"Cutting" your risk of prostate cancer
A PSA test can lead to a hunt for prostate cancer cells. That use of the PSA test, which measures elevated levels of a protein produced in the prostate, is under fire, however. (Mohini Lutchman and Michael Freeman)
The good news, we're told, is that there are many things we can do - or not do - in our adult lives to lower our risk of developing different types of cancer. Want to avoid lung cancer? Don't smoke. Want to lower your risk of skin cancer? Stay out of the sun, or utilize a proper sunscreen.
But a new study published Monday in Cancer suggests that at least one decision our parents make FOR us may have an impact on our predisposition to certain types of cancer.
Researchers at the University of Washington School of Medicine looked at the association between circumcision and the prevalence of prostate cancer. They concluded that circumcision before first sexual intercourse is associated with a 15% reduction in the relative risk of developing prostate cancer.
It's important to note, right off the bat, that this study is not purporting to establish a cause and effect relationship. As is often the case, there are many additional factors at play.
First, a bit of background. It has long been established that men who are uncircumcised are more prone to contracting sexually transmitted infections. As the study's authors point out, "The mechanism(s) by which circumcision reduced acquisition of an STI [sexually transmitted infection] is thought to be related to the microenvironment of the thin, lightly keratinized mucosal lining of the inner foreskin."
This tissue is subject to small tears that allow potential access of pathogens into the bloodstream. Furthermore, "The moist environment under the preputial skin may help pathogens survive for extended periods prior to direct infection." Circumcision, of course, removes this protective environment.
Why is this important? Infections are reported to cause almost 20% of cancers worldwide, either directly by infection, or indirectly via inflammation. Several STIs - such as gonorrhea, Chlamydia, HPV & HIV - have been found in the prostate.
Participants in the study were asked about their family's medical history, which may increase a man's risk of developing prostate cancer, and their PSA screening history, which can lead to overdiagnosis of the condition. Men were also asked to self-report their circumcision status, number of sexual partners, and their history of STIs.
Circumcision was reported in 68.8% of the cases and 71.5% of the controls. Caucasian men more commonly reported circumcision (69%) than African American men (43%). For 91% who reported circumcision, the procedure was performed shortly after birth.
A few potential caveats to note include the reliance on self-reporting when it comes to a man's history of STIs, as well as his sexual partners. A cursory review of the data suggests, for example, that the number of male sexual partners is greatly underreported. Male-to-male sexual activity has been shown to lead to an increased rate in STIs, including HIV.
This gives pause to make one wonder what other facts were underreported, though the numbers of circumcised vs. not circumcised do fall in line with national survey results.
The bottom line from the American Cancer Society: While this is an interesting finding, it's not likely to spur any change in recommendations or medical practice.
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