Race and the histologic grade of prostate cancer

Prostate Cancer, Race, and Health Disparity: What We Know

ABSTRACT

Prostate cancer (PCa) in African American men is one of the most common cancers with a great disparity in outcomes. The higher incidence and tendency to present with more advanced disease have prompted investigators to postulate that this is a problem of innate biology. However, unequal access to health care and poorer quality of care raise questions about the relative importance of genetics versus social/health injustice. Although race is inconsistent with global human genetic diversity, we need to understand the sociocultural reality that race and racism impact biology. Genetic studies reveal enrichment of PCa risk alleles in populations of West African descent and population-level differences in tumor immunology. Structural racism may explain some of the differences previously reported in PCa clinical outcomes; fortunately, there is high-level evidence that when care is comparable, outcomes are comparable.

Re-thinking How We Use Prostate Health Index for African American Men

OBJECTIVE

To assess how the validated Prostate Health Index (PHI) risk stratifications perform with African American (AA) men and establish a threshold PHI value to potentially rule out the need for prostate biopsy.

MATERIALS AND METHODS

AA men meeting FDA-specified indications for PHI testing (>50 years old, PSA 4-10 and negative DRE) who underwent subsequent biopsy were included. Rates of clinically significant prostate cancer (csPCa, as defined by Gleason score ≥7) across accepted PHI stratifications were recorded. Receiver operator curve (ROC) analysis was undertaken to assess PHI performance to predict csPCa. A phi cutoff providing 90% sensitivity was identified. Among AA men with PSA 4-10 ng/mL, the proportion of men who proceeded to biopsy upon physician recommendation was determined.

RESULTS

Two hundred nine patients met primary criteria; 91 (43.5%) of which had csPCA. The area under the curve for PHI predicting csPCa was 0.68 (95% CI: 0.61-0.75). Using a phi threshold of <23.0 to avoid biopsy provided 98.9% sensitivity, 9.3% specificity, and would have avoided 4.7% of biopsies. The proportion of those who proceeded to biopsy upon physician recommendation was 81.8%.

CONCLUSIONS

PHI demonstrated limited performance in our cohort, with current stratifications featuring misleadingly low cancer detection rates for these men. Furthermore, PHI had limited use to avoid prostate biopsy, as the proposed threshold of 23.0 only allowed 4.7% of men to avoid biopsy. Further work is needed to assess and optimize PHI usage in AA men; nonetheless, it may still have use in increasing compliance with biopsy recommendation.

Racial/ethnic disparities in patient experiences with care and Gleason score at diagnosis of prostate cancer: a SEER-CAHPS study

PURPOSE

To determine whether racial/ethnic differences in patient experiences with care, potentially leading to underutilization of necessary care, are associated with disparities in Gleason score at diagnosis.

METHODS

We used the SEER-CAHPS linked dataset to identify Medicare beneficiaries who completed a Consumer Assessment of Healthcare Providers and Systems (CAHPS) survey prior to diagnosis of prostate cancer. Independent variables included aspects of patient experiences with care captured by CAHPS surveys. We conducted survey weighted multivariable multinomial logistic regression analyses, stratified by patient race/ethnicity, to estimate associations of CAHPS measures with Gleason score at diagnosis.

RESULTS

Of the 4,245 patients with prostate cancer, most were non-Hispanic white (NHW) (77.6%), followed by non-Hispanic black (NHB) (8.4%), Hispanic (8.4%), and Asian (5.6%). Excellent experience with getting needed prescription drugs was associated with lower odds of Gleason scores of 7 and 8-10 in NHBs (7: OR = 0.19, 95% CI = 0.05-0.67; 8-10: OR = 0.04, 95% CI = 0.01-0.2) and lower odds of 8-10 in NHWs (OR = 0.61, 95% CI = 0.40-0.93). For NHBs, excellent primary physician ratings were associated with greater odds of a Gleason score of 8-10 (OR = 13.28, 95% CI = 1.53-115.21).

CONCLUSION

Patient experiences with access to care and physician relationships may influence Gleason score in different ways for patients of different racial/ethnic groups. More research, including large observational studies with greater proportions of racial/ethnic minority patients, is necessary to understand these relationships and target interventions to overcome disparities and improve patient outcomes.

The Impact of African Ancestry on Prostate Cancer Disparities in the Era of Precision Medicine

Prostate cancer disproportionately affects men of African ancestry at nearly twice the rate of men of European ancestry despite the advancement of treatment strategies and prevention. In this review, we discuss the underlying causes of these disparities including genetics, environmental/behavioral, and social determinants of health while highlighting the implications and challenges that contribute to the stark underrepresentation of men of African ancestry in clinical trials and genetic research studies. Reducing prostate cancer disparities through the development of personalized medicine approaches based on genetics will require a holistic understanding of the complex interplay of non-genetic factors that disproportionately exacerbate the observed disparity between men of African and European ancestries.

Establishment and characterization of a highly tumorigenic African American prostate cancer cell line, E006AA-hT

Genuine racial differences in prostate cancer (PCa) biology have been considered among the potential reasons to explain PCa disparities. There is no animal model to represent all aspects of human PCa and, more specifically, to be used for PCa disparity research. The lack of a spontaneously transformed in vitro cell-based model system has been a significant impediment to investigating and understanding potential molecular mechanisms, and the hormonal, genetic, and epigenetic factors underlying the biological and clinical aggressiveness of PCa in African American (AA) men.

In this study, we established and characterized the E006AA-hT cell line as a highly tumorigenic subline of the previously characterized primary AA-PCa cell line, E006AA. Extensive characterization of the E006AA-hT cell line was accomplished using cytodifferentiation and prostate-specific markers, spectral karyotyping, cell line authentication assays, cell proliferation and migration assays, and in vitro tumorigenesis assays.

Spectral karyotyping of E006AA-hT showed a hypertriploid chromosome complement and shared cytogenetic changes similar to its parental cells such as diploid X, absence of Y-chromosomes, numerical gains in chromosomes 5,6,8,10,17,20,21, and marker chromosomes of unknown origin. In addition, E006AA-hT also presented numerous clonal and structural aberrations such as insertion, deletion, duplication, and translocations in chromosomes 1-5, 8, 9, 11, 13, 14, 17, and 18. The E006AA-hT cell line was shown to be highly tumorigenic and produced tumors at an accelerated growth rate in both athymic nude and triple-deficient SCID mice.

Silencing the mutated androgen receptor (AR-599 Ser>Gly) did not affect proliferation (loss-of-function), but decreased migration (gain-of-function) in E006AA-hT and its parental cell type. These data support that AR-point mutations may lead simultaneously to different “loss-of-function” and “gain-of-function” phenotypes in PCa cells. E006AA-Par and its subline as the only available spontaneously transformed low- and highly-tumorigenic primary AA-PCa cell lines could be used for basic and translational research aimed in supporting prostate cancer disparity research.

Intake of grains and dietary fiber and prostate cancer aggressiveness by race

Purpose. To examine the associations among intake of refined grains, whole grains and dietary fiber and aggressiveness of prostate cancer in African Americans (AA, n = 930) and European Americans (EA, n = 993) in a population-based, case-only study (The North Carolina-Louisiana Prostate Cancer Project, PCaP). Methods. Prostate cancer aggressiveness was categorized as high, intermediate or low based on Gleason grade, PSA level and clinical stage. Dietary intake was assessed utilizing the NCI Diet History Questionnaire. Logistic regression (comparing high to intermediate/low aggressive cancers) and polytomous regression with adjustment for potential confounders were used to determine odds of high prostate cancer aggressiveness with intake of refined grains, whole grains and dietary fiber from all sources. Results. An inverse association with aggressive prostate cancer was observed in the 2nd and 3rd tertiles of total fiber intake (OR = 0.70; 95% CI, 0.50–0.97 and OR = 0.61; 95% CI, 0.40–0.93, resp.) as compared to the lowest tertile of intake. In the race-stratified analyses, inverse associations were observed in the 3rd tertile of total fiber intake for EA (OR = 0.44; 95% CI, 0.23–0.87) and the 2nd tertile of intake for AA (OR = 0.57; 95% CI, 0.35–0.95). Conclusions. Dietary fiber intake was inversely associated with aggressive prostate cancer among both AA and EA men.

A 6-year analysis of the clinicopathological profile of patients with prostate cancer at the University Hospital of the West Indies, Jamaica

OBJECTIVE To document the clinicopathological characteristics of prostate cancer in a public hospital-based population in Jamaica, over a 6-year period, and examine any trends in these characteristics over time, as prostate cancer is the leading cause of cancer in Jamaican men, but there are few published reports documenting the clinicopathological profile of this disease in the Jamaican population. PATIENTS AND METHODS All patients consecutively diagnosed with prostate cancer by transrectal ultrasonography-guided biopsy at the University Hospital of the West Indies, from January 2000 to December 2005, were identified at time of diagnosis, and relevant clinical and pathological data collected from the accompanying histopathology request forms. RESULTS There were 529 cases of prostate cancer diagnosed over the 6 years. The mean (sd) age was 70.66 (8.74) years, with 137 patients aged 70-74 years. A serum prostate-specific antigen (PSA) level was obtained for 490 (92.6%) patients. Of these, an accurate PSA value was available for 456 (86.2%) patients and a 'minimum level' recorded for the remaining 34, all of whom had a PSA level of >100 ng/mL. Of the patients with available PSA information, only 91 (18.5%) had a level of < or =10.0 ng/mL. By contrast, 155 (31.6%) patients had levels of >100 ng/mL. The median (range, interquartile range) serum PSA level for those patients with accurate values was 30.7 (1-14 260, 11.7-109) ng/mL. Histologically, moderately and poorly differentiated cancers accounted for 198 (37.5%) and 160 (30.2%) cases, respectively. Correlation of the variables under investigation confirmed that there was a statistically significant positive and moderate correlation between serum PSA level and Gleason score (Spearman r 0.49; P < 0.001). Statistical analysis of all other variables, including the number of cases of prostate cancer diagnosed annually, showed no significant differences. CONCLUSION Compared with many countries, including some in the Caribbean, prostate cancer in Jamaican men is diagnosed when they are older and these patients have significantly higher PSA levels at diagnosis, suggesting more advanced disease. Despite increasing public awareness of prostate cancer, it appears that there has been no significant change in the profile of patients with prostate cancer, at the time of diagnosis, over the last 6 years, findings consistent with the absence of an organized screening programme for prostate cancer in Jamaica.

Social disparities and prostate cancer: mapping the gaps in our knowledge

To evaluate the current state of our knowledge regarding social disparities and prostate cancer and to map the domains where substantial knowledge has been acquired as well as those where little is known, with the purpose of identifying important areas for future research. A Medline research was conducted to identify published papers regarding social disparities in prostate cancer since 1990. The results of this review are presented in a social disparities and prostate cancer grid designed to highlight which domains of social disparities have been researched and which neglected. The major social disparity in prostate cancer concerns the extremely high prostate cancer incidence and mortality seen among black Americans. This is also the area where the most research has been performed. Low socioeconomic position is associated with poorer prostate cancer outcomes but not with higher prostate cancer incidence. It remains poorly defined to what extent racial/ethnic differences in prostate cancer result from differences in socioeconomic position (SEP). Understanding the causes of the high prostate cancer mortality seen among black men remains the major challenge in the area of social disparities and prostate cancer.

Physical Activity and the Risk of Prostate Cancer in The Netherlands Cohort Study, Results after 9.3 Years of Follow-up

BACKGROUND

The aim of the current study was to evaluate the relation between physical activity and prostate cancer risk with specific emphasis on interaction with body mass index (BMI) and baseline energy intake.

METHODS

The association between prostate cancer and physical activity was evaluated in the Netherlands Cohort Study, conducted among 58,279 men ages 55 to 69 years at entry. Information regarding baseline nonoccupational physical activity, history of sports participation, and occupational physical activity was collected with a questionnaire in 1986. After 9.3 years, 1,386 incident prostate cancer cases were available for case-cohort analyses. Multivariate incidence rate ratios (RR) and corresponding 95% confidence intervals (95% CI) were calculated using Cox regression analyses.

RESULTS

Neither baseline nonoccupational physical activity (RR, 1.01; 95% CI, 0.81-1.25 for >90 versus <30 minutes per day), history of sports participation (RR, 1.04; 95% CI, 0.90-1.22 for ever versus never participated), nor occupational physical activity (RR, 0.91; 95% CI, 0.70-1.18 for >12 versus <8 KJ/min energy expenditure in the longest held job) showed an inverse relation with prostate cancer risk. We found an increased risk of prostate cancer for men who were physically active for >1 hour per day in obese men (BMI > 30) and men with a high baseline energy intake.

DISCUSSION

The results of this current study do not support the hypothesis that physical activity protects against prostate cancer in men.

Absence of a correlation of androgen receptor gene CAG repeat length and prostate cancer risk in an African-American population

Shorter androgen receptor gene CAG repeat length has been associated with an increased risk of prostate cancer, an earlier age of onset, and more advanced stage of disease. Studies comparing the distribution of CAG repeat lengths within different populations have reported that racial groups with higher prostate cancer incidence also have shorter CAG repeat lengths. We evaluated CAG repeat length in 685 black men in Louisiana, South Carolina, and the District of Columbia who were participating in prostate cancer screening, comparing the 118 who were diagnosed with prostate cancer with 567 who had normal serum prostate-specific antigen levels and no evidence of cancer on digital rectal examination. The median CAG repeat length was 21 among cases and 19 among controls (P = 0.11). Cases were significantly older than controls, with a median age of 68 years compared with 54 years (P < 0.0001). After adjusting for age, we found no association between prostate cancer risk and CAG repeat length (odds ratio, 1.05; 95% CI, 0.98-1.13; P = 0.16). Dividing CAG repeat lengths into septiles and calculating the odds ratio for each revealed no specific repeat-length range with a significantly elevated or depressed risk of prostate cancer, but a trend test showed a significant association between longer CAG repeat lengths and an elevated risk of prostate cancer (P = 0.02). Neither grade nor stage was associated with CAG repeat length. This study confirms earlier reports that black men have shorter CAG repeat lengths than reported white and Asian populations. We did not find an increased risk of prostate cancer among black men with fewer CAG repeats.

The role of area-level influences on prostate cancer grade and stage at diagnosis

BACKGROUND

This research explores area-level social influences on prostate cancer, to test whether area-level influences explain disparities in U.S. prostate cancer burden.

METHODS

The authors geocoded 23,993 1992-1997 Maryland prostate cancer cases, and linked cases to 1990 census data. The authors examined the effect of 17 area-level social variables, measured at block group, tract, and county, modeling individual and multilevel predictors of later stage and higher tumor grade.

RESULTS

Younger age, black race, higher grade or ungraded tumors, and earlier year of diagnosis were associated with later stage. Block group percentage of white-collar workers (O.R. = 0.93, 95% C.I. = 0.89, 0.98), and county resources (O.R. = 0.94, 95% C.I. = 0.89, 0.98), were protective of later stage. Older age, black race, and earlier year of diagnosis were associated with higher grade. Block group income was protective for white men (O.R. = 0.92, 95% C.I. = 0.87, 0.96), but for all men, county resources increased risk of higher grade (O.R. = 1.23, 95% C.I. = 1.16, 1.31).

CONCLUSIONS

Social resources did not significantly reduce racial differences. Results suggest tumor biology is related to relative resources, with better outcomes associated with greater small-area wealth in low-resource counties, but stage at diagnosis is associated with absolute resources, with better outcomes associated with higher small-area social class in high-resource counties.

Prospective study of cancer detection in black and white men with normal digital rectal examination but prostate specific antigen equal or greater than 4.0 ng/mL

BACKGROUND

The serum prostate specific antigen (PSA) concentration with no clinical evidence of prostate carcinoma is higher and more variable in black than in white American men. The influence of this phenomenon on relations between race, PSA, and cancer detection in men with a PSA greater than or equal to 4.0 ng/mL has not been investigated.

METHODS

Between January 1992 and December 2000, 451 black and 480 white men with a normal digital rectal examination and a PSA greater than or equal to 4.0 ng/mL had an initial prostate biopsy at one medical center. The histology of the biopsy specimens and the Gleason score of malignant specimens was determined by one uropathologist.

RESULTS

Cancer was detected in 207 (46%) black and 167 (35%) white men (P = 0.0006). When adjusted for PSA, cancer detection was also greater in the black than the white men, but the difference did not achieve statistical significance (relative risk, 1.30; 95% confidence interval [CI], 0.99-1.71; P = 0.06). Gleason score 7-10 cancer was detected in 88 (20%) black and 45 (9%) white men (P = 0.0001), and the difference remained significant when adjusted for PSA (relative risk, 1.73; 95% CI, 1.16-2.61; P = 0.0008). In the intermediate PSA range of 4.0-9.9 ng/mL, cancer detection and Gleason score 7-10 cancer detection was greater in black than in white men younger than 60, 60-69, and 70 years of age or older, but the difference was significant only for Gleason score 7-10 cancer detection among men 60-69 years of age (P = 0.006).

CONCLUSIONS

There is a direct correlation between Gleason score and cause specific survival with local stage prostate carcinoma. The authors' study indicates that prostate carcinomas with established malignant potential are more likely to be identified in black than in white men with PSA elevation as the only indication of malignancy and raises the possibility that a PSA threshold less than 4.0 ng/mL in black men younger than 70 years of age may reduce racial disparities in prostate carcinoma morbidity and mortality.

The epidemiology of prostate cancer in the United States

OBJECTIVES

To provide a review of prostate cancer epidemiology.

DATA SOURCES

Journal articles and the Surveillance, Epidemiology, and End Results database.

CONCLUSIONS

Numerous risk factors for prostate cancer have been identified. Incidence and mortality rates are higher in certain countries and among racial ethnic groups. Environmental and dietary influences are likely to be significant causes of prostate cancer. Distinguishing those cancers that are clinically significant from those that are not remains a central concern in prostate cancer research.

IMPLICATIONS FOR NURSING PRACTICE

Knowledge of epidemiologic patterns and trends will assist nurses in recognising persons at high risk for the development of prostate cancer and should result in tailored educational interventions.

Racial and ethnic differences in advanced-stage prostate cancer: the Prostate Cancer Outcomes Study

BACKGROUND

African-Americans have twice the risk of non-Hispanic whites for presenting with advanced-stage prostate cancer. To investigate the reasons for this difference, we evaluated the association between race/ethnicity and advanced-stage prostate cancer, adjusting for demographic, socioeconomic, clinical, and pathologic factors.

METHODS

A population-based cohort of 3173 men diagnosed with prostate cancer between October 1, 1994, and October 31, 1995, was analyzed. Medical record abstracts and self-administered survey questionnaires were used to obtain information regarding race/ethnicity, age, marital status, insurance status, educational level, household income, employment status, comorbidity, urinary function, prostate-specific antigen level, tumor grade, and clinical stage. The odds ratio (OR) for advanced-stage prostate cancer was estimated with weighted logistic regression analysis. All P: values were two-sided.

RESULTS

Clinically advanced-stage prostate cancers were detected more frequently in African-Americans (12.3%) and Hispanics (10.5%) than in non-Hispanic whites (6.3%). Socioeconomic, clinical, and pathologic factors each accounted for about 15% of the increased relative risk. After adjusting for all covariates, the risk remained statistically significantly increased for African-Americans (OR = 2.26; 95% confidence interval [CI] = 1.43 to 3.58) but not for Hispanics (OR = 1.23; 95% CI = 0.73 to 2.08).

CONCLUSION

Traditional socioeconomic, clinical, and pathologic factors accounted for the increased relative risk for presenting with advanced-stage prostate cancer in Hispanic but not in African-American men.

Racial differences in the cost of treating men with early-stage prostate cancer

OBJECTIVE

To compare the cost and resource utilization in the evaluation, treatment, and 6-month follow-up of African-American and White men undergoing either external beam radiation therapy (XRT) or radical prostatectomy (RP) for early-stage prostate cancer.

DESIGN

Retrospective analysis of cost and resource utilization data from encrypted patient-specific hospital inpatient, hospital outpatient, and physician/supplier data files.

SETTING

National Medicare claims data from 1993 through 1996.

PARTICIPANTS

A random 5% national sample of Medicare beneficiaries from the Health Care Financing Administration Public Use Files for 1993 through 1996.

MEASUREMENTS

Inpatient, outpatient, and physician/supplier Medicare costs.

RESULTS

African-American men undergoing RP for early-stage prostate cancer had significantly higher costs ($21,878 vs $18,786, P < .0001) than did White men. Most of the difference occurred in the inpatient setting. African-American men undergoing XRT had significantly greater costs ($18,131 vs $15,734, P < .0001) than did White men. Most of this difference was generated by longer duration of XRT treatments.

CONCLUSIONS

In early-stage prostate cancer, charges for RP and XRT in African-American men are higher when compared with those for White men.

Percentage of free PSA in black versus white men for detection and staging of prostate cancer: a prospective multicenter clinical trial

OBJECTIVES

In predominately white populations, measurement of the percentage of free prostate-specific antigen (%fPSA) has been shown to enhance the specificity of total PSA testing for prostate cancer while maintaining high sensitivity and to aid in prostate cancer staging. This study evaluated whether the %fPSA cutoff that maintained a 95% sensitivity in a white population yielded the same sensitivity and specificity in a black population and whether %fPSA was useful in predicting postoperative pathologic features in blacks.

METHODS

We evaluated 647 white and 79 black men, prospectively enrolled at prostate cancer screening and surgical referral centers. Subjects were 50 to 75 years old with digital rectal examination findings that were not suspicious for prostate cancer and total PSA values between 4.0 and 10.0 ng/mL. All had undergone needle biopsy of the prostate. Hybritech's Tandem total and free PSA assays were used.

RESULTS

Ninety-five percent sensitivity was attained with a %fPSA cutoff of 25% in both races. Use of this cutoff could have avoided unnecessary biopsies in 20% of white and 17% of black subjects (P = 0.69). In receiver operating characteristic (ROC) curve analysis, the area under the curve (AUC) for %fPSA was significantly higher than for total PSA in both blacks (0.76 versus 0.56, P <0.01) and whites (0.70 versus 0.54, P <0.001). In both races, higher %fPSA values indicated a lower risk of cancer and also predicted favorable pathologic features in radical prostatectomy specimens.

CONCLUSIONS

A 25% fPSA cutoff detected 95% of cancers and reduced unnecessary biopsies in both races. Higher %fPSA values were associated with favorable postoperative histopathologic findings in both races.

Clinical characteristics in black and white men with prostate cancer in an equal access medical center

OBJECTIVES

To determine whether black men with newly diagnosed prostate cancer in an equal access health care center are more likely to present with metastatic disease, more poorly differentiated tumors, higher serum prostate-specific antigen (PSA) levels, and/or at younger ages compared with white men.

METHODS

A retrospective survey was conducted that identified black and white men with newly diagnosed prostate cancer at the Los Angeles Regional Veterans Affairs Clinics between 1991 and 1997. Patient data were analyzed for racial differences in age at diagnosis, clinical stage, PSA level, and Gleason score of the prostate biopsy specimens.

RESULTS

A total of 477 evaluable patients (230 black, 247 white) with newly diagnosed prostate cancer were identified. No significant differences in the average age (66.9 +/- 7.3 versus 67.9 +/- 7.5) or clinical stage at diagnosis were found between black and white men. Among black men, 87% presented with clinically localized disease (T1-2, Nx, M0) compared with 88% of white men. Only 6% of black men presented with distant disease (Tx, Nx, M1) compared with 4% of white men. Black men had higher median PSA levels than white men (14. 2 versus 9.4 ng/mL, P = 0.0001). Black men also had slightly higher average Gleason scores (6.2 versus 5.9, P = 0.025).

CONCLUSIONS

This is the first study to show a low and equal percentage of black and white men presenting with metastatic prostate cancer. In this equal access center, no differences were found in patient age or clinical stage of prostate cancer between black and white men at the time of diagnosis. However, black men presented with higher serum PSA values and slightly higher Gleason scores.

Prostate cancer in African-American men: outcome following radiation therapy with or without adjuvant androgen ablation

PURPOSE

To compare the outcome of irradiated clinically localized prostate cancer in African-American and white patients.

METHODS AND MATERIALS

This was a retrospective review of 1,201 men, 116 African-American and 1,085 white, with T1-T3, N0/NX, M0 prostate cancer receiving external radiation between 1987 and 1996. Pretreatment characteristics, treatment parameters, and outcome (relapse or rising prostate-specific antigen [PSA] levels, local recurrence, metastatic relapse, and survival) were compared between the groups using univariate and multivariate statistical methods.

RESULTS

There were no significant differences between African-American and white patients in T-stage, Gleason score, prostatic acid phosphatase (PAP) level, and testosterone level. African-Americans had a significantly lower incidence of abnormal digital rectal findings and a proportionally higher incidence of obstructive urinary symptoms at presentation and tended to be somewhat younger. A major difference between the two groups was in the significantly higher PSA levels among African-Americans (median, 14 ng/ml) than among white patients (median, 9.5 ng/ml). This translated into a higher incidence of unfavorable disease according to our criteria (39% vs. 25%) among African-Americans and, thus, to the more frequent use of adjuvant androgen ablation and to somewhat higher radiation doses in these patients. With a median follow-up of 42 months the overall 6-year freedom from relapse for African-Americans was 63% compared to 61% for whites (p = 0.634). We found no significant differences in biochemical relapse rates between any subgroups of African-Americans and whites. Specifically, even patients who did not have androgen ablation, when stratified by PSA levels, had similar outcomes regardless of race. Likewise, local recurrence and metastasis rates were not significantly different between the two groups.

CONCLUSIONS

Although African-American patients tend to have higher pretreatment PSA levels than white patients, the outcome for the disease is similar in the two groups when stratified by known pretreatment prognostic factors. Our data provide no evidence for the hypothesis that prostate cancer in African-Americans is intrinsically more virulent than in whites.

Racial differences in clinically localized prostate cancers of black and white men

PURPOSE

Tumor grade, deoxyribonucleic acid (DNA) ploidy, proliferation, p53 and bcl-2 expression were examined in clinically localized prostate cancers of black and white American men to learn whether these features showed racial differences.

MATERIALS AND METHODS

A total of 117 prostate cancers (43 black and 74 white patients) obtained at radical prostatectomy for clinically localized disease were assigned Gleason scores by a single pathologist. Enzymatically dissociated nuclei from archival prostate cancers were examined by DNA flow cytometry using propidium iodide staining and the multicycle program to remove debris and sliced nuclei and to perform cell cycle analysis. For immunostaining after microwave antigen retrieval we used a DO-1/DO-7 monoclonal antibody cocktail for p53 and the clone 124 antibody for bcl-2.

RESULTS

Significantly more black than white men had Gleason score 7 tumors. The DNA ploidy distribution of Gleason 6 or less tumors was similar for both races. As anticipated, the ploidy distribution of higher grade prostate cancer in white men was more abnormal but, unexpectedly, this was not found for higher grade prostate cancer in black men. No significant racial differences were found in S phase fractions, p53 or bcl-2 immunopositivity. However, for prostate cancer in black men there was a significant association between bcl-2 immunopositivity and higher S-phase fractions.

CONCLUSIONS

The aggressive prostate cancers of black men may be characterized by the 2 features of high proliferation and a block to programmed cell death.