Doctor Explains 5 Concerning Symptoms That Could Signal Colon Cancer

A cancer specialist has shared five key symptoms that might be warning signs of colon cancer, which is one of the most common and deadly cancers in the United States.

According to estimates from the American Cancer Society, there were 'about 106,590 new cases of colon cancer' in 2024 alone.

Colon cancer is considered the 'second most common cause of cancer deaths' in the US, making it vital to know what to look out for.

You can get a colonoscopy to check for colon cancer Getty Stock Images/ PonyWang

Dr. Waqqas Tai, an oncology fellow, took to TikTok to raise awareness about 'five things you need to look out for if you think you have colon cancer.'

'Pencil thin' stools

If you notice that your stools are thinner than usual—like the size of a pencil or pen—it could be a red flag. Dr. Tai explained this symptom could signal something more serious going on in your colon.

"That might be a sign there is a tumor there compressing your colon causing the stool to come out thinner," Dr. Tai pointed out in his video.

Blood in your stool

Another important warning sign is the presence of blood in your stool. It’s easy to mistake it for something like hemorrhoids, which can also cause bleeding but are usually harmless.

However, Dr. Tai emphasized that if you notice blood when you check the toilet bowl, it's essential to visit your doctor to get it checked out and rule out anything more serious.

There are several signs it's good to keep an eye on Getty Images/ Bymuratdeniz

Even though it might be tempting to assume it’s nothing, Dr. Tai urges people not to take any chances and to see their healthcare provider.

Low blood count

The third sign Dr. Tai highlighted involves a low blood count. Anemia in men and women without a clear cause, like heavy periods in women, could be a sign of colon cancer.

"If you're anaemic on a complete blood count (CBC), for men, there is no healthy reason a man should be anaemic," Dr. Tai explained.

He mentioned that doctors often look for this as one of the top indicators when trying to diagnose colon cancer.

It's important to keep an eye on your bowel movements Getty Stock Images/ Boonchai Wedmakawand

"Women, if you don't have heavy periods, you also should not have a low hemoglobin," he added, noting that it’s crucial for people to get a colonoscopy if their blood count is low. "And so you also need a colonoscopy."

Yo-yoing bowel movements

If your bowel movements swing between severe diarrhea and severe constipation, this could be another warning sign.

While it might not necessarily mean colon cancer, especially if it’s related to other gastrointestinal issues, Dr. Tai recommends seeing a doctor if you’re also experiencing any of the other symptoms he mentioned.

Fevers, sweating, and weight loss

These so-called 'B symptoms'—unexplained weight loss, random fevers, and waking up drenched in sweat—are also important to pay attention to.

If you’re experiencing these symptoms and find yourself losing weight despite eating enough, Dr. Tai advises getting checked out as soon as possible.