This test may also work for other cancers such as stomach cancer and pancreatic cancer.
The second at-home test involves feeling your body lying on your back on a flat surface with your knees bent and feet planted on the ground or floor. From this position, you should feel a tube that is about 2 inches around. If this tube feels lumpy, it may mean a tumor in your colon.
Lastly, the doctor can also use a scope to examine the inside of your large intestine. This test is called colonoscopy.
How accurate are colon cancer home tests?
While these tests are helpful when looking for colon cancer in the early stages, they do not always give accurate results because they have low sensitivity levels.
The guaiac fecal occult blood test has "20% to 40%" accuracy when detecting hidden blood in the stool, and the digital rectal exam (where you feel for lumps) has 30% accuracy. Colonoscopy is effective because it shows clear images of your colon. This test can show abnormalities in your colon that are not able to be seen with the other tests.
The results of the first two at-home tests will only be accurate if they are positive, which means that hidden blood or a lumpy feeling must be found to detect something wrong with your health. If these tests both come back negative, there might not be anything wrong with you even though you may be experiencing symptoms such as constipation and diarrhea.
The guaiac fecal occult blood test is an excellent option for finding colon cancer because it is inexpensive and easy to do while still accurate. However, while at-home tests are helpful when finding colon cancer, they are not precise enough to be used on their own.
If the results of this test come back positive, you should see your doctor right away so that they can perform another more accurate test, such as a colonoscopy.