What are the first signs of rectal cancer?

Rectal cancer can affect the passage of stool and the lining of the rectum. Blood may appear bright red or be mixed with stool; mucus, urgency, narrower stools, constipation, diarrhoea, or repeated urges after a bowel movement may also occur. Tiredness from anaemia, abdominal discomfort, or unplanned weight loss can accompany bowel symptoms. Haemorrhoids, fissures, infection, inflammatory bowel disease, and dietary changes can cause similar findings, so blood in stool does not by itself establish cancer.

Book a medical review for blood in stool or a bowel change that persists, recurs, or is unlike your usual pattern. Note the colour and amount of blood, stool frequency, pain, mucus, and any weight or appetite change. Assessment may include an examination, blood tests, stool testing, and referral for a camera examination of the bowel when appropriate. If rectal cancer is diagnosed, treatment may involve chemotherapy before surgery, radiotherapy, surgery, or a stoma depending on the findings.

Seek urgent help for heavy or ongoing rectal bleeding, black stools, fainting, severe abdominal pain, repeated vomiting, or inability to pass stool and gas. Contact a clinician promptly for recurrent bleeding, worsening bowel blockage symptoms, or marked weakness. These signs can arise from conditions other than cancer but should not be ignored.

Ask what may explain the bleeding or bowel change, which tests are needed, and how quickly they should happen. If a lesion is found, ask whether tissue sampling and imaging are required, how treatment affects bowel function, and whether a temporary or long-term stoma is possible.