Lung cancer is the most common cancer worldwide and the leading cause of cancer death in both men and women in the United States. The five-year survival rate is only 18.6 percent, and more than half of people with lung cancer die within one year of diagnosis. These devastating statistics bring to light the gravity of the current lung cancer landscape. Despite continued efforts by physicians and scientists around the world to improve the statistics, lung cancer remains almost impossible to cure and difficult to control with the current treatment modalities of surgical resection, chemotherapy, radiation therapy, and immunotherapy.Complete surgical resection of the primary tumor is currently the only cure for lung cancer, and only in some cases. However, almost 70 percent of cases are deemed inoperable at the time of diagnosis due to advanced stage of the disease. The addition of focused ultrasound as an alternative or complement to current therapies has the potential to improve lung cancer outcomes, especially for those whose tumors are inoperable.
In addition to primary lung cancer, focused ultrasound could potentially treat metastatic lung nodules from other primary cancers, such as colon cancer. Both primary and metastatic lung tumors often present with severe pain, pneumonia, and hemoptysis – coughing up blood. At the 2018 Focused Ultrasound Foundation Symposium, Joan Vidal-Jove, MD, PhD, a surgical oncologist from Barcelona University Hospital, presented the first case report of a patient with a metastatic lung tumor treated with focused ultrasound. This particular case was unique, as the tumor was located in the lung periphery, making it more readily accessible to the focused ultrasound beam, while avoiding air in the beam path.
As recently as five years ago, the prevailing belief was that focused ultrasound could never be applied to human, in vivo lung tissue due to its unique anatomy and structure. Any air, including the air within the alveoli – small air spaces within the lung where gas exchange occurs – distorts and reflects ultrasound energy, making it impossible to focus the beams in a single, precise area. Additional challenges to treating lung tumors are caused by the overlying ribs, which do not allow ultrasound beams to pass through, and motion due to breathing. However, a novel approach called one lung flooding may now allow focused ultrasound access to lung tumors.
One lung flooding involves filling one lung with saline in order to “wash out” all of the air within that lung. The fluid allows focused ultrasound to reach the target efficiently and safely. General anesthesia is employed during this process, and the non-treated lung is mechanically ventilated. One lung flooding has been shown to be safe and effective at creating an air-free lung environment in which focused ultrasound can be successfully applied in preclinical models.
The advent of this technique has created much hope for focused ultrasound in an area where there used to be none. Frank Wolfram, PhD, a medical physicist in Germany, was the primary investigator for these groundbreaking lung flooding studies. In a recent trip to the Foundation, he shared this work and his vision for future clinical trials involving focused ultrasound for primary and metastatic lung cancers.Although research is in the preclinical stage, the fact that progress is being made and we are closer than ever to a human clinical trial is promising, given the initial impression that it was near impossible to treat lung tissue with focused ultrasound. There are scientists and clinicians around the globe who are excited about the potential impact that focused ultrasound could have on lung tumor treatments and improving the quality of life and survival for those with both primary and metastatic lung tumors. It is the Foundation’s mission to safely expedite this process in order to touch the lives of patients as soon as possible.
Lauren Powlovich, MD, is the Science Associate and Medical Writer at the Focused Ultrasound Foundation.