Colorectal cancer, commonly called bowel cancer, is the second most common cancer in both men and women. Eighty per cent of cases are sporadic with no known hereditary genetic associations. Colorectal cancer is preceded by adenomas (polyps), which if undetected become invasive cancer.
Incidence and mortality
There are more than 12,500 new cases each year. The risk of being diagnosed by age 85 is 1 in 10 for men and 1 in 15 for women. More than 4372 people die of colorectal cancer each year.
Screening
Screening with a test for blood in the faeces is available through the National Bowel Cancer Screening Program to Australians who turn 55 or 65 between 1 May 2006 and 30 June 2008. Abnormal tests are followed up with a colonoscopy.
Symptoms and diagnosis
Symptoms of colorectal cancer include:
- change in bowel habit with diarrhea, constipation or the feeling of incomplete emptying
- thin bowel movements
- blood in the motion or abdominal bloating or cramping.
More general symptoms are:
- tiredness
- weight loss
- unexplained anaemia
Diagnosis is by a colonoscopy.
Staging
Staging is determined by how far the cancer has penetrated through the bowel wall. Stage I is superficial, stage II is deeper and stage III is when the cancer has gone through the thickness of the wall or out into the tissues or lymph nodes beside the bowel. Stage 4 means the cancer has spread to other organs, commonly the liver.
A CT scan can be used to detect spread to the liver or lungs. A blood test, CEA (carcinoembryonic antigen) if elevated, can be used to monitor the progress of the disease.
Causes
Risk factors include age, inherited genetic risk, inflammatory bowel disease, obesity and smoking.
Prevention
Not smoking, a healthy diet with plenty fresh fruit and vegetables, and maintaining a healthy body weight all contribute to reducing the risk of bowel cancer.
Treatment
Stage I and II disease can be treated with surgery alone to remove the bowel and surrounding lymph nodes. Stage III disease requires surgery and additional chemotherapy to try to prevent recurrence. Widespread disease is treated with chemotherapy. More recently targeted therapies are being trialed in addition to chemotherapy.
Prognosis
With stage I colorectal cancer 90% of patients will still be alive at five years. This falls to 87% with stage II, 57% with stage III and 10% for widespread disease.
For more information, please contact The Cancer Council Helpline on 13 11 20 (cost of a local call).