By Carolyn Keister Baker -- Daily Staff Writer

WINCHESTER — Certainly no one relishes the idea of getting a colonoscopy or similar colon test, but everyone of average risk by the time they reach their 50th birthday should be screened for precancerous polyps and colorectal cancer, according to recommendations set out by the American Cancer Society.

Unfortunately, though, studies indicate most Americans continue to ignore this life-saving recommendation.

A majority of Americans age 50 and over who should be tested are not being screened for colorectal cancer — the third most common cancer and the second leading cause of cancer deaths in the United States, according to the society's Web site.

Last week, the society expanded its recommendations for early detection of colon cancer, placing its seal of approval on two additional screening methods, including virtual colonoscopy.

March is Colorectal Cancer Awareness Month.

For the past four years, Winchester Imaging has offered virtual colonoscopy, a screening method that may be more acceptable in the minds of many patients — patients who fear the idea of an optical colonoscopy.

In contrast, optical colonoscopy — the more invasive test — requires a doctor to guide a thin flexible tube, or colonoscope, through the entire length of the colon.

With virtual colonoscopy patients undergo a computerized tomography scan, which takes axial images of the colon. No tubes or scopes are used except a tip inserted in the rectum to expand the colon with carbon dioxide.

"People seem to prefer virtual colonoscopies over optical colonoscopies," says Dr. Ronald G. Repasky, radiologist and director of Winchester Imaging. When patients leave the office after the test, they are able to go about their daily routine, he says.

Recent studies coordinated by the American College of Radiology Imaging Network indicate that virtual colonoscopy is comparable to optical colonoscopy for detection of cancer and polyps, according to the Web site of the American College of Radiology. The ACRIN trials "put virtual colonoscopies back on the map," says Repasky.

Stacey Smith, lead CT scan technician at Winchester Imaging, can attest to the fact that patients find the virtual colonoscopy more palatable.

"This is way easier," Smith says. "[The test] is a lot less invasive. It is pretty ingenious."

Patients don't need to be sedated and there is no need for intravenous drips, she explains.

While a half hour is blocked off for each patient, the actual CT scan takes only about 10 minutes, Smith says. Patients lie on a table, in turn on their stomach and back, while the images are taken, she explains. A technician will massage the patient's stomach to help distribute air through their system, she adds.

Patients may experience a feeling of fullness from the air distending the bowel, Repasky says. Winchester Imaging uses carbon dioxide because it is better absorbed by the body and patients feel less bloated, he says.

The worst part of the test is probably the bowel prep, which is also required for the optical colonoscopy. "You are not going to get around that," Repasky says.

The bowel prep includes a restricted, low-residue diet, beginning two days before the exam at lunchtime, and bowel cleansing, starting a day before the test. Patients may not eat or drink after 9 p.m. the night before and up until the screening, according to patient instructions.

Once the images are taken, the information, through the use of a computer, allows radiologists to "live in a virtual world and look at all the walls of the colon," Repasky explains.

"We are looking for imperfections," Repasky says. The technology allows the radiologists to take a virtual, three-dimensional "fly-through," seeing first the front walls of the colon on the way in and then the back walls on the way out.

"I think it is pretty incredible," Repasky says.

The downsides of optical colonoscopy are the small risks of perforated bowel and bleeding.

With virtual colonoscopy, patients are exposed to radiation, which possibly could lead to a future malignancy, Repasky says. While the risk is there, the danger is relatively small, he says.

The risk associated with getting a CT scan can be compared to the risk of smoking 140 cigarettes in a lifetime, spending seven months in New York City or driving 4,000 miles in a car, Repasky explained.

Virtual colonoscopy also has the disadvantage of not allowing the removal of polyps if they are found. Patients who have significant polyps have to go through a regular colonoscopy to remove them on another day, Repasky says.

Winchester Imaging is performing about two to five virtual colonoscopies a month, Repasky says. As of now, insurance doesn't usually cover the exam, except for patients who have a bleeding problem or are on blood thinners, or can't be given the type of anesthesia used or who have had a previous unsuccessful optical colonoscopy, he says.

The American Cancer Society's endorsement of virtual colonoscopy may influence insurance companies to include coverage for virtual colonoscopies in the future, Repasky says. Insurance companies in some regions of the country are already doing so, he says.

The test and interpretation costs about $900, Repasky says. A spokesman at the Endoscopy Center at Winchester Medical Center reports that a colonoscopy with physician fees costs just under $1,500.

For more information, residents may access Winchester Imaging's Web site at www.winchesterimaging.com.

* Contact Carolyn Baker at cbaker@nvdaily.com