LOS ANGELES--"Prostate cancer is a disease of options," Douglas Keyser, MD, said at the American Society for Therapeutic Radiology and Oncology (ASTRO) meeting. And individual treatment decisions are difficult to make because of the lack of randomized studies and head-to-head comparisons between radiation therapy and surgery.
Now, new data from the Departments of Radiation Oncology and Urology, at the Cleveland Clinic Foundation, show that in early prostate cancer, results with radiation therapy and surgery are nearly identical, Dr. Keyser said at a scientific session on genitourinary cancer.
The investigators reviewed charts from 1,467 consecutive prostate cancer patients treated between 1987 and 1996 at the Cleveland Clinic, looking for those with early prostate cancer (pretreatment PSAs of 10 ng/mL or less and clinical stage T1 or T2 disease) who had received either radiation therapy or surgery with no adjuvant or neoadjuvant therapy.
Of the resulting 607 patients, 253 had been treated with radiation therapy and 354 with radical prostatectomy (one third of whom had positive surgical margins). "The radiation patients were significantly older, but overall the pretreatment characteristics of the two groups were very similar," Dr. Keyser said.
The study endpoint was biochemical relapse-free survival, which was defined as a rise in PSA above 0.2 after prostatectomy, and a rise of greater than 1.0 from the nadir after radiation therapy. The data were also analyzed using a newer definition of biochemical failure--three consecutive rising PSA levels above the nadir.
"Overall biochemical relapse-free survival was very good for the entire group (75% at 5 years) as we would expect for these patients," Dr. Keyser said. And the 5-year results were the same for radiotherapy (75%) and prostatectomy (76%). These results did not vary in the reanalysis based on the newer definition of biochemical failure.
An analysis of outcome based on pretreatment factors showed that patients with Gleason scores of 7 or greater "seemed to fare better with radiation therapy, perhaps due to the higher margin-positive rate in these patients," he noted.