For men with a small prostate gland (less than 55cc) and an early stage cancer (i.e. low Gleason score of 6 or less and a PSA less than 10) then a seed implant alone may be quite effective.

For patients with more advanced cancer (higher Gleason score or PSA over 10) then a combination of external beam irradiation plus seeds may be a good approach

For patients with low risk cancer but a big gland, shrinking the gland down first with hormone therapy (e.g. Lupron or Zoladex) may be an option and then once the gland is less than 55cc proceeding with a seed implant

what are the seeds?
do I become radioactive?
selecting the patient
how is the procedure done?
what is the proper dose?
results of seeds implants

more about prostate seeds

see the American Brachytherapy Society (ABS) guidelines
see EORTC guidelines, basic seed info
see American College of Surgeons Trial