Editorial
Copyright ©The Author(s) 2015. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Clin Oncol. Dec 10, 2015; 6(6): 189-193
Published online Dec 10, 2015. doi: 10.5306/wjco.v6.i6.189
Current role of spacers for prostate cancer radiotherapy
Michael Pinkawa
Michael Pinkawa, Department of Radiation Oncology, RWTH Aachen University, 52057 Aachen, Germany
Author contributions: Pinkawa M solely contributed to this paper.
Conflict-of-interest statement: No conflict of interest is declared by any of the authors.
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: Michael Pinkawa, MD, Professor, Department of Radiation Oncology, RWTH Aachen University, Pauwelsstrasse 30, 52057 Aachen, Germany. mpinkawa@ukaachen.de
Telephone: +49-241-8035314 Fax: +49-241-8082543
Received: May 28, 2015
Peer-review started: May 31, 2015
First decision: August 7, 2015
Revised: August 12, 2015
Accepted: August 30, 2015
Article in press: August 31, 2015
Published online: December 10, 2015
Processing time: 195 Days and 3.1 Hours
Abstract

Radiotherapy is an established curative treatment method for prostate cancer. Optimal tumor control rates can only be achieved with high local doses, associated with a considerable risk of rectal toxicity. Apart from already widely adapted technical advances, as intensity-modulated radiation therapy, the application of spacers placed between the prostate and rectum has been increasingly used in the last years. Biodegradable spacers, including hydrogel, hyaluronic acid, collagen or an implantable balloon, can be injected or inserted in a short procedure under transrectal ultrasound guidance via a transperineal approach. A distance of about 1.0-1.5 cm is usually achieved between the rectum and prostate, excluding the rectal wall from the high isodoses. Several studies have shown well tolerated injection procedures and treatments. Apart from considerable reduction of rectal irradiation, a prospective randomized trial demonstrated a reduction of rectal toxicity after hydrogel injection in men undergoing prostate image-guided intensity-modulated radiation therapy. The results are encouraging for continuing evaluation in dose escalation, hypofractionation, stereotactic radiotherapy or re-irradiation trials in the future.

Keywords: External-beam radiotherapy, Intensity-modulated radiotherapy, Brachytherapy, Spacer, Hydrogel, Biodegradable balloon, Hyaluronic acid, Collagen, Prostate cancer, Toxicity

Core tip: Radiotherapy is widely used for the treatment of prostate cancer. Technical advances allow improved tumor control with increasing prescription doses, but rectal wall is known to be a dose-limiting organ. A new method that has been increasingly used in the last years is the application of a biodegradable spacer to increase the distance between the prostate and rectal wall. Clinical studies, including a prospective randomized trial, have reported considerable dosimetric advantages for the rectum, well tolerated insertion procedures and radiotherapy treatments.