Reasons for the disparities in screening
Many reasons have been proposed to explain why African Americans receive less screening, including poor communication between physicians and minority patients due to lack of cultural competency among physicians, lack of health insurance (and poor access to quality care as a result), and deficiency of knowledge about screening. Though awareness is rising, many African Americans are unaware of early detection methods for prostate cancer (eg, PSA testing), and other barriers such as cost and transportation exist that may prevent African American men from being screened.34,35
As gatekeepers, primary care physicians are in a position to address these shortcomings in patient education and to enhance the physician-patient relationship.36
Black men have higher PSA levels, with or without cancer
Physicians must also be aware of racial differences in PSA levels and realize that the predictive value of PSA in the diagnosis of prostate cancer may differ between African Americans and whites.
Black men, with or without prostate cancer, have been found to have higher PSA levels. Kyle and colleagues37 found that African American men without prostate cancer had significantly higher mean PSA levels than white men across all age groups. Furthermore, Vijayakumar et al38 found that African Americans with newly diagnosed localized prostate cancer had higher serum PSA levels than whites at diagnosis.
Although PSA cutoff levels have not been officially modified according to race, primary care physicians should have a lower threshold for referring African American men who have a suspiciously high PSA level for further urologic evaluation. Close partnership between the internist, family practitioner, and urologist will aid in the optimal use of PSA testing for the early detection of prostate cancer.
When to start PSA screening? How often to screen?
The age at which African American men should begin to have their PSA levels checked (with or without a digital rectal examination) continues to debated. However, the American Cancer Society39 recommends that African American men who have a father or brother who had prostate cancer before age 65 should begin having discussions with their physician on this topic and, with their informed consent, screening at age 45.
The frequency of PSA screening depends on the individual’s PSA level. The National Comprehensive Cancer Network40 recommends that men at high risk be offered a baseline PSA measurement and digital rectal examination at age 40 and, if the PSA level is higher than 1 ng/mL, that they be offered annual follow-ups. If the PSA level is less than 1 ng/mL, they recommend screening again at age 45. Risk factors for prostate cancer include family history as well as African American race.41
How should PSA levels be interpreted?
Interpreting PSA results is important in detecting prostate cancer at early stages.
At first, we believed the normal range of PSA for all men was 4.0 ng/mL or less. However, the American Urological Association now recognizes that the normal PSA range, in addition to varying along racial lines, also is age-dependent.42 The Cleveland Clinic Minority Men's Health Center's suggested normal ranges of PSA in African American men are:
- Age 40–49: ≤ 2.5 ng/mL
- Age 50–59: ≤ 3.0 ng/mL
- Age 60–69: ≤ 3.5 ng/mL
- Age 70–79: ≤ 4.5 ng/mL
- Age > 80: ≤ 5.0 ng/mL.
Remember that an elevated PSA does not necessarily signify prostate cancer, and that these are reference ranges only and may vary in individual men.
SURVIVAL AFTER DIAGNOSIS
African American men with prostate cancer have significantly higher mortality rates than white men. The possible causes of worse outcomes are many, and there have been many studies that attempted to address this disparity. The question of a more biologically aggressive cancer was previously discussed, but additional factors such as socioeconomic factors, comorbidities, and treatment received have also been studied, and data are mixed.43–45
In a large SEER database review, once confounding variables of socioeconomic status, cancer stage, and treatment received were eliminated, African Americans had similar stage-for-stage survival from prostate cancer.46 Another study found, in 2,046 men, that differences in socioeconomic status explained the difference in mortality rates between white and black patients.47
However, other studies that adjusted for socioeconomic status as well as patient and tumor characteristics found that African American and Hispanic men were more likely to die of prostate cancer than white men.48
Do African American men receive less-aggressive care?
Studies have also determined that there may be differences in treatments offered to patients, which in turn negatively affect survival.28,49–53 Potentially curative local therapies (including radical surgery or radiation) may be recommended less often to black men because of major comorbidities or socioeconomic considerations.49–52
Additionally, potential metastatic disease may be identified in a less timely and accurate manner, as African American men are less likely to undergo pelvic lymph node dissection. This was associated with worse survival in men with poorly differentiated prostate cancer.53
However, returning to the possibility that prostate cancer is biologically more aggressive in African American men, some studies have shown that even after adjusting for treatment, African Americans continue to have worse survival rates.54,55 One study in men with stage T1 to T3 prostate cancer who chose brachytherapy for treatment reported that after adjusting for PSA, clinical stage, socioeconomic status, and comorbidities, African American and Hispanic race were associated with higher all-cause mortality rates.55
Equal care, equal outcomes?
In total, these results suggest that factors unrelated to tumor biology may be additional reasons for the poorer survival rates in African American men with prostate cancer. More favorable survival outcomes for African Americans with localized disease may be achieved with uniform assignment of treatment.
Fowler and Terrell56 reviewed the outcomes of 148 black and 209 white men with localized prostate cancer treated with surgery or radiation therapy over an 11-year period at a Veterans Administration hospital. Not surprisingly, the black men presented more often with advanced disease. However, survival outcomes were equivalent between whites and blacks when treatment was assigned in a uniform manner without regard to race. After a median follow-up of 96 months, there were no significant differences in all-cause, cause-specific, metastasis-free, clinical disease-free, or PSA recurrence-free survival rates in 109 black and 167 white men with low-stage cancer treated with surgery or radiation therapy or in 39 black and 42 white men with high-stage disease treated with radiotherapy.56
Similarly, Tewari et al57 studied a cohort of 402 African American and 642 white men, all of whom underwent radical prostatectomy for clinically localized prostate cancer. They were followed for PSA recurrence to determine if race-specific differences in PSA doubling time or histopathologic variables might account for the higher mortality rate in black men. While there were race-specific differences in baseline serum PSA and incidence of high-grade prostatic intraepithelial neoplasia, race was not an independent risk factor for biochemical recurrence. Instead, other variables such as the Gleason pathology score, bilateral cancers, and margin positivity were independently associated with biochemical recurrence.
Furthermore, researchers at Louisiana State University58 retrospectively analyzed data from 205 men of different races with early-stage prostate cancer. The African American men had a higher serum PSA level, suggesting more advanced disease or greater tumor burden at presentation, but no statistically significant differences were found among the pretreatment biopsy variables, including prostate volume (measured by ultrasonography), Gleason score, millimeters of cancer within the biopsy specimen, and percentage of cancer within the biopsy specimen. After treatment, there were no significant differences in survival outcomes along racial lines, leading the authors to conclude that early detection and treatment of prostate cancer in African Americans would be the best approach to lowering mortality rates.
Taken together, these data suggest that if localized prostate cancer is treated adequately and appropriately, African American patients may have improved survival rates.