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Bummer.

There's a new procedure in some hospitals that is less invasive. They use a cat-scan of the intestine and abdomen and a 3D reconstruction of the image data. The only "invasive" part are (a) the pre-test purge, and (b) right before the test, they inflate your bowel with air. Supposedly they can see pretty small polyps. It is called colonography.

It doesn't require a GI guy to do the test. It is read by a radiologist.

By coincidence, I had a colonoscopy this week. My doctor mentioned this "virtual" colonoscopy. He said it was good, but that currently it is estimated to find 90% of all polyps, etc.

That means the virtual colonoscopy misses 10%, whereas a colonoscopy essentially misses 0%. I for one would not roll the dice on 10% when missing it could mean cancer goes undetected.

How long does one have to diet before either test? A while back on CNN it was mentioned that a blood test for colon cancer was in the works.

There's a new procedure in some hospitals that is less invasive. They use a cat-scan of the intestine and abdomen and a 3D reconstruction of the image data. The only "invasive" part are (a) the pre-test purge, and (b) right before the test, they inflate your bowel with air. Supposedly they can see pretty small polyps. It is called colonography.

And it's not ready for "prime time" yet:

CT colonography sensitivity low

NEW YORK (Reuters Health) - Compared with conventional colonoscopy, the sensitivity of computed tomographic colonography is quite low, even for lesions of at least 10 mm, according to results of a large, multicenter study reported in the April 14th issue of the Journal of the American Medical Association.

Several studies from single centers have suggested a high degree of sensitivity for CT colonography, Dr. Peter B. Cotton, at the Medical University of South Carolina in Charleston, and associates note. (See Reuters Health reports, March 18, 2004 and December 1 2003.) Their own study was designed to evaluate the accuracy of CT colonography in routine practice at nine major hospital centers.

Included were 615 patients referred for clinically indicated elective colonoscopy between 2000 and 2001. Colonoscopy was performed within 2 hours of the colonography.

When using a threshold of 6 mm, the sensitivity was 39% compared with conventional colonoscopy; sensitivity was 55% for lesions of at least 10 mm. CT colonography missed two of eight cancers.

At the one center that had "substantial" prior experience with CT colonography, the sensitivity was 82% for lesions of 6 mm or more. Sensitivity at all of the other centers combined was 24%, with no improvement in accuracy as the number of cases at each center was increased.

Preference questionnaires after both procedures were performed showed that 46% of the participants preferred CT colonography versus 41% who preferred conventional colonoscopy.

"Even if the results of CT colonography continue to be good in the hands of experts, it has yet to be proven that this expertise can be taught and disseminated reliably into daily practice," Dr. Cotton's team concludes.

"The differences between what virtual colonoscopy can do and what it will do if applied in ordinary practice circumstances are so great that physicians must be cautious" in implementing this strategy, Dr. David F. Ransohoff at the University of North Carolina at Chapel Hill maintains in a JAMA editorial.

JAMA 2004;1713-1719,1772-1774.

http://www.oncolink.upenn.edu/resources/article.cfm?c=3&s=8&ss=23&id=10649&month=04&year=2004

"Anecdote" is not an ideal source to base your healthcare decisions. In five minutes, I found the above objective assessment of CT colonography, and also found the following article citing a 0.2% (2 out of 1000) complication rate for colonoscopy (in an elderly population, yet!):

Colonoscopy in elderly people is a safe procedure with a high diagnostic yield: a prospective comparative study of 2000 patients. Karajeh MA, Sanders DS, Hurlstone DP. Gastroenterology and Liver Unit, Royal Hallamshire Hospital, Sheffield S10 2JF, South Yorkshire, UK. BACKGROUND AND STUDY AIMS: Optical colonoscopy is considered the gold standard for colorectal examination and has the advantage of allowing biopsies and polypectomy. However, the data on its safety and effectiveness in the elderly population are limited and somewhat conflicting. We prospectively assessed whether there are differences in completion rates, diagnostic yield, complication rates and 30-day mortality between patients aged > or = 65 years and patients aged < 65 undergoing colonoscopy at our centre. PATIENTS AND METHODS: Data were collected prospectively on 2000 colonoscopies performed over a 2-year period (January 2002 to January 2004). We compared 1000 consecutive colonoscopies in patients aged > or = 65 with 1000 consecutive colonoscopies in patients aged < 65 (control group). Data were collected on sedation; on completion rates, both crude and adjusted to discount failures due to obstructive disease; on diagnostic yield; complications, and on 30-day mortality. RESULTS: The median age was 75 years (51 % women) for the elderly group and 54 years (59 % women) for controls. The proportion of patients who received sedation was similar for both groups (59 % vs. 62 %, P = 0.97) but the mean dose of midazolam was lower in the elderly group (3.8 mg vs. 4.5 mg, P < 0.0001). The crude completion rate was lower for the elderly group (81.8 % vs. 86.5 %, P = 0.004), but the adjusted rate was similar for both groups (88.1 % elderly vs. 87.6 % control, P = 0.18). The overall diagnostic yield was higher in the elderly group (65 % vs. 45 %, P < 0.0001) with higher rates of carcinoma detected (7.1 % vs. 1.3 %, P < 0.0001). The complication rate was low (0.2 % per group). CONCLUSIONS: Colonoscopy in the elderly is safe and effective with a high diagnostic yield. Colonoscopy may now be the imaging modality of choice in the elderly population.

It doesn't require a GI guy to do the test. It is read by a radiologist.

The down side is that if a polyp is found, you have to have a full scoping to remove it. You end up paying for two procedures to get one result.