A new 4D software program that combines the “breathing-adapted radiotherapy” (BART) technique will improve the treatment of lung cancer, said Nicolas Peguret, MD, and colleagues from Hôpitaux Universitaires de Genève during a presentation at the second annual European Lung Cancer Conference (ELCC) in Geneva last week.
According to the researchers, BART allows doctors to reduce the amount of radiation administered by timing delivery to a particular moment of the respiratory cycle, as some lesions in lungs may move up to four centimeters when patients inhale and exhale. This presents a challenge for physicians treating the cancer with radiotherapy, they said.
"One of the main problems with BART is how to choose the optimal respiratory phase in which to treat the patient," explained Peguret. “It may vary from one patient to another because of the variation in tumor localization and in movements of the tumor and of other nearby organs."
As a result, Peguret and his colleagues developed a software program that allows doctors to determine a moment during the respiratory cycle that may present an optimal tumor position for the targeting of a lesion. For each patient, a 4D CT scan is performed and a set of CT slices for each of the 10 respiratory phases is recorded. Next, the software will allow the radiation oncologist to determine if there is a respiratory phase that is most effective for radiotherapy, said the researchers.
Peguret noted that the software does not require special equipment and will not result in additional costs for facilities. “It simply provides the doctor with information about the movement of the tumor," he said. “Depending on the oncologist's clinical objectives, he or she will choose the optimal phase for radiotherapy in an individual patient.”
According to the research team, a phase II clinical trial is currently underway, with results expected early in 2011.
"By applying this software together with BART, it may be possible not only to reduce the radiation fields but also to adapt the radiation volume taking into account the varying positions of the tumor and the organs at risk," Perguret concluded.