It is common knowledge that screening for colorectal cancer saves lives. Colorectal cancer is the second leading cause of cancer-related deaths and is the leading cause of cancer-related deaths among non-smokers.
It was not until 1993 that the first evidence emerged demonstrating that screening for colorectal cancer saves lives. This made intuitive sense but in the world of science and medicine, data and results mean everything. The evidence from that 1993 Minnesota Colorectal Cancer Control Study showed that the annual use of the fecal occult blood test (FOBT) decreased mortality from colorectal cancer by 33%. A positive FOBT would lead to the recommendation for the patient to undergo a colonoscopy to explain the presence of the occult blood (blood is not normally found in stool and an explanation has to be identified). Colonoscopy leads to the discovery of polyps and cancer which can then be treated.
Recently, studies were reported demonstrating long-term evidence that screening for colorectal cancer is indeed saving lives. As a rule in medicine, the longer the results hold up, the stronger the evidence. Today, no one would question the life-saving benefits of screening for colorectal cancer.
The first study found a decrease in the risk of developing colorectal cancer and death from colorectal cancer among patients up to 22 years after undergoing a screening colonoscopy or sigmoidoscopy compared to those patients who did not undergo any form of screening. The benefit was stronger for colonoscopy than sigmoidoscopy (colonoscopy looks at the entire colon; sigmoidoscopy looks at the lower 1/3 of colon).
In the second study, the authors followed up on the data from the original Minnesota Colorectal Cancer Control Study that was reported in 1993. They found that up to 30 years after performing a FOBT test, there was a 32% reduction in death due to colorectal cancer for patients that had an annual FOBT and a 22% decrease for patients having a FOBT every other year. Men appeared to benefit more than women.
Lastly, a recent study from Europe analyzed data from 11 countries and demonstrated that those countries with higher rates of colonoscopy screening or screening with FOBT had lower rates of colorectal cancer and mortality from colorectal cancer.
A screening colonoscopy saves lives and is the preferred screening test for colorectal cancer. If one is not inclined to undergo a screening colonoscopy, other options include the FIT test (newer version of FOBT) or CT colonography (virtual colonoscopy). Screening for colorectal cancer is more cost effective than either mammography (for breast cancer) or prostate-specific antigen (PSA) (for prostate cancer) testing. Colorectal cancer is the most preventable cancer. Discuss colorectal cancer with your health care provider.
Here’s to your colon health!
Frank Farrell, MD, MPH, AGAF