Experts Discuss Emerging Treatments and Multidisciplinary Approaches to Prostate Cancer Care

"The development of stereotactic radiosurgery capabilities has opened up new possibilities for the noninvasive treatment of kidney and prostate cancer," said Lee E. Ponsky, MD, director of the Center for Urologic Oncology and Minimally Invasive Therapies at University Hospitals Case Medical Center (Cleveland, OH, USA). "Urologists and surgeons need to be aware of these developments, and work closely with colleagues in radiation oncology to evaluate the role of radiosurgery in the treatment of prostate and kidney cancer."

Dr. Ponsky discussed several preclinical and clinical trials taking place at his institution, looking at the viability of radiosurgery for treating small renal masses (kidney cancer), as well as early stage prostate cancer. "We have now treated about 20 kidney, and over 60 prostate cancer patients. We have reason to be cautiously optimistic. There have been no adverse events among the kidney cancer patients related to treatment. The initial data from the prostate cancer trial look promising. Patients received five treatments, initially on consecutive days; now we spread this out to treat every other day. We're seeing minimal side effects and an encouraging PSA [prostate-specific antigen] response in these early trials," he said.

Constantine A. Mantz, MD, chief medical officer at 21st Century Oncology (Fort Myers, FL, USA) presented on SABR as an emerging treatment for prostate cancer. Dr. Mantz has been conducting phase II trials using Varian's Trilogy machine to deliver SABR treatments for early stage prostate cancer, and has presented on the effectiveness and safety of this approach at international medical meetings.

"We're finding that SABR may enable improved outcomes while maintaining, if not further reducing, the already-low complication rates that we have been seeing with earlier advances like intensity modulation and image-guidance," Dr. Mantz said. "For our SABR treatments, we use imaging and beam-shaping technology in a way that allows us to compress the typical two-month course of radiation therapy down to only five visits over a two-week period."

John Ravera, MD, research director at the Cancer Center of Irvine (CA, USA), discussed the use of hybrid prostate radiation therapy (HPRT), which combines the use of high-dose-rate brachytherapy with image-guided radiotherapy (IGRT), which targets the tumor with high-energy X-rays delivered from outside the body. "HPRT is best managed through a close collaboration between urologists and radiation oncologists," Dr. Ravera said.

Historically, clinicians at the Cancer Center of Irvine had been using permanent seed implants to treat prostate cancer, so they were used to close collaboration with urologists. "Our cancer center is right next to the surgical center," Dr. Ravera said. "We've always collaborated; urologists helped us place the seeds for low-dose-rate brachytherapy. More recently, we worked together to test an interesting procedure for reducing rectal bleeding and diarrhea, which are the most common side effects from radiotherapy for prostate cancer."

Dr. Ravera and his colleagues evaluated a physical spacer for separating the prostate from the rectum during radiotherapy treatment. "We completed an FDA [US Food and Drug Administration]-approved study of ten patients, using a cross-linked hyaluronan gel that we injected between the prostate and rectum. Once injected, the gel would solidify and move the rectum away from the prostate. We didn't need much separation because IGRT is a very precise way of delivering dose. Less than a centimeter of space between the two organs enabled us to reduce the amount of incidental dose reaching the rectum. For these men, we saw a significant decrease in rectal side effects."

"As radiation oncology continues to evolve and technology developments blur the distinction between surgical and nonsurgical interventions, we think that multidisciplinary care will become more and more the norm," said Calvin Huntzinger, MS, senior director, Varian Surgical Sciences. "Varian is committed to helping facilitate this teamwork so that the benefits of noninvasive radiosurgery can be made available to more patients."

Related Links:
Varian Medical Systems
Center for Urologic Oncology and Minimally Invasive Therapies at University Hospitals Case Medical Center
21st Century Oncology