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Colorectal cancer is the second leading cause of cancer-related deaths and is the leading cause of cancer-related deaths among non-smokers. It is common knowledge that screening for colorectal cancer saves lives. However, this life-saving message still has barely reached the majority of Americans. In 2010, only 55% of Americans aged 50 to 75 underwent a colonoscopy. This year, 97,000 new cases of colon cancer and 40,000 new cases of rectal cancer are expected. Unfortunately, 50,000 deaths due to colorectal cancer are expected this year. Often colon cancer and rectal cancer statistics are lumped together and referred to collectively as colorectal cancer or just colon cancer.

It was not until 1993 that the first evidence emerged demonstrating that screening for colorectal cancer saves lives. The Minnesota Colorectal Cancer Control Study demonstrated that the annual use of the fecal occult blood test (FOBT) decreased mortality from colorectal cancer by 33%1. 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, four 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 screening2. The benefit was stronger for colonoscopy than sigmoidoscopy A colonoscopy looks at the entire colon; sigmoidoscopy looks at the lower one-third of the colon.

In the second study, the authors followed up on the data from the original Minnesota Colorectal Cancer Control Study that was reported in 19933. 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.

A third 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 cancer4.

Lastly, in February the American Cancer Society reported that the incidence of colon cancer and the death rates from colon cancer have declined since the mid-1980s as a result of more people undergoing colonoscopy screening5. Over the last decade, the incidence of colon cancer declined 30% among Americans 50 and older. The decline in deaths due to colon cancer fell about 3% a year between 2001 and 2010, compared with 2% a year in the previous decade. The trend was most pronounced among older Americans. The rate of colon cancers among those 65 and over dropped about 7% a year from 2008 to 2010. Unfortunately, the rate of colon cancer has risen about 1% a year in Americans under age 50, likely due to declining physical exercise and rising rates of obesity and diabetes.

A screening colonoscopy saves lives and is the preferred screening test for colorectal cancer. Colonoscopy is safe and the cleansing preparation process has dramatically improved compared to 5 years ago. The days of drinking a gallon of cleansing solution are gone. The use of the sedative medication propofol is widely used and will insure a painless procedure. If a patient is not inclined to undergo a screening colonoscopy, other options would include: annual FIT test (newer version of FOBT); sigmoidoscopy every 5 years along with FIT test every 3-5 years; or CT colonography (virtual colonoscopy) every 5-10 years. Screening for colorectal cancer is more cost effective than either mammography (for breast cancer) or prostate-specific antigen (PSA) testing (for prostate cancer). Colorectal cancer is preventable. Discuss screening for colorectal cancer with your healthcare provider.

  1. Mandel JS, Bond JH, Church TR, Snover DC, Bradley GM, Shuman LM, Ederer F. Reducing mortality from colorectal cancer by screening for fecal occult blood. N Engl J Med 1993; 328: 1365-1371.
  2. Nishihara R, Wu K, Lochhead P, Morikawa T, Liao X, Qian ZR, Inamura K, Kim SA, Kuchiba A, Yamauchi M, Imamura Y, Willett WC, Rosner BA, Fuchs CS, Giovannucci E, Ogino S, Chan AT. Long-term colorectal-cancer incidence and mortality after lower endoscopy. N Engl J Med 2013; 369:1095-1105
  3. Shaukat A, Mongin SJ, Geisser MS, Lederle FA, Bond JH, Mandel JS, Church TR. Long-term mortality after screening for colorectal cancer. N Engl J Med 2013; 369: 1106-1114.
  4. Gastrointestinal cancer: irrefutable evidence that CRC screening reduces mortality. Nature Reviews Clinical Oncology 2013; 669.
  5. Siegel R, DeSantis C, Jemal A. Colorectal cancer statistics, 2014. CA Cancer J Clin 2014; 64: 104-117.

Frank Farrell, MD

Dr. Frank Farrell is a board certified gastroenterologist with two decades of experience. He's currently in full-time clinical practice and is the Medical Director of San Francisco Gastroenterology. He is an active staff member and is involved in the Gastroenterology Fellowship training program at California Pacific Medical Center.

Dr. Farrell received his Bachelor of Arts in Biology, Cum Laude from Seattle University, his Masters in Public Health from University of California, Berkeley, his Doctorate in Medicine from UCSF, School of Medicine, and completed his Internship, Residency, and Chief Residency in Internal Medicine at Mount Zion Medical Center in San Francisco. He completed his Fellowship in Gastroenterology at California Pacific Medical Center in San Francisco. Dr. Farrell has a special interest in colon health and screening colonoscopy.

Dr. Farrell is a member of the American Gastroenterological Association (AGA), the American College of Gastroenterology (ACG), the American Society for Gastrointestinal Endoscopy (ASGE), the California Medical Association (CMA), and the San Francisco Medical Society (SFMS). He was recognized as a Fellow of the AGA for his commitment to the field of gastroenterology and superior achievement in private practice.