Focal therapy—a minimally invasive cancer treatment approach that targets only the specific area of the body with cancer, rather than the entire organ—provides a good option for people with early-stage cancer or those with cancer in a small part of their body. For people with prostate cancer, focal therapy has been used for more than a decade in small studies and at select institutions such as NYU Langone Health. However, there are no long-term studies that show whether focal therapy is an equivalent cancer treatment to more conventional treatments, such as radical prostatectomy or radiation therapy.
Samir Taneja, MD, a urologic oncologist and leader of the Genito-Urologic Program at NYU Langone’s Perlmutter Cancer Center, is the national co-principal investigator of VAPOR 2, a single-arm clinical trial that is evaluating the use of water vapor ablation as focal therapy for localized favorable intermediate-risk (Gleason Grade Group 2, Gleason score 3+4) prostate cancer.
“Focal therapy is an investigational paradigm in that we know we can localize and destroy tumors, but we as of yet don’t know whether that is equivalent to conventional treatments,” said Dr. Taneja, who is also the James M. Neissa and Janet Riha Neissa Professor of Urologic Oncology in the Department of Urology and professor in the Department of Radiology at NYU Grossman School of Medicine. “There are no long-term comparative studies or long-term survival data for focal therapy approaches. The VAPOR 2 study is one of a few studies that are forthcoming that will not just assess the ability of the energy source to focally destroy the tumor, but also monitor patients over a longer period of time to determine how effective this is as a cancer treatment.”
The VAPOR 2 study uses the Vanquish water vapor ablation device, which consists of a small device that is inserted through the urethra into the prostate. The wand is equipped with a small catheter needle that extends into the targeted treatment area and delivers water vapor to the prostate tissue. When the vapor is delivered to the targeted tissue, the stored thermal energy is released onto the cancerous cells as the vapor is condensing back to its liquid state. This energy transfer causes immediate disruption (ablation) of the cellular membrane, ultimately leading to cell death. Water vapor remains within the natural boundaries of the prostate, minimizing damage to the surrounding structures.
“The Vanquish device is combined with an image-tracking system that enables the urologist to localize the tumor using MRI, direct the needle to that area, and treat the tumor with a margin of normal tissue around it,” said Dr. Taneja, who also co-directs the Smilow Comprehensive Prostate Cancer Center.
Water vapor is currently used by urologists to successfully treat benign prostatic hyperplasia, or enlarged prostate. An earlier study of the Vanquish technology, VAPOR 1, showed that 87 percent of the 15 patients enrolled in that trial did not have Gleason Grade Group 2 or worse disease 6 months after treatment. In addition, no serious adverse effects were reported with the approach, and no device-related toxicities were observed.
VAPOR 2 is designed to treat people with localized intermediate-risk prostate cancer and monitor them for three years. During that time, if recurrence or evidence of clinically significant disease elsewhere in the prostate shows up on a biopsy, the participants can be treated again and re-ablated using Vanquish at least once. The trial’s endpoint is to determine how many of the participants are free of clinically significant cancer at the end of three years.
“From a patient’s perspective, the advantage of water vapor ablation therapy is avoiding side effects associated with surgery or radiation,” Dr. Taneja said. “The early data from VAPOR 1 suggests that the risk of urinary and sexual side effects that we commonly see with surgery and radiation is very minimal with this technology.”