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World J Clin Oncol. Dec 10, 2014; 5(5): 921-930
Published online Dec 10, 2014. doi: 10.5306/wjco.v5.i5.921
Image-based brachytherapy for cervical cancer
John A Vargo, Sushil Beriwal
John A Vargo, Sushil Beriwal, Department of Radiation Oncology, Magee Womens Hospital of UPMC, University of Pittsburgh Cancer Institute, Pittsburgh, PA 15213, United States
Author contributions: Vargo JA and Beriwal S both had significant contribution to conception and design, acquisition of data, and interpretation of data; both drafted the article and revised it critically for important intellectual content; both approved the version to be published.
Correspondence to: Sushil Beriwal, MD, Department of Radiation Oncology, Magee Womens Hospital of UPMC, 300 Halket St, University of Pittsburgh Cancer Institute, Pittsburgh, PA 15213, United States. beriwals@upmc.edu
Telephone: +1-412-6414600 Fax: +1-412-6416601
Received: December 12, 2013
Revised: June 23, 2014
Accepted: July 15, 2014
Published online: December 10, 2014
Abstract

Cervical cancer is the third most common cancer in women worldwide; definitive radiation therapy and concurrent chemotherapy is the accepted standard of care for patients with node positive or locally advanced tumors > 4 cm. Brachytherapy is an important part of definitive radiotherapy shown to improve overall survival. While results for two-dimensional X-ray based brachytherapy have been good in terms of local control especially for early stage disease, unexplained toxicities and treatment failures remain. Improvements in brachytherapy planning have more recently paved the way for three-dimensional image-based brachytherapy with volumetric optimization which increases tumor control, reduces toxicity, and helps predict outcomes. Advantages of image-based brachytherapy include: improved tumor coverage (especially for large volume disease), decreased dose to critical organs (especially for small cervix), confirmation of applicator placement, and accounting for sigmoid colon dose. A number of modalities for image-based brachytherapy have emerged including: magnetic resonance imaging (MRI), computed tomography (CT), CT-MRI hybrid, and ultrasound with respective benefits and outcomes data. For practical application of image-based brachytherapy the Groupe Europeen de Curietherapie-European Society for Therapeutic Radiology and Oncology Working Group and American Brachytherapy Society working group guideline serve as invaluable tools, additionally here-in we outline our institutional clinical integration of these guidelines. While the body of literature supporting image-based brachytherapy continues to evolve a number of uncertainties and challenges remain including: applicator reconstruction, increasing resource/cost demands, mobile four-dimensional targets and organs-at-risk, and accurate contouring of “grey zones” to avoid marginal miss. Ongoing studies, including the prospective EMBRACE (an international study of MRI-guided brachytherapy in locally advanced cervical cancer) trial, along with continued improvements in imaging, contouring, quality assurance, physics, and brachytherapy delivery promise to perpetuate the advancement of image-based brachytherapy to optimize outcomes for cervical cancer patients.

Keywords: Cervical cancer, Brachytherapy, Image-based brachytherapy, 3D-planning, Magnetic resonance imaging-based brachytherapy, Groupe Europeen de Curietherapie-European Society for Therapeutic Radiology and Oncology Working Group guidelines

Core tip: Brachytherapy is an integral part of radical pelvic radiation therapy for cervical cancer. While image-based planning has gained wide acceptance in external beam radiotherapy, the integration of image-based planning for brachytherapy has lagged significantly. More recently advances in planning software/hardware have lead to increased use of image-based brachytherapy. Herein, we highlight the clinical advantages of 3D brachytherapy planning for cervical cancer. We present multiple modalities for image-based brachytherapy including outcome data and dose constraints. Finally we outline practical guidelines for contouring target volumes and critical organs; and present future directions in image-based brachytherapy aimed towards improving cervical cancer outcomes.