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Constipation
Constipation, or difficulty having bowel movements, is a problem for many people with cancer. Understanding its causes and learning how to prevent and manage constipation can improve your quality of life.
What is constipation?
When it is hard to have a bowel movement (poop); or when you aren’t going as many times as you usually do, it is called constipation.
As stool moves through your bowels, some of the water in the stool is absorbed by the colon (also known as the large intestine). The longer the stool stays in the colon, the more water is absorbed. The more water taken from stool, the harder the stool becomes, which can make it harder to move your bowels and lead to constipation.
Constipation can also lead to other problems such as:
- Nausea and vomiting
- Hemorrhoids
- Anal fissures (small tears in tissues lining the anus)
- Rectal prolapse (when part of the rectum slips out of the anus)
- Bowel obstruction (blockage)
- Urinary retention (difficulty peeing) or bladder incontinence
Learn more about the digestive system in the 3D Anatomy Gallery.
What causes constipation?
Constipation is usually caused by more than one factor. The more risk factors you have, the more likely you are to have constipation.
Here are some things that increase your chances of constipation:
- Certain cancers, especially colorectal
- Advanced cancers
- Some chemotherapy (chemo) medicines, especially vincristine and other vinca alkaloids
- Immunomodulatory medicines including thalidomide, lenalidomide, and pomalidomide
- Other medicines such as opioids, antidepressants, and barium sulfate (contrast for CT and MRI imaging scans)
- Not getting much physical activity
- Low fluid intake, and low fiber diet
- Overuse of laxatives
What are symptoms of constipation?
Constipation can be different depending on the person. Having one bowel movement every other day might be “regular” for one person and but might indicate constipation for another.
Symptoms of constipation often include:
- Difficulty or discomfort having a bowel movement
- Having small, hard bowel movements (sometimes described as pellets)
- Belly feels bloated and firm
- Stomachache or cramps
- Passing a lot of gas or frequent burping
- Vomiting or nausea
- Not having regular bowel movements within a certain period of time (ask your cancer care team how long that is before treatment starts)
- Leakage of small amounts of liquid stool that looks like diarrhea
Call 911 or go to the emergency room
- If you have bleeding from your rectum that won’t stop
- If you have sudden, intense belly pain that won’t stop
- If you can’t urinate (pee) or eat for a day or more
Treatment for constipation
The main goal of treating constipation is to have regular, comfortable bowel movements. What you eat has a big effect on your bowels, so many people start there when managing constipation.
Fiber
Fiber is a type of carbohydrate (or carb) that the body can’t digest. It helps to manage sugar (glucose) levels, lower cholesterol, and promote good digestion.
Insoluble fiber helps move food through the bowels without removing too much water. Good sources of insoluble fiber include wheat bran, quinoa, brown rice, potatoes, fruits with edible skin, almonds, walnuts, seeds, and leafy green vegetables. This type of fiber is best for preventing and managing constipation. Getting 20 to 35 grams of insoluble fiber in your diet every day is one of the best ways to prevent and manage constipation.
Soluble fiber can make constipation worse because it slows the bowels and pulls out more water. Common soluble fiber sources include oats, berries, bananas, flaxseed, chia seeds, and psyllium husk. Soluble fiber is better for preventing and managing diarrhea.
Laxatives
There are a few types of laxatives. Most of them are taken by mouth (orally).
- Bulk-forming laxatives work by making the stool swell up to be bulky, softer, and easier to pass.
- Stimulant laxatives work by irritating nerve endings in the bowel, which causes bowel muscles to move stool along faster.
- Osmotic laxatives work by drawing water into the bowel, making the stool softer and easier to pass.
- Stool softeners make it easier for water to get into the stool, making it softer.
Laxatives can be habit-forming and shouldn’t be used long-term. Always check with your doctor or cancer care team before starting a laxative, even if they’re over the counter.
Enemas and suppositories
Enemas and suppositories are medicines placed into the rectum through the anus.
- Enemas are liquid and work by softening the stool and lubricating the bowel. Common types include saline, mineral oil, and stimulant enemas.
- Suppositories are soft solids that dissolve or melt at body temperature to soften the stool. Common types include glycerin and bisacodyl suppositories.
Enemas and suppositories are often used for short-term relief of constipation and sometimes work faster than medicines taken by mouth. Always check with your doctor or cancer care team before starting a laxative, even if they’re over the counter.
Medicines
For long-term (chronic) constipation that doesn’t get better with other treatments, prescription medicines are sometimes used. There are also prescription medicines for chronic constipation caused by opioid pain medicines.
Pelvic therapy and biofeedback
Pelvic floor muscle (Kegel) exercises can strengthen the muscles that support the bowel, rectum, and anus.
Biofeedback uses sensors placed near the anus to show on a screen which pelvic muscles are being used. Pelvic therapy done with biofeedback often works better than therapy alone.
Tips for managing constipation
There are also things you can do at home to help with constipation.
- Get more physical activity (such as walking). Movement stimulates the muscle in the bowel to move as well (called peristalsis).
- Try to have a bowel movement around the same time every day (the bowels are more active after meals and walking).
- Use a footrest to raise your feet 8 to 12 inches above the ground while trying to have a bowel movement. This can make it easier.
- Avoid foods and drinks that cause gas, such as dairy, eggs, apples, avocados, beans, peas, cabbage, broccoli, and fizzy drinks.
- Avoid chewing gum and straws, which can cause gas.
Talk to your doctor or cancer care team
If you have constipation, make sure your doctor or cancer care team knows about it. Constipation can cause serious problems if it isn’t managed.
Tell them if you:
- Haven’t had a bowel movement in 3 or more days
- Notice any blood in your stool
- Have belly pain or vomiting
Ask your doctor or cancer care team what you should call right away for versus what can wait until office hours. Make sure you know who to contact and how to contact them when the office is closed.
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- References
Developed by the American Cancer Society medical and editorial content team with medical review and contribution by the American Society of Clinical Oncology (ASCO).
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Last Revised: April 22, 2024
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