An increasing number of young adults are being diagnosed with colorectal cancer, and a leading cancer specialist has pointed out a symptom that is rarely discussed and often ignored.

According to Dr. Yousuf Zafar, a gastrointestinal oncologist in the United States, a persistent sensation that the bowels have not been fully emptied after using the toilet can be a warning sign of colorectal cancer.

In a recent TikTok video, Dr. Zafar explained:
“One symptom that doesn’t get talked about enough is the feeling that your bowels are not completely empty after a bowel movement.”

This sensation may occur because a tumor is narrowing or partially blocking the passage through which stool normally passes.

Such tumors are often located in the rectum—the final section of the colon—or in the longest part of the colon itself.

The colon is responsible for processing food waste into stool. When it becomes obstructed, it can lead to several uncomfortable and serious symptoms. According to Cancer Research UK, bowel obstruction can cause pain, nausea, and vomiting of large amounts of undigested food or intestinal fluid.

Dr. Zafar’s warning comes amid growing concern over the rising number of colorectal cancer cases among younger people. In the UK alone, an estimated 42,000 individuals are diagnosed with colorectal cancer each year, and approximately 17,400 people die from the disease annually.

One notable victim was British journalist Dame Deborah James, who passed away at the age of 40 after a highly public battle with the disease. She worked tirelessly to raise awareness about colorectal cancer. Alarmingly, data show that cases among people in her age group have doubled over the past three decades.

Other Warning Signs of Colorectal Cancer

In another video, Dr. Zafar shared additional early warning signs of colorectal cancer, noting that some symptoms may not cause pain.

The most widely recognized sign is blood in the stool or rectal bleeding.
“I can’t tell you how many of my patients noticed blood in their stool for months, or even over a year, before coming to see me,” he warned.

Another symptom to watch for is persistent abdominal pain or cramping that does not resolve on its own.

Unexplained weight loss is a third key warning sign and one that Dr. Zafar described as particularly important.
“If you’re losing weight and it’s not because of dieting or exercise, pay attention to that,” he advised.

The final symptom he mentioned is anemia, which can cause fatigue, weakness, and shortness of breath.
“If you have anemia without a clear cause, you should talk to your doctor about whether you need screening for colorectal cancer,” Dr. Zafar said.

In his closing message, Dr. Zafar emphasized:
“Remember, it’s possible to have no symptoms at all. That’s why age-appropriate screening is so important. But if you have any of the symptoms I’ve mentioned, talk to your doctor.”

According to the UK’s National Health Service (NHS), other symptoms of colorectal cancer may include needing to pass stool more or less frequently than usual, as well as changes in stool consistency, such as looser stools, diarrhea, or unusual constipation.