We all have digestive problems from time to time. Maybe you indulged in a little too much cheese one night or aren’t getting enough fiber in your diet — or you’re consuming too much — and you’re feeling a little plugged up.
While these kinds of issues can be uncomfortable and embarrassing, you might not want to brush them off as your average stomach ache or chalk them up to a past irritable bowel syndrome (IBS) diagnosis. There are a lot of similarities between colorectal cancer and digestive diseases like IBS. For starters, they both share symptoms like abdominal pain and constipation. If you’ve ever been up at night wondering if your constant bowel movements might be something bigger than a sensitive system, we feel your pain.
To better understand how the two conditions differ, we’re comparing the warning signs and symptoms below.
Colon cancer is more common than you think
Colorectal cancer is a term used to describe both colon and rectal cancer, both of which affect the large intestine. Even though most of these cancers start as non-cancerous lesions called polyps, some don’t — so it’s important to get them detected early in case you need to get them removed.
“It's a much rarer event for people to have a polyp that has cancer in it,” Sophie Balzora, MD, president and co-founder of The Association of Black Gastroenterologists and Hepatologists (ABGH), told Katie Couric Media in a 2024 interview. “That's why colonoscopies are so effective: You can actually prevent colon cancer or colorectal cancer from occurring, because you remove that pre-cancerous benign polyp before it becomes colorectal cancer.”
Colorectal cancer is more common — and more deadly — than many people realize. Excluding most nonmelanoma skin cancers, it ranks among the most frequently diagnosed cancers in the U.S. and is the second leading cause of cancer deaths overall. The American Cancer Society estimates it will claim more than 55,000 lives in 2026 alone.
While most diagnoses still occur in people over 50, physicians are seeing a steady uptick in younger patients. Among those under 50, incidence rose by about 2.9 percent per year from 2013 to 2022 — a trend that has intensified calls for earlier screening and greater symptom awareness.
Colorectal cancer is now the leading cause of cancer death in men under 50 and the second leading cause in women in that age group — a striking shift from the early 1990s, when it ranked fifth. And unlike many other major cancers, death rates in younger adults have continued to edge upward, increasing by about 1.1 percent annually since 2005, according to the latest report from ACS.
What are the common symptoms of colon cancer?
The scary part is you may not even know you have colon cancer. “Most people with colon cancer have no symptoms at first — this is why screening is so important,” Donald Karcher, MD, professor of pathology at George Washington University, told us in 2024.
But even when they do develop, the symptoms can seem subtle and mirror those of an upset stomach or IBS, like more frequent constipation or diarrhea.
One major sign our experts never ignore is rectal bleeding. While it could just be hemorrhoids or inflamed veins, he points out that “blood in the stool is always concerning, especially if the person hasn’t had a recent colonoscopy.” Due to this bleeding, you might become anemic or iron-deficient, meaning you don’t have enough healthy red blood cells to carry oxygen to the body’s tissues.
What are the symptoms of IBS?
IBS is an intestinal disease that can cause changes in bowel habits.
IBS is hard to diagnose because it can’t be seen. The main symptoms are constipation, diarrhea, or a combination of the two, accompanied by abdominal pain. You might also experience the following:
- Bloating
- Mucus in stool
- Incomplete bowel movements
- Relief of symptoms after a bowel movement
- Excess gas
Keep in mind, the two diseases are not connected, and having IBS doesn’t increase your risk of colon cancer. However, some cancer treatments can disturb your stomach. Unlike inflammatory bowel disease (IBD), IBS does not cause inflammation, which is a key factor in colorectal cancer risk.
How do you know you have colon cancer — and not just IBS?
Delayed diagnoses aren’t uncommon: In a 2019 survey conducted by the Colorectal Cancer Alliance, 67 percent of respondents saw at least two physicians before being properly diagnosed with the disease, and some saw as many as four. So, to avoid what could be a detrimental misdiagnosis or delayed diagnosis, it’s important to keep in mind that colon cancer symptoms can be mistaken for something like IBS.
While it can be difficult to distinguish the two, colon cancer has other alarming signs, such as sudden weight loss. “If you're losing weight without making any major dietary or exercise changes, that can be abnormal,” said Dr. Balzora. “That's something that should be formally evaluated to figure out why it's happening.”
Additional colon cancer symptoms include:
- A change in the shape of your stool, where it may suddenly become thin and resemble a pencil
- Fatigue (likely due to iron deficiency)
- A change or sudden loss in appetite
Judy Trieu, MD, who specializes in interventional endoscopy, told us that a lot of these concerning symptoms might not be cancer, but it’s best to err on the side of caution and consult your doctor if you’re experiencing digestive issues. “In the end, these symptoms are vague and should be further characterized by a medical professional to determine whether a colonoscopy should be performed to rule out colon cancer,” she said.
How can you protect yourself from colon cancer?
Getting regular screening tests — or colonoscopies — is key to preventing your chances of getting colon cancer. These are generally recommended for all adults, starting at age 45. During the procedure, doctors go into the rectum with cameras to look for any potentially cancerous tumors or lesions.
Beyond tests and screenings, there are also some things you can start doing today. Dr. Trieu recommended making sure you’re eating a balanced diet and leading an active lifestyle. This includes exercising regularly and limiting your intake of processed foods, such as boxed, canned, and pre-packaged foods. She also advises eating “a balanced diet of high fiber, fresh vegetables and fruits, and whole grains.” Precautions and changes like these can be life-saving at most, and at the very least, your non-cancerous stomach issues could improve.
