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Prostate cancer screening in high-risk men
African American Hereditary Prostate Cancer Study Network
Version of Record online: 12 JAN 2006
Copyright © 2006 American Cancer Society
Volume 106, Issue 4, pages 796–803, 15 February 2006
How to Cite
Weinrich, S. P. and African American Hereditary Prostate Cancer Study Network (2006), Prostate cancer screening in high-risk men. Cancer, 106: 796–803. doi: 10.1002/cncr.21674
- Issue online: 3 FEB 2006
- Version of Record online: 12 JAN 2006
- Manuscript Accepted: 13 SEP 2005
- Manuscript Revised: 26 JUL 2005
- Manuscript Received: 3 DEC 2004
- The Commonwealth of Kentucky Research Challenge Trust Fund
- African American Hereditary Prostate Cancer Study Network
- National Institutes of Health (NIH). Grant Number: N01-HG-75418
- African American men;
- prostate cancer screening;
- health disparities;
- hereditary prostate cancer
There are scant data available on prostate cancer screening among high-risk African American men with positive family histories. It is important to determine whether or not their screening rates differ from those in the general population.
This study computed rates of previous digital rectal examination (DRE) and prostate-specific antigen (PSA) screening for prostate cancer in cancer-free (unaffected) relatives age 40–69 years from African American families that had four or more men with prostate cancer. The rates for these 134 high-risk African American men from the African American Hereditary Prostate Cancer Study (AAHPC) were compared with nationwide estimates obtained from participants in the 1998 and 2000 National Health Interview Survey (NHIS), for which the numbers of demographically comparable subjects were 5583 (4900 Caucasians, plus 683 African Americans) and 3359 (2948 Caucasians, 411 African Americans), respectively.
Men in the AAHPC cohort (with a strong positive family history) had significantly less screening than both African Americans and Caucasians in the NHIS cohorts. Only about one-third (35%) of the men in the AAHPC unaffected cohort had ever had a DRE, and only about 45% of them had ever received a PSA test. These rates were much lower than those obtained for African American men in the NHIS: 45% for DRE and 65% for PSA. These discrepancies increased with age.
Older African American men with positive family histories report surprisingly low rates of DRE and PSA screening compared with their counterparts in the NHIS surveys. At-risk men need to be informed of the benefits and limitations of prostate cancer screening and actively involved in decision-making for or against prostate cancer screening. Cancer 2006. © 2006 American Cancer Society.
Prostate cancer is the most common cancer in American men other than skin cancer. It is estimated that about 230,110 new cases of prostate cancer will be newly diagnosed in the U.S., with about 29,900 deaths from this disease.1 Multiple epidemiological studies have confirmed that prostate cancer occurs at a higher prevalence and with greater morbidity in African American men than in most other populations.2–7 Family history has been found to be a significant risk factor for development of prostate cancer in most studies.8–16 The exception is the Finnish Cancer Registry, with 80,000 men, which found that the risk associated with family history was not substantially increased.17 Affected males from families with hereditary prostate cancer account for 5–10% of all reported cases of prostate cancer in the U.S. and Europe.11, 18, 19
Historically, African American men have participated in prostate cancer screening less than other racial groups.4, 20–26 Even though at present, and most likely for many years to come, early detection aimed at diagnosing prostate cancer when it is still in a curable stage is the standard recommendation for men in high-risk families,9 the efficacy of prostate cancer screening has not been established.27–32 Nationally, controversy surrounds the efficacy of prostate cancer screening with respect to men with less than 10 years of life expectancy and to men without a positive family history. However, most experts agree that men with a positive family history who are at high risk for developing prostate cancer could benefit from prostate-specific antigen (PSA) screening at earlier ages and at shorter intervals compared with the general male population.10, 33–35 A positive family history was a predictor for participation in free screening in a cohort of 1580 men, 71% African American.36
Three studies with mostly white men from high-risk families report different screening rates for unaffected men. Most of the 64 unaffected men in the University of Michigan Prostate Cancer Genetics Project report having prostate cancer screening in their lifetime; 95% report ever having had a PSA test and 97% ever having had a digital rectal examination (DRE).37 In contrast, 56 men with a positive family history were no more likely to be screened than 100 men without a positive history in Pennsylvania.38 Similarly, Cormier et al.39 reported on prostate cancer in the past 2 years (in contrast to ever in lifetime) in first-degree relatives of men with prostate cancer. Over one-third (38%) of 138 unaffected brothers and sons had not been screened with a PSA in the past 2 years. This is despite the men's knowledge that they were at increased risk because of family history. The strongest predictor for the men's screening was the influence of their physicians. Men who discussed prostate cancer screening with their physicians were 18 times more likely to be screened than men who did not talk to their physicians about screening.39 Only one study reports screening practices of African American men with a positive family history. Sartor40 obtained an increased prostate cancer detection rate (4.2%) in 169 African American men with a positive family history, in contrast to the 2.45–3.2% found in two different Caucasian community-based studies the same year. This cross-sectional descriptive study compared screening in high-risk African American men with a strong family history to screening nationwide in age-matched men in the National Health Interview Survey.
MATERIALS AND METHODS
Data on demographics and previous DRE or PSA screening were obtained from three sources: 1) the African American Hereditary Prostate Cancer (AAHPC) Study Network; 2) the 1998 National Health Interview Survey (NHIS); and 3) the 2000 National Health Interview Survey (NHIS). The first dataset from the AAHPC Study Network comprised highly aggregated African American prostate cancer families recruited nationwide at seven sites (Atlanta, GA; Chicago, IL; Detroit, MI; New York, NY; South Carolina; Houston, TX; and Washington, DC). The AAHPC41–43 is a family linkage study whose goal is to identify prostate cancer susceptibility loci that may be responsible for familial aggregation of prostate cancer in African Americans, and has recruited over 100 African American families with four or more affected men nationwide. For this report, inclusion criteria were: 1) male gender, 2) absence of clinical prostate cancer, 3) 40–69 years of age, and 4) complete data on birth date, highest educational level, marital status, and history of DRE and PSA screening. Among the 200 men with no diagnosis of prostate cancer in the AAHPC study, 134 satisfied these inclusion criteria and were included in the statistical analyses.
The second and third datasets were obtained from the NHIS, which is conducted annually by the National Center for Health Statistics at the Centers for Disease Control and Prevention to describe the health status of the civilian, noninstitutionalized, household population of the U.S.44 Prostate cancer screening history was addressed for DRE in 1998 and for PSA in 2000. As a result, NHIS has no data to describe the joint distribution of answers to the DRE and PSA screening questions, but does allow estimates of the rates for each procedure separately. The same four inclusion criteria that were used for the AAHPC were applied to the 1998 and 2000 NHIS samples when they were analyzed, yielding the NHIS subgroup sample sizes data (Table 1) for the screening rate comparisons.
|African American men (AAM)||Caucasian men (CM)|
|NHIS 1998 (for DRE)||683||4,900|
|NHIS 2000 (for PSA)||411||2,948|
Both the AAHPC and the NHIS maintain current human subjects approval. All personal identifying information was kept confidential. The authors had no way to identify individual subjects, as coded numeric identification codes were used.41 Details of the recruitment procedures of the AAHPC families and the NHIS have been documented previously.41, 42, 44 Data reported in this study were obtained from questionnaire information from these three sources.
The same set of analyses was carried out for each of the three samples (AAHPC, NHIS 1998, NHIS 2000). Each of four demographic variables was used in turn to stratify each sample: age (40–49 yrs, 50–59 yrs, 60–69 yrs), educational level (high school or less, more than high school), marital status (married/living as married, not currently married), and self-reported health status (excellent, very good, good, fair, poor). SUDAAN45 was used to obtain stratum-specific estimates of the population percentage screened within each of the above strata, along with valid estimates of their standard errors. These calculations took into account both the survey case weights in the NCHS data and the correlation, or clustering of responses, within each family or sample cluster. For general information about SUDAAN and about analyzing clustered case-weighted survey data, see www.rti.org/sudaan and www.rti.org/sudaan/pdf_files/brogan.pdf.
Finally, pooled estimates of previous DRE or PSA screening rates—adjusted for age and educational level to the NHIS standard population—were computed to allow comparisons between the AAHPC and NHIS samples. Because the reference population was NHIS 1998 or 2000 African American men (AAM), the NHIS rates required no adjustment.
The comparison of AAHPC overall adjusted DRE and PSA screening rates to NHIS 1998/2000 rates was the only formal statistical test carried out. All other rate estimates were treated as descriptive, although their standard errors were computed.
SAS-callable SUDAAN (v. 8 and v. 9) was used to perform all statistical analyses. For the AAHPC data, “stratum” and “cluster” were “study site” and “family,”, respectively, and all case weights were equal to one. For the NHIS data, the techniques recommended by the National Center for Health Statistics were used in SUDAAN to handle the case weights and survey design variables to compute the age-and-educational level adjusted estimates of population screening rates and their standard errors and to adjust the AAHPC screening rates to the NHIS standard populations.
Sample and Estimated Population Characteristics
Table 2 shows the breakdown of the sample into strata by age, education, marital status, and self-described health status. Case-weighted estimates of the corresponding proportion of the total survey population are given, along with the actual sample count (in parentheses) that belongs to each stratum. Because case weights can differ substantially between strata, the sample proportions can differ noticeably from their population estimates.
|Demographics||Number reporting on their DRE history||Number reporting on their PSA history|
|AAHPC African American||NHIS 1998b African American||NHIS 1998b Caucasian||AAHPC African American||NHIS 2000b African American||NHIS 2000b Caucasian|
|Total sample||100% (134)||100% (683)||100% (4900)||100% (134)||100% (411)||100% (2948)|
|40–49 yrs||41.8% (56)||53.7% (342)||45.6% (2180)||41.8% (56)||44.3% (164)||38.2% (1061)|
|50–59 yrs||37.3% (50)||28.3% (206)||32.0% (1534)||37.3% (50)||34.5% (155)||36.1% (1041)|
|60–69 yrs||20.9% (28)||18.0% (135)||22.4% (1186)||20.9% (28)||21.2% (92)||25.7% (846)|
|High school or less||41.0% (55)||58.2% (405)||42.6% (2159)||41.0% (55)||54.0% (216)||38.0% (1158)|
|More than high school||59.0% (79)||41.8% (278)||57.4% (2741)||59.0% (79)||46.0% (195)||62.0% (1790)|
|Married/living as married||62.7% (84)||59.6% (303)||79.4% (3295)||62.7% (84)||65.1% (201)||80.4% (2013)|
|Not married||37.3% (50)||40.4% (380)||20.6% (1605)||37.3% (50)||34.9% (210)||19.6% (935)|
|Excellent||23.1% (31)||23.8% (145)||30.1% (1418)||23.1% (31)||24.3% (95)||31.1% (885)|
|Very good||32.8% (44)||24.9% (170)||34.5% (1662)||32.8% (44)||24.7% (111)||34.1% (979)|
|Good||28.4% (38)||28.1% (200)||23.5% (1186)||28.4% (38)||30.3% (126)||23.5% (710)|
|Fair||14.2% (19)||17.6% (124)||8.6% (460)||14.2% (19)||15.4% (60)||8.0% (261)|
|Poor||1.5% (2)||5.7% (44)||3.3% (174)||1.5% (2)||5.3% (19)||3.3% (113)|
There were only trivial differences in the distribution of ages among the three groups of African American subjects. After case weighting, the AAHPC and NHIS 2000 populations were each about 40–45% age 40–49, 35–37% age 50–59, and 21% age 60–69 years. The estimated population proportions for NHIS 1998 AAM were higher for men age 40–49 years (about 54%) and lower for men age 50–59 (28%). The estimated population age distribution for Caucasian men in both NHIS surveys contained fewer 40–49-year-old men and more 60–69-year-old men than was the case for AAM (Table 2).
The AAHPC cohort was well educated. Fifty-nine percent of the AAHPC population had at least some postsecondary education, versus only 42–46% of AAM in the NHIS populations. AAHPC education rates were similar to those observed for Caucasian men in the NHIS surveys. The estimated population proportion of AAM that were married was about three-fifths in the AAHPC and each of the NHIS 1998 and NHIS 2000 surveys, versus about four-fifths for Caucasian men. AAHPC subjects' self-ratings of their health status were very similar to those reported by AAM in the NHIS surveys, although the NHIS data tended to indicate a higher proportion of AAM who rated their own health as “Poor” than did the AAHPC data. NHIS Caucasian subjects were more likely to describe their own health as “Excellent” or “Very Good” than the NHIS AAM were (Table 2).
Estimated Population Crude and Adjusted Rates of Previous DRE and PSA Screening
The overall estimated DRE screening rate for the AAHPC population was less at 35.1% compared with 44.9% for the 1998 NHIS AAM population. For previous PSA screening, the estimated population rates were 44.8% and 64.8%, respectively. However, the pattern of variation by age group in screening rates shows obvious differences between the AAHPC and the NHIS participants. Both for DRE and for PSA, screening rates for AAHPC 40–49-year-old men were quite close to NHIS rates for 40–49-year-old AAM. But at older ages the AAHPC men reported lower rates of previous screening than their NHIS counterparts, and in most cases that difference increased with age (Figs. 1, 2).
In comparison to the NHIS Caucasian men, both AAHPC subjects and NHIS AAM reported lower age-specific DRE screening rates, particularly the men age 50 and above. But for PSA screening the 40–49-year-old AAHPC subjects were comparable to their NHIS AAM counterparts, and higher than their Caucasian men counterparts. Above 50 years, the rates for AAM and Caucasian men in the NHIS were much higher, and quite comparable to each other, yet AAHPC rates were dramatically lower for 60–69 years old (Figs. 1, 2).
In reference to education, DRE screening rates were comparable for AAHPC subjects and NHIS AAM with a high school education or less: 38.2% versus 39.9%. But 47.2% of NHIS Caucasian men had received a DRE screen; this difference was statistically significant. PSA screening rates differed for AAHPC subjects and NHIS AAM and NHIS Caucasian men with a high school education or less: 45.5% versus 61.0%, and 60.6%, respectively.
When the AAHPC screening rates were adjusted for age and educational level using the NHIS AAM joint distribution of age and education as the reference population, the adjusted rate for DRE screening increased from 35.1% to 38.1% (standard error [SE] = 5.1%), and the adjusted rate for PSA screening increased only slightly, from 44.8% to 45.8% (SE = 5.1%). The NHIS rates for AAM were 44.9% (SE = 2.6%) and 64.8% (SE = 2.6%), and two-sided hypothesis tests to compare the AAHPC and NHIS AAM rates yielded P = 0.12 and P < 0.001, respectively.
After adjustment, stratum-specific screening rates for strata formed using age group, educational level, or marital status changed very little in most cases. This was not the case when subjects were grouped by their self-reported health status, however (Table 3). In most cases, stratum-specific AAHPC screening rates were lower than the corresponding adjusted or unadjusted NHIS stratum-specific screening rates for health status.
|Demographics||DRE percent screened (SE)||PSA percent screened (SE)|
|AAHPCan = 134||NHIS 1998b African American n = 683||AAHPCan = 134||NHIS 2000b African American n = 411|
|Total sample||35.1% (4.7%)||38.1% (5.1%)||44.9% (2.6%)||44.8% (5.0%)||45.8% (5.1%)||64.8% (2.6%)|
|40–49 yrs||42.9% (6.1%)||44.9% (7.1%)||42.6% (3.4%)||58.9% (7.7%)||59.1% (8.3%)||52.5% (4.9%)|
|50–59 yrs||26.0% (6.6%)||28.1% (8.3%)||41.4% (4.2%)||40.0% (8.4%)||39.7% (9.3%)||73,6% (4.4%)|
|60–69 yrs||35.7% (9.8%)||33.3% (9.9%)||57.1% (5.1%)||25.0% (9.2%)||27.8% (10.0%)||75.9% (5.3%)|
|High school or less||38.2% (7.2%)||40.8% (7.6%)||39.9% (3.3%)||45.5% (7.1%)||46.1% (7.1%)||61.0% (4.0%)|
|More than high school||32.9% (5.0%)||34.3% (5.0%)||51.8% (3.4%)||44.3% (5.7%)||45.4% (5.4%)||69.2% (3.9%)|
|Married/living as married||33.3% (5.4%)||36.3% (5.8%)||44.8% (3.3%)||42.9% (5.9%)||44.3% (6.2%)||67.5% (3.6%)|
|Not married||38.0% (6.6%)||41.6% (8.0%)||44.9% (3.4%)||48.0% (7.1%)||49.8% (6.9%)||59.7% (3.9%)|
|Excellent||35.5% (9.5%)||31.0% (6.6%)||32.7% (4.8%)||54.8% (8.0%)||42.7% (7.4%)||52.0% (5.3%)|
|Very good||29.6% (6.3%)||32.3% (7.8%)||43.4% (4.7%)||38.6% (7.9%)||35.4% (7.8%)||61.9% (5.4%)|
|Good||34.2% (7.6%)||39.2% (8.3%)||49.2% (4.5%)||36.8% (8.2%)||37.9% (7.3%)||71.6% (4.3%)|
|Fair||47.4% (11.6%)||55.9% (5.9%)||55.5% (5.1%)||57.9% (11.3%)||78.2% (7.0%)||66.2% (5.8%)|
|Poor||50.0% (*)||50% (*)||48.2% (10.0%)||50% (*)||50% (*)||93.9% (4.8%)|
The pattern of variation in unadjusted AAHPC screening rates versus health status was rather confusing. However, after adjustment for age and educational level it became somewhat simpler. AAHPC subjects who rated their own health as “Fair” had the highest adjusted rates of screening—55.9% for DRE, 78.2% for PSA. There were too few men in the “Poor” category to permit meaningful comparisons. Adjusted rates for the “Excellent,” “Very Good,” and “Good” categories may have been constant, or—at best—exhibited a weak association between better health and lower screening rates (see Table 3 for details).
The lack of screening in age-eligible African American men with strong positive family histories as measured by the national African American Hereditary Prostate Cancer (AAHPC) is cause for concern. Men in the African American Hereditary Prostate Cancer cohort had a 100% positive family history with 4 or more men per family. Over half (54%) have never received a PSA screen, and almost two-thirds (62%) have never received a DRE. The AAHPC study, designed to recruit high-risk families into a hereditary family linkage study, did not assess and therefore cannot explain this low screening rate.
The finding of increased screening in older men in the NHIS is consistent with other studies. However, the decrease in screening in men age 60–70 years old in the AAHPC is cause for concern, as the average age at which AAM are diagnosed with prostate cancer is 65.
The novel observation that “Fair” self-reported health status was associated with the highest rates of screening was quite striking, and has not been reported elsewhere in the literature. No P-value was computed for this isolated a posteriori finding, which should be replicated before being accepted as proven. The association may reflect increased contact with physicians, or increased self-decision for screening, but no data are currently available to evaluate these possibilities.
Clinical and research recommendations evolve from this study. The need for a through assessment that includes past screening behavior as well as family history of cancer and self-reported health status is supported by the data. At risk AAM need to be informed of the benefits and limitations of prostate cancer screening and actively involved in decision-making concerning prostate cancer screening.
Numerous research questions evolve from this research. Replication is needed to determine whether lower screening rates are observed in other at-risk AAM. Qualitative research that includes cultural factors that influence screening need to be researched. The known influence of physician recommendation's concerning screening37 needs to be assessed in high-risk AAM. Known predictors that include access to healthcare and health insurance need to be measured.
It is important to note the differences in the AAHPC and the NHIS samples before drawing inferences to other populations. The AAHPC cohort was more educated: 59% versus only 42–46% of AAM in the NHIS populations had postsecondary education. The AAHPC data were obtained from African American families that had four or more men in their family diagnosed with prostate cancer from seven sites in the US. Approximately 70% of the data was obtained in physicians' offices. In contrast, the NHIS data were obtained from nationwide personal interviews conducted in homes. Men in the NHIS were selected based on randomized nationwide sampling. Men in the AAHPC were selected based on positive prostate cancer family histories.
It is important to note that a second national survey, the 2001 Behavioral Risk Factor Surveillance System, with 49,315 men age 50 years,46 had higher PSA screening rates than either the AAHPC cohort or the NHIS cohort. PSA screening in one's lifetime was less in both the AAHPC (45.8%) and the NHIS (64.8%) than the PSA screening rate of 75% reported in the 2001 Behavioral Risk Factor Surveillance System of 49,315 men age 50 years.46 Additional research is needed to explain these screening discrepancies.
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