IMPORTANT TESTOSTERONE TREATMENT WARNING: Who Should Not Enroll in Testosterone Replacement Therapy? Men who have or had prostate cancer or breast cancer should not take testosterone replacement therapy. All men considering testosterone replacement therapy should undergo a thorough prostate cancer screening prior to starting any testosterone therapy with a rectal exam and PSA test. Men who have or have had cardiovascular disease, or are at risk for coronary disease, or have had a history of heart disease may not be candidates for testosterone treatment. Blood testing, thorough physical examination and careful screening by your physician is absolutely essential before considering a testosterone therapy program of any kind.