Doctors Warn: Unusual Fatigue May Signal Colon Cancer—Here's How Symptoms Differ
Right-sided colon cancer often goes undetected because it bleeds internally without obvious symptoms like bloody stools, instead causing unexplained fatigue and anemia. Doctors urge colonoscopy screening starting at age 40, as early polyp r
Doctors are sounding the alarm about colon cancer, particularly the right-sided variant, which presents with subtle and easily overlooked symptoms. A hepatogastroenterology specialist, Dr. Chien Cheng-hong, revealed that in April alone, he diagnosed three right-sided colon cancer patients—all sharing the absence of typical warning signs like bowel habit changes, bloody stools, or weight loss. One 50-year-old female patient had only one symptom: unusual fatigue.
Dr. He Chien-lin, a colorectal surgeon, describes right-sided colon cancer as a "silent vampire," gradually draining blood without detection. Unlike left-sided tumors that often produce visible symptoms, right-sided cancers bleed slowly and internally. Because the right colon is wider, blood lingers there longer, gets broken down by bacteria, and blends invisibly with stool. This silent bleeding resembles a slow leak, causing iron deficiency anemia with symptoms like dizziness, fatigue, and shortness of breath—often only discovered during blood tests.
Left-sided colon cancer presents more obvious signs: changes in bowel habits (constipation or diarrhea), abnormally thin stools, incomplete bowel movements, frequent straining, and clearly visible blood in stool (bright red or dark). The narrower left colon makes tumors more obvious obstacles to passage.
Doctors warn that unexplained iron-deficiency anemia, chronic fatigue, or weight loss—even without bloody stools—should raise suspicion of right-sided colon issues. Prevention's best defense: colonoscopy screening. About 95% of colon cancers originate from polyps. Early detection and removal significantly reduce cancer risk. General screening should begin at age 40, with repeat screenings every 3-5 years. Those with a family history should start screening 10 years earlier than the relative's diagnosis age.
