By Amar U. Kishan, MD
Per the NCCN guidelines, the treatment options for High-Risk prostate cancer are surgery, beam radiation, or a combination of beam radiation plus radioactive seeds. Hormonal therapy (with Lupron for example) is usually given along with the radiation for two to three years. But patients certainly wonder if one of these three treatment options is better than the other two. A study published recently in the October 2016 issue New England Journal of Medicine compared surgery and beam radiation prospectively in men with mostly Low-Risk prostate cancer. It showed equivalent survival rates. A prospective study for High-Risk prostate cancer, however, is unavailable. Only retrospective studies are available.
THE BEST COMPARATIVE STUDY FOR HIGH-RISK PROSTATE CANCER
I recently authored a study that compares surgery versus beam radiation, versus beam radiation plus radioactive seeds, in men with High-Risk prostate cancer. Specifically, only men who had Gleason 9 or 10 were included. This was a multi-institutional retrospective study. Our study, published in July 2016, in European Urology, compared three groups of men: 230 men treated with beam radiation, versus 87 men who had beam radiation plus seed radiation, versus 170 men who had surgery. The largest study previously published evaluating men with Gleason 9 or 10 only included 363 total patients (and did not focus on comparing treatments), making our study the largest of its kind to date.
VARIATIONS BETWEEN THE THREE GROUPS
The patients in our study who had surgery had a substantially more favorable clinical status compared to the other two groups: They were younger (median age of 62, versus 70), had lower PSA levels, and their disease stage was lower. It should also be noted that about half of the men initially treated with surgery subsequently underwent treatment with radiation as well. As for the two groups that underwent radiation, the duration of hormonal treatment administered to the men who had radiation plus seeds was shorter (12 months) compared to the men who had radiation alone (24 months).
WHAT DID WE FIND?
The estimated 10-year cure rate (PSA levels that continued stable at a low level) was 16% for surgery, versus 60% for beam radiation, versus 70% for radiation plus seeds. There was a trend towards better survival from cancer in the men who had radiation plus seeds. Survival was 88% with radiation plus seeds, 78% with radiation, and 80% with surgery. Patients treated with seeds had significantly fewer metastases compared to the other two groups (rates of 10% versus 39% and 33%, respectively).
SUMMARY AND FUTURE DIRECTIONS
Short to medium duration hormonal therapy with seeds, therefore, appears to offer the greatest chance of preventing metastases when compared with either RP or dose-escalated radiotherapy combined with longer duration hormonal therapy. These results are interesting, but should be interpreted realizing that our study was not a randomized trial. It is possible that factors outside our control may have influenced the results. Nevertheless, it is encouraging to note that even for this very aggressive type of prostate cancer, the 10-year survival rate from prostate cancer is over 80%. So, patients with Gleason score 9 to 10 disease should certainly pursue aggressive curative treatment. Further studies are in process. Our group has now gathered data from 10 institutions across the country to replicate this study on a larger scale. The final analysis is not complete, but preliminary analysis appears to show once again that seed implantation results in better survival than either beam radiation or surgery. ▲
Amar U. Kishan, MD, is an Assistant Professor-in-Residence at the University of California, Los Angeles, where he practices radiation oncology. He has specific clinical and research expertise in treating prostate cancer and other genitourinary malignancies, and is actively involved in trials investigating the role of novel radiation oncology techniques in the treatment of high-risk prostate cancer. When faced with high-risk disease, the optimal approach is pursuing a curative treatment like surgery or radiation. This article examines a study comparing cure rates between these two options. Dr. Kishan authored the largest study comparing these two options. In this article, he shares the results.