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World J Clin Oncol. Oct 10, 2014; 5(4): 568-575
Published online Oct 10, 2014. doi: 10.5306/wjco.v5.i4.568
Proton beam therapy for locally advanced lung cancer: A review
Steven E Schild, William G Rule, Jonathan B Ashman, Sujay A Vora, Sameer Keole, Aman Anand, Wei Liu, Martin Bues
Steven E Schild, William G Rule, Jonathan B Ashman, Sujay A Vora, Sameer Keole, Aman Anand, Wei Liu, Martin Bues, Department of Radiation Oncology, Mayo Clinic Arizona, Scottsdale, AZ 85259, United States
Author contributions: All the authors participated in conceiving this review. Schild SE wrote the draft manuscript and the other authors edited and provided substantive additions to the manuscript; Bues M, Ashman JB and Liu W wrote the physics sections and created the figures.
Supported by Mayo Clinic provided the authors the time to write this manuscript. Conflict of Interest Statement: None of the authors has a conflict of interest regarding this manuscript
Correspondence to: Steven E Schild, MD, Professor, Chair, Department of Radiation Oncology, Mayo Clinic Arizona, 13400 E, Shea Blvd, Scottsdale, AZ 85259, United States. schild.steven@mayo.edu
Telephone: +1-480-3421262 Fax: +1-480-3423972
Received: December 28, 2013
Revised: March 28, 2014
Accepted: April 25, 2014
Published online: October 10, 2014
Abstract

Protons interact with human tissue differently than do photons and these differences can be exploited in an attempt to improve the care of lung cancer patients. This review examines proton beam therapy (PBT) as a component of a combined modality program for locally advanced lung cancers. It was specifically written for the non-radiation oncologist who desires greater understanding of this newer treatment modality. This review describes and compares photon (X-ray) radiotherapy (XRT) to PBT. The physical differences of these beams are described and the clinical literature is reviewed. Protons can be used to create treatment plans delivering significantly lower doses of radiation to the adjacent organs at risk (lungs, esophagus, and bone marrow) than photons. Clinically, PBT combined with chemotherapy has resulted in low rates of toxicity compared to XRT. Early results suggest a possible improvement in survival. The clinical results of proton therapy in lung cancer patients reveal relatively low rates of toxicity and possible survival benefits. One randomized study is being performed and another is planned to clarify the clinical differences in patient outcome for PBT compared to XRT. Along with the development of better systemic therapy, newer forms of radiotherapy such as PBT should positively impact the care of lung cancer patients. This review provides the reader with the current status of this new technology in treating locally advanced lung cancer.

Keywords: Protons, Proton beam therapy, Lung cancer, Photons, X-rays, 3-D radiotherapy, Intensity modulated photon radiotherapy, Intensity modulated radiotherapy, Intensity modulated proton therapy

Core tip: This review was written for the non-radiation oncologist who wishes to understand the use of proton beam therapy (PBT) for locally advanced lung cancer. PBT can be used to create treatment plans delivering significantly lower doses of radiation to the adjacent organs at risk (lungs, heart, esophagus, and bone marrow) than photon (X-ray) radiotherapy (XRT). PBT combined with chemotherapy has resulted in relatively low toxicity and favorable survival. One randomized study is being performed and another is planned to clarify the differences in outcome for PBT compared to XRT. Newer forms of radiotherapy such as PBT should positively impact lung cancer patients.