Improving Cancer Screenings Time and Again

Colorectal cancer detection improved with repeat sigmoidoscopy screens

(RxWiki News) Okay, having tubes inserted where the sun doesn't shine is no fun. Still colorectal cancer screenings are essential. New studies show one method gets the job done.

Having repeat flexible sigmoidoscopy screenings increases the detection of colorectal cancer or advanced benign tumors (adenomas), according to recently published research.

This procedure uses a thin, lighted tube that's inserted through the rectum into the sigmoid - lower colon.

"Begin colorectal cancer screening at the age of 50."

Endoscopic exams, which use special instruments to look at the inside of the intestines, are more accurate than fecal occult blood testing, which examines the feces for blood, for detecting colon cancers and precancerous tumors.

Repeated screening is more accurate than single screens.

Colorectal cancer screenings suggest having a baseline colonoscopy, which looks at the entire colon, begin at age 50 and occur every 10 years thereafter. Flexible sigmoidoscopies (FSG) should also start at age 50 and are best repeated at least every five years. These may need to occur more often depending on the risk level of the patient and what is discovered.

The Prostate, Lung, Colorectal, and Ovarian (PLCO) cancer screening clinical trial looked at the effectiveness of repeated FSG screenings and sought to determine how often they should be conducted. 

For this study, Joel L. Weissfeld, M.D., MPH, associate professor in the department of epidemiology at the University of Pittsburgh, and colleagues analyzed data from this trial.

Researchers analyzed results from 77,447 participants between the ages of 55-74 who had had a FSG at the time they enrolled in the study. These patients were then screened again three and five years  later.

Among the total participants, 67,073 had at least one FSG and 39,442 had two FSGs.

The second FSG increased the number of detected cancers or advanced adenoma by 26 percent in women and by 34 percent in men, researchers learned.

It should be noted that the first screen found colorectal cancer or advanced adenomas (non-cancerous tumors)  in 3.8 percent of the people and in 4.5 percent of the participants after two screens.

This amounted to an increased detection of 34 percent.

The researchers point out: "Although repeated FSG increases screening yields, it also increases the costs of screening, the need for diagnostic intervention, and the risks of complication."

A flexible sigmoidoscopy costs vary widely depending on where it's performed, along with physician and pathology (lab) fees. 

Complications following the procedure are rare, but may include tearing in the intestine wall or bleeding from the site.

There were other limitations to the study, as well, the researchers noted. "Despite our ability to measure the yields from first and repeat FSG, it may not be possible to distinguish specific mortality benefits derived from first as opposed to repeat FSG," they wrote.

The study was published January 31, 2011 in the Journal of the National Cancer Institute.

Funding for this research came from National Cancer Institute.

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Review Date: 
January 31, 2012