An astounding drop in colon cancer rates because of colonoscopies

Over the last 10 years there has been an astounding drop in colon cancer rates in the U.S.

Colon cancer rates have fallen by 30% over the past decade in people over age 50, and colonoscopies are getting much of the credit, according to a report released (last) Monday.

"This is one of the great public health success stories of the decade," says Richard Wender, chief cancer control officer at the American Cancer Society.

Colorectal cancer ranks second only behind lung cancer as a cause of cancer death in the U.S. killing more than 50,000 Americans annually. According to the ACS, there are about 100,000 new cases of colon cancer and 40,000 new cases of rectal cancer each year. The lifetime risk is about 5%.

The survival rate for colorectal cancer has been increasing over the last 20 years because of better screening. The median age of diagnosis is 69 years old, and the overall 5-year survival rate is about 65%.

In a previous post I urged people to follow the recommendations of the American Cancer Society and CDC and begin colonoscopy screening when they turned 50. Americans have been heeding this message:

"Screening rates have climbed in recent years. The number of Americans ages 50 to 64 who have had a colonoscopy — which allow doctors to detect and remove polyps before they turn malignant — has nearly tripled, growing from 19% in 2000 to 55% in 2010."

As a result, "[d]eclines in colon cancer rates became more dramatic in more recent years, falling at an annual rate of 7.2% a year from 2008 to 2010."

Wow.

These data are a testament to the effectiveness of colonoscopy screening in preventing colon cancer. Indeed, the CDC estimates that up to 60% (if not more) of colorectal cancer deaths are preventable by screening. It takes about 10 to 15 years for a polyp (pre-cancerous growth) to develop into a dangerous tumor. A colonoscopy can identify and remove polyps at an early stage before they become harmful. In addition, screening can find cancers at an early stage before metastasis when they can be treated effectively by surgery and chemotherapy.

The biggest declines in colon cancer incidence coincided with those who qualify for Medicare (i.e. people over age 65), which makes colonoscopies available for free. Thanks to the ACA and other health insurance programs, more free screening should be available for those younger than 65.

Ultimately the goal is to increase colon cancer screening rates to 80% by 2018 (from 55% in 2010). I would expect achieving this objective would continue the trend (see Figure 1) driving down colon cancer deaths and incidence.

Figure 1. There has been a dramatic decline in colorectal cancer incidence and death in both men and women in recent years. This decline is largely due to more widespread screening by colonoscopy.