由 Brendon Nafziger
, DOTmed News Associate Editor | August 30, 2013
From the September 2013 issue of HealthCare Business News magazine
Coleman explains, and sometimes up to 10 years.
“It’s one of those very tricky disease processes, and in many cases can take a long time to play out,” Coleman says.
A further difficulty is that if doctors decide to take a “watch and wait” approach with men with intermediate or low-risk disease, they often find that 25 to 35 percent of the men will not have cancer on a repeat biopsy.
However, more data should be coming soon. At Memorial Sloan-Kettering, they’ve run two prospective clinical trials using HIFU as a focal therapy to treat prostate tumors. The studies have been finished, and Coleman says they’re just analyzing the data, and expect to publish results before the end of the year.
But those aren’t the only prostate possibilities. Coleman says Sloan-Kettering will also likely investigate another protocol for HIFU in so-called salvage prostate treatments, a sort of back-up therapy for cancer patients who were not cured by radiation therapy.
Another potential approach to HIFU treatments of prostate cancer is to change the location of the therapy altogether. At his lab in Sunnybrook University in Toronto, Dr. Rajiv Chopra, now an associate professor of radiology at UT Southwestern Medical Center in Dallas, is working on a system to apply HIFU from a new angle.
For HIFU, Chopra says there are two practical choices for treatment in order to reach the prostate: you can insert the transducers through the urethra, or through the rectum. Most prostate HIFU treatments now take place through the rectum, he says. But one problem with this method is time.
“If you had to pick one big challenge in the field, it’s how to speed up the treatment,” he says.
Although it only takes a few seconds to heat the tissue, doctors have to wait for blood to remove the heat and for surrounding tissue to cool down, or they risk cooking the intervening muscle and organs. As a result, treatments can last three or four hours. But with the transurethral approach, it could be faster. Here, the transducer tipped catheters are threaded up the urethra, so the heat can be applied directly to the gland.
“So therapies are 20 minutes, 30 minutes,” Chopra says.
Chopra’s team in Toronto has developed a custom-made, transurethral MR-guided HIFU, which is now working off a Philips MRI and modified Sonalleve software. Previously, the team had been using a GE magnet; the basis for the first human feasibility study published in Radiology last year, but made the switch in 2011.
Chopra says they’re still in the early days, and the study using the new Philips software only began in 2012. So far, only five patients have been treated using the modified Sonalleve software, for a study that will likely be published in 2014. In this study, the prostate will be ablated, but then removed following the procedure to examine histological evidence that the cancers were all destroyed.