Defining Success: In defining what it means to be free of prostate cancer, or "disease-free", medical researchers consider PSA level to be most important. When considering radiation treatment, (seeds or external beam), physicians use "biochemical progression-free survival" (BPFS) as the definition of success. In keeping with the recommendations of the American Society of Therapeutic Radiation Oncology, progression is generally defined as three consecutive increases in the PSA level following treatment. With radiation, the goal is not the reduction of PSA to a certain absolute level. Instead, radiation treatment is successful if the PSA falls to any given level and remains essentially constant at that level. For example, if a man’s PSA drops from 8.0 to 2.0 following an implant and remains at 2.0, he is considered a success, or "disease-free". If another man’s PSA level falls from 7.0 to 0.5 and remains constant, he is also considered a success. With radiation treatment, patients who maintain low and stable PSA levels for several years are found to be cured of cancer.

     In contrast, it should be noted that physicians consider surgery to be successful when the PSA level drops to 0.0 following treatment. This is a reasonable expectation since, with early stage disease, all of the cancer should be removed along with the prostate. With radiation, however, cancer cells are not killed immediately. Instead, radiation destroys the mechanisms that allow tumor cells grow and multiply with the effect that the cells weaken and die over time. This is why, following an implant (or external beam radiation), a man will find that his PSA level falls gradually, taking anywhere between 1 and 4 years to reach its lowest point. In addition, many normal prostate cells will remain viable after radiation and normal cells will produce some PSA. Therefore, the presence of some PSA in the blood following radiation treatment should not be a cause for alarm. Again, this outcome is to be expected given the way that radiation works on the structure of tumor cells and the fact that the remaining normal prostate cells will produce PSA as they do in a non-cancerous prostate.

     The distinction between the way in which success is defined for surgery and for radiation is important to keep in mind when considering these treatment alternatives. It can help to avoid some of confusion and uncertainty that men and their families can experience when faced with the often bewildering array of facts and opinions regarding the proper choice of treatment.

     What the Data Show: Since performing the first ultrasound-guided seed implants in the U.S. in the mid-1980’s, the physicians at the Seattle Prostate Institute have carried out more than 5,000 of these procedures and have patients who have been followed for more than 10 years. As can be seen in the figures below, the results of our research give us confidence that seed implants are capable of curing prostate cancer in the long run and that their effectiveness appears to be equal to that of other forms of treatment.