When to Worry About Changes in Bowel Habits With Rectal Cancer

A tumour in the rectum can change the space available for stool and affect the sensation of needing to open the bowel. This may cause urgency, frequent small bowel movements, straining, incomplete emptying, or a change in stool shape. Similar symptoms can arise from haemorrhoids, infection, medicines, or other bowel conditions, so a symptom does not establish the cause by itself.

Record the change, including its start, stool appearance, frequency, urgency, pain, mucus, and any visible blood. Mention medicines, radiotherapy, surgery, laxatives, and anti-diarrhoeal treatment to the team. Follow the bowel plan provided and avoid starting or stopping medicines without advice. Your clinicians may assess the rectum and decide whether further tests are needed.

Seek urgent care for heavy bleeding, black stools, severe or worsening abdominal or rectal pain, repeated vomiting, a swollen abdomen, faintness, or inability to pass stool or gas. These symptoms can signal bleeding, obstruction, or dehydration. Contact the cancer team promptly if the bowel change is affecting hydration, nutrition, sleep, or normal activities.

Ask whether the change could relate to the tumour, treatment, or another condition; which symptoms need same-day contact; and whether an examination or imaging is appropriate. Ask how to manage urgency, constipation, or diarrhoea safely while your care plan continues.