Here’s a comparison between colon cancer related constipation & IBS.

“Constipation as a symptom itself can be caused by colon cancer or irritable bowel syndrome (IBS) with predominant constipation,” says Franjo Vladic, MD, a board certified gastroenterologist with Center for Digestive Health and Endoscopy Center in Ohio.

Can you tell the difference between constipation from IBS and that from colon cancer?

Dr. Vladic says, “IBS with predominant constipation is a benign condition, meaning that the patient does not present with any alarm symptoms, such as unintentional weight loss, blood in stools, abdominal distention, nausea or vomiting.

“If a patient presents with any of these alarm symptoms, coupled with constipation, their provider should consider an organic etiology being the cause of the constipation.

“Without any alarm symptoms, the constipation is likely from IBS or another benign condition that should not cause any potential concern.”

Does colon cancer related constipation look different than IBS constipation?

When colon cancer causes constipation, there is nothing compositionally different about the stools vs. when the constipation has a benign cause such as irritable bowel syndrome.

The constipation from colon cancer is caused by an obstruction in the colon, which holds the stools back, preventing an easy void, or delaying a void (the tumor can shift out of the way, allowing backed-up stools to finally void).

IBS does not involve any abnormal composition of stool matter, either.

Thus, the appearance of the stools, from colon cancer related constipation, would be the same as that from IBS, when the patient views the BMs in the toilet bowl.


The big variable is the absence—or presence—of those other alarming symptoms.

But here’s something to consider:

It’s entirely possible to have both IBS and colon cancer.

If you’re worried, consider a home stool test called Cologuard, which uses state-of-the-art DNA technology to detect abnormal cells in feces.

Dr. Vladic’s special interests include acid reflux, colitis, colon cancer, GERD, heartburn, IBS, liver disease, obesity, pancreatitis and peptic ulcer, among many others.
Lorra Garrick has been covering medical, fitness and cybersecurity topics for many years, having written thousands of articles for print magazines and websites, including as a ghostwriter. She’s also a former ACE-certified personal trainer.  


Top image: Shutterstock/Aaron Amat