BERKELEY, CA (www.UroToday.com) - Lincoln Medical and Mental Health Center, located in Bronx, New York, serves patients with socioeconomic and health care disparities.
The patient population is comprised of immigrants from Caribbean islands, Africa, and Central and South America, with some exceptions. Two years ago, a formal cross sectional study was instituted to elaborate risks, benefits, and selection criteria for transrectal prostate biopsy. The goal was to develop an algorithm or scoring system to identify high-risk patients for screening. However, PSA density showed complete overlap in men with and without prostate cancer.
The histologic diagnosis of prostate cancer involves disruption of the basal cell layer. In these men basal cell hyperplasia had an inverse association with prostate cancer, suggesting a protective effect. Inverse association between prostate cancer and prostatitis was an unexpected finding and we are working to characterize this relationship further. Although atypical small acinar proliferation on initial biopsy is thought to have a 40% positive repeat biopsy rate, we did not observe this finding in our population, but continue to examine for missed association.
Theories regarding prostate cancer as being caused by a communicable disease led us to examine rates of hepatitis A, B, C, HIV and syphilis IgG, as well as look at tuberculin skin tests to determine if immunologic anergy had any association. All associations were indeterminate or negative, with the exception of hepatitis C antibody. The odds ratio was approximately 12. Although there were limitations to our initial study, our most recent estimates place the true odds ratio between 2 and 20. Prior to this study, hepatitis C had not been considered a risk factor for prostate cancer. Review of the literature revealed multiple studies had ruled out hepatitis C based largely on patient questionnaires conducted before the year 2000, when sensitivity to detect serum hepatitis C antibody was low. Scrutiny of these patients revealed increased rates of metastases and 5-year mortality, with histories significant for intravenous heroin or inhalational cocaine. These findings were presented in a short podium presentation at the American Urological Association Annual Meeting 2011.
Association between hepatitis C and prostate cancer in substance abusers generates several important hypotheses in the pathogenesis of prostate cancer. Inhalational cocaine use has been linked to hepatitis C transmission through the sharing of intranasal straws. Nasal secretions and microscopic amounts of blood combined with nasal capillary trauma are sufficient to transmit the virus. The concept of viral co-infection in high-risk populations raises the suspicion of an undiscovered virus traveling with hepatitis C in these men. In theory, if a ubiquitous virus infecting through nasal secretions or mucus membranes is the cause of prostate cancer, then this could explain how people living in the same home, or first degree relatives, could contract the disease. There is also increased knowledge to be gained by studying intravenous drug users as they may be transmitting an unknown agent through needles or have an immunodeficiency which could increase our knowledge of this disease.
Although several pathways of how hepatitis C may infect have been hypothesized, it is not as well understood by researchers as HIV. Although seven genotypes have been identified, there is no significant clinical difference distinguishing genotypes. Elucidating the dependant mechanism is now crucial as we estimate the lifetime rate of prostate cancer in these men is 77-88%. We are currently initiating a clinical trial to characterize this association. However, the research will be limited to studying genotypes 1 and 2 in our specific population, and we encourage collaboration with colleagues from around the globe to conduct similar studies on their patients.
Written by:
Annika Krystyna and Murray David Schwalb as part of Beyond the Abstract on UroToday.com. This initiative offers a method of publishing for the professional urology community. Authors are given an opportunity to expand on the circumstances, limitations etc... of their research by referencing the published abstract.
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