Colorectal Cancer Rate Drops with Increased Testing

Incidence rates decreased 3% per year last decade thanks in part to timely screening tests, report says.

A decline in the colorectal cancer death rate is partly attributable to a surge in the number of people getting recommended screening tests, according to a report from the American Cancer Society (ACS) released on March 17, 2014.

While colorectal cancer remains the third leading cause of cancer deaths in both men and women in the United States, incidence rates overall dropped by an average of 3.4% each year from 2001 through 2010. In addition, the colorectal cancer death rate, which decreased by approximately 2% per year during the 1990s, fell by approximately 3% per year last decade.

The report credits changes in behavior (ie, reduced rates of smoking and red meat consumption and increased aspirin use), the introduction and dissemination of early detection tests, and advances in medical treatment for the decline in the death rate.

“These continuing drops in incidence and mortality show the lifesaving potential of colon cancer screening; a potential that an estimated 20 million of Americans over 50, who have never been screened, have not benefitted from,” said Richard C. Wender, MD, the American Cancer Society’s chief cancer control officer in an ACS news story. “Continuing this hopeful trend will require concrete efforts to make sure all patients, particularly those who are economically disenfranchised, have access to screening and to the best care available.”

The report notes that in 2014 an estimated 136,830 people will be diagnosed with colon cancer and 50,310 people will die from the disease, with 60% of cases and 70% of deaths occurring in patients aged 65 and older. The estimates differ slightly by sex, with nearly 30% of cases and more than 40% of deaths in women predicted to occur in those aged 80 and older, and 20% of cases and 30% of deaths in men predicted to occur in those aged 80 and older.

An estimated 1 in 20 people in the United States will be diagnosed with colon cancer in their lifetime, according to the report. The lifetime probability of a colorectal cancer diagnosis is estimated at 4.7% for women and 5% for men. Incidence and mortality rates overall are 30% to 40% higher in men than women.

“The reasons for higher rates in men are not completely understood, but likely reflect etiologic factors related to complex interactions between sex hormones and risk factor exposures, as well as differences in screening behavior for those aged 50 years and older,” the report states.

The authors note that colonoscopy rates among adults aged 50 to 75 jumped from 19% in 2000 to 55% in 2010.

The report also finds a stark difference in incidence and mortality rates by race and ethnicity in the United States. Colorectal cancer incidence rates in African-Americans are approximately 25% higher than in whites and 50% higher than in Asian/Pacific Islanders. In addition, the mortality rate in African-Americans is approximately 50% higher than in whites.

“Much of this disparity is due to the disproportionately low socioeconomic status in the black community,” the report authors write. “Low socioeconomic status is associated with a higher risk of colorectal cancer incidence and death. A recent study estimated that differences in the prevalence of behavioral risk factors and obesity account for approximately 40% of the socioeconomic disparity in colorectal cancer incidence.”

Significant progress has already been made in reducing colorectal cancer rates, but the authors predict that increased use of screening and other risk-reducing interventions, as well as chemotherapy in appropriate patients, could reduce US colorectal cancer mortality rates by 50% by 2020.

“Further reductions in the burden of colorectal cancer will require comprehensive implementation of known cancer control interventions across the nation and to all segments of the population, with a particular emphasis on those individuals who are economically disenfranchised,” the report concludes.