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Posted: Sep 04, 2015
In the November 2014 issue of Prostate Forum, we feature conversations with: Dr. Fritz Schroder of Erasmus University about his European prostate cancer screening and Avodart After Radical Therapy for Prostate Cancer Study (ARTS) trials; and Dr. Fabio Almeida of Southwest PET/CT Institute about a new clinical trial he’s conducting on Zytiga versus Zytiga + Xofigo in men with asymptomatic bone metastases who have progressed on initial hormonal therapy.
Here’s Dr. Snuffy Myers’s introduction to the issue. If you’d like to read the conversations with Dr. Schroder and Dr. Almeida, download the issue. Or better yet, subscribe! That way you won’t miss any of the informative interviews we have lined up for the next year.
IN THIS ISSUE
by Dr. Charles Snuffy Myers
In this issue, we have the privilege of interviewing one of the major figures in urology, Dr. Fritz Schroder. As you will see, he has had a very long and diverse career. His contributions range from the establishment of human prostate cancer models for laboratory use to the organization and conduct of key randomized controlled trials.
Schroder’s interview provides a number of important insights. The conversation focuses on the European prostate cancer screening trial with which he was involved. As I have outlined in earlier newsletters, this screening trial is the screening trial that has had the greatest influence on my own thinking. I was very impressed by the years that it took to get from the initial idea for a trial like this to the publication of results mature enough to guide decision-making. As Dr. Schroeder outlines, the trial idea was triggered by a presentation by Dr. William Catalona in 1990—a full 24 years ago. Preliminary trials were started 20 years ago. This illustrates one of the major problems we face in obtaining definitive results in cancers that grow as slowly as prostate cancer. The conversation also reveals the complexity involved in multi-institutional and multi-national studies. Because of the trial’s multi-institutional and multi-national design, we can derive interesting insights into how the details of screening in various countries appear to have a large impact on the benefit from screening. In Finland, there was no benefit to screening, while in Sweden and in the Netherlands there seems to be a major benefit. The analysis of these differences, which are still ongoing, will be very useful.
Dr. Schroeder’s assessment of the utility of screening was also interesting. I think most of us agree that over-diagnosis is a problem, largely because it leads to over-treatment. I think it is also important to note that he thinks improved diagnostic tools like MRI have the potential to reduce the over-diagnosis and over-treatment problem. In this, he agrees with the opinion expressed by Dr. Laurence Klotz in his interview on active surveillance (see Prostate Forum Volume 15 # 10) and Dr. Jelle Barantz in his interview on the Combidex scan (see Prostate Forum Volume 15 Number 11). Both Drs. Klotz and Schroder are participating in a randomized trial testing MRI’s use in this aspect.
At AIDP, I have certainly been impressed at the difference prostate MRI has made in the evaluation of individual patients. However, I have also been impressed by the fact that prostate MRI is difficult to do well at the community level because of the training that radiologists must undergo. The hardware and software MRI requires are also quite expensive. As a result, a hospital can only afford to get involved with MRI if they can be assured of a constant source of patients. In the United States, I suspect in the end this will mean that MRI will only be available in fairly large tertiary referral hospitals or specialized radiology centers.
I think the major reason for over-diagnosis and over-treatment in the United States is the one that Dr. Schroder mentions-the economics of medicine in this country. There is a strong financial incentive for community urologists and radiation therapists to treat prostate cancer rather than do watchful waiting or active surveillance. For this reason, I was very pleased to note that the American Urologic Association made active surveillance such a major focus at their annual meeting.
However, at the community level, I still encounter surgeons and radiation oncologists who tell men with small Gleason 6 cancers that they need to be treated right away or it will be too late. One potential solution is for Medicare and the private insurance companies to refuse to pay these doctors when they treat cancers like this. It would seem relatively straightforward to require certain pathologic findings or imaging results before Medicare approves payment.
The second part of Dr. Schroder’s conversation focuses on the ARTS trial, which randomized men with PSA-only recurrent prostate cancer to either observation or Avodart. As these patients are a major part of my practice, this trial has had a major impact on how we man- age patients. ARTS showed that Avodart slows prostate cancer progression. In fact, the odds that a patient would need hormonal therapy were reduced by more than 50%. The ARTS trial also documented that Avodart has very few mild side effects. There was some increase in breast symptoms on Avodart, but this was balanced by better sexual function in the men on Avodart.
Earlier trials that tested the ability of Proscar or Avodart to prevent prostate cancer reported an increased detection of aggressive prostate cancer. As a result, the FDA required both drugs to carry a warning about this risk.
As Dr. Schroder states, subsequent analysis convincingly showed these findings were artifacts. Additionally, when Avodart was tested in the active surveillance setting, there was no evidence of an increased risk of aggressive prostate cancer. These findings were reviewed in the conversation with Dr. Fleshner we published last year (see Prostate Forum Volume 15 Number 6), the lead investigator on that trial.
Finally, the ARTS trial failed to show any evidence of increase in cancer aggression in its Avodart arm. At this point, I think it is clear that Avodart does not increase the aggressiveness of prostate cancer and that the drug should no longer be required to carry an FDA- mandated warning of this risk. It is a testament to serious problems at the FDA that this warning has not been removed.
The final portion of this issue of Prostate Forum announces an important new clinical trial that Dr. Fabio Almeida is conducting. Dr. Almeida’s trial takes men with asymptomatic bone metastases who have progressed on initial hormonal therapy and randomizes them to Zytiga versus Zytiga + Xofigo. I have been very impressed with the impact of Xofigo in men with low volume bone metastatic prostate cancer. We have had several patients enter complete remission with disappearance of all bone lesions after a 6-month course of Xofigo. For most patients, the side effects are very mild. I regard Xofigo as a major addition to our set of tools to treat this disease. Bayer, the company that markets Xofigo, told AIDP that I had referred more patients for Xofigo than any other oncologist in the United States. That is an indication of my enthusiasm for the agent.
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