Drop in Colon Cancer Rates for Older Americans

Screening with colonoscopy accounts for much of the drop in colorectal cancer rates among US adults over age 50.

The rates of colon cancer in US adults aged 50 and older have decreased by 3% per year over the last 10 years. The largest decrease is in adults over the age of 65-an annual decline of 5.4% over the last 5 years compared with 3.2% for adults between the ages of 50 and 64.

The reason for the steady decline is increased colonoscopy screening, which has increased from 19% in 2000 to 55% in 2010 in adults between the ages of 50 and 75. These are the results of an analysis by the American Cancer Society (ACS) published in CA: A Cancer Journal for Clinicians.

Lead author Rebecca Siegel, MPH, director of surveillance information at the ACS, attributes the increased colonoscopy rates to the expansion of Medicare coverage for colonoscopy screening-for high-risk individuals in 1998 and for all beneficiaries in 2000. “There has also been increased awareness of colorectal cancer screening due to campaigns by organizations like the [ACS] and the Colon Cancer Alliance in the early 2000s,” said Siegel.

Because colorectal cancer typically progresses slowly from precancerous polyps to invasive cancer, screening can either detect these precancerous polyps or discover cancer during its early, localized stage when treatment can lead to a long-term survival.

Incidence overall decreased by about 2% each year over the last 20 years and the decrease has been most significant among those aged 65 and older, with rates of tumors located in the distal colon decreasing by more than 5% annually from 2001 to 2010. Rates decreased by 3.9% in adults 50 and older overall in every location within the colon or rectum.

Deaths from colorectal cancer decreased about 2% annually during the 1990s and by 3% annually during the last 10 years.

In adults younger than 50, however, rates of colorectal cancer increased by 1.1%. This increase was only for tumors of the distal colon and rectum-which have been linked to obesity and potentially harmful diet habits.

“Although colorectal cancer in adults younger than 50 only represents 10% of total cases, increasing incidence in this group is of particular concern because young adults have the potential undue impact on both productive life-years lost and families with children at home,” said Siegel. “In addition, if the cause is related to the obesity epidemic or unfavorable dietary patterns, we may now be seeing just the tip of the iceberg.”

The decreases in incidence rates did not have an effect on survival rates, which generally improve as a result of earlier detection and improvements in treatment.

The study and accompanying report (Colorectal Cancer Facts & Figures) is part of an initiative by the National Colorectal Cancer Roundtable to increase rates of screening up to 80% by the year 2018.

Siegel emphasized that individuals “have a lot of control over their [colorectal cancer] risk because we know a lot about how to prevent this cancer.” To reduce risk, Siegel suggests that individuals receive screening according to recommended guidelines, establish and maintain a healthy weight, stay physically active, do not smoke, eat a healthy diet based on a high consumption of plants and low in red and processed meat, limit alcohol consumption, and take in the recommended amount of calcium.