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World J Gastroenterol. Aug 28, 2016; 22(32): 7311-7321
Published online Aug 28, 2016. doi: 10.3748/wjg.v22.i32.7311
Technical advances in external radiotherapy for hepatocellular carcinoma
Shin-Hyung Park, Jae-Chul Kim, Min Kyu Kang
Shin-Hyung Park, Department of Radiation Oncology, Kyungpook National University Hospital, Daegu 41944, South Korea
Jae-Chul Kim, Min Kyu Kang, Department of Radiation Oncology, Kyungpook National University School of Medicine, Daegu 41944, South Korea
Author contributions: Park SH and Kang MK analyzed the literature and wrote the paper; Kim JC contributed to the critical revision of the manuscript for important intellectual content.
Conflict-of-interest statement: No conflict of interest.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Min Kyu Kang, MD, Assistant Professor, Department of Radiation Oncology, Kyungpook National University Medical Center, 807 Hoguk-ro, Buk-gu, Daegu 41404, South Korea. mkkang@knu.ac.kr
Telephone: +82-53-2002653 Fax: +82-53-2002029
Received: March 29, 2016
Peer-review started: April 2, 2016
First decision: May 30, 2016
Revised: June 21, 2016
Accepted: July 21, 2016
Article in press: July 21, 2016
Published online: August 28, 2016
Abstract

Radiotherapy techniques have substantially improved in the last two decades. After the introduction of 3-dimensional conformal radiotherapy, radiotherapy has been increasingly used for the treatment of hepatocellular carcinoma (HCC). Currently, more advanced techniques, including intensity-modulated radiotherapy (IMRT), stereotactic ablative body radiotherapy (SABR), and charged particle therapy, are used for the treatment of HCC. IMRT can escalate the tumor dose while sparing the normal tissue even though the tumor is large or located near critical organs. SABR can deliver a very high radiation dose to small HCCs in a few fractions, leading to high local control rates of 84%-100%. Various advanced imaging modalities are used for radiotherapy planning and delivery to improve the precision of radiotherapy. These advanced techniques enable the delivery of high dose radiotherapy for early to advanced HCCs without increasing the radiation-induced toxicities. However, as there have been no effective tools for the prediction of the response to radiotherapy or recurrences within or outside the radiation field, future studies should focus on selecting the patients who will benefit from radiotherapy.

Keywords: Hepatocellular carcinoma, Radiotherapy, 3D-conformal radiotherapy, Intensity-modulated radiotherapy, stereotactic ablative body radiotherapy, Charged particle therapy, Image-guided radiotherapy

Core tip: Radiotherapy techniques have greatly improved in the last two decades. After the introduction of 3-dimensional conformal radiotherapy, the use of radiotherapy for hepatocellular carcinoma (HCC) has increased substantially. Currently, more advanced techniques including intensity-modulated radiotherapy, stereotactic ablative body radiotherapy, charged particle therapy, and image-guided radiotherapy are increasingly used for the treatment of HCCs. These techniques facilitate the delivery of higher dose radiotherapy for early to advanced HCCs, while minimizing radiation-induced toxicities. This review will cover the technical aspects of modern radiotherapy techniques along with their clinical applications.