March 11, 2011 - The prospect of increasing radiation therapy treatment speed using dynamic, arc-based radiation therapy is capturing the imagination of Indian clinicians, if Vivek Mehta’s recent experience is any indication. Mehta, M.D., a radiation oncologist at Seattle’s Swedish Cancer Institute (SCI), gave three lectures on Elekta volumetric modulated arc therapy (VMAT) at the National Annual Conference of the Association of Radiation Oncologists of India (AROICON), which drew capacity attendance and provoked vibrant discussion among participants.
“VMAT is an emerging technique that is coming to India,” said Mehta, director, Center for Advanced Targeted Radiation Therapies. “Due to Swedish’s leadership in implementing VMAT, it was appealing to the AROICON committee to have us talk about it to their members.”
Mehta presented results from SCI’s first 100 patients treated with Elekta VMAT. One presentation was on nonstereotactic VMAT, one covered high-dose, hypofractionated VMAT using a stereotactic body radiotherapy (SBRT) technique for lung tumors, and a third discussed general VMAT use. Many attendees were as interested in how VMAT compared with intensity-modulated radiotherapy (IMRT) on efficiencies of treatment speed.
"Clinicians asked whether VMAT is better than IMRT, in which clinical cases IMRT might be superior and what planning challenges VMAT may present," he said. “What made our presentation interesting was the actual proof from our center. For the first 100 patients treated, we ran a comparison IMRT plan. We could show how we did on conformality, speed and QA, and how many times we ended up using one, two or three arcs and how long each plan took to deliver based on the number of arcs.”
Mehta stressed that the first 100 VMAT patients actually represented the first 100 patients considered for VMAT, who also were candidates for IMRT. Both VMAT and IMRT plans were developed for these patients and the patient received either, based on the superiority of the plan as assessed by the physician.
“Out of those first 100 cases we looked at, 95 patients went on to receive VMAT,” Mehta notes. “The audiences were interested in the reasons why five percent of the patients had IMRT, and we were able to give them various reasons, such as the IMRT plan in a particular case gave a steeper dose fall-off near an organ-at-risk. The ‘take-home’ message was VMAT can replace the bulk of your IMRT and is efficient, but it doesn’t completely replace IMRT, which is okay because you still have IMRT.”
Another interest among Indian clinicians is related to resources.
“Ninety-five percent of patients in India pay for cancer treatment, so improving efficiency — treating more patients during a given day — enhances the clinic’s financial stability,” he said. “A technique such as VMAT SBRT is an enabler for them to treat these patients in a time-efficient manner without the capital outlay of a new machine.”
For more information: www.elekta.com.