Colorectal Adenoma Detection Rates High in Black Patients

CHICAGO — The detection rates of adenoma and advanced adenoma were alarmingly high in a small group of predominantly black men and women who underwent free screening colonoscopy in an urban hospital that caters to ethnic minorities, according to new research.

“We need to study more patients to confirm whether what we observed in this small group of patients is truly representative of the black population,” said Muhammed Hassan, MD, a resident in pathology at Howard University Hospital in Washington, DC.

“If we do find it representative, we may need to offer screening colonoscopy at an earlier age, and perhaps follow-up more frequently for patients of African descent,” he said during a poster presentation here at the American Society for Clinical Pathology 2017 Annual Meeting.

“We were seeing a lot of adenomas in black patients, so we thought we should check the biopsies of asymptomatic patients going for screening colonoscopy after the age of 50, which is the standard recommendation,” Dr Hassan told Medscape Medical News.

For their analysis, he and his colleagues retrospectively assessed asymptomatic patients who underwent free screening colonoscopy in 2016 at Howard University Hospital. Of the 52 patients, 47 were black, three were Hispanic, one was Asian, one was white, 28 were male, and 24 were female.

Biopsies were stained with standard hematoxylin and eosin stain, and three levels were examined.

In the Howard cohort, polyps were identified in all patients except one male (98.0%). Adenomas were detected in 78.8% of the patients, and advanced adenomas were detected in 35.0%.

For adenomas, the detection rate was 92% in males and 81% in females; for advanced adenomas, the detection rate was 27% in males and 42% in females.

The researchers compared their Howard cohort of predominantly black patients with cohorts of patients from other studies of different ethnic groups who were undergoing their first screening colonoscopy at approximately 50 years of age.

In one of the comparator studies, rates of adenoma detection were not significantly different between Hispanic and white patients, and there were no real differences between Hispanic and white males and females (Gastrointest Endosc2013;77:430-435). In addition, there was no difference in the rate of advanced adenomas between Hispanic and white patients.

By contrast, detection rates of adenomas and advanced adenomas in the Howard cohort of predominantly black patients were strikingly higher for men and women, both Hispanic and white, than in this comparator study.

Table. Rates of Detection in the Howard and Comparator Cohorts

Predominantly Black Howard Cohort Comparator Cohort
Detection Female Patients, % Male Patients, % Hispanic Patients, % White Patients, %
Adenoma 81.0 92.0 45.0 48.0
Advanced adenoma 43.0 28.0 3.0 4.0
2 or 3 adenomas 47.6 34.6 15.0 18.0
Proximal polyps 38.0 50.0 18.0 19.0

It is too soon to revise recommendations so that screening colonoscopy is initiated in black patients before the age of 50, Dr Hassan emphasized to Medscape Medical News. Many more patients must be screened before these early observations can be applied to the black population overall.

In the meantime, the researchers suggest that advanced adenomas detected on screening colonoscopy require complete excision, with clear margins, and more frequent surveillance colonoscopy because of the high risk for malignant transformation.

This is a good study, conducted in a hospital that serves a predominantly black population, said Zubair Baloch, MD, PhD, from the Hospital of the University of Pennsylvania in Philadelphia, who is chair of the meeting education committee.

“Still, it’s just one study. When you go to a center that is seeing a particular demographic, their results may be skewed,” he told Medscape Medical News.

Even though it is recommended that screening colonoscopy begin around the age of 50, “we don’t know how many patients were, in fact, 55 or even 60 in this cohort,” he pointed out.

“If the majority of the population is older than 50, the risk for adenomas is already higher,” he added.

Dr Baloch also wondered if patients were truly asymptomatic at the time of the screening colonoscopy. Symptoms are more or less checked off automatically by patients before they undergo screening. It is not clear whether the patients in the Howard cohort had any risk factors for colorectal cancer, such as a family history, which is increasingly acknowledged as a real risk factor for colonic polyps.

“This study showed me a trend, but it needs to be validated,” Dr Baloch concluded.

Dr Hassan and Dr Baloch have disclosed no relevant financial relationships.

American Society for Clinical Pathology (ASCP) 2017 Annual Meeting: Poster SA103. Presented September 7, 2017.

Source: Medscape Medical News © 2017