Prostate cancer is more common in HIV-positive men and is significantly correlated with both an individual’s age and duration of HIV infection, according to American research published in the July 15th edition of Cancer. Neither the use of HAART nor CD4 cell count were found to be protective against the risk of prostate cancer.
The study’s investigators believe that prostate cancer is likely to occur with increasing frequency in HIV-positive men as HAART extends life-expectancy, and that screening for prostate cancer should be carried out in older HIV-positive men.
Certain cancers have been previously shown to occur more frequently in HIV-positive individuals, and to be unaffected by the use of HAART.
In 2002 investigators from the US Naval Medical Center in San Diego reported a cluster of cases of prostate cancer in HIV-positive men aged over 45 in AIDS. None of the men had a family history of prostate cancer, an acknowledged risk for the malignancy. The discovery of this case cluster prompted the investigators to conduct a prospective study to establish the incidence and risk factors for prostate cancer in a cohort of HIV-positive men aged over 35 years.
At annual health checks the men were monitored for prostate-specific antigen (PSA), and had a digital rectal examination. Data were gathered from medical records on age, ethnicity, duration of HIV infection, CD4 cell count, HIV viral load, and the use of anti-HIV medication.
In total 269 men with a median age of 43.3 years had a digital rectal examination, with 216 men also undergoing PSA testing. Of the men who had PSA tests, seven (3.2%) were found to have elevated PSA values, although none of these men were found to have an abnormal prostate on digital examination.
Prostatitis, inflammation of the prostate, was diagnosed in three individuals, and one patient had a high grade prostatic intraepithelial neoplasia (pre-cancerous cells).
A review of medical records revealed a further five cases of prostate neoplasia in the study population in the preceding two years. Over a third of men in the cohort (four of eleven) aged over 60 years had a diagnosis of prostate cancer. There was no relationship between the occurrence of these cancers and CD4 cell count, the men having a mean CD4 cell count of 509 cells/mm3.
Multivariate analysis revealed that African American ethnicity (p = 0.020), and duration of HIV infection (p = 0.047) were significantly associated with the risk of prostate cancer.
Investigator Dr Nancy Crum told aidsmap.com “the cause of prostate cancer is unknown; we suspect immune dysfunction as a possible cause,” however she pointed out that “many of our cases had near normal CD4 cell counts.” She also postulated that chronic or recurrent inflammation of the prostate may be a causative agent in the development of prostate cancer.
The incidence of prostate cancer in older HIV-positive men in this cohort “was significantly higher than would be expected in the general population,” said Dr Crum.
No relationship was found between the use of HAART and the development of prostate cancer. Although the introduction of HAART has led to a decrease in the incidence (and an improvement in the outcome of) the AIDS-defining cancers Kaposi’s sarcoma and non-Hodgkin’s lymphoma, this has not been the case for certain other cancers, most notably anal cancer.
The San Diego investigators conclude that prostate cancer is common in older HIV-positive men and is associated with the duration of HIV infection. “As the life expectancy of men with HIV infection increases, prostate carcinoma screening will become increasingly important,” they note. However, Dr Crum cautioned, “these are preliminary data; we recommend that further studies be performed to confirm our findings.”
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Crum NF et al. Increased risk of prostate cancer in HIV infection? AIDS 16: 1703-1704, 2002.
Crum NF et al. Prostate carcinoma among men with human immunodeficiency virus infection. Cancer 101: 294-299, 2004.