With the side effects of current prostate cancer treatments sometimes worse than the disease itself – incontinence and impotence, to name just a couple – several companies are trying to find a cure that either eliminates or significantly reduces these problems.
Profound Medical (PMI; Toronto), a spin-off of Sunnybrook Health Sciences Centre (also Toronto) founded last fall, knew when it decided to develop a device to treat prostate cancer that it would require the kind of visibility only found with MRI. That presented the challenge of designing a device that is completely MRI-compatible, including the motor.
As a solution to that problem, the company partnered with Johnson Medtech (Shelton, Connecticut), the medical products division of Johnson Electric, which makes non-magnetic Nanomotion actuators that are being used to power PMI's MRI-compatible image-guided tumor treatment device.
According to PMI, the device is expected to treat prostate cancer in a fraction of the time and cost of existing methods, based on extensive modeling, simulation and pre-clinical trials.
Johnson Medtech said its Nanomotion actuators enable the precision of motion and accuracy of treatment necessary for safely conducting the image-guided prostate cancer therapy within the strong magnetic field of the MRI.
CTO Michael Bronskill, PhD, and Rajiv Chopra, PhD, chief science officer, initially developed PMI's device at the Sunnybrook center. The company said it is working toward FDA approval for the device.
"When designing our prostate cancer treatment device, we knew that it would require the visibility exclusively available in an MRI environment. However, conventional motors were a roadblock to creating a working proof-of-concept device and bringing this important development to reality – and only Johnson Medtech could provide the solution," Bronskill said. "Johnson Medtech's Nanomotion non-magnetic motors provide the motion necessary to enable our tissue coagulation device to effectively treat prostate cancer patients within the MRI environment, and with a degree of precision that is crucial to success."
Alan Feinstein, president of the Nanomotion division at Johnson Medtech, told Medical Device Daily that the company has been working with Sunnybrook, and now PMI, for about four or five years to develop this prostate cancer device. He said it is one of "numerous" devices that Johnson Medtech has helped with because the device is required to function in the magnetic field of MRI path and the motor and the entire mechanism needs to be nonmagnetic.
PMI's device uses an MRI for imaging and a planar ultrasound applicator for treatment. The MRI guides the probe that heats the cancerous tissue to destroy the diseased area, according to the company.
In the past, the magnetic nature of electric motors and their metal components made it impossible for motorized medical devices to function within the MRI environment. To overcome this challenge, PMI selected Nanomotion's HR2-1-N-3 piezo ultrasonic non-magnetic motors to rotate the device's probe. When combined with the real-time non-invasive visibility into the human body provided by the MRI, the sophisticated low-speed Nanomotion actuators in PMI's device enable medical professionals to operate the probe at a microscopic scale to conduct this procedure, the companies said.
Feinstein said the motor has a non-magnetic metal body as well as some ceramic material and some plastics.
According to PMI, prostate cancer afflicts millions of men around the world, with an estimated 400,000 new cases diagnosed each year. Several prostate cancer treatments are available, including radiation, the company noted. But even the treatments with high success levels leave the patient with enduring and sometimes permanent impotency and incontinence problems in the vast majority of cases.
PMI says its minimally-invasive thermal ablation device powered by Nanomotion's motors treats prostate cancer as well as or better than radiation, and projects to deliver significantly fewer side effects based on pre-clinical research. While some radiation methods often require up to 12 weekly one-hour treatments, PMI's device completes the treatment process in just one visit, and with far greater accuracy for targeting the affected area, the company said.
"Scientists have worked for years to develop a prostate cancer treatment that yields no inconvenient side effects to the patient, but the extreme degree of precision required to target and treat a small area has been limited by human ability and legacy devices," said Jim Dick, senior VP of Johnson Electric and chairman of Nanomotion. "Working together with Profound Medical, Johnson Medtech is proud to be part of the design team that solved the challenges of delivering a device to treat prostate cancer victims more quickly and safely."
Just last year a U.S. task force recommended that men 75 or older should not even be screened for prostate cancer because of evidence of more harm than benefit from carrying out this procedure and providing therapy based on a positive diagnosis (Medical Device Daily, Aug. 6, 2008). These harms are especially important, the task force noted, because some men who are treated for prostate cancer would never have developed symptoms in their lifetime.
PMI says its technology combines the therapeutic benefits of thermal ultrasound with the "unparalleled accuracy, sensitivity, and precision of MRI to allow the most precise treatment of a region or the whole prostate." This accuracy of treatment is critically important, the company says, if the nerve bundles for potency, and the continence of the urethra and rectum are to be spared.
Current management strategies for localized prostate cancer include watchful waiting, radiation therapy, active surveillance (periodic biochemical monitoring with conversion to curative treatment if disease progresses), radical prostatectomy, and brachytherapy (or radioactive seed implantation therapy).
Other companies also are working to provide a treatment for prostate cancer without the side effects of conventional radiation therapy.
Recognizing that movement of the prostate during treatment is one of the major limiting factors of prostate cancer treatment, Accuray (Sunnyvale, California) introduced a device last year, the InTempo adaptive imaging system, to help radiologists overcome the challenge. The imaging device is designed to enhance the CyberKnife robotic radiosurgery system's ability to track and correct for motion of the prostate during treatment. The system is like an artificial intelligence that calculates where the prostate is. The more the device sees the organ moving, the faster the pictures are taken, automatically correcting the robot (MDD, Sept. 24, 2008).