What are common early symptoms of colorectal cancer?

Often "silent": Unfortunately, colon cancers may develop "under the radar" for quite some time before symptoms occur. The earliest sign is usually anemia caused by a slowly bleeding tumor. As the cancer grows, it may block the colon causing cramping pain, bloating, and/or pencil-thin stools. The gold standard for diagnosing colorectal cancer is screening colonoscopy at age 50, or earlier with a family history.

Colorectal cancer: There are classic symptoms of decreased caliber of stool and constipation or change in bowel habits. But it can also present as a rectal bleed and weight loss.