Researchers from VU University Medical Center in Amsterdam have reported that RapidArc® radiotherapy from Varian Medical Systems (NYSE: VAR) has clinical advantages over earlier fixed-beam approaches to stereotactic treatments of lung tumors. Their findings, based on treatment of 85 medically inoperable lung cancer patients, were reported at the recent annual meeting of the American Society for Radiation Oncology (ASTRO) in Chicago and a condensed version has been published in the 'Green Journal' (Radiotherapy and Oncology) 93 (2009).
"RapidArc enabled much faster treatment for these patients, with treatment in just six minutes, reducing the risk of patient motion and achieving superior dose conformity around the target while reducing dose to the chest wall by almost a third," says Dr. Wilko Verbakel, medical physicist. "Dose conformity is extremely important when you are treating close to critical structures and the conformity you see with RapidArc is always better or at least as good as with fixed-beam IMRT and certainly better than achievable with ten static non-coplanar beams or dynamic conformal arc."
Clinicians at VU deliver stereotactic RapidArc treatments using the Novalis Tx(TM) radiosurgical platform from Varian and BrainLAB. The high dose delivery capability of Novalis Tx combined with the speed of RapidArc enables stereotactic treatments with beam-on time of as little as six and a half minutes, even for the highest doses, which previously took about 30 minutes to deliver.
Hypo-fractionated stereotactic lung treatments at VU are delivered in three sessions of 18 Gy each, five sessions of 11 Gy each or eight sessions of 7.5 Gy each, depending on the size and position of the tumor. Planning, described by Dr. Verbakel as 'very easy' using RapidArc, is based on 4D CT scans and the treatment field allows a small margin to account for tumor motion caused by breathing. Additional recent research by the team at VU has shown that, unlike with some other advanced radiation delivery techniques, treatment of a moving tumor with RapidArc has no negative dosimetric consequences.
RapidArc®, Varian's technology for delivering volumetric modulated arc therapy (VMAT), enables clinicians to deliver a highly-precise image-guided intensity-modulated treatment quickly, often with as little as one or two revolutions of the treatment machine around the patient. This enables treatments that are up to eight times faster than alternative approaches.
Professor Suresh Senan, radiation oncologist at VU, adds, "We are very encouraged by these findings and RapidArc is now our standard technique for all patients with stage 1 lung tumors."
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