The NCI specifically lists narrower or differently shaped stools among possible changes associated with colon cancer. Institut National du Cancer
## 8\. A Combination of Several Symptoms
Perhaps the most important warning sign is not one symptom at all—it is a pattern.
A person may experience abdominal pain together with changes in bowel habits. Another person might notice rectal bleeding and unexplained fatigue. Someone else might have diarrhea accompanied by iron-deficiency anemia or unexplained weight loss.
Having one or more of these symptoms does not prove that someone has colorectal cancer. In fact, many common medical conditions can produce similar symptoms.
But combinations and persistent symptoms deserve particular attention.
Research highlighted by the NCI found that, among adults younger than 50 who were later diagnosed with colorectal cancer, abdominal pain, rectal bleeding, diarrhea, and iron-deficiency anemia were associated with increased likelihood of diagnosis. The researchers emphasized that younger adults should not automatically dismiss these symptoms because of their age. Institut National du Cancer
