Despite growing knowledge of the importance of colorectal screenings for cancer detection and prevention, many adults forgo the routine endoscopic procedure. Now, an anesthesia preference study suggests that patients may be more likely to undergo the endoscopic cancer screenings if assured they will be unconscious, with anesthesia administered by a physician anesthesiologist.

The study's findings were presented last fall at an annual meeting of the American Society of Anesthesiologists. To determine patient preference, the study compared the use of traditional intravenous sedation using midazolam/fentanyl administered by endoscopy nurses to propofol anesthesia administered by anesthesiologists during upper or lower endoscopic procedures in 2003 and again in 2007.

"Modern anesthetics have been designed to safely anesthetize a patient for necessary procedures such as colonoscopies and endoscopies that would have not been possible or tolerated well by patients in the past," says Dr. Steven M. Frank, an anesthesiologist at Greater Baltimore Medical Center and the study's lead researcher. "Propofol allows for a much deeper level of anesthesia, where patients are completely unconscious while also allowing for a rapid wakeup and recovery."

Of 155 total patients, 93 returned surveys related to their two endoscopic procedures. With 60 percent of patients responding, the data showed a seven-to-one patient preference to be completely "asleep" during the endoscopic procedure. Four times as many patients responded that they would be more likely to undergo routine cancer-screening endoscopies if they knew they would be unconscious under the care of an anesthesiologist as opposed to receiving drugs given by a nurse.

"Given that anxiety, pain, and discomfort are major deterrents to colorectal cancer screening, our findings suggest that the routine use of propofol anesthesia may improve cancer screening rates, disease detection, and reduce mortality from a leading cause of cancer death in the U.S.," Frank says.

The researchers concluded that "while most patients did not feel pain undergoing either procedure, they did indicate feeling safer knowing a physician anesthesiologist was rendering their care during the procedure."

Colorectal screening

Meanwhile, in a change from its previous recommendation, the U.S. Preventive Services Task Force now recommends that adults age 50 to 75 be screened for colorectal cancer using annual high-sensitivity fecal occult blood testing, a sigmoidoscopy every five years with annual fecal occult testing in between, or colonoscopy every 10 years.

The task force says good evidence exists that using any of those methods save lives. The recommendation and an accompanying summary of evidence were posted online in a publication called the Annals of Internal Medicine and appeared in a November print edition of the journal.

The task force recommends against routine colorectal cancer screening in adults between the ages of 76 and 85 because the benefits of regular screening were small compared with the risks. It recommends that adults over the age of 85 not be screened at all because the harms of screening may be significant, and other conditions may be more likely to affect their health or well-being.

For people of all ages, the task force found insufficient evidence to assess the benefits and harms of computed tomographic (CT) colonography and fecal DNA testing as screening methods for the disease. Further, these task force recommendations don't apply to people with a personal history of certain types of polyps who are being monitored regularly for the condition or to those who have a family history of rare syndromes that increase a person's chances of getting colon cancer.

The recommendation strengthens the task force's position announced in 2002, when it recommended screening for colorectal cancer but noted that evidence was insufficient to recommend one screening method over another. This is also the first time that the task force has indicated an age that people should stop being screened for colorectal cancer.

Although colonoscopy is considered to be the standard against which other screening tests are compared, the test isn't perfect and may in fact miss some polyps and colorectal cancer. Because colonoscopy is an invasive procedure, it has greater risk of complications than any other screening methods.

Sigmoidoscopy, which involves inspecting just the lower parts of the colon, or fecal occult blood testing are less invasive and have a lower risk of harm. However, patients who receive positive test results for detection of polyps will require a follow-up colonoscopy regardless of the screening test used. Because the risks and benefits of all tests vary, patients and clinicians are encouraged to decide together which test is appropriate.

"Screening for colorectal cancer saves lives," says task force Chairman Dr. Ned Calonge, who also is chief medical officer for the Colorado Department of Public Health and Environment. "Current rates for colorectal cancer screening are much lower than other types of cancer screening. We hope patients and physicians will discuss the potential benefits and harms and choose an appropriate screening method for them."

Colorectal cancer is the third most common cancer and the second leading cause of cancer death in the U.S. Research funded by the Agency for Healthcare Research and Quality (AHRQ) and the National Cancer Institute, part of the National Institutes of Health, and featured in the September 2008 Medical Care Supplement examined ways to improve the delivery of colorectal cancer screening in primary care. In 2005, only about half of adults age 50 and older had been screened for the disease.

The task force, which is supported by AHRQ, claims to be the leading independent panel of experts in prevention and primary care. It conducts assessments of the scientific evidence for the effectiveness of a broad range of clinical preventive services, including screening, counseling, and preventive medications.