Whites prefer virtual colonoscopy; minorities like conventional

Aug 19, 2007

Blacks and other racial and ethnic minorities, who are already screened for colorectal cancer (CRC) in lower numbers and suffer its consequences more acutely than the U.S. population as a whole, don't seem too impressed with virtual colonoscopy.

In a study from New York University Medical School in New York City, minority subjects who underwent both virtual and conventional colonoscopy on the same day reported more pain and discomfort with virtual colonoscopy (VC or CT colonography, CTC) than whites who followed the same screening protocol. Minorities significantly preferred conventional colonoscopy compared to whites, a majority of whom opted for VC.

Certainly one should avoid inferring too much from a single-center study of 272 screening subjects. But the paper does raise important questions about potential cultural influences on screening, the adequacy of education and outreach programs about colorectal cancer screening, and potential differences in screening populations that could affect compliance. As is, less than half of the eligible CRC screening population (i.e., all adults over 50 years of age) ever comes in for screening.

"One reason for the low rates of participation in CRC screening programs is the reluctance of patients to undergo an invasive endoscopic examination," wrote study authors Dr. Roshini Rajapaksa, Dr. Michael Macari, and Dr. Edmund Bini from the NYU medical center's departments of gastroenterology and radiology. "Previous studies have shown that racial/ethnic differences exist in the proportion of people who undergo CRC screening, as well as racial/ethnic variation in the types of screening tests used. In addition, there are known racial/ethnic disparities in the incidence, clinical presentation, and long-term outcome of CRC, with the highest incidence and mortality rates found in blacks."

As for screening subjects' overall preferences, previous studies have shown conflicting results, although a clear majority of studies have demonstrated a preference for virtual colonoscopy versus the conventional exam.

"The reasons for these conflicting findings are unknown, but it is possible that some of the differences could be owing to racial/ethnic differences in how patients perceive these tests," Rajapaksa and her colleagues wrote. "Because previous studies have shown decreased participation in CRC screening in racial/ethnic minorities, we hypothesized that these groups would prefer a less invasive screening test than OC. Therefore, we conducted a prospective study to evaluate the hypotheses that there were marked racial/ethnic differences in patient experiences with and preferences for CTC and OC, and that racial/ethnic minorities were more likely than whites to prefer a less invasive test (CTC) over OC (Clinical Gastroenterology and Hepatology, August 3, 2007, epublication before print).

The study screened 272 patients between 2000 and 2003 (134 whites, 71 blacks, 53 Hispanics, and 14 who self-identified race as "other") from a total of 356 subjects who were invited to participate.

Patients were referred for colorectal screening either for screening or indications suggestive of colorectal polyps or cancer. Candidates were excluded for reasons that included prior colonic surgery or inability to undergo both exams on the same day.

Before the exams, the subjects were interviewed to obtain detailed demographic and clinical information including age, sex, race, education and income levels, as well as any existing medical conditions, family or personal history of colorectal polyps or cancer, according to the authors. Subjects were asked to detail any prior colon screening exams or interventions.

The subjects underwent virtual before conventional colonoscopy on the same morning. The day before the exams, all underwent cathartic bowel preparation with either two 45-mL doses of sodium phosphate (Phospho-soda, Fleet Pharmaceuticals, Lynchburg, VA) or 4 L polyethylene glycol electrolyte solution (Golytely, Braintree Laboratories, Braintree, MA) if there were contraindications to sodium phosphate.

"After the sedation from the OC had worn off, a questionnaire was administered to assess pain, discomfort, bloating, embarrassment, anxiety, and patient satisfaction using a 10-point scale (1 = least, 10 = greatest)," Rajapaksa et al wrote.

CT scans were acquired on a four-detector-row scanner (Somatom Plus 4 Volume Zoom, Siemens Medical Solutions, Malvern, PA) following manual room-air insufflation to patient tolerance. Scout images were acquired to ensure adequate colonic distension. Once distension was assured, patients were imaged first in prone then in supine positions.

The patients then proceeded immediately to the gastroenterology suite, where optical colonoscopy was performed with conscious sedation using intravenous administration of midazolam and meperidine.

The results showed that while the proportion of subjects who preferred virtual colonoscopy over conventional colonoscopy was not significantly different overall (52.9% versus 47.1%, p = 0.36), those identifying as racial or ethnic minorities were significantly less likely than whites to prefer VC over the conventional exam (whites, 65.7%; blacks, 45.1%; Hispanics, 35.8%; and other, 35.7%; p < 0.001), the authors reported.

"There were no significant differences in age or sex among the four racial/ethnic groups," they wrote. "However, a significantly higher proportion of blacks and Hispanics had less than 12 years of education. In addition, there were significant differences among racial/ethnic groups in the proportion of subjects who had a prior flexible sigmoidoscopy, as well as in the indications for the present (optical colonoscopy). Although screening was the most common indication for OC in whites and persons who designated their race/ethnicity as 'other,' a positive fecal occult blood test was the most common indication for OC in blacks, and hematochezia and iron-deficiency anemia were the most common indications for OC in Hispanics."

Overall, patients representing racial and ethnic minorities were less satisfied with their virtual colonoscopy exams (whites, 8.4 ± 1.7; blacks, 7.8 ± 1.7; Hispanics, 7.4 ± 1.8; and other, 7.5 ± 2.1; p = 0.001). Their responses also indicated that they were significantly less willing to undergo CTC again in the future (whites, 95.5%; blacks, 80.3%; Hispanics, 84.9%; and other, 85.7%; p = 0.006).

Patient Experiences With CTC Stratified According to Race/Ethnicity	White (n = 134)	Black (n = 71)	Hispanic (n = 53)	Other (n = 14)	p value

Abdominal pain	2.9 ± 2.1	3.4 ± 2.2	4.8 ± 2.6	3.4 ± 2.3	< 0.001

Discomfort	3.8 ± 2.2	4.1 ± 2.4	4.7 ± 2.7	4.8 ± 2.7	0.19

Bloating	5.3 ± 2.6	5.3 ± 2.8	6.0 ± 3.0	5.9 ± 2.9	0.32

Embarrassment	1.9 ± 1.4	2.6 ± 2.3	2.8 ± 2.3	1.8 ± 2.4	0.03

Anxiety	2.8 ± 2.2	3.9 ± 3.3	3.9 ± 3.2	4.3 ± 3.5	0.17

Satisfaction	8.4 ± 1.7	7.8 ± 1.7	7.4 ± 1.8	7.5 ± 2.1	0.001


NOTE. Patient experiences were scored on a scale of 1-10, with 1 being least and 10 being greatest.

"Contrary to our a priori hypothesis, we found that racial/ethnic minorities actually preferred OC over CTC, whereas whites preferred CTC over OC. These findings have important clinical implications for CRC screening among the large population of racial/ethnic minorities in the United States," the group wrote.

Patient Experiences With OC Stratified According to Race/Ethnicity	White (n = 134)	Black (n = 71)	Hispanic (n = 53)	Other (n = 14)	p value

Abdominal pain	4.8 ± 2.3	3.1 ± 2.5	3.0 ± 2.1	3.4 ± 3.3	< 0.001

Discomfort	4.2 ± 2.6	3.2 ± 1.9	3.6 ± 2.4	3.1 ± 1.5	0.07

Bloating	3.6 ± 2.4	2.8 ± 2.1	2.6 ± 1.5	2.6 ± 1.6	0.02

Embarrassment	1.8 ± 1.3	2.0 ± 2.5	2.0 ± 1.7	2.4 ± 2.6	0.08

Anxiety	3.3 ± 2.5	4.1 ± 3.3	3.2 ± 2.4	4.5 ± 3.7	0.62

Satisfaction	7.8 ± 1.8	8.5 ± 1.7	8.2 ± 2.0	8.0 ± 2.0	0.004


NOTE. Patient experiences were scored on a scale of 1-10, with 1 being least and 10 being greatest.

The study is one of very few to evaluate racial and ethnic differences in colon screening experiences, the authors noted. Its strengths include a prospective design, the use of multivariable logistic regression analysis to adjust for potential confounding variables, and the ethnic diversity of its subjects.

Patient Preferences for CTC and OC Stratified According to Race/Ethnicity	White (n = 134)	Black (n = 71)	Hispanic (n = 53)	Other (n = 14)	p value

Preferred CTC over OC	65.7%	45.1%	35.8%	35.7%	< 0.001

Willing to undergo CTC again in the future	95.5%	80.3%	84.9%	85.7%	0.006

Willing to undergo OC again in the future	93.3%	94.4%	96.2%	96.9%	0.89

Prefer CTC over OC in the futuret	66.4%	46.5%	35.8%	35.7%	< 0.001


Factors Associated With Patient Preferences for Computed Tomography Colonography.

Still, they acknowledged "significant limitations" that may have affected the results. These included a single-center design, and a patient cohort consisting mostly of men. The subjects had already agreed to colorectal cancer screening, making the results difficult to generalize to the population as a whole, the authors noted.

Significantly, patients who were unwilling to be screened with optical colonoscopy were unable to participate. "Patients who refuse OC are an important group of individuals who certainly deserve consideration if we are to make a positive impact on the number of people who undergo CRC screening, although they are a difficult group to study," Rajapaksa et al wrote.

Moreover, the outdated VC exam methods used in the study were also less patient-friendly than today's techniques, the team wrote. The use of four-detector-row scanners made for scan times as long as 30 seconds (compared to 12 and six seconds with 16-slice and 64-slice scanners, respectively). And the use of manual room-air insufflation as opposed to automated CO₂ insufflation has been shown to increase patient discomfort, especially in the period right after the procedure.

Finally, patients were ushered off the CT table and into their colonoscopy exam rooms without the radiologists having had an opportunity to review the findings. Future screening trials will include optical colonoscopy only if a clinically significant polyp is found, which would eliminate the need for repeat bowel cleansing.

"However, it is unclear how these CTC-related factors may impact racial/ethnic preferences for colon imaging tests," they wrote.

Minorities' strong preference for optical colonoscopy over CT colonography "suggests that promoting the use of CTC in these populations at the present time is unlikely to overcome racial/ethnic disparities in CRC screening," the group concluded. However, new CTC techniques in use are likely to change how patients perceive the exam over time, and it is possible that these technologic advances "will help to overcome racial/ethnic disparities in CRC screening," they wrote.

By Eric Barnes
AuntMinnie.com staff writer
August 20, 2007

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