Side effects and risks
The tissues that line the prostate and rectum are sensitive and vulnerable to cuts, tears, and abrasions. Massaging the prostate too hard can easily cause pain. For example, in the study described above, 8.3% of the participants reported discomfort after prostate massage.
Overly aggressive prostate massage can also cause rectal bleeding, putting you at risk for bacterial infection or worsening hemorrhoids.
Also, manual prostate massage is not recommended for men with acute bacterial prostatitis. Massage increases inflammation and can help spread bacteria to the urethra, other parts of the urinary tract, and the bloodstream.
However, several small studies on the effects of a doctor's prostate massage have shown it to be useful as a therapy for chronic prostatitis in combination with antibiotics.
Prostate and cancer massage
Men with suspected prostate cancer should not receive treatment for (or participate in) prostate massage, as this can cause tumor cells to shed and spread to nearby tissues .
There is some evidence that massaging the prostate before certain tests for prostate cancer can increase the sensitivity of the test, increasing the likelihood that the cancer will be found.
However, a prostate specific antigen (PSA) blood test should not be performed immediately after prostate massage, as this can lead to false positive results.
Even if cancer is not a problem, it is important not to damage the prostate. The thin, flexible membrane that covers the prostate, the prostate plexus, is filled with nerves that act like the corpus spongiosum of the penis.
Massaging the prostate too hard can damage the nerves of the corpora cavernosa, the two chambers of erectile tissue that run throughout the penis. Damage to the corpora cavernosa can cause pain and erectile dysfunction.