International Journal of Radiation Oncology*Biology*Physics
Clinical InvestigationComparison of Measurements of the Uterus and Cervix Obtained by Magnetic Resonance and Transabdominal Ultrasound Imaging to Identify the Brachytherapy Target in Patients With Cervix Cancer
Introduction
Brachytherapy for cervix cancer is essential for controlling local disease by allowing high doses of radiation to be delivered to the residual disease from within the cervix and tumor (1). The success of brachytherapy rests on accurate identification of the uterus, cervix, and residual disease; accurate placement of the intrauterine applicator within the uterine canal; and sparing of surrounding normal tissue (2). Historically, brachytherapy applicators were placed under direct vision, and implant quality was assessed with x-rays. These traditional methods, however, do not enable evaluation of the uterine and cervical anatomy, the residual tumor, or the correct placement of the applicators within the cervical canal (2). Although considered outdated in some parts of the world, traditional methods continue in many countries, particularly in those with a high incidence of cervix cancer (3). The use of soft tissue imaging for cervix brachytherapy is increasing in some advanced economies and well-resourced departments (4). The Groupe Européen de Curiethérapie and European Society for Radiotherapy and Oncology (GEC-ESTRO) have been instrumental in advancing the use of soft tissue imaging with a particular emphasis on the use of MRI (5). MRI has superior anatomy and tumor recognition when used in brachytherapy (6). Unfortunately, MRI is expensive and difficult to access for many clinical centers. It is also not suitable for patients with implanted devices, those with claustrophobia, and those with large body habitus. These drawbacks make it necessary to find alternative imaging modalities that provide information of similar quality to MRI but are more readily accessible and affordable 7, 8. Ultrasound is an inexpensive imaging modality that offers good soft tissue information and is widely available. The aims of this study were to compare measurements of the uterus and cervix obtained with transabdominal ultrasound to those obtained using MRI to determine the level of agreement between the imaging modalities. The purpose was to determine whether transabdominal ultrasound can be substituted for MRI in the application of conformal brachytherapy in cervix cancer.
Section snippets
Methods and Materials
This study was approved by the Divisional Review Panel for Retrospective studies at the Peter MacCallum Cancer Centre and by the Monash University Human Research Ethics Committee (MUHREC).
Results
Data from 198 patients was included in this study. Six patients were excluded because of insufficient data; 4 of these had missing information for 1 or more measurements and 2 were excluded because of data fluctuations caused by large fibroids that were unable to be visualized in the ultrasound field of view. Measurements from the external os to 4 cm along the applicator were available for 192 patients. Measurements around the tip of the applicator were available for 172 of these patients.
Discussion
Improving brachytherapy practices for patients with cervix cancer requires new avenues to make it possible for all treating clinicians to identify the brachytherapy target. This study has shown that ultrasound can be used to delineate the cervix and uterus to determine the target for use in planning conformal brachytherapy treatments for cervix cancer. The greatest potential of incorporating ultrasound into the brachytherapy program is the ability to improve accuracy of applicator placement and
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Cited by (41)
Ultrasound-guided Brachytherapy for Cervix Cancer
2021, Clinical OncologyCitation Excerpt :Another important reason to include ultrasound to guide applicator placement is to avoid abandonment of the brachytherapy procedure. Patients are more likely to experience recurrences and failure when treatment has been abandoned due to inability to deliver brachytherapy because of persistent disease, canal stenosis, uterine pathologies and anatomical variations [9–11]. The use of ultrasound can assist with safe and accurate applicator placement in these difficult circumstances and reduce the likelihood of abandoning the procedure.
Place of modern imaging in brachytherapy planning
2018, Cancer/RadiotherapieIntermediate-term results of trans-abdominal ultrasound (TAUS)-guided brachytherapy in cervical cancer
2018, Gynecologic OncologyCitation Excerpt :The largest study, by Van Dyk et al., reported very promising first results and treatment-related toxicities [12]. A recently published study by Van Dyk et al. measured TAUS versus MRI, and showed the correlations between the two imaging modalities [13]. Our preliminary study reported the successful use of TAUS-guided brachytherapy in 29 patients, with good treatment results while limiting toxicity.
Use of 3D transabdominal ultrasound imaging for treatment planning in cervical cancer brachytherapy: Comparison to magnetic resonance and computed tomography
2017, BrachytherapyCitation Excerpt :Although the addition of 3DTAUS to CT seems to lead to improved treatment plans, the cohort size is too small to draw definitive conclusions. Nonetheless, we believe that our work is in line with previously reported clinical data confirming the clinical usefulness of ultrasound, in particular this state-of-the-art 3D transabdominal technology, for treatment planning in cervical cancer brachytherapy (10, 11). Further investigation is needed to confirm the usefulness of 3DUS in GYN brachytherapy, not only for real-time guidance, but also as an additional imaging modality to supplement MRI and/or CT imaging in an effort to improve volumetric treatment planning.
Conflict of interest: none.