Focal therapy and one possible future for prostate cancer research
Posted Feb 24 2010 12:00am
Historically, the treatment of localized prostate cancer has fallen into one of two general categories: (a) kill or surgically remove all of the prostate (and prostate cancer) cells in the patient or (b) monitor the patient until he needs hormone therapy (with the hope that he never does).
Most of the research into the treatment of early-stage prostate cancer until very recently has been concentrated on the nuances of the two options outlined above: how to do the surgery; how much radiation, and of which type; how to monitor patients instead of treating them; etc. Then, in about 2005, people started to explore the possibilities of “focal therapy” as a method to treat localized prostate cancer first using cryotherapy, then using brachytherapy, high-intensity focused ultrasound, and photodynamic therapy.
Ahmed and Emberton have now published an article outlining the need for an international research strategy which could be used to evaluate focal therapy over time; which should be “pragmatic” in nature and include the use of focal therapies in a broad spectrum of patient types; and which should include a focus on landmark diagnostic studies incorporating imaging techniques and biomarkers in addition to studies directed at the biology of prostate cancer over time.
The theoretical opportunity offered by focal therapy is that it offers “a middle ground” between current models of active surveillance and radical forms of treatment because the idea is that one treats only the cancer, with a margin, and preserves as much normal prostate as is practical. It is certainly true that early studies have shown an absence of rectal toxicity and preservation of genitourinary function in a very high proportion of patients. However, to date, there are still issues around identifying specific areas of cancer in what is commonly a multifocal disease. “Hemiablative” techniques, in which one lobe of the prostate is frozen or treated in some other way, have, to date, not uncommonly been associated with biochemical disease recurrence, when cancer left (unidentified) in the untreated lobe of the prostate continues to grow.
The “New” Prostate Cancer InfoLink believes there is significant merit to the concept proposed by Ahmed and Emberton, in which an international working group collaborates to build and execute a well-planned research strategy over time as opposed to having multiple centers competing with each other. Such a strategy would accelerate enrollment into well-coordinated clinical trials and would avoid the historic situation in which competing trials were initiated at the same time.