May 12, 2011
LONDON, May 12, 2011 /PRNewswire/ -- European cancer experts have reported on developments of some promising radiosurgical techniques for treating lung and liver cancer using new linear accelerator technology from Varian Medical Systems (NYSE: VAR). Among the achievements outlined at a packed "Emerging Technologies Symposium" at the annual conference of the European Society for Therapeutic Radiology and Oncology (ESTRO) in London was the ability to treat metastatic liver cancer, an often inoperable condition, with high dose rate radiosurgery by using RapidArc® radiotherapy on Varian's TrueBeam™ platform.
In front of an audience of more than 500 oncology professionals, clinicians from leading cancer centers in Italy, Denmark and the Netherlands gave detailed accounts of pioneering radiotherapy and radiosurgery treatments at their centers. The program was chaired and moderated by Dr. David Landau, consultant clinical oncologist at Guy's and St Thomas' NHS Foundation Trust and honorary senior lecturer at Kings College, London, UK.
Dr. Marta Scorsetti, head of radiation oncology at the Humanitas Clinic in Milan, described an ongoing study involving 43 patients that is aimed at assessing the safety and feasibility of using RapidArc to deliver stereotactic body radiotherapy (SBRT) in the treatment of liver metastases. Results, after seven months, were a local tumor control rate of nearly 94%.
"There is undoubtedly a great need for improved therapies for liver cancers that cannot be treated surgically, especially those larger than 5 centimeters," said Dr. Scorsetti. "Advances in tumor imaging, radiation therapy planning, and motion management have made it possible for high dose radiation therapy to be used safely for treating liver metastases. SBRT offers the possibility of a non-invasive treatment, delivered in few treatment sessions."
Professor Ben Slotman, head of radiation oncology at VU University Medical Center in Amsterdam, presented data from his hospital's lung cancer program. Clinicians there have treated more than 800 stage 1 lung tumor patients in the last eight years. The Center, which receives referrals from more than 70 Dutch hospitals, treats patients on six Varian linear accelerators, including two TrueBeam devices and a Novalis Tx™ machine.
"We recently published the results of a population based study, demonstrating that the introduction of stereotactic body radiotherapy (SBRT) in two Dutch provinces resulted in a sixteen percent increase in the use of radiotherapy with patients above 75 years of age, and that this resulted in improved survival,"(1) says Prof. Slotman.
Since 2008, all lung SBRT treatments at VU have been delivered using Varian's RapidArc technology, many on the TrueBeam system. According to Prof. Slotman, the main benefit of RapidArc for lung patients is the shorter treatment time with less risk of motion than with earlier generations of technology. "This is especially important for SBRT, where high doses are delivered over fewer treatment sessions," he says. "The delivery of the highest dose for lung tumors was reduced from 30 minutes to just six minutes. With the introduction of TrueBeam technology, the integration between imaging and treatment delivery has been improved. By using the High Intensity Mode in the very near future, we expect to reduce the treatment time to less than three minutes."
Professor Cai Grau, head of radiotherapy research at the Department of Oncology, Aarhus University Hospital in Denmark, outlined his center's work in dynamic adaptive radiotherapy techniques for head and neck cancer treatments.
Speed is a critical issue when using images to adapt a treatment over a multi-week course of radiotherapy. "Re-optimizing the treatment plan based on daily 3-D images of the patient's anatomy allows us to reduce risks associated with anatomical changes such as tumor shrinkage over a course of treatment," said Professor Grau.
Doctors at Aarhus University Hospital treat patients on 10 Varian linear accelerators, all of them equipped with the On-Board Imager® device for image-guided radiotherapy, and capable of three-dimensional cone-beam CT imaging. Two TrueBeam systems are currently being installed and are due to start treating clinically in four months.
Designed to advance the treatment of lung, breast, prostate, head and neck, and other types of cancer, Varian's TrueBeam platform for image-guided radiotherapy and radiosurgery was introduced in April 2010 as the first fully-integrated system designed from the ground up to treat a moving target with a high level of speed and accuracy.
Applicable for all forms of advanced external-beam radiotherapy including image-guided radiotherapy and radiosurgery (IGRT and IGRS), intensity-modulated radiotherapy (IMRT), stereotactic body radiotherapy (SBRT) and RapidArc® radiotherapy, TrueBeam can deliver treatments with a dose delivery rate of up to 2400 monitor units per minute, double the maximum output of conventional systems. This makes it possible to offer shorter treatment times for patients, and to improve precision by leaving less time for tumor motion during dose delivery. More than 225 TrueBeam systems have now been ordered by treatment centers around the world, and more than 65 installations are completed or in process.
RapidArc technology quickly delivers a precise image-guided IMRT (intensity modulated radiotherapy) treatment two to eight times faster than conventional IMRT.(2,3) Dose is delivered through a beam-shaping aperture that is continually reshaped to match the shape of the tumor as the treatment machine rotates around the patient. Over 1,600 RapidArc systems have been ordered, with nearly 1,000 of those deployed at treatment centers around the world.
Editorial contact: Neil Madle, Varian Medical Systems, +44 7786 526068
About Varian Medical Systems
Varian Medical Systems, Inc., of Palo Alto, California, is the world's leading manufacturer of medical devices and software for treating cancer and other medical conditions with radiotherapy, radiosurgery, and brachytherapy. The company supplies informatics software for managing comprehensive cancer clinics, radiotherapy centers and medical oncology practices. Varian is a premier supplier of tubes and digital detectors for X-ray imaging in medical, scientific, and industrial applications and also supplies X-ray imaging products for cargo screening and industrial inspection. Varian Medical Systems employs approximately 5,500 people who are located at manufacturing sites in North America, Europe, and China and approximately 70 sales and support offices around the world. For more information, visit http://www.varian.com.
(1) Palma et al., Impact of Introducing Stereotactic Lung Radiotherapy for Elderly Patients With Stage I Non–Small-Cell Lung Cancer: A Population-Based Time-Trend Analysis. J Clin Oncol 28, 5153-5159, 2010.
(2) Mayo et al., Initial Experience with Volumetric IMRT (RapidArc) for Intracranial Stereotactic Radiosurgery. Int J Radiat Oncol Biol Phys 78:5, 1457-1466, Dec 2010.
(3) May Y et al. Hypofractionated stereotactic radiotherapy for brain metastases: a dosimetric and treatment efficiency comparison between volumetric modulated arc therapy and intensity modulated radiotherapy. Technol Cancer Res Treat. 9:5, 499-507, Oct 2010.
SOURCE Varian Medical Systems