As colon cancer progresses, bowel symptoms often become more obvious. In stage 3, tumors spread and narrow the colon, leading to:
Constipation and diarrhea (often alternating)
Blood in stool—bright red or dark/maroon depending on tumor location
Bloating, cramps, and signs of anemia
“Bowel obstruction, either partial or total, may eventually result.”
Advanced Stage (Stage 4)
In stage 4, cancer may spread to other organs. Stool may become “viscous and dark,” also known as melena, especially in right-sided tumors. Additional symptoms include:
Nausea, vomiting, and weight loss
Bowel perforation or organ-related symptoms from metastasis
Still, “many patients with metastatic colon cancer may be completely asymptomatic” if there’s no blockage, bleeding, or rupture.
Always consult a doctor if you notice ongoing changes in bowel habits. “If detected in its early stages, colon cancer is very curable.”
