Racial Variation in Prostate Cancer Care Explored

February 1, 1997

In the United States, racial variations have been documented in the incidence, mortality, and clinical management of cancers of the breast, colon, lung, and prostate.[1-4] In conjunction with similar findings from nonmalignant diseases, such as cardiovascular and cerebrovascular disease, these data suggest that racial variations in medical care are widespread.[5-8] However, few empirical studies explain why these racial variations exist at all.

In the United States, racial variations have been documented in theincidence, mortality, and clinical management of cancers of the breast,colon, lung, and prostate.[1-4] In conjunction with similar findings fromnonmalignant diseases, such as cardiovascular and cerebrovascular disease,these data suggest that racial variations in medical care are widespread.[5-8]However, few empirical studies explain why these racial variations existat all.

There are several potential explanations for these findings. First isa consideration of racial discrimination in medical care.[9] Second, differencesin socioeconomic status and income, rather than race, might be importantfactors. For example, racial differences in incidence and survival forsome cancers have been linked to socioeconomic status.[10-12] Socioeconomicstatus may also account for variations in patterns of care.

Third, clinical factors may differ according to race/ethnicity, includingdisease pathophysiology, stage at presentation, or comorbid conditionsthat may be contraindications to some therapies or otherwise modify thechoice of treatment. Fourth, there may be racial or cultural differencesin patient preferences for care.

Understanding the extent of, and factors associated with, racial variationsin the care of men with prostate cancer is especially important. Recentadvances in prostate cancer screening have resulted in higher rates ofearly-stage disease among whites more so than blacks.

The Concept of Race

Race is regarded as a social concept that reflects historical socialand economic events and not as a biological entity.[13-15] Indeed, somehealth researchers contend that race has no biological meaning and shouldbe abandoned as a variable in analyses, particularly because the concepthas been used in the past to bolster racist arguments of the purportedinherent superiority of some racial groups.[16,17]

The socioeconomic aspects of race have been evaluated previously, whilepotential biological aspects have been virtually ignored.[18,19] Althoughrace is intimately intertwined with socioeconomic status (at least in theUS), the two terms reflect different concepts.[20,21]

For example, race may also be an indicator of genetic proclivities forcancer development, a proxy for economic factors, eg, ability to pay forcare, or a marker for cultural orientation, eg, patient preferences forcertain therapies or misunderstandings about some therapies.

The policy implications of these alternative explanations are widelydifferent, varying from educational strategies, health care financing reform,or program targeting to high-risk populations.

Among males, prostate cancer is second only to lung cancer in incidenceand mortality, with significant racial differences in both factors.[1]In 1992, the age-adjusted incidence rate for prostate cancer was 187.6per 100,000 for blacks vs 139.4 per 100,000 for whites, yielding an overallrate ratio of 1.3.

The age-adjusted mortality rate for prostate cancer for 1988 to 1992was 53.5 per 100,000 for blacks vs 24.0 per 100,000 for whites, a mortalityrate ratio of 2.2. This is one of the largest ratios for site-specificcancer mortality.

Blacks consistently present at a later stage of prostate cancer. However,adjusting for stage at presentation does not eliminate the racial disparitiesin survival rates; rather, the survival gap between blacks and whites demonstratesa broadening with advanced stage.

Patterns of Care

Racial/ethnic differences are apparent in the care of prostate cancerpatients. For example, black patients are substantially more likely thanwhites to receive hormonal therapy alone but are less likely to undergoprostatectomy alone. This pattern appears to persist over time.

There is a relatively extensive and consistent literature regardingthe role of clinical and socioeconomic factors in explaining racial differencesin types of prostate cancer therapy, but no literature on the importanceof either patient preferences or the patient-physician interaction.

It is not known if differences in care contribute to the lower survivalrates among blacks. Some studies have reported that when treatments aresimilar between blacks and whites, outcomes are similar. Among patientson standard oncology protocols, there is uniformity in evaluation and treatment,as well as overall survival and disease-free survival.[22] Similarly, inequal access systems, no significant racial difference in overall survivalis reported.[23,24]

However, the literature linking specific treatments with outcomes accordingto race does not consistently indicate these findings. In one study, timeto recurrence was shorter among the black vis-à-vis the white patientswho underwent a radical prostatectomy.[25]

Stage at Presentation

Studies suggest that stage at presentation is a primary explanationof the racial difference in therapy. Among patients in the Virginia CancerRegistry who have local or regional disease, blacks are more likely thanwhites to receive either no treatment or hormonal therapy but less likelyto receive either surgery or radiation.[26] With adjustment for socioeconomic,clinical, and health care system characteristics, there is no racial differencein either the likelihood of receiving any treatment versus no treatmentor in receiving hormonal therapy or orchiec-tomy versus surgery or radiation.

However, SEER data indicate that, among localized disease patients,blacks are only two thirds as likely to receive radical prostatectomy orradiation.[27]

Ability to Pay

Given the general importance of ability to pay for care in gaining accessto health care, it is reasonable to expect that socioeconomic status isan important determinant of therapy. However, review of the evidence fromfederal and non-federal patterns of care studies suggest that ability topay may have little or no role in explaining racial variations in the typesof therapy for prostate cancer.

Within the health care systems of the Veterans Health Administrationor Department of Defense medical centers, financial incentives for providingor withholding care are minimal. However, one patterns of care study foundracial variations in care similar to those seen in the nonfederal healthcare sector.[23]

Moreover, even in studies that control for socioeconomic status, racialdifferences in type of therapy persist.[26] In addition, clinical factorssuch as comor-bid conditions may account for some of the variation in care.[26]

Finally, ability to pay is just one dimension of socioeconomic status.Other dimensions of socioeconomic status, such as education or knowledge,may be worth exploring as possible additional factors that have a rolein explaining the racial differences in prostate cancer therapy.

Variations in Patient Preferences

Neither racial variations in patient preferences, knowledge, and beliefsnor the role of the patient's race in the patient-physician decision-makingprocess has been thoroughly investigated as a potential explanation ofthe observed racial differences in patterns of care.

Recent investigations suggest that blacks are less likely to see themselvesas being at high risk of prostate cancer and may have a more pessimisticview of the impact of prostate cancer on quality of life and of the prognosis.[28-30]Such attitudes may indirectly account for the racial differences in thetherapies used by influencing when in the natural history of this diseaseblack patients present.

Future Research

Given that racial variation in the clinical stage at presentation primarilyexplains the observed differences in use of therapies, there are at leasttwo compelling avenues for future investigations of racial differencesin the treatment of prostate cancer.

One is racial differences in disease pathophysiology and their implicationsfor screening and early detection programs. Blacks may experience a moreaggressive form of prostate cancer.[31] There is a long history of epidemiologicalstudies that document a higher incidence and earlier onset of prostatecancer among blacks.[32-36]

Also, time to recurrence may be shorter in black than in white prostatecancer patients, despite similar treatment and similar clinical stage atpresentation.[22,25] Finally, latent prostate cancers are greater in volumeamong blacks than whites.[37,38]

Even if a more aggressive form of prostate cancer does not afflict blacks,studies show consistently that blacks present at a later clinical stageof disease than whites even in equal access systems such as the VeteransHealth Administration and Department of Defense.[23,39,40]

Existing evidence, which is far from sufficient, indicates that blacksdo not perceive themselves to be at high risk for prostate cancer, whilethe epidemiology of prostate cancer clearly indicates that they are athigh risk. Moreover, blacks may be delaying evaluation because of fearsregarding disease prognosis.[28,30]

Prostate cancer is one of several cancers that affect US racial andethnic groups differently, with blacks experiencing a higher incidenceand mortality rate than whites. Black patients with prostate cancer areless likely to receive definitive therapy. This pattern of care differenceappears to be attributable primarily to the later clinical stage of diseaseat presentation; socioeconomic considerations, which relate to access tocare, appear to play a lesser role.

Other patient-related factors, for example, preferences for certaintherapies, have not been well studied; consequently, their ability to explainracial variations in treatment is unclear.

Potential areas for future research should focus on the reasons forthe detection of the disease at a later clinical stage and, hence, itsworse prognosis.

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