Of those found to have prostate cancer, overtreatment is common because most cases of prostate cancer are not expected to cause any symptoms due to low rate of growth of the prostate tumor. Therefore, many will experience the side effects of treatment, such as for every 1000 men screened, 29 will experience erectile dysfunction, 18 will suffer urinary incontinence, 2 will have serious cardiovascular events, one will suffer pulmonary embolus or deep venous thrombosis, and one perioperative death. Since the expected harm relative to risk of death are perceived by patients as minimal, men found to have prostate cancer usually (up to 90% of cases) elect to receive treatment.