Although colon cancer screening is now widely recommended, rates of colon cancer screening remain low. Only 53% of men and women aged 50 years and older have had FOBT in the past 12 months or lower endoscopy in the past 5 years.8
In contrast, 80% of eligible women have had a Pap smear in the past 3 years and 78% of eligible women have had a mammogram in the past 2 years.25
This is the first community-based study to systematically address barriers to colorectal cancer screening in ethnic minority populations. Screening rates were generally lower in Latinos and Vietnamese than in whites, although more Vietnamese reported receiving FOBT in the past 1 year than did whites or Latinos. Knowledge, attitudes, and beliefs varied among ethnic groups as well. In general, Vietnamese and Latinos were less knowledgeable about colorectal cancer and colorectal cancer screening tests than were whites, although more Vietnamese knew about FOBT than did members of other ethnic groups.
Prior studies have shown low rates of colorectal cancer screening among Latinos and Vietnamese. In the 1997 Behavioral Risk Factor Surveillance Survey, only 13% of eligible Latino individuals had had FOBT during the preceding year and only 20% had had sigmoidoscopy or proctoscopy during the preceding 5 years. These rates were significantly lower than those of non-Latino whites (20% and 31%, respectively).14,15
Latinos were also significant less likely to have a digital rectal examination, FOBT or sigmoidoscopy even when direct financial barriers were removed.9
In an earlier survey, using a Vietnamese-language version of the CDC's Behavioral Risk Factor Surveillance System (BRFSS), 35% of eligible men and 38% of eligible women had had a fecal occult blood test.15
In another study, for each of 5 cancer screening tests (including FOBT and rectal examination), Vietnamese were less likely than the general US population to report that they had had the procedure.26
These prior studies did not assess predictors of screening, and also were performed at a time when colorectal screening was not as widely endorsed.
Vietnamese respondents seemed to have generally positive attitudes about colorectal cancer screening, although, with the exception of FOBT, screening rates were lower than those of whites. They were much less likely to describe the screening tests as embarrassing or uncomfortable. They were much more likely to think they needed sigmoidoscopy or colonoscopy, although they were less likely to have had them. Low rates of screening in the Vietnamese in the face of generally more positive attitudes about screening suggest that other factors may be important. For example, Vietnamese were more concerned that a screening test would find cancer than were Latinos or whites, which may have led to test avoidance and thus the low rates found. Another possibility for the more positive responses from the Vietnamese participants is that their responses reflected “acquiescence bias,” a phenomenon where individuals of some ethnicities may have a greater tendency than whites to provide socially desirable responses.27,28
Although this phenomenon has also been described in the Latino population, we did not find evidence of it in this study.
The results of our study have some similarities to and some differences from those of prior studies of cancer screening in the Vietnamese. Prior studies of knowledge of cancer and causes of cancer in the Vietnamese population have revealed that there are many misconceptions about cancer and its causes.26
In our study, although most Vietnamese had heard of colorectal cancer, many had not heard of a colorectal polyp and were unfamiliar with sigmoidoscopy and colonoscopy. Studies of barriers to breast and cervical cancer screening have shown that being of recent immigrant status, having less education, not having insurance, not having a regular physician, and having a Vietnamese physician were all associated with lower rates of cancer screening.29
Low income has been found to be a predictor of recognition of, intention to receive, and receipt of cancer screening tests among Vietnamese American women.30
In our study, having a Vietnamese physician was not associated with having had colorectal cancer screening, but was associated with an increased likelihood of planning to undergo colonoscopy. We were interested in whether acculturation affected being up to date with colorectal cancer screening or planning to be screened, but the majority (99%) of respondents in our study were of low acculturation, limiting our ability to assess this association.
Attitudes about colorectal cancer screening were generally more negative in Latinos than in whites or Vietnamese. For example, many more Latinos did not feel that they needed colorectal cancer screening if they felt healthy. In addition, Latinos were more likely than whites or Vietnamese to describe FOBT or sigmoidoscopy/colonoscopy as embarrassing and to feel that the preparation for sigmoidoscopy/colonoscopy was unpleasant.
Studies in the Latino population suggest that fatalistic attitudes and fear of cancer are barriers to cancer screening,31
and that there are misperceptions about the causes of cancer.32–36
The results of our survey suggest that perceived discomfort and embarrassment may be barriers as well. Understanding and overcoming these barriers will be important in improving rates of colorectal cancer screening in the Latino population.
In our study, physician recommendation was by far the most important factor influencing previous colorectal cancer screening and intention to be screened. Other important predictors of being up to date with screening included increasing age, having insurance, going to the doctor more frequently, family recommending it, and thinking that testing was necessary. Vietnamese were less likely to have had sigmoidoscopy in the past 5 years, but were more likely to plan to have sigmoidoscopy in the next 5 years than were Latinos or whites. Several factors predicted planning to be screened. Vietnamese were more likely to plan to have sigmoidoscopy than were Latinos and whites. Those who knew someone with colorectal cancer or who worried about developing colorectal cancer were more likely to be screened. Family recommendation and thinking the test was necessary even if one felt healthy also predicted future screening.
Our study had several limitations. All participants lived in a single geographic area, and therefore may not be representative of individuals living in other parts of the US. However, our survey was community-based, which suggests a broader spectrum of individuals than would be the case if the survey had been clinic-based. As with any telephone survey, respondents without a telephone would not be included.
Prior receipt of colorectal cancer screening tests was reported by self-report. Although review of medical records might provide more accurate information, it is not feasible for a telephone survey. In addition, prior study has shown that although under-reporting of sigmoidoscopy and FOBT may occur, it tended to be less for endoscopic procedures than for FOBT and, importantly, there was no differential bias by ethnicity in the level of under-reporting.37
Thus, even if under-reporting occurs, any differences seen between ethnic groups should remain significant.
In addition, our response rate was only 50%, which is somewhat lower than we had anticipated. Part of the reason for this may be related to the listed sample we obtained. Although the sample was chosen to have at least one eligible member per household, a larger number of households than expected did not have an eligible household member. Another potential factor might be the survey content—individuals may be less comfortable talking about colorectal cancer than other health topics.
Despite our efforts to ensure optimal translation, the possibility of translation difficulties remains. The average survey length in the Vietnamese respondents was 28 minutes compared with 16 minutes for whites and Latinos. Since there are no Vietnamese words for “sigmoidoscopy” and “colonoscopy,” explaining these tests was more complicated and took longer to explain in Vietnamese than in Spanish or English. However, because each procedure was described, there was no difference between ethnic groups in the way the study was administered.
It is interesting that more Vietnamese reported having had FOBT and knowing about FOBT than did members of other ethnic minority groups. In the focus groups conducted during the survey development phase, we found that many Vietnamese confused stool testing for ova and parasites with FOBT. Many Vietnamese reported being tested for ova and parasites at the time of immigration to the US. Although we took this into account in designing the survey question, and tried to clearly define FOBT, it is possible that this confusion remained, resulting in falsely high reports of FOBT testing and familiarity in the Vietnamese population. Alternatively, it is possible that FOBT, as the least expensive and most available screening test, actually is being performed more in the Vietnamese population.
Despite these limitations, this is the first community-based survey to address this important topic for Vietnamese and Latinos in their own language and in comparison with non-Latino whites in the same geographic area.
Current rates of colorectal cancer screening and barriers and facilitators to colorectal cancer screening differ among racial/ethnic groups, although for all groups physician recommendation was the most important factor influencing being up to date with screening and intending to be screened. Further understanding of these similarities and differences will be important if we are to develop culturally and linguistically appropriate interventions to increase rates of colorectal cancer screening in ethnic minority populations.