Exploratory analysis on the effect of race on clinical outcome in patients with advanced prostate cancer receiving bicalutamide or flutamide, each in combination with LHRH analogues. The Casodex Combination Study Group

Disparities With Systemic Therapies for Black Men Having Advanced Prostate Cancer: Where Do We Stand?

PURPOSE

Prostate cancer represents the most common cancer diagnosis in Black men and is the second leading cause of cancer death in this population. Multilevel disparities have been well-documented in Black men with prostate cancer and play a role in poorer survival outcomes when compared with White men with prostate cancer. In this review, we highlight the changing trend in disparities for systemic therapy outcomes in Black men diagnosed with metastatic prostate cancer.

METHODS

We reviewed data from real-world registries and prospective clinical trials with a particular focus on equal access settings to compare outcomes to systemic therapies between Black and White men with metastatic prostate cancer.

RESULTS

In metastatic prostate cancer, there is growing evidence to suggest that Black men may have similar, if not better, outcomes to systemic therapies than White men with advanced disease, as corroborated by prospective studies and clinical trials where health care delivery and follow-up are more likely to be standardized.

CONCLUSION

This review illustrates the importance of nonbiological drivers of racial disparities in Black men with advanced prostate cancer. Mitigating barriers to health care access and delivery as well as including participation in clinical trials will be pivotal to ongoing efforts to address disparities in systemic therapy outcomes for Black men with metastatic 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.

Lack of Racial Survival Differences in Metastatic Prostate Cancer in National Cancer Data Base (NCDB): A Different Finding Compared to Non-metastatic Disease

Background: Inconsistent findings have been reported in the literature regarding racial differences in survival outcomes between African American and white patients with metastatic prostate cancer (mPCa). The current study utilized a national database to determine whether racial differences exist among the target population to address this inconsistency.

Methods: This study retrospectively reviewed prostate cancer (PCa) patient data (N = 1,319,225) from the National Cancer Database (NCDB). The data were divided into three groupings based on the metastatic status: (1) no metastasis (N = 318,291), (2) bone metastasis (N = 29,639), and (3) metastases to locations other than bone, such as brain, liver, or lung (N = 952). Survival probabilities of African American and white PCa patients with bone metastasis were examined through parametric proportional hazards Weibull models and Bayesian survival analysis. These results were compared to patients with no metastasis or other types of metastases.

Results: No statistically supported racial disparities were observed for African American and white men with bone metastasis (p = 0.885). Similarly, there were no racial disparities in survival for those men suffering from other metastases (liver, lung, or brain). However, racial disparities in survival were observed among the two racial groups with non-metastatic PCa (p < 0.001) or when metastasis status was not taken into account (p < 0.001). The Bayesian analysis corroborates the finding.

Conclusion: This research supports our previous findings and shows that there are no racial differences in survival outcomes between African American and white patients with mPCa. In contrast, racial disparities in the survival outcome continue to exist among non-metastatic PCa patients. Further research is warranted to explain this difference.

Disparities in prostate cancer incidence and mortality rates: Solvable or not?

Prostate cancer (PCa) is recognized as a disease possessing not only great variation in its geographic and racial distribution but also tremendous variation in its potential to cause morbidity and death and it, therefore, ought not to be considered a homogenous disease entity. Morbidity and death from PCa are disproportionately higher in men of African ancestry (MAA) who are generally observed to have more aggressive disease and worse outcomes following treatment compared to men of European ancestry (MEA). The higher rates of PCa among MAA relative to MEA appear to be multifactorial and related to inherent differences in biological aggressiveness; a continued lack of awareness of the disease and methods of prevention; a lower prevalence of screen-detected PCa; comparatively lower access to quality healthcare as well as systemic and institutionalized disparities in the administration of optimal care to MAA in developed countries such as the United States of America where high-quality care is available. Even when access to quality healthcare is assured in equal access settings, it appears that MAA still have worse outcomes after PCa treatment stage-for-stage and grade-for-grade compared to MEA, suggesting that, inherent racial, ethnic and biological differences are paramount in predicting poor outcomes. This review has explored the different contributing factors to the current disparities in PCa incidence and mortality rates with emphasis on the incongruence in how research has been conducted in understanding the disease towards developing therapies.

Overall Survival of Black and White Men With Metastatic Castration-Resistant Prostate Cancer Treated With Docetaxel

PURPOSE

Several studies have reported that among patients with localized prostate cancer, black men have a shorter overall survival (OS) time than white men, but few data exist for men with advanced prostate cancer. The primary goal of this analysis was to compare the OS in black and white men with metastatic castration-resistant prostate cancer (mCRPC) who were treated in phase III clinical trials with docetaxel plus prednisone (DP) or a DP-containing regimen.

METHODS

Individual participant data from 8,820 men with mCRPC randomly assigned in nine phase III trials to DP or a DP-containing regimen were combined. Race was based on self-report. The primary end point was OS. The Cox proportional hazards regression model was used to assess the prognostic importance of race (black v white) adjusted for established risk factors common across the trials (age, prostate-specific antigen, performance status, alkaline phosphatase, hemoglobin, and sites of metastases).

RESULTS

Of 8,820 men, 7,528 (85%) were white, 500 (6%) were black, 424 (5%) were Asian, and 368 (4%) were of unknown race. Black men were younger and had worse performance status, higher testosterone and prostate-specific antigen, and lower hemoglobin than white men. Despite these differences, the median OS was 21.0 months (95% CI, 19.4 to 22.5 months) versus 21.2 months (95% CI, 20.8 to 21.7 months) in black and white men, respectively. The pooled multivariable hazard ratio of 0.81 (95% CI, 0.72 to 0.91) demonstrates that overall, black men have a statistically significant decreased risk of death compared with white men ( P < .001).

CONCLUSION

When adjusted for known prognostic factors, we observed a statistically significant increased OS in black versus white men with mCRPC who were enrolled in these clinical trials. The mechanism for these differences is not known.

Pilot study on the detection of antiandrogen resistance using serial diffusion-weighted imaging of bone metastases in prostate cancer

PURPOSE

To evaluate serial apparent diffusion coefficient (ADC) measurements of bone metastases in prostate cancer to determine whether antiandrogen resistance can be detected and time to progression estimated.

MATERIALS AND METHODS

Diffusion-weighted imaging (DWI) was performed at 1.5T in nine patients with treatment-naïve metastatic prostate cancer (20 lesions) before antiandrogen treatment, after 1, 2, and 3 months of treatment, and thereafter every 4 months over 31 months or until antiandrogen resistance was detected. Tumor volumes were stable over time. Time courses of the ADCs when averaged over entire lesions and on functional diffusion maps (fDMs) were analyzed using marginal linear model (MLM) analysis.

RESULTS

Starting at 1 month, MLM analysis revealed decreasing mean ADCs (P = 0.001) over time. Simultaneously, the percentage of voxels with significantly higher ADCs decreased (P = 0.004), whereas the percentage of voxels with significantly lower ADCs increased (P < 0.001) on fDMs. Both mean ADCs (P = 0.042) and percentages of voxels with significantly higher ADCs on fDMs (P = 0.039) decreased more rapidly over time in patients with a shorter progression-free interval (PFI). Likewise, higher (P = 0.001) and more rapidly increasing (P = 0.002) percentages of voxels with significantly lower ADCs on fDMs were associated with a shorter PFI.

CONCLUSION

The results of our pilot study suggest that the evolution of ADCs over time may permit early identification of antiandrogen resistance in bone metastases. J. Magn. Reson. Imaging 2016;43:1407-1416.

Differences in vitamin D status may account for unexplained disparities in cancer survival rates between African and white Americans

Considerable disparities in cancer survival rates exist between African Americans (AAs) and white Americans (WAs). Various factors such as differences in socioeconomic status (SES), cancer stage at time of diagnosis, and treatment—which this analysis considers primary explanatory factors—have accounted for many of these differences. An additional factor not usually considered is vitamin D. Previous studies have inversely correlated higher solar ultraviolet-B (UVB) doses and serum 25-hydroxyvitamin D (25(OH)D) concentrations with incidence and/or mortality rates for about 20 types of cancer and improved survival rates for eight types of cancer. Because of darker skin pigmentation, AAs have 40% lower serum 25(OH)D concentrations than WAs. This study reviews the literature on disparities in cancer survival between AAs and WAs. The journal literature indicates that there are disparities for 13 types of cancer after consideration of SES, stage at diagnosis and treatment: bladder, breast, colon, endometrial, lung, ovarian, pancreatic, prostate, rectal, testicular, and vaginal cancer; Hodgkin lymphoma and melanoma. Solar UVB doses and/or serum 25(OH)D concentrations have been reported inversely correlated with incidence and/or mortality rates for all of these cancers. This finding suggests that future studies should consider serum 25(OH)D concentrations in addressing cancer survival disparities through both measurements of serum 25(OH)D concentrations and increasing serum 25(OH)D concentrations of those diagnosed with cancer, leading to improved survival rates and reduced disparities.

Black men have lower rates than white men of biochemical failure with primary androgen-deprivation therapy

INTRODUCTION

Black men have a higher incidence of advanced stage at diagnosis and mortality from prostate cancer than do men in other racial groups. Given that androgen-deprivation therapy (ADT) is one of the mainstays of treatment for advanced prostate cancer, we investigated the development of biochemical failure, or recurrence of elevated prostate-specific antigen (PSA) levels, among different races in men receiving ADT.

METHODS

Patients with prostate cancer who received ADT in the Kaiser Permanente Southern California Cancer Registry between January 2003 and December 2006 were eligible for inclusion in our study. Patients who had prior treatment for their cancer with surgery or radiation were excluded. Treatment failure was defined as an increase in PSA of >2 ng/mL from PSA nadir, with no subsequent decrease in PSA. We compared the biochemical failure rate in white patients to those in black, Hispanic, and Asian/other patients. The Cox proportional hazards regression model was used to estimate hazards ratios.

RESULTS

Our study population consisted of 681 patients: 416 (61%) were white; 107 (16%) were black; 107 (16%) were Hispanic; and 51 (7%) were Asian or another race. After we controlled for all demographic variables and for variables related to prostate cancer, blacks were the only group with a lower risk of treatment failure compared with whites. The hazard ratios for treatment failure were as follows: black versus white, 0.66 (p = 0.03); Hispanic versus white, 1.00 (p = 0.8); Asian/other race versus white, 1.5 (p = 0.1). In this multivariate analysis, pretreatment PSA level and cancer stage were the only other variables associated with a higher risk of treatment failure.

CONCLUSION

Among patients receiving ADT as primary monotherapy for prostate cancer, blacks may have a lower rate of biochemical failure compared with whites. Although the etiology of this finding is unclear, it suggests the possibility that prostate cancer in black men may be more androgen sensitive than it is in white men.

Do African American Men Have Lower Survival From Prostate Cancer Compared With White Men? A Meta-analysis

Prostate cancer is the second leading cause of cancer-related mortality in men. This meta-analysis was conducted to investigate the relationship between race and survival from prostate cancer. A systematic review of articles published from 1968 to 2007 assessing survival from prostate cancer was conducted. Analysis of unadjusted studies reported that African American men have an increased risk of all-cause mortality (hazard ratio [HR] = 1.47, 95% confidence interval [CI] = 1.31-1.65, p < .001). However, examination of adjusted studies identified no difference (HR = 1.07, 95% CI = 0.94-1.22, p = .308). No statistically significant difference was observed in prostate cancer—specific survival in both analyses using unadjusted (HR = 1.11, 95% CI = 0.94-1.31, p = .209) and adjusted studies (HR = 1.15, 95% CI = 0.95-1.41, p = .157). This meta-analysis concludes that there are no racial differences in the overall and prostate cancer—specific survival between African American and White men.

Redefining hormone resistance in prostate cancer

Prostate cancer relies on signaling through the androgen receptor (AR) for maintenance and progression; and androgen-deprivation therapy remains a cornerstone of treatment for advanced prostate cancer. An effective clinical classification of prostate cancer should account for the extent of the disease as well as the mechanisms that are driving the growth of the tumor. The previous terms hormone-sensitive and hormone-refractory described response to treatment. It has become clear that these terms do not reflect the mechanism of disease relapse; however over the last decade there has been a better understanding of androgen-receptor mediated signaling effects and incomplete suppression of androgens in prostate cancer. The Prostate Cancer Clinical Trials Working Group 2 (PCWG2) now recommends addressing the spectrum of clinical states based on castration status as this ligand-centered terminology can more accurately describe the patients' disease, and ultimately provides a useful framework for patient management and drug development. Optimized use of androgen-deprivation therapy, low molecular weight inhibitors of adrenal androgen biosynthesis, and new AR antagonists are promising new therapeutics that can further define the meaning of castrate state. As hormone resistance is redefined to include patients that are refractory to treatments that ablate adrenal and in situ tumoral androgens, a meaningful new clinical state in patients will be forged. We propose a model for incorporating these patients into the current PCWG2 conceptualization of the disease.

Racial differences in clinical outcome after prostate cancer treatment

Prostate cancer is the number one killer in the United States. A comparison of US and Japanese population is discussed in this chapter to identify risk factors for prostate cancer. Screening of prostate cancer is common among Americans, but not among Japanese. A comparison of survival in different populations is also presented; and prognosis after hormonal treatment in different populations is included.

Use of androgen deprivation therapy for metastatic prostate cancer in older men

OBJECTIVE

To assess factors associated with early or delayed androgen deprivation therapy (ADT) among men diagnosed with metastatic prostate cancer, and to assess the relationship between ADT and overall survival, as there is uncertainty about the ideal timing for initiating ADT in men with metastatic prostate cancer.

PATIENTS AND METHODS

We studied a population-based cohort of American men aged >or=66 years diagnosed with metastatic prostate cancer during 1992-2002 and followed to 2003. We assessed the receipt of ADT early (4 months), or not at all, using multinomial logistic regression to identify factors associated with treatment, and Cox proportional-hazard models to assess whether treatment was associated with survival.

RESULTS

Overall, 69.5% of men received early ADT and 7.3% delayed. Adjusted rates of early ADT were lower for black than white men (58.3% vs 71.0%), and of delayed ADT were higher for black than white men (12.7% vs 6.2%). Receipt of ADT was associated with improved survival (adjusted hazard ratio 0.69, 95% confidence interval 0.66-0.73). The benefit of early treatment did not differ from delayed treatment (P = 0.58).

CONCLUSIONS

A large minority of men with metastatic prostate cancer, particularly black men, receive delayed or no ADT. Early or delayed ADT was associated with similarly prolonged survival. After controlling for patient and tumour characteristics, survival did not differ by race, and receipt of ADT did not contribute to racial differences in survival.

Racial differences in prostate cancer treatment outcomes: a systematic review

Although differences in prostate cancer incidence and mortality between black and white men are widely accepted, the existence of racial differences in treatment outcomes remains controversial. We conducted a systematic review of racial differences in prostate cancer treatment outcomes. Systematic review of literature from 1992-2002 was conducted. Database searches were performed using the terms: "prostate cancer" (keyword) or "prostate neoplasm" (subject heading) + "blacks" (subject heading) or "blacks" (keyword) + "African-Americans" (subject heading or "African-Americans" (keyword). Two hundred fifty-eight relevant articles were identified; 29 fit the inclusion criteria. All but 3 were retrospective. Seven (24%) studies were conducted at Veterans Affairs medical centers. Treatment included radical prostatectomy (15 studies), hormonal therapy (5 studies), and radiotherapy (12 studies). Three studies included more than 1 treatment. Twenty-three (79%) studies, observed no significant difference in treatment outcomes between races. The remainder found worse outcomes among black men, including worse 5-year survival (HR range, 2.35-96.74) and higher rates of PSA failure (OR range, 1.15-1.69). Most studies investigating racial differences in prostate cancer treatment outcomes over the past 10 years found no difference between races after controlling for tumor and patient characteristics. Efforts to narrow the gap between black and white prostate cancer mortality should focus on ensuring that all patients receive optimal treatment and that all patients become informed about the use of screening for early cancer detection. Research should focus on interventions to reduce advanced presentation of the disease and disease-related mortality among black men.

Study of Hormone Refractory Prostate Cancer: Hospital Care and Palliative Care Resource Use at a VA Medical Center

Palliative care plays a central role in the management of hormone refractory prostate cancer patients (HRPC), yet little is known about palliative care resource use. Computerized medical records of a retrospective cohort of 89 consecutive HRPC patients seen at a VA medical center from 1994 to 1999 were reviewed for hospital and palliative care resource use in the last 6 months of life. There were 51 Caucasian and 38 African American patients; 95% of patients were admitted to the hospital for symptom management (median of 2 admissions); 98% visited clinics (median 19 visits); 35% went to the emergency room (median of 1 visit); 60% died in the hospital (median length of last hospitalization of 22 days); 49% received palliative radiation; 52% used rehabilitation; 57% received blood transfusion (median 2 units). Thirty-five patients (40%) received hospice care (median stay 35 days). The most frequently prescribed medications included opioids (90%), laxatives (89%), H2-blockers (57%), antiemetics (55%), diuretics (49%), and corticosteroids (43%). The prevalence of patients receiving opioids, as well as the dose of opioids increased over time. There was no difference in categories of palliative care resource use or survival by race. The median survival for all patients was 13 months. The results begin to highlight the extent of care and resources needed by patients with end-stage HRPC. This information will be of importance in planning palliative care for patients with HRPC and in designing future prospective studies.