Symptoms of colorectal cancer

Colorectal cancer may not cause any signs or symptoms in its early stages because the cancer is very small. Symptoms often appear once a tumour grows into surrounding tissues and organs. Other health conditions can cause the same symptoms as colorectal cancer.

See your doctor if you have these signs or symptoms:

  • diarrhea
  • constipation
  • stool (poop) that looks narrower than usual
  • feeling like the rectum is not completely empty after a bowel movement
  • bright or very dark red blood in the stool
  • bleeding from the rectum
  • gas, abdominal cramps and feeling bloated
  • pain or discomfort in the rectum
  • a lump in the abdomen or rectum
  • fatigue and weakness
  • anemia, which can cause fatigue and shortness of breath
  • nausea and vomiting
  • loss of appetite
  • weight loss
  • a blockage in the intestine (called a bowel obstruction)
  • swollen lymph nodes
  • enlarged liver
  • jaundice
  • a buildup of fluid in the abdomen (called ascites)
  • pain in the abdomen, back, buttocks or legs
  • breathing problems

Expert review and references