Featured Research

from universities, journals, and other organizations

Increased use of colonoscopy screening could explain decrease in colorectal cancer rates

Date:
October 23, 2012
Source:
Stanford University Medical Center
Summary:
Use of colonoscopy for colorectal cancer screening could explain a significant decrease in the cancer's incidence over the past decade, according to a new study.

Use of colonoscopy for colorectal cancer screening could explain a significant decrease in the cancer's incidence over the past decade, according to a new study from researchers at the Stanford University School of Medicine. Although colonoscopy is now the most common colorectal cancer screening method, there has been conflicting evidence as to its effectiveness compared with sigmoidoscopy, a method that examines only a portion of the colon.

Related Articles


The team scrutinized data collected from more than 2 million patients over the past 20 years, and found that a drop in colorectal cancer incidence correlated with Medicare's extension of colonoscopy coverage in 2001.

"Widespread colonoscopy screening may actually be having an impact in the risk of colon cancer at the level of the general population," said Uri Ladabaum, MD, MS, associate professor of gastroenterology and hepatology and senior investigator for the study. The results were published online Oct. 23 in Gastroenterology.

Colorectal cancer is the second-leading cause of cancer-related deaths in the United States, according to the federal Centers for Disease Control and Prevention. The American Cancer Society and other groups recommend colorectal cancer screening for people at average risk beginning at age 50. Colonoscopies are recommended once every 10 years for average-risk adults, and more often in those found to have precancerous lesions known as polyps.

Several methods are currently available for the screening. Less-invasive methods, such as stool sample analysis, cause minimal discomfort but some patients consider them a hassle, and the tests need to be performed regularly to be effective. And although these methods occasionally detect precancerous polyps, their primary purpose is detecting early stage cancers.

Colonoscopy and sigmoidoscopy are endoscopic screening methods used both for early cancer detection and for precancerous polyp removal. Sigmoidoscopy only extends into the lower (or distal) part of the colorectum, while colonoscopy extends beyond the lower colorectum and into the upper (or proximal) colon. Although sigmoidoscopy has demonstrated clear benefits in preventing cancers in the lower colorectum, U.S. doctors have increasingly relied on colonoscopy and have made it the most common method of colon cancer screening.

"The faith for a long time has been that looking more deeply into the colon must be better because we're looking at more of the colon," said Ladabaum. Despite the presumed benefits of colonoscopy, the actual superiority of the procedure as compared with sigmoidoscopy has been the subject of conflicting studies.

With the hope of shedding some light on this murky issue, Ladabaum's team examined available data on the surgery rates for colorectal cancer, and interpreted these in light of the dramatic rise in the use of colonoscopy that began more than a decade ago. The researchers analyzed data from more than 2 million patients collected from the Nationwide Inpatient Sample, a large database that includes more than 1,000 hospitals. Ladabaum and colleagues looked for trends in colorectal cancer surgery, which reflect cancer incidence. They also specifically looked for differences in rates of cancer in the lower versus the upper colon, as colonoscopy is hoped to have a benefit in preventing cancers in both areas due to its extended reach.

The results of the study suggest that increased use of colonoscopy may explain the decrease in incidence of upper colon cancer -- through the identification, and removal, of precancerous polyps -- in the last decade. The overall rate for removing, or resecting, colorectal cancer dropped from 71.1 to 47.3 per 100,000 persons between 1993 and 2009. Resection rates for lower colorectal cancer decreased gradually (at a rate of about 1.2 percent per year) from 1993 to 1999, and then dropped more steeply (to a rate of 3.8 percent per year) from 1999 to 2009. In contrast, the resection rate for upper colon cancer remained steady until 2002, and then started dropping at a rate of 3.1 percent per year until 2009.

These results support the idea that the drop in the incidence of lower colorectal cancer might be associated with screening in general, since some patients were already undergoing stool tests and sigmoidoscopy in the early 1990s, whereas the reduction in upper colon cancer incidence might be specifically associated with colonoscopy, Ladabaum said.

Interestingly, the drop in upper colon cancer incidence was seen not only for people within the suggested screening ages, but also for those over age 75. Currently, there is no consensus on whether to screen people older than 75, Ladabaum said. While some of these older patients may opt to get colonoscopies, he said he thinks these results could mean that colonoscopy screening at an earlier age prevents colorectal cancer later in life.

The availability of a screening technique that effectively detects and removes precancerous lesions makes colorectal cancer a uniquely preventable cancer, he added. "We really do have an opportunity to find the pre-cancers, before there is even a cancer there," said Ladabaum.

The study's first author is Parvathi Myer, MD, a former postdoctoral scholar at Stanford. Other co-authors are research associate Ajitha Mannalithara, PhD, and adjunct professor Gurkirpal Singh, MD.

The study was funded by the National Institutes of Health.


Story Source:

The above story is based on materials provided by Stanford University Medical Center. The original article was written by Jessica Shugart. Note: Materials may be edited for content and length.


Journal Reference:

  1. Parvathi A. Myer, Ajitha Mannalithara, Gurkirpal Singh, Uri Ladabaum. Proximal and Distal Colorectal Cancer Resection Rates in the United States Since Widespread Screening by Colonoscopy. Gastroenterology, 2012; 143 (5): 1227 DOI: 10.1053/j.gastro.2012.07.107

Cite This Page:

Stanford University Medical Center. "Increased use of colonoscopy screening could explain decrease in colorectal cancer rates." ScienceDaily. ScienceDaily, 23 October 2012. <www.sciencedaily.com/releases/2012/10/121023152315.htm>.
Stanford University Medical Center. (2012, October 23). Increased use of colonoscopy screening could explain decrease in colorectal cancer rates. ScienceDaily. Retrieved January 31, 2015 from www.sciencedaily.com/releases/2012/10/121023152315.htm
Stanford University Medical Center. "Increased use of colonoscopy screening could explain decrease in colorectal cancer rates." ScienceDaily. www.sciencedaily.com/releases/2012/10/121023152315.htm (accessed January 31, 2015).

Share This


More From ScienceDaily



More Health & Medicine News

Saturday, January 31, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

CDC: Get Vaccinated for Measles

CDC: Get Vaccinated for Measles

Reuters - US Online Video (Jan. 30, 2015) The CDC is urging people to get vaccinated for measles amid an outbreak that began at Disneyland and has now infected more than 90 people. Linda So reports. Video provided by Reuters
Powered by NewsLook.com
Obama To Outline New Plan For Personalized Medicine

Obama To Outline New Plan For Personalized Medicine

Newsy (Jan. 30, 2015) President Obama is expected to speak with drugmakers Friday about his Precision Medicine Initiative first introduced last week. Video provided by Newsy
Powered by NewsLook.com
NFL Concussions Down; Still on Parents' Minds

NFL Concussions Down; Still on Parents' Minds

AP (Jan. 30, 2015) The NFL announced this week that the number of game concussions dropped by a quarter over last season. Still, the dangers of the sport still weigh on players, and parents&apos; minds. (Jan. 30) Video provided by AP
Powered by NewsLook.com
U.S. Wants to Analyze DNA from 1 Million People

U.S. Wants to Analyze DNA from 1 Million People

Reuters - US Online Video (Jan. 30, 2015) The U.S. has proposed analyzing genetic information from more than 1 million American volunteers to learn how genetic variants affect health and disease. Rough Cut (no reporter narration). Video provided by Reuters
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins