In the past, epidemiologic studies have shown that statin use does not affect prostate cancer incidence, but that it might reduce the risk for clinical progression and disease-related death.
Now, an observational study, published online May 8 in BJU International, adds to the evidence that statins might interfere with prostate cancer recurrence or progression.
In the study of more than 1100 men who underwent radical prostatectomy (RP), researchers retrospectively compared biochemical recurrence in men who started statins after surgery with recurrence in men who were never users.
This is only the second effort to examine the impact of post-RP statin use on biochemical recurrence.
The timing of statin use is very important, said an expert not involved with the study.
"The central clinical question is whether adding statins after diagnosis/treatment might be beneficial for prostate cancer patients, so trying to isolate the relevant timing is useful," said Kathryn Wilson, ScD, from the Department of Epidemiology at the Harvard School of Public Health in Boston, in an email to Medscape Medical News.
The findings run counter to the bulk of other research related to the matter of timing, she explained.
"I think the approach of looking at statin-naïve patients is interesting. Previous studies that have looked at both pre- and postdiagnosis statin use find the benefit to be more associated with prediagnosis use," said Dr. Wilson.
In the observational study, after adjustment for clinical and pathological characteristics, post-RP statin use was associated with a 36% reduced risk for biochemical recurrence (hazard ratio, 0.64; P = .004).
In all, only 16% post-RP statin users (65/400) had biochemical recurrence, compared with 45% of nonusers (337/746), report Stephen Freedland, MD, from the division of urology at the Duke University School of Medicine in Durham, North Carolina, and colleagues.
The average follow-up time was 92.7 months for post-RP statin users and 59.9 months for never users. The data on the men were culled from the Shared Equal Access Regional Cancer Hospital (SEARCH) database.
"Randomized controlled trials are warranted to formally test the hypothesis that statins slow prostate cancer progression," the authors conclude.
However, Dr. Wilson, who called the study "solid" with "sound methods and thoughtful analysis," said it has multiple shortcomings.
The "largest" concern was the primary outcome of prostate-specific antigen (PSA) recurrence, which is "a very weak proxy for prostate cancer death," she said.
Only about one-third of men who have a PSA recurrence die from prostate cancer, Dr. Wilson explained. "There are many instances of studies finding associations for fatal prostate cancer but not for PSA recurrence, and vice versa."
Dr. Wilson said she would like to see this study repeated in other populations with metastatic or lethal prostate cancer as the primary outcome.
Despite the adjusted analysis of biochemical recurrence, the disparities between the 2 patient groups are a worry, she said.
"I'm also a bit concerned by the much higher follow-up time and the more favorable disease characteristics (grade, stage, surgical margins) in the statin users. It's possible that the men who got statins were a healthier group — better prostate cancer prognosis and perhaps fewer comorbidities," she said.
Dr. Freedland and colleagues had concerns about another possible hidden health disparity between the study groups. When the men were prescribed statins, it might have inspired them to adopt a "healthier lifestyle," including dietary changes, weight loss, and exercise.
In an email to Medscape Medical News, Dr. Freedland suggested that could be a silver lining in the possible confounding cloud of a healthier lifestyle.
"We may be able to slow prostate cancer recurrence — either with statins or the healthy things one does when they start a statin. If true, it suggests we can modify prostate cancer recurrence — with drugs, lifestyle, or both."
The study was supported by funding from the National Cancer Institute.
BJU Int. Published online May 8, 2014. Abstract
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Cite this: Statins and Prostate Cancer: Novel, Encouraging Study - Medscape - May 13, 2014.