Decrease in uterine perforations with ultrasound image-guided applicator insertion in intracavitary brachytherapy for cervical cancer: A systematic review and meta-analysis

Integration of Ultrasound in Image-Guided Adaptive Brachytherapy in Cancer of the Uterine Cervix

Cervical cancer continues to be a public health concern, as it remains the second most common cancer despite screening programs. It is the third most common cause of cancer-related death for women, and the majority of cases happen in developing nations. The standard treatment for locally advanced cervical cancer involves the use of external beam radiation therapy, along with concurrent chemotherapy, followed by an image-guided adaptive brachytherapy (IGABT) boost. The five-year relative survival rate for European women diagnosed with cervical cancer was 62% between 2000 and 2007. Updated cervical cancer treatment guidelines based on IGABT have been developed by the Gynecological working group, which is composed of the Group Européen de Curiethérapie-European Society for Therapeutic Radiology and Oncology. The therapeutic strategy makes use of three-dimensional imaging, which can be tailored to the target volume and at-risk organs through the use of computed tomography or magnetic resonance imaging. Under anaesthesia, the brachytherapy implantation is carried out. Ultrasonography is utilised to assess the depth of the uterine cavity and to facilitate the dilation of the uterine canal during the application insertion. In this study, we examine data from the international literature regarding the application of ultrasound in cervical cancer brachytherapy.

High-Dose-Rate Three-Dimensional Image-Guided Adaptive Brachytherapy (3D IGABT) for Locally Advanced Cervical Cancer (LACC): A Narrative Review on Imaging Modality and Clinical Evidence

Background: Brachytherapy (BT) is a critical component of radiotherapy for locally advanced cervical cancer (LACC), and it has rapidly developed in recent decades. Since the advent of three-dimensional image-guided adaptive brachytherapy (3D-IGABT), magnetic resonance imaging (MRI) has emerged as the primary modality for image guidance. Meanwhile, other imaging modalities, such as computed tomography, 18F-fluorodeoxyglucose positron emission tomography, ultrasound, and their combinations have also been widely studied. Materials and methods: We reviewed studies on different imaging modalities utilized for target delineation and planning. Emerging techniques in IGABT like real-time image guidance and 3D printing were also included. We summarized research on their feasibility and concentrated on their clinical outcomes. Results: MRI-guided BT was the gold standard, and CT-guided BT was the most widely applied. Other modalities have shown feasibility and promising efficacy in dosimetry studies and preliminary outcomes. The longer-term clinical outcomes associated with these approaches require further elucidation. Conclusions: As 3D-IGABT was validated by promising clinical outcomes, the future of BT for LACC is expected to progress toward the refinement of more effective image-guided procedures. Moreover, achieving operational consensus and driving technological advancements to mitigate the inherent limitations associated with different imaging modes remain essential.

Application of three-dimensional multi-imaging combination in brachytherapy of cervical cancer

BACKGROUND

Three-dimensional (3D) imaging has an important role in brachytherapy and the treatment of cervical cancer. The main imaging methods used in the cervical cancer brachytherapy include magnetic resonance imaging (MRI), computer tomography (CT), ultrasound (US), and positron emission tomography (PET). However, single-imaging methods have certain limitations compared to multi-imaging. The application of multi-imaging can make up for the shortcomings and provide a more suitable imaging selection for brachytherapy.

PURPOSE

This review details the situation and scope of existing multi-imaging combination methods in cervical cancer brachytherapy and provides a reference for medical institutions.

MATERIALS AND METHODS

Searched the literature related to application of three-dimensional multi-imaging combination in brachytherapy of cervical cancer in PubMed/Medline and Web of Science electronic databases. Summarized the existing combined imaging methods and the application of each method in cervical cancer brachytherapy.

CONCLUSION

The current imaging combination methods mainly include MRI/CT, US/CT, MRI/US, and MRI/PET. The combination of two imaging tools can be used for applicator implantation guidance, applicator reconstruction, target and organs at risk (OAR) contouring, dose optimization, prognosis evaluation, etc., which provides a more suitable imaging choice for brachytherapy.

Contemporary image-guided cervical cancer brachytherapy: Consensus imaging recommendations from the Society of Abdominal Radiology and the American Brachytherapy Society

PURPOSE

To present recommendations for the use of imaging for evaluation and procedural guidance of brachytherapy for cervical cancer patients.

METHODS

An expert panel comprised of members of the Society of Abdominal Radiology Uterine and Ovarian Cancer Disease Focused Panel and the American Brachytherapy Society jointly assessed the existing literature and provide data-driven guidance on imaging protocol development, interpretation, and reporting.

RESULTS

Image-guidance during applicator implantation reduces rates of uterine perforation by the tandem. Postimplant images may be acquired with radiography, computed tomography (CT), or magnetic resonance imaging (MRI), and CT or MRI are preferred due to a decrease in severe complications. Pre-brachytherapy T2-weighted MRI may be used as a reference for contouring the high-risk clinical target volume (HR-CTV) when CT is used for treatment planning. Reference CT and MRI protocols are provided for reference.

CONCLUSIONS

Image-guided brachytherapy in locally advanced cervical cancer is essential for optimal patient management. Various imaging modalities, including orthogonal radiographs, ultrasound, computed tomography, and magnetic resonance imaging, remain integral to the successful execution of image-guided brachytherapy.

Ultrasound guidance for cervical implantation

Ultrasound can provide real-time imagery without the risk of radiation exposure, and it is widely available at a relatively low cost. It can provide updated three-dimensional information that can improve the physician’s spatial awareness during a brachytherapy procedure for cervical cancer. There is mounting evidence demonstrating the numerous benefits of ultrasound-guided brachytherapy in the published literature. This evidence supports its routine use to improve the safety and the effectiveness of cervical brachytherapy. In this report we will review various methods in which ultrasound imaging has been used during cervical brachytherapy. We also include a description of our own institutional approach to ultrasound-guided cervical implementation that has been in use for all cervical brachytherapy procedures over the past two decades.

Analysis of Applicator Insertion Related Acute Side Effects for Cervical Cancer Treated With Brachytherapy

Purpose

To report applicator insertion-related acute side effects during brachytherapy (BT) procedure for cervical cancer patients.

Materials and Methods

Between November 2017 and December 2019, 407 BT fractions were performed in 125 patients with locally advanced cervical cancer. Acute side effects recorded comprised anesthesia-related side effects, mechanical-related side effects and infection, whose frequency and degree were recorded. Pain was assessed using numeric rating scale; vaginal bleeding volume was counted by weighing gauze pieces used in packing. The BT procedure comprised eight stages: anesthesia, applicator insertion, image acquisition, transport, waiting for treatment, dose delivery, applicator removal, and removed which denoted 0.5-12.0 h period after removal, with time of each stage recorded. Factors influencing acute side effects were assessed by Spearman correlation and Mann-Whitney U test.

Results

The most common acute side effect was pain, followed by vaginal bleeding. The mean scores for pain were highest during removal time, 4.9 ± 1.6 points. The mean vaginal bleeding volume was 44.4 ml during removal time. Mean total procedure time was 218.8 (175-336) min, having positive relationship with frequency of acute side effects. The total procedure time with acute side effects was longer than that without acute side effects. The longest procedure time was waiting time, 113.0 (91.0-132.0) min. More needles generated higher pain scores and larger volume of vaginal bleeding.

Conclusion

Pain and vaginal bleeding were the most common acute side effects, especially during removal time, which physicians should focus on. Shortening patients' waiting time helps to reduce the total procedure time, thus, reduce acute side effects. While meeting dose requirement, less needles are helpful to reduce acute side effects.

MRI-Directed Brachytherapy for Cancer of the Uterine Cervix: A Case Report, Review, and Perspective on the Importance of Widespread Use of This Technological Advance in the United States

Cervical cancer remains a major health challenge in the United States (US), especially among the low socioeconomic and African American populations. The demographics of Mississippi constitute a relatively high percentage of this high-risk population. External beam radiation therapy (EBRT) combined with concurrent chemotherapy and followed by brachytherapy is the gold standard of treatment for stage IB3 through IVA cervical cancer. Arguably, brachytherapy is the most important component of this treatment process. Patterns of Care studies (PCS) and other more recent studies have shown that brachytherapy cannot be omitted or replaced by conventional or image-guided EBRT. The last decade has witnessed the expanding use of image-guided brachytherapy (IGBT). Studies have established the superiority of IGBT over point-based brachytherapy. MRI is associated with superior soft tissue definition compared with CT and is emerging as the new standard of care. The Gynaecological Groupe Européen de Curiethérapie and the European Society for Radiotherapy and Oncology [(GYN) GEC-ESTRO] have recommended that the dose be prescribed to the high-risk clinical target volume (HR-CTV). This volume includes residual tumor present at the time of brachytherapy, the cervix, and any gray areas seen on the scan. The (GYN) GEC-ESTRO has shown that a dose of >8500 cGy delivered in <50 days results in an approximate 10% increase in pelvic control (PC), disease-specific survival, and overall survival (OS) compared to historical controls. The normal tissue toxicity is comparable or better than historical controls as well. This dose, while maintaining normal tissue constraints, may only be achievable with a hybrid intracavitary/interstitial (IC/IS) needle device guided by MRI-based targeting. 

The University of Mississippi Medical Center (UMMC) has initiated an MRI-based cervical brachytherapy program and has treated 18 patients to date; our experience confirms the above findings. In this report, we propose that MRI guidance is necessary and a hybrid IC/IS needle device is required to achieve adequate dose coverages.

Prevention of uterine perforation during intracavitary brachytherapy of cervical cancer

Purpose

Intracavitary brachytherapy (ICBT) is a part of standard treatment for loco-regionally advanced cervical cancers. ICBT requires a tandem applicator insertion through cervical canal into uterine cavity. Accurate placement through cervical canal, which is distorted by cancer, is crucial to successful treatment. The objective of this study was to investigate actual complication rate of a Smit sleeve insertion performed by experienced gynecologists in a tertiary referral center.

Material and methods

Clinical data of 328 patients with cervical cancer treated using ICBT, between January 2013 and August 2019, were retrospectively evaluated. Predisposing factors that could have increased the risk of uterine perforation were recorded. Pre-operative ultrasound was carried out for visualization of uterine curvature and selection of an appropriate Smith sleeve length. All applications were performed by a gynecologic oncology fellow or an expert gynecologist.

Results

317 patients were suitable for analysis. Only one (0.3%) applicator placement resulted in uterine perforation. In two patients, Smit sleeve dislocated after first brachytherapy and reinserted. Adequate applicator placement was achieved, and treatment was completed as planned in 316 cases.

Conclusions

A cervical sleeve technic, which reduced the need for multiple insertions and placement of this instrument by an expert gynecologist minimize the risk of complication relative to historical controls.

Updated applications of Ultrasound in Uterine Cervical Cancer

Cervical cancer is a common gynecologic malignancy worldwide. It is the fourth for both incidence and mortality. For cervical cancer, imaging and pathology assessments are incorporated in the revised 2018 Federation of Gynecology and Obstetrics (FIGO) staging system. Uses of imaging techniques for the pre-treatment work-up of cervical cancer have been increasing. Among imaging techniques for the evaluation of cervical cancer, ultrasound is cheaper, faster and widely available than other imaging techniques such as computed tomography (CT) or magnetic resonance imaging (MRI). Advanced technique in ultrasound, such as three-dimension (3D) ultrasound and color Doppler, have improved the clinical application of ultrasound in cervical cancer. Ultrasound may provide highly accurate information on detecting tumor presence and evaluating local tumor extent if performed by ultrasound-trained gynecologists; the experience of readers is also critical for correct pretreatment staging and assessment of response to treatment. Sonographic images could be useful to predict response of neoadjuvant chemotherapy, radiotherapy, chemotherapy and concurrent chemoradiotherapy in patients with cervical cancer. This review article attempted to present the most updated specific applications of ultrasound in cervical cancer.

Clinical Application of Ultrasound Guidance for Parametrial Treatment of Advanced Cervical Cancer

OBJECTIVES

To evaluate the accuracy of ultrasound (US) in determining the positions of parametrial implants by comparing US with magnetic resonance imaging (MRI) for advanced cervical cancer.

METHODS

Patients undergoing brachytherapy with parametrial implantation for cervical cancer from February 2017 to February 2019 were involved in the study. The transverse section of the cervix (surface S₁ ) and the transverse section 1 cm above the external cervix (surface S₂ ) were selected from MRI and US images as the observation planes. In the MRI observation plane, the distances between the uterine titanium needles and the uterine tube/implanter were set as M₁ to M₄ ; in the US observation plane, the distances between the uterine titanium needles and the uterine tube/implanter were set as D₁ to D₄ . The differences and consistency in M and D of each group were then compared.

RESULTS

There were no significant differences between M and D in each group (P = .058; P = .821; P = .870; and P = .936, respectively). The intraclass correlation coefficients of M and D in each group were 0.970, 0.968, 0.952, and 0.956. A regression analysis showed that the relationships between M and D in each group were as follows: M₁ = 0.9449D₁  + 0.1812; M₂ = 0.9463D₂  + 0.0965; M₃ = 0.9176D₃  + 0.1233; and M₄ = 0.9253D₄  + 0.1224.

CONCLUSIONS

In parametrial brachytherapy for cervical cancer, US can accurately determine the positions of parametrial implantation needles, which is already applicable on MRI, and can provide assistance in parametrial brachytherapy for advanced cervical cancer.

Pelvic Insufficiency Fractures After External Beam Radiation Therapy for Gynecologic Cancers: A Meta-analysis and Meta-regression of 3929 Patients

PURPOSE

To estimate the overall rate, symptomatic proportion, and most common sites of pelvic insufficiency fracture (PIF) after external beam radiation therapy for gynecologic cancers based on posttreatment computed tomography, magnetic resonance imaging, positron emission tomography, or bone scintigraphy.

METHODS AND MATERIALS

A systematic search of databases (PubMed and EMBASE) was performed (CRD42019125679). The pooled summary of overall PIF and the proportion of symptomatic cases were calculated using the random-effects model weighted by the inverse variance. A multivariate meta-regression was performed to evaluate potential sources of heterogeneity regarding PIF fractures.

RESULTS

Twenty-one studies met the inclusion criteria (total 3929 patients). Five hundred four patients developed PIF, translating to an overall rate of 14% (95% confidence interval, 10%-18%, based on 21 studies). Among these cases with PIF, the proportion of symptomatic patients was 61% (95% confidence interval, 52%-69%, based on 14 studies). The total number of PIFs was 704 (mean, 1.72 PIFs per each patient to develop PIF, based on 14 studies). More recent series (P = .0074) and the use of intensity modulated radiation therapy (P = .0299) were associated with lower fracture rates. The most common fracture sites were sacroiliac joint (39.7%), body of the sacrum (33.9%), pubis (13%), lumbar vertebra (7%), iliac bone (2.8%), acetabulum (2.1%), and femoral head/neck (1.5%). The median time to fracture was 7.1 to 19 months after radiation therapy.

CONCLUSIONS

The incidence of PIF after radiation therapy for gynecologic cancers is high (14%), with the majority affecting the sacral bone or joint (73.6%), although this risk appears to be lower with intensity modulated radiation therapy. Posttreatment bone surveillance is warranted in this population because nearly 40% of patients were asymptomatic at the time of PIF diagnosis.