![]() Mapping the positions of brachytherapy "seeds" SURVIVING PROSTATE CANCER WITHOUT SURGERY provides the latest information about high tech tools that are now being used to diagnose and treat patients. |
Reports -- Related Published Articles![]() Comparison of Color-flow Doppler image (left) with conventional gray-scale ultrasound image (right). Special to: Doctors Health Journal Physicians at Memorial Sloan-Kettering Cancer Center in New York first began using brachytherapy to treat prostate cancer in the early 1970’s, but had no way to position the seeds other than making an abdominal incision and exposing the prostate gland. They used needles to insert seeds one-by-one in a blood-filled field, making satisfactory seed distribution difficult. As a result, the implant procedure was not always successful and fell into disrepute. However, the development of transrectal ultrasound imaging in the early 1980’s made it possible for physicians to use real-time imaging to guide seed-bearing needles into the prostate. Ultrasound-guided implants enabled physicians to more easily deposit radioactive seeds throughout the gland. Success rates improved dramatically. In the aforementioned report in Cancer, there is evidence supporting the use of this procedure in intermediate- and high-risk patients. The study included 161 patients with advanced high-risk prostate cancer treated with brachytherapy between 1991 and 1995. Each patient had at least one of the three high-risk features (see Table); 77% had at least two or more high-risk features; and 66% had all three. The median patient age was 67. All patients’ pre-treatment risk factors, except for staging, were independently reviewed by a team of physicians at the University of Washington in Seattle. Clinical staging using DRE was not included because it was subjective rather than objective (although 60% of patients had locally advanced T3 malignancies). Forty-three percent of patients had PSAs greater than 15; 70% had PSAs greater than 10, and 30% had elevated PAPs. Sixty-five percent of patients had Gleason scores greater than 7. Patients were treated with Pd-103 seeds with a minimum brachytherapy dose of 8,000 to 9,000 centigray and supplemental external beam radiation doses of 4,140 to 5,040 centigray. None of the patients in the study received iodine (I-125) implants; the investigators prefer Pd-103 seeds because of their non-migrating concave shape and steep radiation fall-off. Despite the aggressive nature of the cancers in this study group, no local recurrences were documented, even in patients with biochemical failure, all who underwent restaging prostatic biopsies. Ten years later, 79% of patients had PSAs of less than 0.2 ng/ The failure rate is not as significant as it may seem at first glance. Only two of the 20% of patients with rising PSAs following treatment died from their disease; the remainder were considered failures because a very low PSA nadir was chosen to denote cure, and they simply did not meet this strict post-treatment PSA criteria. In fact, many have stable PSAs between 0.3 and 4.0. They are functioning well, believe they are cured, and probably are cured. Finally, with the advent of Intensity Modulated Radiation Therapy (IMRT), coupled with Pd-103 seeds, even fewer side effects are anticipated. Dr. Dattoli is a board-certified radiation oncologist, and a noted author and speaker in this complex field of medicine. He is currently physician-in-chief at the Dattoli Cancer Center & Brachytherapy Research Institute, Sarasota, Florida. High-Risk Features PSA greater than 10 Elevated prostatic acid phosphatase Gleason score between 7 and 10 © Renal & Urology News |
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