COMMENTARY

HIFU for Prostate Cancer an 'Experimental Therapy'

Gerald Chodak, MD

Disclosures

June 11, 2014

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Hello. I am Dr. Gerald Chodak for Medscape. Over the past several years I have commented on the concept of focal therapy for prostate cancer treatment. I want to revisit this concept because of an article by Dr. Giannarini and colleagues[1] in the Journal of Clinical Oncology.

These authors describe several problems associated with the current status of this therapy, starting with the idea of identifying the index lesion. Is it the largest tumor or is it the one with the highest grade? Answers to both questions are unclear. The authors cite evidence showing that neither the largest nor the highest-grade tumor was indeed the one associated with metastatic prostate cancer.

You say, "Well, even if we can't identify the exact lesion, we can still treat half the gland." But as this article points out, studies show that 84% of the time, patients have bilateral disease.[1] Therefore, treating half the prostate will not solve the problem either. Moreover, even if you can identify and remove the index lesion, the long-term impact of doing that is completely unknown.

Do the other tumors play any role in the ultimate outcomes? If you look at case series, patients may do well, but that is not because the focal therapy was effective, but rather because the patients had a cancer that was not worth treating in the first place. Another problem is that some patients have tumors that cannot be reached, either with extensive anterior disease or apical lesions.

An Alternative to Active Surveillance?

What about the idea that focal treatment is useful psychologically in patients who cannot cope with active surveillance? Is it really ethical to offer a patient a treatment, even with low morbidity, just because he is having trouble dealing with the concept of conservative therapy? I do not believe that that is a justifiable or ethical argument. Furthermore, the morbidity is not zero. Focal therapy can cause strictures, erectile dysfunction, and other problems. Focal therapy is not completely free of morbidity.

Finally, if you provide treatment, how will you monitor it? Can you use prostate-specific antigen levels? Probably not. What about using an imaging modality? Will it be exact enough? That is completely unclear.

If you do repeat biopsies, it is unclear whether you can avoid the sampling error. In the end, you may have to tell the patient, "Now that you have had this treatment, we will simply have to watch and wait," which is exactly what they were trying to avoid in the first place.

Interesting Concept, but Justifiable?

In the end, we are left with an interesting concept and a treatment that is applicable for some other cancers. Completely unclear, however, is whether focal treatment will ever be viable for low-risk prostate cancer. Could you treat intermediate-risk cancers in this way? Perhaps. But you may end up with treatment failures, and in that case, was it a justifiable therapy? Probably not.

The only way we will ever know whether this therapy has merit is to conduct a randomized trial. Case series simply do not allow us to evaluate the safety and efficacy of focal treatment because many patients may have a cancer that simply is not life-threatening. To use focal therapy and report that patients did well in the long term is really not evidence that this is a justifiable treatment.

In my opinion, only IRB-approved protocols should be used to treat patients. Men certainly should not be charged for this experimental therapy, and really, without a randomized trial, we will never know whether focal therapy works in the long term.

I look forward to your comments. Thank you.

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