Advances in imaging technology have dramatically improved the ability of physicians and their patients to take a more conservative approach to treating prostate cancer. Because physicians can more accurately biopsy the prostate, many men with tumors that are unlikely to be lethal now opt for “active surveillance” — closely monitoring rather than treating the cancer and thereby avoiding the side effects associated with the two mainstays of prostate cancer treatment, surgery and radiation. Now, a multidisciplinary team headed by UCLA urologist Leonard S. Marks, MD, is pursuing a new frontier in prostate cancer treatment — focal therapy, which uses various approaches to target the cancer in ways that are far less invasive than traditional treatments, resulting in fewer side effects.
What is driving the effort to develop focal therapies for prostate cancer?
The rationale behind focal therapies is to destroy the tumor while leaving the normal tissue alone. This dramatically reduces adverse side effects such as incontinence and erectile dysfunction that are associated with radical prostatectomy (traditional prostate cancer surgery) and radiation. The analogy is the lumpectomy for breast cancer. It used to be that the only approach to surgical treatment of breast cancer was radical mastectomy; then studies showed that when breast-conserving surgery was appropriate, survival was equal. The same has been true for other cancers such as thyroid, colon and lung, for which partial removal can be effective. Now we are beginning to see this approach ramped up for certain prostate cancers.
What is making these therapies possible?
It is the advent of sophisticated MRI. When we were using transrectal ultrasound, we couldn’t actually see the cancer. Instead, we relied on the PSA [prostate-specific antigen] test. When a patient’s PSA was elevated, we would do a biopsy. Even though it was guided by ultrasound to show where the prostate was, since we were not able to see the cancer, if we found something, we were likely to remove or radiate the entire prostate. Within the last decade, for the first time we can see cancer in the prostate gland, put a biopsy needle specifically into that spot, characterize how aggressive it might be and, for low-risk patients who choose active surveillance over treatment, track it through repeat biopsies. This ability to see the cancer also has opened the door to focal therapy approaches to treating it more precisely.
Is this a middle ground between active surveillance and traditional surgery or radiation?
Exactly. Active surveillance is the most rapidly growing management strategy for prostate cancer. Many men with low-risk tumors who would have gotten surgery 10 or 20 years ago now are choosing active surveillance, thanks to our ability to view and follow the cancer to make sure it doesn’t become a threat. But there’s a large group of men who fall into the intermediate-risk category, where the cancer is not immediately life-threatening but is too risky to follow in active surveillance.
What are the focal therapy approaches currently available or under investigation?
The first form of focal therapy for prostate cancer was cryotherapy, which involves removing part of the prostate by freezing it. This technology has been around for a while, but the delivery systems have improved, and we currently offer it through a clinical trial. High-intensity focused ultrasound, or HIFU, uses powerful ultrasonic energy to destroy the tumor. We have been performing HIFU at UCLA since 2010 and have an Food and Drug Administration-approved HIFU device for the noninvasive treatment of prostate cancer, though this treatment is not yet covered by insurance. At UCLA, we are studying laser focal ablation. Using the same technology as for our targeted prostate biopsy to pinpoint the cancer, we insert a laser fiber to deliver energy to heat and destroy the tumor while keeping the surrounding tissue intact. We have a $3.1 million grant from the National Cancer Institute to develop and commercialize this treatment. For the sake of full disclosure, I am the co-founder of a company that is collaborating with UCLA to do so.
Who would be a candidate for focal treatment?
This is for men with intermediate-risk prostate cancer, in which the tumor is confined to one identifiable part of the prostate, and the prostate gland is not too large. It’s important to note that although we think the time is right to move forward with this treatment, because we are still early in its use, every man who gets a focal therapy treatment at UCLA undergoes a follow-up MRI-guided biopsy six months later, just to make sure that we did what we set out to do. Based on our cryotherapy experience, which is the best documented of the focal therapy treatments here, about 80 percent of the men getting those follow-ups have had no cancer in the tissues.
