How diarrhea severity is graded during cancer treatment

This page is for people having chemotherapy or immunotherapy who have diarrhea. It explains how diarrhea is graded, why immunotherapy is different, and when to call.

Call 911 if you are too weak or dizzy to stand, cannot keep any fluid down, or become confused or unresponsive. NCI describes dehydration from severe diarrhea as life threatening. It warns that grades 3 and 4 diarrhea can be life threatening in themselves.

A fever changes the timing. On chemotherapy the CDC counts it as a medical emergency, so telephone your team the moment you see the reading, day or night, and go to an emergency department if they cannot be reached.

Call your care team right away if you have blood or mucus in your stools, belly pain or cramping, fever, dizziness, or diarrhea that lasts or keeps getting worse. NCI lists blood or mucus, dizziness, fever and weight loss among the problems that can come with diarrhea. NCI says dehydration can be life-threatening, so tell your team if you have diarrhea. If you are on an immune checkpoint drug, do not wait for a high count at all. NCI notes these drugs can inflame the colon.

If your team has written you a lower number than the ones here, theirs is the one to use.

Say on the phone which treatment you are receiving. Are you on immunotherapy? Say so early in the call.

Clinicians grade side effects. Diarrhea is one where the grade is easy to understand. NCI describes it as extra bowel movements measured against your own daily normal.

Grades 1 and 2 cover up to six bowel movements above your normal daily number. NCI says these can usually be managed at home. Grades 3 and 4 mean seven or more above your normal daily number. NCI states they can be life threatening and may need treatment in a hospital.

One caution about using those grades as a rule for yourself. They describe severity. They are not a rule for when to pick up the phone. Your own call threshold comes from your team and your treatment.

Your normal is the reference point. That is why nobody can grade this for you without asking.

A counting scale only works if you know your usual pattern. Without it, you cannot report a change accurately, and the person on the phone is working blind.

Worth noting down:

• How many bowel movements a day you normally have
• How many you had today
• Whether the stool is soft, loose or watery
• Whether there is any blood
• What you have managed to drink

A note on your phone is enough. It is the difference between saying it is bad and saying it went from two to nine.

NCI lists several causes of diarrhea during cancer treatment. The descriptions are not the same.

For chemotherapy, NCI explains that the drugs destroy rapidly dividing cells. That includes healthy cells lining the digestive tract. For immunotherapy, the wording changes. Certain drugs cause inflammation of the colon, called colitis. The colon is the large bowel.

That is a different mechanism. NCI does not publish a separate counting scale for immunotherapy on this page. The counting stays the same. The underlying problem may not.

Radiation to the abdomen, pelvis or rectum is also listed as a cause. So are surgery on digestive organs, targeted therapy, and bone marrow or stem cell transplant.

NCI also lists causes that have nothing to do with the cancer drug itself. Infections are one. A weakened immune system makes them more likely. Antibiotics, anti-inflammatory drugs, and some diabetes and depression medicines appear on the list. So do supplements and herbal products.

Stress and anxiety after a cancer diagnosis are named too. That does not make the symptom imaginary. And it does not mean it should go unreported.

For grades that can be handled at home, NCI's suggestions are simple.

• Drink clear liquids such as water and broth, at room temperature
• Eat small, frequent meals of low-fiber foods
• Include foods with sodium and potassium, such as potatoes, bananas and broth
• Avoid alcohol, dairy, spicy foods, caffeine, dried beans, fruit juices, sugar-free gum or candy, and high-fat items
• Keep the anal area clean using warm water

Medicines exist too. NCI mentions loperamide and diphenoxylate with atropine among what a doctor may prescribe. Probiotics or fiber supplements may also be offered. Ask before you start any of them.

The dangerous pattern is a slow one. Each day is a little worse than the last. Nobody calls. Dehydration arrives quietly.

Is today worse than yesterday? Was yesterday worse than the day before? That is the moment for the phone call. Make it even if no single day felt alarming on its own.