The utility of proton beam therapy with concurrent chemotherapy for the treatment of esophageal cancers.

Steven H Lin

doi:10.3390/cancers3044090

Abstract

The standard of care for the management of locally advanced esophageal cancers in the United States is chemotherapy combined with radiation, either definitively, or for those who could tolerate surgery, preoperatively before esophagectomy. Although the appropriate radiation dose remains somewhat controversial, the quality of the radiation delivery is critical for the treatment of esophageal cancer since the esophagus is positioned close to vital structures, such as the heart and lung. The volume and relative doses to these normal tissues affect acute and late term complications. Advances in radiation delivery from 2D to 3D conformal radiation therapy, to Intensity Modulated Radiation Therapy (IMRT) or charged particle therapy (carbon ion or proton beam therapy (PBT)), allow incremental improvements in the therapeutic ratio. This could have implications in non-cancer related morbidity for long term survivors. This article reviews the evolution in radiation technologies and the use of PBT with chemotherapy in the management of esophageal cancer.

Highlights

The standard of care for the management of locally advanced esophageal cancers in the United States is chemotherapy combined with radiation, either definitively, or for those who could tolerate surgery, preoperatively before esophagectomy
To determine reproducibility for interfractional variability, daily orthogonal KV imaging to assess setup, and to assess the overall depth of free breathing for the patient throughout the course of the 5 week treatment, as the depth of breathing can change for some patients and can alter the GEJ location, as we have recently reported after analyzing interfraction tumor motion using weekly 4DCT imaging for a group of esophageal cancer patients [31]
Proton beam with concurrent chemotherapy has been utilized at MD Anderson since 2006 as part of a prospective clinical trial assessing normal tissue toxicities in patients treated with protons

Summary

Advances in Radiation Delivery

Since radiation is an important component in the management of stage II-III esophageal cancer in the Western world, the delivery of radiation therapy is an important consideration. In the current era of CT-based planning, better visualization of the normal tissue anatomy is possible during the treatment planning process Using this anatomical information, beams could be arranged so that the radiation dose could better conform around structures while encompassing the treatment target volume. The advantage of IMRT can be seen for cervical esophageal sites In another planning study by Fenkell et al [24], five patients with tumors in the cervical esophageal region were chosen for planning studies comparing 3DCRT with IMRT, with escalating doses at 56, 63, and 70 Gy. The authors found IMRT improved target volume coverage with better conformality as well as decreased dose to adjacent normal structures, such as the brainstem, spinal cord, and the parotids

Further Improving IMRT Delivery to Improve Cardiac Dosimetry

Challenges in the Use of PBT for the Treatment of Esophageal Cancer

The Clinical Experience of PBT for the Treatment of Esophageal Cancer

Proton Beam Treatment Planning for Esophageal Cancers at MD Anderson

Findings

Conclusions