Adjuvant therapies found not to confer a significant survival advantage.
A study of men with high-grade prostate cancer treated initially with radical prostatectomy (RP) revealed a median overall survival rate of 140 months, which the lead investigator called “surprisingly good.”
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“The optimal management for high-risk prostate cancer is controversial,” said the investigator, Ryan Terlecki, MD, chief administrative resident in the department of urology at Wayne State University/Karmanos Cancer Institute in Detroit.
“Previously, RP was recommended only in patients who could be cured by surgery alone. Fortunately, due to a stage migration, many more patients with poorly-differentiated disease may be identified at a point when local therapy may
be curative.”
He and his colleagues conducted a 10-year follow-up study of 145 patients treated initially with RP for Gleason 8 or higher tumors. The patients were then divided into four groups based on whether they received any subsequent modalities of therapy.
Thus, the four groups consisted of RP alone, RP plus androgen deprivation therapy (ADT), RP plus radiation, and RP plus radiation and ADT. Patients who had received any form of cancer-directed therapy prior to surgery were excluded from the study. The mean age at surgery was 64 years. Only increasing age and African-American race were significant risk factors for poorer survival.
Adjuvant therapies did not confer a significant improvement in survival, Dr. Terlecki said. In fact, after adjusting for age, race, Gleason sum, and pathologic stage of disease, men who received all three modalities of therapy combined had twice the mortality risk as men who received either surgery alone, surgery with hormonal therapy, or surgery with radiation.
“While it is most likely that the patients receiving all modalities of therapy had biologically more aggressive disease, the fact that this is not explained by baseline characteristics or pathologic stage suggests that discretionary use of additional modes of treatment may be advantageous,”
Dr. Terlecki said.
He also emphasized the importance of using overall survival as the primary study end point rather than biochemical disease-free survival. “Overall survival,” he explained, “is the most critical end point since it has been shown that biochemical progression does not necessarily lead to clinical progression.”
Finally, he said that the findings need to be interpreted with caution given the study’s retrospective design as well as a selection bias with regard to which patients were selected for surgery.
In addition, the results were not stratified by individual surgeons, and surgeons may vary with regard to their patients’ clinical outcomes and their choice of additional therapies.
Overall, surgery provides the most complete staging information and eliminates the bulk of large-volume disease, and thus initial surgery may help doctors select which patients are appropriate for multi-modal regimens and optimize patient outcomes, Dr. Terlecki said.
Advances in systemic therapy have sparked interest in the use of multi-modal therapy to optimize outcomes in men with high-risk prostate cancer, he added.
