Because African-American men diagnosed with prostate cancer experience higher mortality and lower disease-free survival rates than do Caucasian men, the safety of active surveillance (AS) in this population has been a topic of considerable debate.
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New research conducted by Cleveland Clinic’s Glickman Urological & Kidney Institute suggests that AS is a viable option for African-American prostate cancer patients with low- or intermediate-risk disease, enabling long treatment-free periods and reasonable post-treatment outcomes.
“We compared the outcomes of African-American patients on AS with non-African-American patients with similar characteristics,” says Cleveland Clinic urologic oncology fellow Lewis Thomas, MD, lead author of the research presented at the 2019 American Society of Clinical Oncology Genitourinary Cancers Symposium. “The main takeaway of our study is that the decision on whether to go on AS for prostate cancer should not be based on whether the patient is African-American or Caucasian. In other words, African-American patients should not be excluded from AS.”
Advantages of AS
Outcomes studies of African-American men on AS are rare, and some show contradictory results. Dr. Thomas says the lack of clear guidance was one of the motivating factors for his group’s research, a retrospective matched cohort study.
Active surveillance in men with characteristics of low-risk prostate cancer involves monitoring with periodic digital rectal exams (DRE), prostate-specific antigen (PSA) blood tests and prostate biopsies. Treatment is initiated upon objective markers of disease activity or by patient decision. Low-risk prostate cancer is especially amenable to AS due to its typically slow progression. It has been estimated that more than 30 percent of men have slow-growing prostate cancer that does not require immediate treatment.
AS has multiple advantages in low-risk prostate cancer, Dr. Thomas says, including reduced cost of care and fewer long-term side effects.
“Active surveillance offers men with low-risk prostate cancer good quality of life instead of being subjected to the negative side effects of surgical or radiation treatment,” he says, which may include erectile dysfunction, bladder dysfunction or stress urinary incontinence.
Balancing risk factors and patient preferences
Advanced magnetic resonance imaging and genomic testing have aided physicians’ ability to differentiate between patients who are more or less suitable for AS, Dr. Thomas says. The determination of when AS is appropriate boils down to balancing the risk factors for negative outcomes with individual patients’ preferences regarding treatment.
“Overall, large national data sets indicate that physicians and patients are becoming more and more comfortable with AS, which is good because it reduces the burden of treatment for prostate cancer,” he says.
Comparable or better outcomes observed in African-American patients
In the Cleveland Clinic analysis, a cohort of 59 African-American prostate cancer patients was matched 1:1 to non-African-American patients, based on three National Comprehensive Cancer Network (NCCN) parameters: risk, age at diagnosis, and year of diagnosis. Cohort outcomes, including receipt of treatment, post-treatment recurrence, metastases development, prostate cancer-specific mortality and NCCN risk reclassification, were compared.
While the rates of risk reclassification during AS were higher among African-American men than the non-African-American cohort (54 percent vs. 39 percent, p=0.09), the analysis found that the rates of treatment (46 percent vs. 44 percent) and post-treatment recurrence (11 percent vs. 19 percent) were similar in the two groups.
The reclassifications of many in the African-American cohort were due to PSA rise, not pathologic upgrading. African-American patients experienced longer time to reclassification and time to treatment than non-African-American patients. No cancer-specific mortalities were recorded in either cohort, and the rate of metastases development was the same (one patient per group).
“We found that African-American patients came off of AS at a slightly higher rate than their non-African-American counterparts,” Dr. Thomas says, “but when they did get treatment, they had good outcomes and were able to stay on AS at least as long as non-African-American patients and, often times, even longer.
Assessing the utility of AS on a larger cohort
Although these findings were based on a relatively small sample size, they serve as an important basis for future, larger studies, Dr. Thomas says. He and his collaborators are considering analyzing an expanded patient cohort in the near future.
“We are currently working on building a more comprehensive AS database and having more patients to report on, since the major limitation of our study was its size,” he says. “We are optimistic that we will be able to build a more comprehensive data set to validate our initial findings.”