Colorectal cancer is a disease in which cancer cells form in the tissues of the rectum; colorectal cancer occurs in the colon or rectum. Aden carcinomas comprise the vast majority (98%) of the colon and rectal cancers; rarer rectal cancers include lymphoma (1.3%), characinoid (0.4%), and sarcoma (0.3%).
Symptoms: Bleeding is the most common symptom of colorectal cancer, occurring in 60% of patients. However, many rectal cancers generate no symptoms and are discovered during digital screening examinations.
Other signs and symptoms of rectal cancer may include the following:
- Change in bowel habits: Often in the form of diarrhea; the caliber of the stool may change; there may be a feeling of incomplete evacuation and tenesmus.
- Occult bleeding:Detected via a fecal occult blood test (FOBT).
- Abdominal pain: Maybe colicky and accompanied by bloating.
- Back pain: Usually a late sign caused by a tumor invading or compressing nerve trunks.
- Urinary symptoms: May occur if a tumor invades or compresses the bladder or prostate.
- Pelvic pain: Late symptom, usually indicating nerve trunk involvement.
- Emergencies such as peritonitis from damage, which may occur with liver metastases.