Research list


An Effective Interstitial Radiation Therapy with Few Side Effects for Early Prostate Cancer

Prostate cancer is the most common type of cancer in the U.S. (responsible for 20% of adult-male deaths), and is increasing sharply in Japan as well. One third of more than 50-years old men are reported to have latent prostate cancer according to the detailed pathological analysis. One form of therapy for early prostate cancer is brachytherapy, which is still rarely performed in Japan. In Kyushu, it was first started at Kyushu University Hospital in March 2005.

Fifty to a hundred radioactive-source capsules (4.5mm in length, 0.8mm in diameter, made of titanium), called seeds, contain a radioactive material (iodine 125), and are implanted into the prostate through the perineum using a syringe under the monitoring with transrectal ultrasound. This treatment employs a larger radiation dose, is more focused and effective than the traditional external beam radiotherapy. For suitable patients there is no difference in the survival prognosis between this treatment and radical prostatectomy. Hospitalization is also short, and complications, such as pain and urinary incontinence, are rare. It is covered by health insurance, so the patient is only responsible for about 400,000 to 500,000 Yen (to be revised in April). In our hospital, patients often request this treatment. Already 42 patients have received the treatment, and we are fully booked until October, 2006.

According to Professor Seiji Naito (urology), the most suitable candidates for this treatment have all of such conditions that (1) the value of PSA test is 10 ng/ml or less than 10, (2) a Gleason score, which is determined through a pathological examination of a biopsy specimen, is 6 or less than 6, (3) the cancer is limited to the prostate, and (4) the prostate size is 30 cm3 or less than 30 cm3. Unfortunately, for each patient who fails to meet these criteria, another suitable treatment such as external radiotherapy or surgical treatment will be recommended..

The number of hospitals that can perform this treatment is limited because the treatment requires cooperation among the urologist, radiation therapy physician, and anesthesiologist, as well as specialized equipment and a ward for radiotherapy. This treatment has been performed in the U.S. since 1980, and, at present, the number of the patients who undergo this brachytherapy are almost equal to that of patients who undergo radical prostatectomy. Patients who have seeds inside their bodies are able to lead normal lives. The radiation dose is so low that even if you stand beside them, you receive almost no exposure. In terms of exposure, the treatment is safe. In Japan, where regulations governing radiation are strict, it was difficult to perform this treatment, and it was finally approved in 2003.