Data shows rates of colorectal cancer screening vary by race, ethnicity and method

Digestive Disease WeekMay 5 2010

Health outcomes explored at DDW 2010

Rates of colorectal cancer screening vary by race and ethnicity as well as method, according to data being presented at Digestive Disease Week- (DDW-) 2010. Scientists examine data on minority and older populations as well as utilization rates of virtual and optical colonoscopies to better understand adherence to recommended screening guidelines. DDW is the largest international gathering of physicians and researchers in the field of gastroenterology, hepatology, endoscopy and gastrointestinal surgery.

Impact of a CT Colonography Colorectal Cancer Screening Program on Optical Colonoscopy: 5 Year Data (Abstract #683a)

Researchers at the University of Wisconsin found that increased accessibility of virtual colonoscopies, colonoscopies completed via CT scan, did not decrease the use of traditional optical colonoscopies for colorectal cancer (CRC) screenings.

Virtual colonoscopy, which was introduced nearly 10 years ago as a non-invasive alternative to colorectal cancer screenings, allows physicians to examine the colon and surrounding areas for polyps and other irregularities. However, virtual colonoscopies only allow physicians to spot certain polyps, creating a need for additional tests if polyps are found. Traditional colonoscopies remain the gold standard test for CRC screenings since doctors are able to identify and remove polyps in one test.

"Previous theoretical studies showed that once virtual colonoscopies became accepted as a national screen test, regular colonoscopies would be reduced by 25 percent," said Patrick Pfau, MD, associate professor and director of clinical gastroenterology at the University of Wisconsin School of Medicine and Public Health. "But since our virtual colonoscopy program began in 2004, we have seen no change. In fact, we have seen an increase in the number of traditional colonoscopies."

In 2004, the University of Wisconsin became the first institution in the U.S. to accept third-party payor coverage for virtual colonoscopy exams. To examine the effects of the virtual colonoscopy program on rates of optical colonoscopies, researchers looked at total CRC screenings from 2003 to 2008 in patients aged 50 to 75. Over this five-year period, the total number of CRC screening exams (virtual + optical colonoscopies) increased 53 percent from 555 screenings per quarter in 2003 to 1,187 in 2008. Virtual colonoscopies peaked at 307 exams performed in the third quarter of 2005, declining to 203 exams performed in the last quarter of 2008.

During this same time, optical colonoscopy exams increased significantly from 555 exams per quarter in 2003 to 995 exams per quarter performed in 2008. In 2009, five years after initiation of the virtual colonoscopy screening program, an average of 1,255 quarterly screening exams were performed with 86.6 percent of the patients screened with optical colonoscopies and 8.5 percent screened with virtual colonoscopies.

Dr. Pfau will present these data on Tuesday, May 4 at 10:30 a.m. CT in 260-262, Ernest N. Morial Convention Center.

Method of Recommendation for Colorectal Cancer Screening Strategies Impacts Adherence (Abstract #124)

It is assumed that better outcomes from colorectal cancer (CRC) screening are achieved by recommending colonoscopy as the preferred screening test. However, this method of recommendation may adversely impact adherence to screening in diverse populations, according to a new study from researchers at the University of California, San Francisco (UCSF) who found that recommending colonoscopy resulted in lower adherence compared with recommendations for fecal occult blood test (FOBT), or a choice of the two procedures.

The findings are important because current screening guidelines stress colonoscopy as the preferred screening strategy.

Researchers conducted a study comparing single and multiple recommendations for CRC screening in a racially diverse population. About 1,000 patients at average risk for CRC were randomly assigned to receive a recommendation by their primary care provider for FOBT, colonoscopy or a choice of the two. Patients completed a survey of recommended tests as well as those they actually adhered to in the following year, and complete follow-up was achieved in 99 percent of the patients.

"The unique aspect of our study was the ability to identify differences in adherence to screening based on the method of recommendation, and whether these varied between different racial and ethnic groups," said John M. Inadomi, MD, professor of medicine at UCSF and chief of clinical gastroenterology, San Francisco General Hospital.

Results showed that overall, 65.1 percent of patients adhered to screening, but there were differences among the groups: 38 percent of patients recommended for colonoscopy alone underwent this screening, 67 percent recommended for FOBT alone returned the test, and 70 percent who were given a choice between colonoscopy or FOBT adhered to either screening strategy. Even when accounting for adherence to FOBT among patients who were recommended colonoscopy only, the combined adherence to either test (58 percent) remained significantly lower compared with the groups who were recommended FOBT alone or provided a choice.

In order to reduce health-care system barriers to screening, researchers made sure that the colonoscopy could be done within two weeks of being scheduled, that the cost of the procedure was not borne by the patient, if patients needed a ride to their procedure they were provided with one, and patients were given instructions for the preparation and the procedure in the preferred language of the patient. Despite these interventions, adherence to colonoscopy remained low.

"If we follow our current guidelines regarding the promotion of colonoscopy as the preferred strategy for colonoscopy screening, in ethnically diverse populations we could be adversely impacting adherence to colon cancer screening," Dr. Inadomi said.

Still, Dr. Inadomi cautioned that these findings cannot be generalized to all populations that are not, as this one was, ethnically and racially diverse and in a safety net setting, with patients who tend to have lower socioeconomic status, education and income. He also cautioned that researchers looked only at the first episode of screening and that further research is being conducted to determine whether these findings are consistent when adherence to programmatic screening, as is required for FOBT, is evaluated.

Dr. Inadomi will present these data on Sunday, May 2 at 10:30 a.m. CT in 288-290, Ernest N. Morial Convention Center.

Adherence to Colorectal Cancer Screening Varies by Race/Ethnicity and Screening Strategy (Abstract #1039)

Limited English proficiency is not a barrier to colon cancer screening if access to health care is available, according to a new study by researchers at the University of California, San Francisco (UCSF).

Disparities in colorectal cancer (CRC) mortality exist between racial and ethnic groups, but mortality from CRC can be reduced by screening with fecal occult blood testing (FOBT) and colonoscopy. Researchers sought to determine whether these disparities represent disparities in access to screening or differences in utilization of screening. Nearly 1,000 patients at average risk for CRC were assigned to receive a recommendation from their primary care provider for FOBT alone, colonoscopy alone, or they could choose between the two.

System barriers were reduced by decreasing or eliminating patient costs of colonoscopy, providing procedure and preparation instructions in their preferred language, providing transportation if needed, and scheduling an appointment within two weeks. More than half (65.1 percent) adhered to any type of CRC strategy, but there was a significant difference in adherence based on racial and ethnic groups: Asians (73 percent) and Latinos (70 percent) adhered more often than Caucasians (62 percent) or African Americans (51 percent).

These findings are important because it suggests there are clear racial/ethnic differences in preference and adherence, depending on the procedure, according to John M. Inadomi, MD, professor of medicine at UCSF and chief of clinical gastroenterology, San Francisco General Hospital. Furthermore, the Asian and Latino patients with limited English proficiency adhered more often than Asians and Latinos with proficient English.

"We're taught that patients who don't speak English have poor health outcomes; however, this study shows that if you provide access to health care, low English proficiency is actually associated with better adherence to cancer screening." He added that this may be attributable to the fact that people with limited English proficiency tend to be immigrants; given the barriers to immigrate to the U.S., one might presume that doing so requires high-achieving adeptness and willingness to utilize health-care resources.

This is especially notable since the CRC screening tests are generally unpleasant, and patients who are recommended for screening are asymptomatic. "People need another motivation to get these tests, and that motivation seems to be a greater understanding of the disease and belief that screening has benefits," Dr. Inadomi said. "This study suggests that healthy immigrants do take advantage of health resources if they are made available to them."

One limitation of the study is that though researchers knew the language proficiency and the preference of the language of the patients, they assumed patients' acculturation and immigrant status. It would have also been optimal if the study design included measurement of their diet, activities and social structure.

Investigators said they plan to study the data further to determine why certain ethnic groups adhered more to certain procedures than others.

Dr. Inadomi will present these data on Wednesday, May 5 at 11:45 a.m. CT in 280-282, Ernest N. Morial Convention Center.

Colonoscopy for Colorectal Cancer Screening in Asymptomatic Elderly African Americans, Hispanics and Asian Americans (Abstract #W1465)

New research from Brooklyn Hospital Center highlights the need for revised and refined colorectal cancer (CRC) screening guidelines in adults aged 75 and older, especially for African American patients, since investigators found high adenoma detection rates in asymptomatic elderly African American and Hispanic CRC screenings. Current CRC screening guidelines recommend against routine screenings for adults 75 years of age and older.

Shashideep Singhal, MD, internal medicine resident at the Brooklyn Hospital Center, and colleagues examined colonoscopy screening results of 510 elderly African American, Hispanic American or Asian American patients with complete colonoscopy records. In these populations, patients with a prior history of advanced adenomas or CRC were more likely to have adenomas detected during screening compared to those with no prior history (28 percent versus 16.1 percent).

Adenoma and CRC detection rates were most significant in African American patients: 20.1 percent adenoma detection rates, 2.3 percent CRC detection. Additionally, African American patients had a higher proportion of advanced adenomas detected on the right side of the colon, ideal for detection and removal via colonoscopy.

"Physicians treating elderly patients need to be aware of the significant risk of asymptomatic advanced adenomas for this population when considering screening recommendations, especially for African American patients," said Sury Anand, MD, chief of gastroenterology and GI fellowship program director at The Brooklyn Hospital Center. "Current national guidelines don't account for the increased risk of some elderly racial groups."

Researchers cautioned that their study did not examine adenomas and CRC in elderly Caucasian patients, so study findings for minorities cannot be compared to the Caucasian population or their accompanying risk factors.

Dr. Singhal will present this data on Wednesday, May 5 at 8 a.m. CT in Hall F, Ernest N. Morial Convention Center.

Prevalence of Colorectal Neoplasia in Asymptomatic Hispanics Undergoing Screening Colonoscopy (Abstract #S1558)

Although cancer rates among Hispanics are typically lower than those among non-Hispanic whites, the prevalence of colonic adenomas (benign tumors) and neoplasia (tumor formation) in Hispanics is similar to that of non-Hispanic whites, according to new research from the University of Puerto Rico Cancer Center.

Studying 647 patients ages 50 and older undergoing colorectal cancer (CRC) screening at a large private gastroenterology practice in Puerto Rico (PR Gastroenterology Institute), researchers found that males were two times more likely to have colorectal neoplasia than women, and were more likely to have multiple polyps compared to women. They also found that patients older than 60 had a 56 percent greater chance of having polyps than those under age 60.

Marcia Cruz-Correa, MD, PhD, associate professor of medicine and biochemistry at the University of Puerto Rico Cancer Center, and study co-author Fernando Ramos, MD, also found that the location of the polyps in Hispanics differed from where they are typically found in non-Hispanic Caucasians: of the patients who had polyps, 70 percent were on the proximal or right side of the colon. Dr. Cruz-Correa attributed the difference in location to underlying molecular differences in the two populations.

"Colorectal cancer screening rates among Hispanics are dangerously low," said Dr. Cruz-Correa. "Currently, only 40 percent get screened despite the fact that colorectal cancer is the second leading cause of death among Hispanic women. As Hispanics become more acculturated to the U.S. lifestyle, they are losing the protective factor of their diet, which may account for the higher rates of colorectal cancer seen in U.S. Hispanics compared to the expected rates of cancer in their country of origin."

Dr. Cruz-Correa added that their findings send a message about the importance of using colonoscopy for CRC screening in Hispanics because it is the most effective method of detecting polyps located on the proximal side of the colon.

Dr. Ramos will present these data on Sunday, May 2 at 8 a.m. CT in Hall F, Ernest N. Morial Convention Center.

Colorectal Cancer Screening in African Americans 45-49 Years Old (Abstract #M1528)

Researchers at Temple University Hospital have found that the presence of high-grade dysplasia detected during colonoscopy is more common in a younger cohort of African American (ages 45 to 49) than their older counterparts, ages 50 to 59, therefore supporting the recommendation that African Americans in the 45 to 49 age group should be screened for colorectal cancer (CRC).

Past research has shown that the incidence of CRC in patients younger than 50 is higher in African Americans. Studies have also shown that African Americans who are going to develop CRC have a one in 10 chance of developing it before the age of 50 compared to a one in twenty chance for Caucasians. Recommendations for screenings of African Americans at an earlier age began in 2005 and were followed by publication of a practice guideline in 2009. However, the recommendation was a "grade 2C" indicating that it was not a strong recommendation.

Frank Friedenberg, MD, professor of medicine at Temple University Hospital, and colleagues sought to further our understanding of the risk of developing CRC at an earlier age for African Americans by examining the results of screening by colonoscopy of African Americans at their institution and comparing the results of those ages 45 to 49 with those ages 50 to 59. Their study of 335 African Americans found adenomatous polyps in 22.3 percent of the younger cohort compared to 19.7 percent of the older cohort. Of the polyps found, 4.5 percent showed high grade dysplasia, indicating they were advanced, in the younger group compared to 0.4 percent in the older group.

Researchers also found that patients in the older group were more likely to consume asprin daily compared to their younger counterparts (26.1 percent versus 13.5 percent), which may have contributed to their lower incidence of polyps since asprin is known to be a protective measure against CRC.

"Our findings certainly support the recommendation that African Americans should consider beginning screening for colorectal cancer at an earlier age," said Dr. Friedenberg. He added that further prospective trials should be done, and that their study indicates a need for efforts to educate the African American community about their increased risk for CRC at a younger age.

Dr. Friedenberg will present these data on Monday, May 3 at 8 a.m. CT in Hall F, Ernest N. Morial Convention Center.

Disappearing Colorectal Metastases after Chemotherapy: Should We Be Concerned? (Abstract # 315)

Patients with colorectal cancer (CRC) that has metastasized to the liver typically receive both aggressive chemotherapy and surgical therapy to remove lesions in the liver, often with outstanding long-term outcomes. When the cancer is initially resectable in the liver, recommendations are inconsistent regarding which therapy should be given first. Despite the possible challenges in identifying lesions for surgical removal that have been reduced in size by chemotherapy, researchers at Johns Hopkins University Hospital have determined that there are multiple potential benefits to providing chemotherapy prior to surgery.

In a study of 177 patients with metastatic CRC, Michael A. Choti, MD, professor of surgery at the Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University Hospital, examined 613 lesions that were treated by preoperative chemotherapy. Of those, 117 lesions disappeared in a pre-operative scan. Choti found that about half of the disappearing lesions (47 percent) were still identifiable during surgery.

According to Dr. Choti, shrinking lesions with chemotherapy prior to surgery, while sometimes making them more difficult to identify, can also make them easier to surgically remove. When a tumor has disappeared and cannot be found at surgery, surgeons attempt to remove an area where a lesion was previously present. However, they found that this was only possible in 30 percent of cases. Even if the areas were left behind, recurrences occurred in 60 percent of cases and many of these can be operated upon a second time. Dr. Choti found no difference in the patients' survival rates among those with unidentified sites left behind compared to those with complete resection.

"This study demonstrates the potential benefit of shrinking metastases in the liver using pre-operative chemotherapy, but there is still disagreement within the field. Further research is needed to determine the optimal sequence of treating metastatic colorectal cancer," said Dr. Choti.

He will act as lead researcher in a multi-institutional, National Cancer Institute-sponsored clinical trial that will study the differences in treating patients with different sequences of chemotherapy and surgical therapy.

Dr. Choti will present these data on Monday, May 3 at 10:30 a.m., 244-245, Ernest N. Morial Convention Center.