Clinical Briefs

By Louis Kuritzky, MD

Computed Tomographic Colonography (Virtual Colonoscopy)

Screening for colon cancer (CCa) has not reached the same level of popular adherence as seen with, for instance, prostate cancer screening by PSA. Although colonoscopy (COL) is highly effective for the detection and elimination of malignant precursors, only about half of the COL-eligible population undergoes the procedure. It has been anticipated that if a highly discriminating screening tool, with less invasive properties than COL, were available, a greater number of persons would adopt it. Virtual colonoscopy (vCOL) is a candidate for such a tool.

vCOL is performed by helical CT scanning of the air-distended (or carbon dioxide distended) colon, after a traditional bowel preparation. Lesions discerned at vCOL then require tissue definition by COL. If vCOL were sufficiently accurate, and well tolerated by patients, it could eliminate many "unnecessary" colonoscopies.

This multicenter study enrolled 617 subjects who underwent both COL and vCOL within a 2-hour interval, of whom 600 ultimately satisfactorily completed both investigations. Examinations were performed by experienced endoscopists and radiologists.

For lesions 10 mm or greater in size, the sensitivity of vCOL was 55%. For smaller lesions (6-10 mm), vCOL sensitivity was 39%. These results are slightly less favorable than seen in some other trials; Cotton and colleagues comment that this may reflect a higher experience level of radiologists in other trials, despite their inclusionary criteria for radiologist competency. These data suggest that current vCOL techniques are not yet sufficiently evolved to recommend supplanting more traditional methods.

Cotton PB, et al. JAMA. 2004;291: 1713-1719.

Ejaculation Frequency and Subsequent Risk of Prostate Cancer

Prostate cancer (pCA) hypothetically could be related to sexual activity. For instance, if men who seek sexual activity more often have higher testosterone levels, and such levels were associated with greater risk of pCA, a sexual activity-pCA relationship could be hypothesized. Similarly, it has been theorized that ejaculating with reduced frequency might expose prostatic tissues to carcinogenic components in retained prostatic secretions.

The Health Professionals Follow-up Study began in 1986 enrolling 51,229 health professionals age 40-75. In 1992, a questionnaire solicited ejaculatory history, asking participants to recall the average monthly number of ejaculations at ages 20-29, 40-49, and in the previous year. Frequency categories (ejaculations per month) were broken down into 1-3, 4-7, 8-12, 13-20, and > 21.

In age-adjusted and multivariate analysis, an 11% lower relative risk of pCA was found in the highest tier of monthly ejaculations (21 or greater). For all lesser ejaculatory frequencies studied, there was no discernible relationship (positive or negative). When specifically looking at advanced pCA, there was a trend towards increased risk among those with high ejaculation frequency. Except for these sub-groups, there was no demonstrable overall relationship between ejaculatory frequency and pCA.

Leitzmann MF, et al. JAMA. 2004;291:1578-1586.

Cost-Effectiveness of Different Combinations of Bupropion SR dose and Behavioral Treatment for Smoking Cessation

The single most effective pharmaceutical intervention which results in sustained smoking cessation is bupropion (BUP). The most often-used treatment regimen requires BUP 150 mg/d for 3 days, followed by 300 mg/d (usually divided b.i.d.) for up to 12 weeks. The added benefit of behavioral counseling or nicotine replacement when used in conjunction with BUP is less clear, although it is commonplace for these tools to be used concomitantly.

Although the favorable effects of BUP for smoking cessation have been consistent, these conclusions are drawn from research centers that might not reflect typical clinical practice settings. Javitz and colleagues evaluated BUP (150 mg or 300 mg QD, sustained release) with 1 of 2 brief counseling interventions: multiple followup calls from a smoking cessation counselor (called PTC’ in the article) or an automated questionnaire series during followup (called TM’ in the article). Either brief counseling intervention could readily be applied in the typical ambulatory setting.

At 12 months, the cessation rates for 300 mg BUP daily were slightly higher than, but similar to 150 mg BUP daily (28.5% vs 22.5%). The more intensive, personalized behavioral intervention (PTC) was also associated with greater mean cessation rates. The authors conclude that the lower BUP dose is more cost effective than 300 mg BUP, with modestly lesser efficacy.

Javitz HS, et al. Am J Manag Care. 2004;10:217-226.

Dr. Kuritzky, Clinical Assistant Professor, University of Florida, Gainesville, is Associate Editor of Internal Medicine Alert.