How Has The Incidence Of Colon Cancer Changed Over Time?


Colon, or colorectal cancer, is cancer of the large intestine or rectum. Colorectal cancer is the third most common type of cancer for both men and women in the United States - the lifetime risk for developing the condition is around 5%. However, there is a lot of good news in the field as well. Colon cancer is highly preventable, and very treatable when caught early. The incidence of colon cancer has been steadily decreasing for decades, thanks to improvements in screening and prevention.

The Numbers

The American Cancer Society reports that the incidence rate of colon cancer started declining in the mid-1980s, and has continued to decline ever since. From 1998 to the present, the incidence rate has declined by about 3.0% per year for men, and 2.3% per year for women. All ethnic groups have experienced a decline in incidence rates, although not at equal rates.

Prior to 1989, white men developed colon cancer more frequently than African American men, while incidence rates for women of both races were similar. However, since 1989 the condition has been more common in African American men and women than in their white counterparts, although rates in both groups have decreased.

It's also worth noting that mortality rates from colon cancer have also decreased over the same period of time. Again, all groups have seen a drop in mortality, but African Americans currently experience a higher mortality rate.

Importance of Screening

Screening for colorectal cancer is the single biggest factor behind the decreased incidence and mortality rates. Routine screening using diagnostic tests like colonoscopies can detect polyps, which have a high potential to develop into cancer. In addition, screening helps to detect cancer early on, when treatment has a high chance of success.

Colonoscopies are recommended for:

  • Individuals over 50
  • African Americans over 45
  • People with a family history of colon cancer
  • Those with inflammatory bowel diseases, such as Crohn's disease and ulcerative colitis
  • People with a personal history of polyps or colon cancer

Factors Influencing Screening

So, why has screening increased since the mid-1980s? Accessibility to and awareness of screening has increased over that same period of time. Colonoscopies are widely available and covered by insurance; there are also clinics that offer screenings for those with no insurance or poor insurance coverage. In addition, although they have a bit of a reputation for being uncomfortable to prepare for and undergo, most people do not experience pain during preparation or the colonoscopy itself.

Variance in terms of accessibility and awareness are also responsible for the shifts we see in the relative incidence rates in African Americans versus those of other ethnicities. Socioeconomic factors play a major role in health education and access to health care. Improving accessibility and awareness across all populations may help to continue the downward trend in the rate of new cases of colon cancer.

If you have one of the risk factors for colorectal cancer explored above, then it's important to get a colonoscopy as recommended.