Focused Ultrasound Therapy
Focused ultrasound is a rapidly evolving, noninvasive, therapeutic technology with the potential to improve the quality of life and decrease the cost of care for patients with both primary and metastatic lung tumors. This novel technology focuses beams of ultrasonic energy precisely and accurately on targets in the body with minimal damage to surrounding normal tissue.
How it Works
Where the beams converge, focused ultrasound produces therapeutic effects that could potentially enable lung tumors to be treated without incisions or radiation.
One mechanism is the production of precise ablation (thermal destruction of tissue). This destruction can be done to completely destroy the target or to partially treat it. Partial treatment is believed to stimulate the patient’s immune response, which may have a broader impact.
Challenges in using focused ultrasound to treat lung tumors have been identified. The main obstacles include the movement of the lungs with respiration, the air spaces in the lungs which can disrupt the energy deposition of the ultrasound beams and limitations based on rib coverage of the target. Efforts are underway to address all of these concerns, including the use of one lung filling (OLF), where the patient is ventilated with the non-treatment lung, and the lung to be treated is filled with saline prior to attempting focused ultrasound therapy.
An isolated case was reported at a scientific meeting in which a metastatic tumor located in the anterior portion of the lung was treated with ultrasound-guided focused ultrasound. See the discussion of this case >
Advantages
The primary treatment options for lung tumors, both primary and secondary, currently include different combinations of surgical resection, chemotherapy and radiation therapy. For primary lung cancer, curative treatment requires complete surgical resection of the tumor. However, more than 50% of patients who are diagnosed with lung cancer have inoperable tumors at the time of diagnosis due to the advanced stage of the disease, insufficient lung function, or patient refusal of a complex surgery.
For certain patients, including those whose tumors are non-operable, focused ultrasound could provide a noninvasive treatment option to preserve quality of life.
It could provide a noninvasive alternative to surgery with less risk of complications – such as infections and blood clots – and shorter recovery times. Focused ultrasound’s precise targeting minimizes damage to non-targeted healthy tissue, and there is no risk of radiation-induced fibrosis, which enables multiple repeat treatments if necessary. Focused ultrasound can also be a complement to drug therapy, enabling enhanced delivery of chemotherapy or immunotherapy to tumors, with lower doses of drugs and minimal toxicity. It also may potentially induce an anti-tumor immune response.
Clinical Trials
A clinical trial is recruiting patients with solid tumors with metastatic lesions, including small cell or non-small cell lung cancers, at the University of Virginia.
Preclinical Laboratory Studies
Preclinical studies suggest that focused ultrasound may play a beneficial role in the treatment of lung tumors. Recent feasibility studies have shown that focused ultrasound can be an effective, minimally invasive way to destroy tumors in the lung, with the potential to target only the tumor and minimal risk of damage to the surrounding tissues. Focused ultrasound could provide a more precise alternative to radiofrequency ablation and offers potential side effects that are significantly more tolerable than those of chemotherapy and radiation therapy. More studies are needed to further establish the safety and efficacy of this treatment modality before research can progress to the clinical stages.
Additional Resources
American Cancer Society
National Cancer Institute
American Lung Association
Regulatory Approval and Reimbursement
Focused ultrasound for the treatment of lung tumors is not yet approved by regulatory bodies or covered by medical insurance companies.
Notable Papers
Cao R, Huang Z, Nabi G, Melzer A. Patient-Specific 3-Dimensional Model for High-Intensity Focused Ultrasound Treatment Through the Rib Cage: A Preliminary Study. J Ultrasound Med. 2019 Nov 13. doi: 10.1002/jum.15170.
Wolfram F, Lesser TG. A simulation study of the HIFU ablation process on lung tumours, showing consequences of atypical acoustic properties in flooded lung. Z Med Phys. 2018 Jul 20. doi: 10.1016/j.zemedi.2018.06.002.
Zhang T, Chen L, Zhang S, Xu Y, Fan Y, Zhang L. Effects of high-intensity focused ultrasound on cisplatin-resistant human lung adenocarcinoma in vitro and in vivo. Acta Biochim Biophys Sin (Shanghai). 2017 Dec 1;49(12):1092-1098. doi: 10.1093/abbs/gmx107.
Wolfram F, Dietrich G, Boltze C, Jenderka KV, Lesser TG. Effects of HIFU induced cavitation on flooded lung parenchyma. J Ther Ultrasound. 2017 Aug 7;5:21. doi: 10.1186/s40349-017-0099-6. eCollection 2017.
Wang Z, Qiao R, Tang N, Lu Z, Wang H, Zhang Z, Xue X, Huang Z, Zhang S, Zhang G, Li Y. Active targeting theranostic iron oxide nanoparticles for MRI and magnetic resonance-guided focused ultrasound ablation of lung cancer. Biomaterials. 2017 May;127:25-35. doi: 10.1016/j.biomaterials.2017.02.037. Epub 2017 Mar 1.
Lesser TG, Schubert H, Gullmar D, Reichenbach JR, Wolfram F. One-lung flooding reduces the ipsilateral diaphragm motion during mechanical ventilation. Eur J Med Res. 2016 Mar 8;21:9.
Wolfram F, Reichenbach JR, Lesser TG. An ex vivo human lung model for ultrasound-guided high-intensity focused ultrasound therapy using lung flooding. Ultrasound Med Biol. 2014 Mar;40(3):496-503.
Wolfram F, Boltze C, Schubert H, Bischoff S, Lesser TG. Effect of lung flooding and high-intensity focused ultrasound on lung tumours: an experimental study in an ex vivo human cancer model and simulated in vivo tumours in pigs. Eur J Med Res. 2014 Jan 7;19:1
Click here for additional references from PubMed.
