Colorectal cancer includes cancers of the bowel or large intestine and cancers of the rectum and anus. Colorectal cancer is the most frequently occurring cancer in Australia (excluding non melanoma skin cancers) with a total of 12,844 new cases in 2001, and it is the second leading cause of cancer death after lung cancer. Historically, incidence of this cancer has been slowly increasing for women; however, the age-standardised rate for men has remained between 76 and 80 per 100,000 since 1991. The age-standardised rate for men is projected to remain at 79, and for women the projections show a continuation of the slow historical increase from 55 in 2001 to 56 in 2011. For both sexes, the expected ageing of the population is projected to cause large increases in the number of cases.
For women, the number of new cases of colorectal cancer is projected to increase by 30% from 5,883 in 2001 to 7,673 in 2011. For men, the number of new cases is projected to increase by 33% from 6,961 in 2001 to 9,249 in 2011.
In the UK it is the third most common cancer after breast and lung cancer. It is the second most common cause of cancer death, causing 10% of all cancer deaths. As for many other cancers, survival for large bowel cancer has improved in recent years. In 2001, there were about 34,500 new cases of bowel cancer diagnosed in this country compared with 35,300 cases in 2000.
In 2006 in Europe the most common form of cancer was breast cancer (429 900 cases, 13.5% of all cancer cases), followed by colorectal cancer (412 900, 12.9%).Cancer remains an important public health problem in Europe and the ageing of the European population will cause these numbers to continue to increase even if age-specific rates remain constant.
The incidence of colorectal cancer increases greatly from around the age of 50 (US National Cancer Institute). At present the American Cancer Society recommends screening for early detection of colorectal cancer and the adenomatous polyps from which over 95% of these cancers develop. Screening is recommended for all men and women, beginning at the age of 50, who are considered to be at average risk for developing colorectal cancer. Currently there are 5 screening options:
- A fecal occult blood test (FOBT) or fecal immunochemical test (FIT) every year, OR
- A flexible sigmoidoscopy every 5 years, OR
- Annual FOBT (or FIT) and flexible sigmoidoscopy every 5 years, OR
- A double-contrast barium enema every 5 years, OR
- A colonoscopy (fibre-optic or virtual CT scan) every 10 years
These screening options do not have optimum take up rates due to the invasive nature of the procedures and/or the practice of collecting one’s own body waste.
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