The effects may last for two to 12 months after the implant and will decrease gradually as the seeds lose their radioactivity. Frequent urination, burning with urination, and urinary urgency occur in 75 percent of men, six weeks to three months after seed implant. These side effects generally last for a few weeks. Dietary changes and bladder medications can control symptoms. Urinary obstruction occurs occasionally, due to an initial swelling of the prostate caused by the seeds.
Obstruction is a higher risk for patients who had obstructive symptoms prior to surgery.
Diarrhea or a change in bowel habits occurs very rarely. Erectile dysfunction , with brachytherapy as the sole treatment, occurs when radiation thickens the walls of blood vessels, limiting the blood supply to the nerves responsible for erections. It is seen in 30-35 percent of men five years after seed implantation. Vascular problems caused by smoking, arteriosclerosis, or diabetes can significantly increase the chances of erectile dysfunction after radiation. It delivers a concentrated dose of radioactivity to the tumor.