International brachytherapy practice patterns: a survey of the Gynecologic Cancer Intergroup (GCIG)

Position-dependent offset corrections for ring applicator reconstruction in cervical cancer brachytherapy

PURPOSE

Due to the tight curvature in their design, ring applicators are usually associated with large positioning errors. The standard practice to correct for these deviations based on global offsets may not be sufficient to comply with the recommended tolerance. In this work, we investigate two methods for applicator reconstruction that implement position-dependent source offset corrections.

METHODS

Measurements were performed using the Varian Interstitial PEEK Ring 60° and a Varian BRAVOS afterloader. Source positioning was characterized by means of autoradiographs acquired for three different loading patterns and three 192Ir sources over a period of 5 months. Additionally, the actual source path was determined by means of a series of planar kV images for different dummy cable positions. The first position-dependent correction method consists of locally modifying the radius of the reconstructed source path according to the measured offsets. The second method, recommended by Varian, simulates a bidirectional movement of the source during applicator reconstruction to compensate for positioning errors.

RESULTS

Autoradiographs showed a quasi-linear increase of the dwell position offsets, with a negligible error at the tip and a value close to 3 mm at the end of the ring. This result, consistent with a circular wire movement with an effective radius 0.5 mm larger than the nominal value, was in agreement with the observations from the kV images. After implementation of the position-dependent correction methods, residual positioning errors for the two methods resulted in a mean value (±1 SD) of 0.0 (±0.3) mm, and a range of [-0.7 mm, 0.7 mm].

CONCLUSION

The two tested methods for applicator reconstruction with position-dependent source offset corrections were able to successfully correct the positioning errors. The method recommended by the manufacturer had the additional advantages of a more straightforward implementation and the potential for use in other applicator types.

The influence of time and implants in high-dose rate image-guided adaptive brachytherapy for locally advanced cervical cancer

PURPOSE

To compare the clinical outcomes of two different schedules of modern image-guided adaptive brachytherapy (IGABT) in patients underwent chemoradiotherapy (CCRT) and high-dose rate (HDR) brachytherapy (BT) for locally advanced cervical cancer treated (LACC) METHODS AND MATERIALS: Data from medical records of all consecutive patients with histologically proven cervical cancer (FIGO 2018 stage IB-IVA) treated by HDR-BT after CCRT at our institution between 2016 and 2021 were reviewed.

RESULTS

Two hundred and 8 patients with LACC FIGO 2018 stages (IB 20.7%; II 26.5%, III 51%, IVA 1.9%) underwent brachytherapy at our institution. Depending on initial clinical features of disease and the clinical response to CCRT, HDR-BT was delivered with one implant (BT1i) or two implants (BT2i) in 39% and 61% of patients respectively. FIGO stages (≥IIB) were 63% vs. 78% for BT1i and BT2i patient group respectively. Combined brachytherapy technique [endocavitary/interstitial (IC/IS)] was required in 14.8% vs. 68.5% for BT1i and BT2i respectively. With a median follow-up of 32.5 months (95% confidence interval, [29.7-35.8]), local relapse was observed in sixteen patients: 8 patients (3.8%) had local (exclusive) relapse and 8 patients (3.8%) had locally persistent and progressive disease, without significant difference for each BT modality group (p = 0.27), even if BT2i group had more aggressive initial disease. The estimated 3-year disease free survival and overall survival for the entire population was 69% (95% confidence interval, [62-75%]) and 88% (95% confidence interval, [82-92%]) respectively. There was a significant difference in the incidence of global toxicity grade G≥2 in favour to the BT2i group (p = 0.026).

CONCLUSIONS

HDR brachytherapy delivered with a long time interval between fractions, two implants, and combined IC/IS brachytherapy is the best way to ensure local control and to perform IGABT with low toxicity, even in advanced stages of disease.

A comparative analysis of survival outcomes and adverse effects between preoperative brachytherapy with radical surgery and concurrent chemoradiotherapy in patients with locally advanced cervical cancer

Background

To compare the long-term efficacy and adverse effects of preoperative brachytherapy combined with radical surgery versus concurrent chemoradiotherapy (CCRT) in patients with locally advanced cervical cancer (LACC).

Methods

This retrospective study analyzed 161 patients with LACC treated at the Affiliated Hospital of North Sichuan Medical College between January 2015 and December 2020. Of these, 76 patients underwent preoperative brachytherapy combined with radical surgery (study group), while 85 received CCRT (control group). After propensity score matching (PSM) to minimize confounding, 124 patients (62 per group) were included in the analysis. Survival outcomes and prognostic factors were evaluated using Kaplan-Meier survival analysis and Cox regression models. Adverse effects of treatment were compared between the groups.

Results

After PSM, the 5-year progression-free survival (PFS) rate in the study group was significantly higher than that in the control group (81.2% vs. 62.7%, P<0.05). There was no significant between-group difference regarding the 5-year overall survival (OS) rate (81.4% vs. 74.9%, P=0.41). Multivariate analysis identified treatment modality (preoperative brachytherapy combined with radical surgery vs. CCRT) as an independent prognostic factor for PFS (HR: 0.458, 95% CI 0.221-0.945, P=0.035). The study group had significantly lower rates of grade 2 acute radiation enteritis, grade 3-4 leukopenia, and anemia compared to the control group (P<0.05), with no significant differences observed in other adverse effects (P>0.05).

Conclusion

Preoperative brachytherapy combined with radical surgery may help improve the PFS of patients with LACC, with fewer adverse effects, making it a potentially viable treatment option for these patients.

Analgesia and Anesthesia Practice Patterns for Gynecologic Brachytherapy Procedures and Potential Impact on Women's Procedural Experience: A National Survey

PURPOSE

The purpose of this study was to determine the current U.S. practice patterns of analgesia (AG) and anesthesia (AS) for gynecologic brachytherapy (BT) procedures.

METHODS AND MATERIALS

A 27-item survey created with expertise from 5 brachytherapists was distributed electronically to 90 U.S. radiation oncology academic programs and publicized on social media and at 2 national meetings from June to October 2023.

RESULTS

Forty-one responses were received (46%). Fifty-four percent identified as female, 66% as Caucasian, and 85% as non-Hispanic/Latino ethnicity. Forty-nine percent use a BT suite ± computed tomography (CT) simulator alone, 39% the operating room ± BT suite or CT simulator or other location, 10% CT simulation room alone, and 2% clinic examination room. Thirty-four percent use general anesthesia alone (GA) for intracavitary BT (n = 41), 20% conscious sedation (CS) alone, 10% oral analgesia (OA) alone, 9% spinal or epidural AS alone, and 27% combination. Among those performing hybrid BT (n = 25), 40% use GA alone, 16% use CS alone, 12% epidural or spinal AS alone, 4% OA alone, and 28% combination. For template interstitial BT (n = 25), 44% use GA alone, 48% epidural alone or in combination with other AS, and 8% CS alone. Twenty-two percent of respondents provide AG or AS during applicator placement only, whereas 32% provide it during placement, planning, treatment, and removal. The most common reasons for not using CS or GA were the lack of AS resources and clinician preference. Seventy-three percent reported the belief that patients suffer from post-traumatic stress disorder symptoms after BT. However, 68% reported not using techniques to alleviate BT-related emotional distress.

CONCLUSIONS

Many U.S. brachytherapists report using GA, CS, or epidural AS; however, 10% are using only OA, and 22% offer AG/AS only during applicator placement. Furthermore, a majority of respondents believe post-traumatic stress disorder symptoms can occur after BT, but few offer any intervention. AS resources and clinician preferences should be targeted for the expansion of higher-quality care.

The Utility of a Y-tandem Applicator in a Patient With Stage IVA Locally Advanced Cervical Cancer in the Setting of a Bicornuate Uterus

We report a case of a patient with a bicornuate unicollis uterus who developed International Federation of Gynecology and Obstetrics (FIGO) Stage IVA adenocarcinoma of the cervix invading the bladder neck, proximal urethra, upper vagina, and parametrium. The patient was treated with definitive chemoradiation therapy, including external beam radiation therapy (EBRT), brachytherapy, and weekly cisplatin infusions. Our patient required an interstitial brachytherapy boost, which was challenging to deliver due to her congenital anatomic anomaly. We were able to utilize the Syed-Neblett template to treat bilateral uteri using the holes in the template base as the entry points for brachytherapy catheters. In addition, a Y-tandem applicator was used to achieve the required angulation at the level of the cervix to reach both uterine walls. After completing both EBRT and brachytherapy, she was free of signs of disease on a follow-up visit approximately two months after treatment. The patient did not have any signs of locoregional disease six months later when she ultimately expired due to widespread pulmonary metastases.

External beam radiotherapy followed by image-guided adaptive brachytherapy in locally advanced cervical cancer: a multicenter retrospective analysis

PURPOSE

To evaluate oncological outcomes and toxicities in patients with locally advanced cervical cancer (LACC) treated with concurrent chemoradiotherapy followed by image-guided adaptive brachytherapy at two Italian centres.

MATERIAL AND METHODS

A retrospective analysis was conducted on 122 patients with LACC treated between 2010 and 2022. Primary endpoints were local control (LC), pelvic control (PC), and nodal control (NC). Secondary endpoints included disease-free survival (DFS), metastasis-free survival (MFS), overall survival (OS), and late toxicity. Correlations between patient characteristics and oncological outcomes were conducted.

RESULTS

Brachytherapy planning was CT and MRI-based in 88 (72.1%) and 34 patients (27.9%), respectively. The mean total dose (EQD2) delivered to high-risk clinical target volume was 82 Gy. Overall treatment time was ≤ 50 days and > 50 days in 48 (39.3%) and 74 patients (60.7%), respectively. At a mean follow up of 101 months, 3 and 5-year LC rates were 87% and 85%, respectively. Five-year PC and NC rates were 77% and 85.1%. Five-year DFS and OS were 61% and 65.4%, respectively, with significant correlations between these outcomes and FIGO stage and nodal status at diagnosis. Gastrointestinal, genitourinary and vaginal adverse effects were the most reported late toxicities and 8 (6.5%) grade 3-5 events were observed. 32 patients (26.2%) had vaginal stenosis and it was significantly related to 3D imaging used for brachytherapy planning.

CONCLUSIONS

The study confirmed the efficacy and safety of chemoradiotherapy and IGABT for LACC. Full implementation of MRI treatment planning and interstitial techniques could further enhance personalized treatment and outcomes.

Clinical Outcomes of 3 Versus 4 Fractions of Magnetic Resonance Image-Guided Brachytherapy in Cervical Cancer

PURPOSE

Magnetic resonance image-guided brachytherapy is essential in the management of locally advanced cervical cancer. This study compares disease and toxicity outcomes in cervical cancer patients treated with 24 Gy/3 fractions (Fr) versus the conventional 28 Gy/4 Fr.

METHODS AND MATERIALS

This retrospective study included 241 consecutive patients with International Federation of Gynecology and Obstetrics 2018 stage IB to IVA cervical cancer treated with definitive chemoradiation between April 2014 and March 2021. Disease-free survival (DFS) was estimated using the Kaplan-Meier method and compared using the log-rank test. Cumulative incidence of local failure (LF), distant failure (DF), and G2+ gastrointestinal (GI), urinary and vaginal toxicity were estimated using the cumulative incidence function with death as a competing risk and compared using Gray's test.

RESULTS

Of the 241 patients, 42% received 24 Gy/3 Fr and 58% received 28 Gy/4 Fr. With a median follow-up of 3.2 (range, 0.2-9.2) years, there were 14 local, 41 regional nodal, and 51 distant failures in 63 (26%) patients. No significant differences were found between the 24 Gy/3 Fr and 28 Gy/4 Fr groups in 3-year DFS (77% vs 68%, P = .21), the 3-year cumulative incidence of LF (5% vs 7%, P = .57), DF (22% vs 25%, P = .86), G2+ GI toxicity (11% vs 20%, P = .13), or G2+ vaginal toxicity (14% vs 17%, P = .48), respectively. The 3-year cumulative G2+ urinary toxicity rate was lower in the 24 Gy/3 Fr group (9% vs 23%, P = .03).

CONCLUSIONS

Patients with cervical cancer treated with 24 Gy/3 Fr had similar DFS, LF, DF, GI, and vaginal toxicity rates and a trend toward a lower G2+ urinary toxicity rate compared with those treated with 28 Gy/4 Fr. A less resource-intensive brachytherapy fractionation schedule of 24 Gy/3 Fr is a safe alternative to 28 Gy/4 Fr for definitive treatment of cervical cancer.

Deep reinforcement learning in radiation therapy planning optimization: A comprehensive review

PURPOSE

The formulation and optimization of radiation therapy plans are complex and time-consuming processes that heavily rely on the expertise of medical physicists. Consequently, there is an urgent need for automated optimization methods. Recent advancements in reinforcement learning, particularly deep reinforcement learning (DRL), show great promise for automating radiotherapy planning. This review summarizes the current state of DRL applications in this field, evaluates their effectiveness, and identifies challenges and future directions.

METHODS

A systematic search was conducted in Google Scholar, PubMed, IEEE Xplore, and Scopus using keywords such as "deep reinforcement learning", "radiation therapy", and "treatment planning". The extracted data were synthesized for an overview and critical analysis.

RESULTS

The application of deep reinforcement learning in radiation therapy plan optimization can generally be divided into three categories: optimizing treatment planning parameters, directly optimizing machine parameters, and adaptive radiotherapy. From the perspective of disease sites, DRL has been applied to cervical cancer, prostate cancer, vestibular schwannoma, and lung cancer. Regarding types of radiation therapy, it has been used in HDRBT, IMRT, SBRT, VMAT, GK, and Cyberknife.

CONCLUSIONS

Deep reinforcement learning technology has played a significant role in advancing the automated optimization of radiation therapy plans. However, there is still a considerable gap before it can be widely applied in clinical settings due to three main reasons: inefficiency, limited methods for quality assessment, and poor interpretability. To address these challenges, significant research opportunities exist in the future, such as constructing evaluators, parallelized training, and exploring continuous action spaces.

Low-dose-rate, high-dose-rate, and pulsed-dose-rate intra-cavitary brachytherapy for cervical cancer: The very first comparison study

Purpose

For cervical cancer patients, intra-cavitary brachytherapy (ICBT) is utilized with various dose-rate systems, such as low-dose-rate (LDR), high-dose-rate (HDR), and pulsed-dose-rate (PDR). This retrospective analysis aimed to compare the therapeutic outcomes of cervical cancer patients treated with either LDR-, HDR-, or PDR-ICBT.

Material and methods

A total of 613 patients were treated with pelvic external beam radiation therapy (EBRT), followed by either LDR- (271 patients), HDR- (259 patients), or PDR- (83 patients) ICBT. Point-based planning was performed according to orthogonal radiographs in LDR patients, and computed tomography (CT) imaging in HDR and PDR patients. ICBT prescribed dose was as follows: for LDR treatment, 30 Gy in a single-session; for HDR: 7 Gy × 3 fractions (once a week fraction); and for PDR: 27 Gy in an hourly pulse of 70 cGy, with all the doses prescribed at point A. Radioactive source used was cesium-137 for LDR, and iridium-192 for HDR and PDR treatments.

Results

Loco-regional control (LRC) rate was 74%, 75%, and 77% in LDR, HDR, and PDR groups, respectively (p = 0.80). The 5-year overall survival (OS) in the three groups, i.e., LDR, HDR, and PDR was 63%, 64%, and 68%, respectively (p = 0.77). Severe late toxicity (RTOG grade ≥ 3) rate in the three groups was comparable (LDR, 12%; HDR, 8%; and PDR, 8.9%, p = 0.36).

Conclusions

Our study revealed comparable LRC, 5-year OS, and late toxicity rates using three dose-rate systems. Lower OS rates were observed in LDR group for stage III patients compared with patients in HDR and PDR groups. Therefore, we suggest that LDR should be used with caution while treating stage III patients.

New Frontiers in Locally Advanced Cervical Cancer Treatment

Despite the introduction of targeted vaccines and screening protocols, locally advanced cervical cancer represents a median proportion of 37% among all cervical carcinomas. Compared to early stages, it presents significantly lower cure rates, with a 5-year disease-free survival rate of 68% and a 5-year overall survival rate of 74%. According to current guidelines, definitive radiotherapy with concomitant chemotherapy represents the gold standard for locally advanced cervical cancer treatment. However, a significant number of patients relapse and die from metastatic disease. The aim of this narrative review is to examine the recent advancements in treating locally advanced cervical cancer, exploring new frontiers in therapeutic approaches. The PubMed database and clinical trial registries were searched to identify relevant articles published on locally advanced cervical cancer treatment up to March 2024, mainly focusing on papers published in the last decade. Abstracts presented at major international congresses that bring relevant evidence were included. Progress achieved in refining radiotherapy techniques, recent evidence regarding neoadjuvant treatment preceding surgery or concurrent chemoradiotherapy, and key findings concerning adjuvant treatment are thoroughly explored. Furthermore, a comprehensive review of prominent phase II and phase III trials examining the integration of immune checkpoint inhibitors is conducted, analyzing the various contexts in which they are applied. In light of the new evidence that has emerged in recent years and is discussed in this article, the appropriate selection of the most suitable therapeutic approach for each patient remains a complex but crucial issue.

The prognostic effect of tumor volume, reduction ratio, and cumulative doses on external beam radiotherapy with central-shielding method and image-guided adaptive brachytherapy for cervical cancer

Objective

To evaluate the prognostic effect of tumor volume at diagnosis, tumor reduction ratio during external beam radiotherapy (EBRT) with central-shielding method, and cumulative minimal dose to 90% of the high-risk clinical target volume (CTVHR D90) on combined EBRT and image-guided adaptive brachytherapy (IGABT) for cervical cancer.

Methods

Consecutive patients who underwent definitive radiotherapy or concurrent chemoradiotherapy for cervical cancer at Gunma University Hospital between January 2010 and December 2019 were retrospectively reviewed. Tumor volume at diagnosis and reduction ratio were calculated using magnetic resonance imaging at diagnosis and before the first IGABT session. The cumulative dose of EBRT and IGABT was calculated as an equivalent dose in 2 Gy fractions (EQD2). Optimal cutoff values were determined according to a receiver operating characteristic curve. Treatment outcomes were evaluated using the Kaplan-Meier method and compared using the log-rank test and Cox proportional hazards regression.

Results

A total of 254 patients were included in the analysis. The median follow-up for all patients was 57 (2-134) months. The 5-year overall survival (OS) was 81.9%, progression-free survival (PFS) was 71.3%, and local control (LC) was 94.5%. The patients were divided into four groups according to tumor volume at diagnosis and reduction ratio. The group with tumor volume at diagnosis ≥ 34.1 cm3 and reduction ratio < 68.8% showed significantly worse OS, PFS, and LC than the other three groups (All p < 0.05). In this group, the patients with a cumulative CTVHR D90 < 69.6 GyEQD2 showed significantly worse PFS and LC (p = 0.042 and p = 0.027, respectively). In the multivariate analysis of OS, adenocarcinoma/adenosquamous carcinoma, International Federation of Gynecology and Obstetrics 2009 stage III/IV, and a reduction ratio of < 68.8% were independent significant poor prognostic factors (p = 0.045, p = 0.009 and p = 0.001, respectively). In the univariate analysis of LC, a reduction ratio of < 68.8% was the only poor prognostic factor (p = 0.041).

Conclusion

The patients with large and poorly responding tumors had significantly worse prognoses in terms of OS, PFS, and LC, suggesting that dose escalation should be considered for such tumors.

Effects of pain management using nonsteroidal anti-inflammatory drug suppositories during brachytherapy for cervical cancer: A single-center prospective observational study

INTRODUCTION

No standardized pain management protocol exists for intracavitary brachytherapy, and various methods of analgesia have been used in different countries and institutions. This study aimed to investigate the effects of pain management during intracavitary brachytherapy using nonsteroidal anti-inflammatory drugs (NSAIDs) or acetaminophen suppositories.

METHODS

In this single-center, prospective, observational study, patients undergoing intracavitary brachytherapy for cervical cancer completed a questionnaire survey after each brachytherapy session, which comprised questions regarding pain intensity, satisfaction with analgesia, and desire for effective anesthesia.

RESULTS

Data analysis was performed using data from 100 brachytherapy sessions of 27 patients. The median numerical rating scale (NRS; 0-10) score for each intracavitary brachytherapy session was 3-4. The median satisfaction scale score for analgesia (5-point scale, 1-5) for each session was approximately 4. Eight patients (29.6%) answered that they desired anesthesia more effective than suppositories at any session of brachytherapy. A comparison of the high (NRS ≥4) and low (NRS ≤3) NRS groups during the first session revealed that the high NRS group tended to have higher NRS scores and lower satisfaction with analgesia during all sessions. A positive correlation was observed between tumor size and the NRS score during the first brachytherapy session.

CONCLUSIONS

The NRS score was approximately 3-4, and satisfaction with analgesia was approximately 4 out of 5 when NSAIDs or acetaminophen suppositories were used as analgesics during intracavitary brachytherapy for cervical cancer. Although the current pain management protocol is clinically acceptable, inadequate analgesia is indicated in approximately 30% of patients.

Locally advanced squamous cervical carcinoma (M0): management and emerging therapeutic options in the precision radiotherapy era

Squamous cervical carcinoma (SCC) requires particular attention in diagnostic and clinical management. New diagnostic tools, such as (positron emission tomography-magnetic resonance imaging) PET-MRI, consent to ameliorate clinical staging accuracy. The availability of new technologies in radiation therapy permits to deliver higher dose lowering toxicities. In this clinical scenario, new surgical concepts could aid in general management. Lastly, new targeted therapies and immunotherapy will have more room in this setting. The aim of this narrative review is to focus both on clinical management and new therapies in the precision radiotherapy era.

Patterns of practice survey for cervical cancer brachytherapy in Morocco

PURPOSE

This study surveyed radiation oncologists in Morocco to explore current practices and perspectives on brachytherapy for cervix cancer.

METHODS AND MATERIALS

A 37-question survey was conducted in April 2023 among 165 Moroccan radiation oncologists using Google Forms.

RESULTS

Of the 93 respondents, 39% treated over 20 patients in 2022 using 3D image-guided brachytherapy (BT) through the HDR technique; 2D techniques were not reported in the last five years. Intracavitary BT is uniformly applied with a tandem and ovoid applicator. Only 14% utilized interstitial needles for hybrid BT. Iridium-192 was the primary radioactive source (63%), followed by cobalt (37%). Ultrasound-guided 47% of applicator insertions. All used CT scans for planning, but only 6% used MRI fusion due to limited availability. Guidelines for target volume and dose prescription were mostly based on GEC-ESTRO recommendations (74%), followed by Manchester Point A (30.4%) and ABS (11%). Over 90% delineated CTV-HR and CTV-IR; 30% delineated GTV. All marked the bladder and rectum, while 52% marked the sigmoid, 5% the small bowel, and 3% the recto-vaginal point. For dosimetry, 12% used ICRU 89 points, 54% used dose-volume histograms (DVH), and 36% used both. Most reported EQD2cc for OARs for the rectum and bladder, with nine still using ICRU point doses. The most common fractionation schema was 7 Gy in four fractions (60%) and 7 Gy in three fractions (55%).

CONCLUSIONS

Brachytherapy remains essential for treating cervical cancer in Morocco. Key areas for improvement include MRI fusion-guided brachytherapy, access to advanced applicators, expanding interstitial techniques, and professional training and national referential.

Single- versus Multi-computed Tomography Simulation for High-dose-rate Postoperative Gynecological Intracavitary Brachytherapy

Introduction

This study aimed to investigate whether there is a dosimetric difference of implementing single instead of multi-computed tomography (CT) simulation treatment planning for high-dose-rate postoperative gynecological intracavitary brachytherapy (BT).

Materials and Methods

Eighty patients were registered in the study. They received three BT fractions of 7 Gy/week (three CTs, three original plans). The organs at risk (OAR), the rectal wall, and the clinical target volume (CTV) were delineated. The delivered doses for the 2cc of OARs (D2cc), 1cc of rectal wall (D1cc), as well as for the 90% and 100% of CTV volume (DCTV90%, DCTV100%) were evaluated. To evaluate the values of the above parameters if the single-CT-simulation method has been chosen, the time of the first treatment plan was corrected for the decay and applied as the second and third CT, retrospectively, creating the next fractions (two revised plans).

Results

No statistically significant (P > 0.05) differences were found between the original and revised plans for the OARs and CTV. However, for the single-CT-simulation method, it was noted that the dose constraints for the total rectal dose were exceeded in some cases (36.3%).

Conclusion

The fact that rectal dose constraints were exceeded in 1/3 of patients with the single-CT-simulation method is dosimetrically significant.

Dose and fractionation regimen for brachytherapy boost in cervical cancer in the US

PURPOSE

Curative-intent radiotherapy for locally advanced and select early stage cervical cancer in the US includes external beam radiotherapy (EBRT) with brachytherapy. Although there are guidelines for brachytherapy dose and fractionation regimens, there are limited data on practice patterns. This study aims to evaluate the contemporary utilization of cervical cancer brachytherapy in the US and its association with patient demographics and facility characteristics.

METHODS

We retrospectively analyzed clinical covariates of cervical cancer patients diagnosed and treated in 2018-2020 with curative-intent radiotherapy from the 2020 National Cancer Database. Associations between patient and institutional factors with the number of brachytherapy fractions were identified with logistic regression. Factors with association (p < 0.10) were then included in a multivariable logistic regression model. All tests were two-sided with significance <0.05 unless specified otherwise.

RESULTS

Among the eligible 2517 patients, 97.3% received HDR or LDR and is further analyzed. More patients received HDR than LDR brachytherapy (98.9% vs 1.1%) and intracavitary than interstitial brachytherapy (86.4% vs 13.6%). The most common number of HDR fractions prescribed were 5 (51.0%), 4 (32.9%), and 3 (8.6%). After adjusting for the other variables in the model, ethnicity, private insurance status, overall insurance status, and facility type were the only factors that were significantly associated with the number of brachytherapy factions (p < 0.0001, p = 0.028, p = 0.001, and p < 0.0001, respectively, n = 2184).

CONCLUSIONS

In the US, various HDR brachytherapy regimens are utilized depending on patient and institutional factors. Future research may optimize cervical cancer brachytherapy by correlating specific dose and fractionation regimens with patient outcomes.

Outcomes and comparison of dosimetric parameters between intracavitary (Fletcher) and combined intracavitary/interstitial (Utrecht) brachytherapy in locally advanced cervical cancer

OBJECTIVE

To report outcomes of combined intracavitary/interstitial (IC/IS) image-guided brachytherapy (IGBT) in locally advanced cervical cancer, and to compare its dosimetric parameters with intracavitary-only (IC) brachytherapy in a first-in-country experience.

METHODS AND MATERIALS

Between January 2021 and September 2022, a total of 160 insertions were done in 40 patients with FIGO IB3-IVA cervical cancer undergoing IGBT using a hybrid (Utrecht) applicator. Corresponding treatment plans for IC brachytherapy were generated during treatment, and optimized. A preplanned comparison of dosimetric parameters, defined in GEC-ESTRO was conducted.

RESULTS

The clinical use of a hybrid IC/IS applicator was feasible in all insertions. An average of 14 needles were inserted in each patient over four fractions. Mean HR-CTV D90 and D98 was 86 (SD 1.9) Gy and 75.7 (SD 2.3) Gy using hybrid applicator, and 80 (SD 5.4) Gy and 69.8 (SD 5.2) Gy using IC applicator, with a mean dose gain of 6.0 (SD 5.0) Gy and 5.9 (SD 4.7) Gy (p <0.001), respectively. Likewise, mean D2cc for bladder and sigmoid were significantly lower in the hybrid technique. Mean contribution of brachytherapy to total HR-CTV D90 (in absolute EQD2 Gy) was 41.7 Gy using IC/IS applicator while 35.7 Gy for IC-only applicator (p = 0.027). Clinical response at 12 weeks showed an overall response rate (ORR) and complete response (CR) rates of 92.5% and 77.5%, respectively.

CONCLUSIONS

IGBT using a hybrid IC/IS applicator showed excellent tolerability and yielded favorable results, resulting in significant dosimetric improvement in terms of primary target dose, and sparing OARs.

Improvement in radiation techniques for locally advanced cervical cancer during the last two decades

Since the National Cancer Institute (NCI) alert of concurrent chemoradiotherapy, radiotherapy has been changed from external beam radiotherapy plus brachytherapy to platinum-based concurrent chemoradiotherapy. Therefore, concurrent chemoradiotherapy plus brachytherapy has become a standard treatment for locally advanced cervical cancer. Simultaneously, definitive radiotherapy has been changed gradually from external beam radiotherapy plus low-dose-rate intracavitary brachytherapy to external beam radiotherapy plus high-dose-rate intracavitary brachytherapy. Cervix cancer is uncommon in developed countries; hence, international collaborations have been critical in large-scale clinical trials. The Cervical Cancer Research Network (CCRN), created from the Gynecologic Cancer InterGroup (GCIG), has investigated various concurrent chemotherapy regimens and sequential methods of radiation and chemotherapy. Most recently, many clinical trials of combining immune checkpoint inhibitors with radiotherapy have been ongoing for sequential or concurrent settings. During the last decade, the method of standard radiation therapy has changed from three-dimensional conformal radiation therapy to intensity-modulated radiation therapy for external beam radiotherapy and from two-dimensional to three-dimensional image-guided approaches for brachytherapy. Recent improvements include stereotactic ablative body radiotherapy and MRI-guided linear accelerator (MRI-LINAC) using adaptive radiotherapy. Here we review the current progress of radiation therapy during the last two decades.

Dosimetric comparison of rectal dose-reductive techniques in intra-cavitary brachytherapy for cervical cancer: A retrospective analysis

Purpose

Rectal complications in radiotherapy for cervical cancer can highly affect quality of life and correlate with rectal dose. Vaginal gauze packing (VP) and rectal retraction (RR) are widely used for rectal dose reduction in high-dose-rate brachytherapy. We aimed to perform a dosimetric comparison of these two methods for three-dimensional image-guided adaptive brachytherapy.

Material and methods

We retrospectively examined 50 patients with cervical cancer treated with definitive radiotherapy, including intra-cavitary brachytherapy, performed with VP and RR. We extracted two fractions for each patient: one fraction with VP and the next fraction with RR, and then compared dose-volume parameters. In total, 50 fractions each were analyzed in VP and RR groups. Dose to 90% (D90) of high-risk clinical target volume (HR-CTV), and minimum dose to most exposed 2.0 cm3 of other organs at risk (D2cm3) for the rectum and bladder were determined from planning computed tomography.

Results

There were no significant differences between VP and RR in D90 of HR-CTV (mean: 7.479 Gy and 7.652 Gy, respectively, p = 0.172). The D2cm3 values for the rectum (mean: 4.234 Gy vs. 4.627 Gy, p = 0.008) and bladder (mean: 5.959 Gy vs. 6.690 Gy, p < 0.001) were significantly lower with VP compared with RR.

Conclusions

VP reduced the dose to the rectum and bladder when compared with RR without impairing the dose to CTV.

ESGO/ESTRO quality indicators for radiation therapy of cervical cancer

BACKGROUND

The European Society of Gynaecological Oncology (ESGO) has previously defined and established a list of quality indicators for the surgical treatment of cervical cancer. As a continuation of this effort to improve overall quality of care for cervical cancer patients across all aspects, ESGO and the European SocieTy for Radiotherapy and Oncology (ESTRO) initiated the development of quality indicators for radiation therapy of cervical cancer.

OBJECTIVE

To develop a list of quality indicators for radiation therapy of cervical cancer that can be used to audit and improve clinical practice by giving to practitioners and administrators a quantitative basis to improve care and organizational processes, notably for recognition of the increased complexity of modern external radiotherapy and brachytherapy techniques.

METHODS

Quality indicators were based on scientific evidence and/or expert consensus. The development process included a systematic literature search for identification of potential quality indicators and documentation of scientific evidence, consensus meetings of a group of international experts, an internal validation process, and external review by a large international panel of clinicians (n=99).

RESULTS

Using a structured format, each quality indicator has a description specifying what the indicator is measuring. Measurability specifications are detailed to define how the quality indicators will be measured in practice. Targets were also defined for specifying the level which each unit or center should be aiming to achieve. Nineteen structural, process, and outcome indicators were defined. Quality indicators 1-6 are general requirements related to pretreatment workup, time to treatment, upfront radiation therapy, and overall management, including active participation in clinical research and the decision making process within a structured multidisciplinary team. Quality indicators 7-17 are related to treatment indicators. Quality indicators 18 and 19 are related to patient outcomes.

DISCUSSION

This set of quality indicators is a major instrument to standardize the quality of radiation therapy in cervical cancer. A scoring system combining surgical and radiotherapeutic quality indicators will be developed within an envisaged future ESGO accreditation process for the overall management of cervical cancer, in an effort to support institutional and governmental quality assurance programs.

ESGO/ESTRO quality indicators for radiation therapy of cervical cancer

BACKGROUND

The European Society of Gynaecological Oncology (ESGO) has previously defined and established a list of quality indicators for the surgical treatment of cervical cancer. As a continuation of this effort to improve overall quality of care for cervical cancer patients across all aspects, ESGO and the European SocieTy for Radiotherapy and Oncology (ESTRO) initiated the development of quality indicators for radiation therapy of cervical cancer.

OBJECTIVE

To develop a list of quality indicators for radiation therapy of cervical cancer that can be used to audit and improve clinical practice by giving to practitioners and administrators a quantitative basis to improve care and organizational processes, notably for recognition of the increased complexity of modern external radiotherapy and brachytherapy techniques.

METHODS

Quality indicators were based on scientific evidence and/or expert consensus. The development process included a systematic literature search for identification of potential quality indicators and documentation of scientific evidence, consensus meetings of a group of international experts, an internal validation process, and external review by a large international panel of clinicians (n = 99).

RESULTS

Using a structured format, each quality indicator has a description specifying what the indicator is measuring. Measurability specifications are detailed to define how the quality indicators will be measured in practice. Targets were also defined for specifying the level which each unit or center should be aiming to achieve. Nineteen structural, process, and outcome indicators were defined. Quality indicators 1-6 are general requirements related to pretreatment workup, time to treatment, upfront radiation therapy, and overall management, including active participation in clinical research and the decision making process within a structured multidisciplinary team. Quality indicators 7-17 are related to treatment indicators. Quality indicators 18 and 19 are related to patient outcomes.

DISCUSSION

This set of quality indicators is a major instrument to standardize the quality of radiation therapy in cervical cancer. A scoring system combining surgical and radiotherapeutic quality indicators will be developed within an envisaged future ESGO accreditation process for the overall management of cervical cancer, in an effort to support institutional and governmental quality assurance programs.

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.

What is appropriate target delineation for MRI-based brachytherapy for medically inoperable endometrial cancer?

PURPOSE

For medically inoperable endometrial cancer (MIEC), the volumetric target of image-guided brachytherapy (IGBT) techniques is not well established. We propose a high-risk CTV (HRCTV) concept and report associated rates of local control and toxicity.

METHODS AND MATERIALS

For all MIEC patients receiving definitive external beam radiotherapy (EBRT) followed by MRI-based IGBT at a single institution, BT dose was prescribed to HRCTV defined as GTV plus endometrial cavity with a planning goal of a summed EQD2 D90 of ≥85 Gy. Freedom from local progression (FFLP) and overall survival (OS) were estimated via Kaplan Meier method.

RESULTS

Thirty two MIEC patients received EBRT followed by MRI-based IGBT between December 2015 and August 2020. Median follow up was 19.8 months. A total of 75% of patients had FIGO stage I/II disease, 56% endometrioid histology, and 50% grade 3 disease. OS was 73.6% (95% CI 57.8%-89.3%) at 12 months and 65.8% (95% CI 48.4%-83.2%) at 24 months. FFLP was 93.8% (95% CI 85.3%-100%) at 12 months and 88.8% (95% CI 86.6%-91.0%) at 24 months. 23 (72%) patients experienced no RT-related toxicity, while 2 of 32 patients (6%) experienced late grade 3+ toxicities (grade 3 refractory vomiting; grade 5 GI bleed secondary to RT-induced proctitis).

CONCLUSIONS

Patients with MIEC receiving definitive EBRT followed by MRI-based IGBT prescribed to the MRI-defined HRCTV demonstrated favorable long-term local control with an acceptable toxicity profile.

Tools for large-scale data analytics of an international multi-center study in radiation oncology for cervical cancer

PURPOSE

To develop and implement a software that enables centers, treating patients with state-of-the-art radiation oncology, to compare their patient, treatment, and outcome data to a reference cohort, and to assess the quality of their treatment approach.

MATERIALS AND METHODS

A comprehensive data dashboard was designed, which al- lowed holistic assessment of institutional treatment approaches. The software was tested in the ongoing EMBRACE-II study for locally advanced cervical cancer. The tool created individualized dashboards and automatic analysis scripts, verified pro- tocol compliance and checked data for inconsistencies. Identified quality assurance (QA) events were analysed. A survey among users was conducted to assess usability.

RESULTS

The survey indicated favourable feedback to the prototype and highlighted its value for internal monitoring. Overall, 2302 QA events were identified (0.4% of all collected data). 54% were due to missing or incomplete data, and 46% originated from other causes. At least one QA event was found in 519/1001 (52%) of patients. QA events related to primary study endpoints were found in 16% of patients. Sta- tistical methods demonstrated good performance in detecting anomalies, with precisions ranging from 71% to 100%. Most frequent QA event categories were Treatment Technique (27%), Patient Characteristics (22%), Dose Reporting (17%), Outcome 156 (15%), Outliers (12%), and RT Structures (8%).

CONCLUSION

A software tool was developed and tested within a clinical trial in radia- tion oncology. It enabled the quantitative and qualitative comparison of institutional patient and treatment parameters with a large multi-center reference cohort. We demonstrated the value of using statistical methods to automatically detect implau- sible data points and highlighted common pitfalls and uncertainties in radiotherapy for cervical cancer.

Opioid consumption and pain in patients with gynecological cancer who underwent spinal anesthesia vs. general anesthesia for interstitial brachytherapy

AIMS

Interstitial brachytherapy (ISBT) is an effective option for delivering conformal high dose radiation to the target volume with better organ-at risk sparing but is thought to be more invasive and painful than other methods. This study investigated pain levels and opioid consumption in patients who received spinal anesthesia (SA) or general anesthesia (GA) for their ISBT.

MATERIALS AND METHODS

Patients that underwent ISBT from April 2014 to September 2018 were analyzed from a prospective institutional database. The most prevalent malignancies were cervical (45%), recurrent endometrial (27%) and vaginal (20%) cancers. Baseline patient characteristics, radiation treatment details, anesthesia records, and inpatient charts were obtained. Opioid consumption was quantified as oral morphine equivalent per day (OMEq/day) from implantation until removal. Pain score levels were collected by using an 11-point scoring system.

RESULTS

Ninety nine patients received GA and 40 patients received SA as their anesthesia for ISBT. During their first admission, 76 patients (55%) required intravenous opioids. Patients receiving SA had significantly lower mean pain scores on the morning of their procedure 6 (Interquartile range [IQR] 2-8) vs. 0 (IQR: 0-1); p < 0.001]. Pain did not significantly differ between cohorts at any other time. During the first admission, SA patients had a lower median opioid usage of 23 (IQR: 9-47) mg/day compared to GA patients at 38 (IQR: 21-71) mg/day (p = 0.011). No difference in opioid consumption was seen during subsequent admissions.

CONCLUSIONS

In patients undergoing ISBT, SA provides better immediate pain control post insertion compared to GA. Patients who received SA used lower amounts of opioids during their first ISBT insertion.

Results of computer tomography-based adaptive brachytherapy in combination with whole-pelvic- and central-shielding-external beam radiotherapy for cervical cancer

PURPOSE

To evaluate treatment results and investigate predictors of local control.

METHODS AND MATERIALS

In this retrospective study of 236 patients with cervical cancer, we administered CT-based adaptive brachytherapy (BT) in combination with whole- pelvic (WP)- and central shielding (CS)- external beam radiotherapy (EBRT) with or without chemotherapy. The study cohort comprised patients with cervical cancer treated with definitive radiotherapy (RT) or concurrent chemoradiotherapy between June 2013 and March 2019. Local control (LC), overall survival (OS), and late toxicity were evaluated. Predictive factors for LC were analyzed by univariate and multivariate analyses.

RESULTS

Median doses of WP- and CS-EBRT and BT were 30.6 Gy_EQD2, 19.8 Gy_EQD2, and 40.3 Gy_EQD2, respectively. The 3-year LC rates for T1b2, T2a, T2b, T3b, and T4 were 100%, 100%, 97.3%, 86.9%, and 91.7%, respectively (p = 0.346). The 3-year OS for Stages IB, IIB, IIIB, IIIC, and IVA were 100%, 94.8%, 82.5%, 81.7%, and 74.6%, respectively (p = 0.037). Rates of Grade 3-4 gastrointestinal and genitourinary toxicities were 3.8% and 1.7%, respectively. Multivariate analysis showed that T3-4, nonsquamous cell histology, and high-risk clinical target volume (CTV_HR) D90 of BT < 36Gy_EQD2 were independently associated with significantly poorer LC.

CONCLUSIONS

The combination of WP- and CS-EBRT and CT-based IGBT with or without concurrent chemotherapy produced favorable LC outcomes with low rates of late toxicities for patients with small or medium-sized tumors. However, LC was less favorable for patients who had large T3 disease, and the use of CS requires caution in these patients.

Stereotactic Body Radiotherapy Boost with the CyberKnife for Locally Advanced Cervical Cancer: Dosimetric Analysis and Potential Clinical Benefits

(1) Aim: To compare the treatment plans of stereotactic body radiotherapy (SBRT) with CyberKnife (CK) and high-dose-rate (HDR) intracavitary/interstitial brachytherapy (IC/ISBT) and examine the feasibility of CK-SBRT as a viable alternative to BT in patients with locally advanced cervical cancer (LACC). (2) Methods: A BT plan of 28 Gy in four fractions delivered previously to 20 patients with LACC was compared with a CK plan based on the same CT images with structures delineation for BT. The SBRT treatment plan was further divided according to two different approaches, with the high-risk planning target volume (HR-PTV) defined by the high-risk clinical target volume (HR-CTV) without and with a 5 mm margin, which were named CK-CTV plan and CK-PTV plan, respectively. The dose distributions and dosimetric parameters of the target volumes and organs at risk (OARs) were recorded and compared for the three boost plans. Radiobiological metrics were calculated based on the EUD for the hybrid plans. Additionally, the relationship between tumor volume and tolerance doses for the OARs in the BT plan and CK-PTV plan was investigated. (3) Results: Target coverage was better with the CK plan than with the BT plan, as the D95%, D98%, HI and CI of the CK-CTV plan and CK-PTV plan were higher than those of the BT plan; an exception was the D50%. Similarly, the TCP of the target was also significantly in favor of the CK hybrid plans (p < 0.01). For the OARs, the CK-CTV plan was superior to the BT plan as regards the rectum D2cc, bladder D2cc and bladder Dmax. The CK-PTV plan could achieve dosimetric parameters comparable to those of the BT plan for OARs concerning the small residual tumor volume. The NTCP of the rectum for the WPI+CK-CTV plans was significantly lower than that of the WPI+BT plans (p < 0.01). (4) Conclusions: CK-based SBRT can achieve better target coverage, dose sparing for the OARs and radiobiological effects compared with the BT plan for tumors that are not excessively large. CK-based SBRT could be an alternative option to administer a radiation boost for patients with LACC.

Applicator for cervical brachytherapy for MRI or CT guided therapy

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Cervical applicator for brachytherapy with anchorage similar to intrauterine device.

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Cervical applicator that can be inserted bedside.

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Cervical applicator that can be associated with less pain compared to current applicators.

Cervical cancer is the second leading cause of cancer death in women aged 20 to 39 years in the USA. Radiation therapy for cervical cancer in the definitive setting is delivered by combining external beam radiation and brachytherapy. The procedure of cervical brachytherapy could be associated with significant discomfort and pain to the patient. Here we describe a novel cervical applicator, that can be inserted bedside, with local anesthesia only. The device is similar to intrauterine device and vaginal ring used for contraception, albeit with channels for high dose rate brachytherapy.

Local Control and Use of External Beam Parametrial Boost in the Era of Image-Guided Brachytherapy for Locally Advanced Cervical Cancer

OBJECTIVE

Historically, external beam parametrial boost (EBPB) has been used in locally advanced cervical cancers to supplement radiation dose. However, it has become controversial in the era of image-guided brachytherapy. Modern 3D imaging and brachytherapy techniques have improved delineation and coverage of tumor. Outcomes with and without parametrial boost were analyzed.

METHODS

Women with cervical cancer involving the parametria (clinically or radiographically) diagnosed between 2001 and 2017 were identified. Clinicopathologic and treatment features, survival and patterns of failure data were collected. Univariate and multivariable data analysis was performed to evaluate association of these variables, including parametrial boost, with local failure-free survival and overall survival. Competing risks analysis was performed for cumulative incidence of local failure, with death and other failures treated as competing events.

RESULTS

A total of 100 women were identified (median follow-up 26.8 mo). Forty-one (41%) received EBPB; these patients were less likely to have received magnetic resonance imaging, positron emission tomography, interstitial, or high-dose rate brachytherapy. Magnetic resonance imaging, positron emission tomography, dose rate, and treatment era were highly correlated (Cramer's V: 0.43 to 0.68, P<0.01). Two-year overall survival and local failure were 78% and 12% for the entire cohort. While the use of EBPB was not associated with any outcome on multivariable analysis, treatment year after 2009 was highly associated with improved outcomes in all models.

CONCLUSIONS

In this study, omission of EBPB did not compromise local control or survival in the modern era, supporting a decreased need for standardized use of parametrial boost.

Interfraction dose deviation and catheter position in cervical interstitial and intracavitary image guided HDR brachytherapy

Interstitial and intracavitary gynecological HDR brachytherapy involve precise, localized delivery to targets with high dose gradients, sparing adjacent organs at risk (OAR). Due to the proximity of the rectum, bowel and bladder to the target, deviations in the applicator or catheter with respect to patient anatomy can significantly increase dose to OAR. The magnitude and direction of applicator and catheter migration at each fraction was assessed for template interstitial and tandem and ring (T&R) cohorts. The cohort included twelve gynecological patients with intact cervical lesions treated with external beam and brachytherapy. Pre-treatment CT images were registered to the simulation CT with respect to the target. Treatment catheter positions transformed into the planning CT coordinate system to evaluate localized catheter displacement and dose distributions calculated at each fraction. Dose was evaluated on the planning CT with planning contours and dwell locations at treatment position. Absolute deviation, depth and deflection angle for all patients were 4.6 ± 4.2 mm, -1.4 ± 4.0 mm, and 3.1 ± 2.3° respectively (n = 516 catheter positions for all treatment fractions and patients, mean ± SD). Absolute catheter deviation and deflection magnitude for interstitial treatments increased overall with each subsequent fraction with an overall increase of catheter retraction at each fraction (p < 0.005, n = 492 catheters, Kruskal-Wallis). A target EQD2 D90 reduction of 10 ± 10% and 7.7 ± 8.7% of the planned dose for interstitial and T&R cohorts respectively. There was an overall increase in bladder and rectal doses at each fraction. Catheter tracking in interstitial and intracavitary gynecological treatments with CT imaging revealed significant changes in catheter positioning with respect to the target volume. Overall deviations increased in magnitude with each subsequent fraction in the interstitial treatments. This caused patient dosimetry deviations, including target dose reduction and adjacent OAR doses changes.

Changing Landscape of Radiation Therapy for Advanced Cervical Cancer With a Focus on Interstitial Brachytherapy: A Canadian Practice Patterns Survey

PURPOSE

To document the evolution of radical radiation therapy and interstitial brachytherapy (ISBT) utilization practice patterns across Canada, including use of imaging, technical details, and usage of anesthesia/analgesia, and to compare advanced (AC) versus nonadvanced (nAC) brachytherapy (BT) center practices.

METHODS AND MATERIALS

All Canadian centers with BT services were identified. One gynecology radiation oncologist per center was sent a 64-item questionnaire regarding the center's practice for patients with cervical cancer. Centers were categorized based on availability of advanced BT expertise (AC) versus those referring patients to other centers for advanced BT techniques (nAC). Aggregate responses are reported and compared with practice patterns identified in our previous survey. Descriptive statistics were used to summarize data, and the Fisher exact test, Fisher-Freeman-Halton, or Mann-Whitney-Wilcox test was used for comparisons.

RESULTS

Thirty-seven of 38 respondents completed the survey (response rate: 97.4%). Compared with 2015, there has been an increase in utilization of magnetic resonance imaging as the sole imaging modality for BT planning: 3 of 26 (11%) versus 12 of 37 (32%; P = .03). The number of centers with the ability to perform ISBT increased in 2020 compared with 2015 (26/37 [70%] vs 13/26 [50%], P = .710); this trend is likely due to an increase in use of hybrid (Vienna, Utrecht, Venezia) applicators (36% [2015] vs 84% [2020]; P = .175). Fifteen (40%) centers had the ability to perform perineal-ISBT (P-ISBT). Sixteen and 21 centers were identified as AC and nAC, respectively. All 16 AC centers had the ability to perform ISBT, compared with only 10 nAC centers (P < .001). A higher proportion of AC centers had fellowship-trained radiation oncologists performing brachytherapy, compared with nAC centers (94% vs 14%, P < .001). In terms of anesthesia, conscious sedation was the only available choice at low-patient-volume centers (8/37, 21%) performing intracavitary BT only. Those performing ISBT had choice of general, spinal, and epidural anesthesia.

CONCLUSIONS

In Canada, high-quality, modern management radiation therapy practices are consistently offered to patients with cervical cancer. There is a trend toward increased utilization of ISBT. Accumulation of evidence toward the use of ISBT, increased utilization of high-quality imaging modalities such as magnetic resonance imaging, and availability of hybrid applicators are potential contributors for this upward trend.

Risk Stratification of Early-Stage Cervical Cancer with Intermediate-Risk Factors: Model Development and Validation Based on Machine Learning Algorithm

Background

Adjuvant therapy for patients with cervical cancer (CC) with intermediate‐risk factors remains controversial. The objectives of the present study are to assess the prognoses of patients with early‐stage CC with pathological intermediate‐risk factors and to provide a reference for adjuvant therapy choice.

Materials and Methods

This retrospective study included 481 patients with stage IB–IIA CC. Cox proportional hazards regression analysis, machine learning (ML) algorithms, Kaplan‐Meier analysis, and the area under the receiver operating characteristic curve (AUC) were used to develop and validate prediction models for disease‐free survival (DFS) and overall survival (OS).

Results

A total of 35 (7.3%) patients experienced recurrence, and 20 (4.2%) patients died. Two prediction models were built for DFS and OS using clinical information, including age, lymphovascular space invasion, stromal invasion, tumor size, and adjuvant treatment. Patients were divided into high‐risk or low‐risk groups according to the risk score cutoff value. The Kaplan‐Meier analysis showed significant differences in DFS (p = .001) and OS (p = .011) between the two risk groups. In the traditional Sedlis criteria groups, there were no significant differences in DFS or OS (p > .05). In the ML‐based validation, the best AUCs of DFS at 2 and 5 years were 0.69/0.69, and the best AUCs of OS at 2 and 5 years were 0.88/0.63.

Conclusion

Two prognostic assessment models were successfully established, and risk grouping stratified the prognostic risk of patients with CC with pathological intermediate‐risk factors. Evaluation of long‐term survival will be needed to corroborate these findings.

Implications for Practice

The Sedlis criteria are intermediate‐risk factors used to guide postoperative adjuvant treatment in patients with cervical cancer. However, for patients meeting the Sedlis criteria, the choice of adjuvant therapy remains controversial. This study developed two prognostic models based on pathological intermediate‐risk factors. According to the risk score obtained by the prediction model, patients can be further divided into groups with high or low risk of recurrence and death. The prognostic models developed in this study can be used in clinical practice to stratify prognostic risk and provide more individualized adjuvant therapy choices to patients with early‐stage cervical cancer.

Adjuvant treatment for patients with cervical cancer remains controversial. This article assesses the prognosis of early‐stage cervical cancer with pathological intermediate‐risk factors and provides a reference for choice of adjuvant therapy.

Feasibility of fusing three-dimensional transabdominal and transrectal ultrasound images for comprehensive intraoperative visualization of gynecologic brachytherapy applicators

PURPOSE

In this study, we propose combining three-dimensional (3D) transrectal ultrasound (TRUS) and 3D transabdominal ultrasound (TAUS) images of gynecologic brachytherapy applicators to leverage the advantages of each imaging perspective, providing a broader field-of-view and allowing previously obscured features to be recovered. The aim of this study was to evaluate the feasibility of fusing these 3D ultrasound (US) perspectives based on the applicator geometry in a phantom prior to clinical implementation.

METHODS

In proof-of-concept experiments, 3D US images of application-specific multimodality pelvic phantoms were acquired with tandem-and-ring and tandem-and-ovoids applicators using previously validated imaging systems. Two TRUS images were acquired at different insertion depths and manually fused based on the position of the ring/ovoids to broaden the TRUS field-of-view. The phantom design allowed "abdominal thickness" to be modified to represent different body habitus and TAUS images were acquired at three thicknesses for each applicator. The merged TRUS images were then combined with TAUS images by rigidly aligning applicator components and manually refining the registration using the positions of source channels and known tandem length, as well as the ring diameter for the tandem-and-ring applicator. Combined 3D US images were manually, rigidly registered to images from a second modality (magnetic resonance (MR) imaging for the tandem-and-ring applicator and X-ray computed tomography (CT) for the tandem-and-ovoids applicator (based on applicator compatibility)) to assess alignment. Four spherical fiducials were used to calculate target registration errors (TREs), providing a metric for validating registrations, where TREs were computed using root-mean-square distances to describe the alignment of manually identified corresponding fiducials. An analysis of variance (ANOVA) was used to identify statistically significant differences (p < 0.05) between the TREs for the three abdominal thicknesses for each applicator type. As an additional indicator of geometric accuracy, the bladder was segmented in the 3D US and corresponding MR/CT images, and volumetric differences and Dice similarity coefficients (DSCs) were calculated.

RESULTS

For both applicator types, the combination of 3D TRUS with 3D TAUS images allowed image information obscured by the shadowing artifacts under single imaging perspectives to be recovered. For the tandem-and-ring applicator, the mean ± one standard deviation (SD) TREs from the images with increasing thicknesses were 1.37 ± 1.35 mm, 1.84 ± 1.22 mm, and 1.60 ± 1.00 mm. Similarly, for the tandem-and-ovoids applicator, the mean ± SD TREs from the images with increasing thicknesses were 1.37 ± 0.35 mm, 1.95 ± 0.90 mm, and 1.61 ± 0.76 mm. No statistically significant difference was detected in the TREs for the three thicknesses for either applicator type. The mean volume differences for the bladder segmentations were 3.14% and 2.33% and mean DSCs were 87.8% and 87.7% for the tandem-and-ring and tandem-and-ovoids applicators, respectively.

CONCLUSIONS

In this proof-of-concept study, we demonstrated the feasibility of fusing 3D TRUS and 3D TAUS images based on the geometry of tandem-and-ring and tandem-and-ovoids applicators. This represents a step toward an accessible and low-cost 3D imaging method for gynecologic brachytherapy, with the potential to extend this approach to other intracavitary configurations and hybrid applicators.

IBS-GEC ESTRO-ABS recommendations for CT based contouring in image guided adaptive brachytherapy for cervical cancer

MR Imaging is regarded asthe gold standardfor Image Gudied Adaptive Brachytherapy (IGABT) for cervical cancer. However, its wide applicability is limited by its availability, logistics and financial implications. Use of alternative imaging like CTand Ultrasound (US) for IGABT has been attempted. In order to arrive at a systematic, uniform and international approach for CT based definition and contouring of target structures, GEC ESTRO, IBS and ABS agreed to jointly develop such recommendations based on the concepts and terms as published in the ICRU Report 89. The minimum requirements are clinical examination & documentation, CT or MR imaging at diagnosis and at a minimum, CT imaging with the applicator in place. The recommendations are based on (i) assessment of the GTV at diagnosis and at brachytherapy, (ii) categorizing the response to external radiation into different clinical remission patterns, (iii) defining various clinico-radiological environments and (iv) definition & delineation of a target on CT imaging at the time of brachytherapy with the applicator in situ. CT based target contouring recommendations based on 4 remission categories within 8 defined environments, aim at improving the contouring accuracy for IGABT using CT, US and MRI as available. For each clinico-radiological environment, there is an attempt to minimize the specific uncertainties in order to arrive at the best possible contouring accuracy. Evaluating feasibility & reproducibility, to achieve a benchmark towards a gold standard MR IGABT and further clinical research including outcomes with CT Based IGABT will become the next steps.

Stereotactic body radiation therapy (SBRT) of adrenal gland metastases in oligometastatic and oligoprogressive disease

BACKGROUND

Stereotactic body radiation therapy (SBRT) as a form of noninvasive treatment that is becoming increasingly used to manage cancers with adrenal gland metastases. There is a paucity of data on safety and efficacy of this modality. The aim of the study was to evaluate the safety and efficacy of adrenal gland SBRT in oligometastatic and oligoprogressive disease.

MATERIALS AND METHODS

In this retrospective study, we performed a single-institution analysis of 26 adrenal lesions from 23 patients with oligometastatic or oligoprogressive disease treated from 2013 to 2019 with the goal of achieving durable local control. Palliative cases were excluded. Radiation dosimetry data was collected. Kaplan Meier product estimator and Cox proportional hazards regression analysis were used for statistical analysis.

RESULTS

The median dose was 36 Gy in 3 fractions (range: 24-50 Gy and 3-6 fractions) with a median biologically effective dose (BED10) of 72 (range: 40-100). 1-year local control rate was 80% and median local control was not achieved due to a low number of failures. 1- and 2-year overall survival rates were 66% and 32%. Toxicity was mild with only one case of grade 2 nausea and no grade 3-5 toxicity. Higher neutrophil to lymphocyte ratio was associated with worse overall survival and a trend toward worse progression-free survival. In addition, worse performance status and lower BED10 were associated with worse survival. No such association could be shown for primary tumor location, histology, size or stage.

CONCLUSION

Adrenal SBRT for oligometastatic or oligoprogressive disease is a safe and effective form of treatment.

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.

Toxicities and Recurrences after Co-60 High-Dose-Rate Brachytherapy for Cervical Cancer in a Tertiary Government Hospital in the Philippines

Introduction Despite the rising popularity of high-dose-rate (HDR) brachytherapy and use of Co-60 in the country, local data on brachytherapy outcomes are lacking. The study reviewed the incidence of toxicities and recurrences in patients with cervical cancer treated with Co-60 intracavitary HDR brachytherapy in a tertiary government hospital in the Philippines.

Methods Records of patients with cervical cancer who completed external beam radiotherapy (EBRT) and brachytherapy from 2016 to 2018 were reviewed. Patient-related (age, smoking history, body mass index, histology, stage, mass size) and treatment-related (overall treatment time [OTT], EBRT machine used, brachytherapy fractionation, dose prior to midline shielding/central tumor dose [CTD]) parameters were analyzed for possible associations with the incidence of toxicities and recurrences.

Results One hundred and sixty-three patients were identified and reviewed for baseline characteristics. Patients who had inadequate follow-up (<90 days) were excluded in the analysis of outcomes. Among the remaining 132 patients, median follow-up duration was 389 days. Gastrointestinal (GI) and genitourinary (GU) toxicities were present in 19.7% (n = 26) and 1.5% (n = 2), respectively. Recurrence was noted in 31.8% (n = 42). The most commonly involved sites of locoregional and distant recurrence was the uterocervix (n = 16, 59.3%) and para-aortics (n = 42, 31.8%), respectively. CTD was significantly associated with toxicities (p = 0.03), while OTT was borderline significantly associated with recurrence (p = 0.06).

Conclusion We present outcomes of GI and GU toxicities, and locoregional and distant recurrences after chemoradiation and Co-60 HDR brachytherapy in a tertiary government hospital in the Philippines. Our study suggests that CTD was significantly associated with incidence of toxicities, while OTT was weakly associated with recurrence. Interventions should be made to control these factors, especially in high-volume, low-resource cancer centers.

Characterization of combined intracavitary/interstitial brachytherapy including oblique needles in locally advanced cervix cancer

PURPOSE

To characterize and report on dosimetric outcomes of image guided adaptive brachytherapy (IGABT) using intracavitary and interstitial (IC/IS) applicators including oblique needles (O-needles) in locally advanced cervical cancer (LACC).

METHODS AND MATERIALS

Twenty LACC patients treated with radio-chemotherapy and offered IC/IS-IGABT including O-needles were analyzed. An in-house 3D-printed vaginal template was used to steer the needles parallel and obliquely in relation to the tandem, supplemented with free-hand needles if needed. Implant characteristics and loading patterns were analyzed. Using the equivalent dose in 2Gy-fractions (EQD2) concept, cumulative (EBRT+BT) V85, V75, V60Gy, targets/OARs doses and high dose volumes (150%, 200% and 300% (100% = 85 Gy EQD2₁₀)) were evaluated.

RESULTS

Median(range) tumor width at diagnosis was 5.5(3.6; 7.5)cm; CTV_HR volume was 45(23; 136)cm³ with maximum distance from tandem to CTV_HR border of 3.4(2.5; 4.8)cm. T-stage distribution was IIB/III/IVA in 6(30%)/9(45%)/5(25%) of patients. At BT, 13(65%) patients had distal parametrial/pelvic wall infiltration. Median(range) number of needles per patient was 11(8-18). Average distribution of intrauterine, vaginal and interstitial dwell times were 31%, 25% and 44%, respectively. Median(range) dwell-time per dwell position was 11(2-127)% of average point-A based standard loading. Median V_85Gy/V_150%/V_200%/V_300% were 85(38; 171)/41(21; 93)/22(12; 41)/7(4; 19) cm³; CTV_HR D_90% was 93(83; 97)Gy EQD2₁₀; bladder/rectum/sigmoid/bowel D_2cm3 were 78(64; 104)/65(52; 76)/59(53; 69)/61(47; 76)Gy EQD2₃.

CONCLUSIONS

The use of O-needles in patients with large and/or unfavorable tumors resulted in excellent target coverage and OARs sparing. Intrauterine and vaginal loadings were reduced compared to standard loading and almost half of the loading was shifted into IS needles. This was achieved with gentle loading in the majority of dwell positions.

Dose rate in the highest irradiation area of the rectum correlates with late rectal complications in patients treated with high-dose-rate computed tomography-based image-guided brachytherapy for cervical cancer

The purpose of this study was to evaluate the effect of dose rate to the rectum on late rectal complications in patients treated with computed tomography (CT)-based image-guided brachytherapy (IGBT) for cervical cancer. The subjects were 142 patients with cervical cancer who underwent Ir-192 high-dose-rate (HDR)-IGBT between March 2012 and January 2018. The dose rate to the rectum was calculated using in-house software. The minimum, mean and maximum effective dose rate (EDR) was calculated for voxels of the rectal volume covered by cumulative doses >D0.1cc, >D2cc, and > D5cc. The average EDR of three to four brachytherapy sessions was calculated (EDR for patients; EDRp). The total dose of the rectum was calculated as the biologically equivalent dose in 2-Gy fractions (EQD2). The associations between EDRp for D0.1cc, D2cc, and D5cc and the respective rectal EQD2 values with late rectal complications were then analyzed. The median follow-up period was 40 months. Patients with rectal complications of ≥Grade 1 received a significantly higher mean EDRp for D0.1cc-5cc and had a greater EQD2 for D0.1cc-5cc. Multivariate analysis was performed using the mean EDRp for D2cc, EQD2 for D2cc, heavy smoking and BMI. Of these four variables, mean EDRp for D2cc (HR = 3.38, p = 0.004) and EQD2 for D2cc (HR = 2.59, p = 0.045) emerged as independent predictors for late rectal complications. In conclusion, mean EDRp and EQD2 were associated with late rectal complications in patients treated with HDR CT-based IGBT for cervical cancer.

MRI-guided adaptive brachytherapy in locally advanced cervical cancer (EMBRACE-I): a multicentre prospective cohort study

BACKGROUND

The concept of the use of MRI for image-guided adaptive brachytherapy (IGABT) in locally advanced cervical cancer was introduced 20 years ago. Here, we report on EMBRACE-I, which aimed to evaluate local tumour control and morbidity after chemoradiotherapy and MRI-based IGABT.

METHODS

EMBRACE-I was a prospective, observational, multicentre cohort study. Data from patients from 24 centres in Europe, Asia, and North America were prospectively collected. The inclusion criteria were patients older than 18 years, with biopsy-proven squamous cell carcinoma, adenocarcinoma, or adenosquamous carcinoma of the uterine cervix, The International Federation of Gynecology and Obstetrics (FIGO) stage IB-IVA disease or FIGO stage IVB disease restricted to paraaortic lymph metastasis below the L1-L2 interspace, suitable for curative treatment. Treatment consisted of chemoradiotherapy (weekly intravenous cisplatin 40 mg/m2, 5-6 cycles, 1 day per cycle, plus 45-50 Gy external-beam radiotherapy delivered in 1·8-2 Gy fractions) followed by MRI-based IGABT. The MRI-based IGABT target volume definition and dose reporting was according to Groupe Européen de Curiethérapie European Society for Radiation Oncology recommendations. IGABT dose prescription was open according to institutional practice. Local control and late morbidity were selected as primary endpoints in all patients available for analysis. The study was registered with ClinicalTrials.gov, NCT00920920.

FINDINGS

Patient accrual began on July 30, 2008, and closed on Dec 29, 2015. A total of 1416 patients were registered in the database. After exclusion for not meeting patient selection criteria before treatment, being registered but not entered in the database, meeting the exclusion criteria, and being falsely excluded, data from 1341 patients were available for analysis of disease and data from 1251 patients were available for assessment of morbidity outcome. MRI-based IGABT including dose optimisation was done in 1317 (98·2%) of 1341 patients. Median high-risk clinical target volume was 28 cm3 (IQR 20-40) and median minimal dose to 90% of the clinical target volume (D90%) was 90 Gy (IQR 85-94) equi-effective dose in 2 Gy per fraction. At a median follow-up of 51 months (IQR 20-64), actuarial overall 5-year local control was 92% (95% CI 90-93). Actuarial cumulative 5-year incidence of grade 3-5 morbidity was 6·8% (95% CI 5·4-8·6) for genitourinary events, 8·5% (6·9-10·6) for gastrointestinal events, 5·7% (4·3-7·6) for vaginal events, and 3·2% (2·2-4·5) for fistulae.

INTERPRETATION

Chemoradiotherapy and MRI-based IGABT result in effective and stable long-term local control across all stages of locally advanced cervical cancer, with a limited severe morbidity per organ. These results represent a positive breakthrough in the treatment of locally advanced cervical cancer, which might be used as a benchmark for clinical practice and all future studies.

FUNDING

Medical University of Vienna, Aarhus University Hospital, Elekta AB, and Varian Medical Systems.

Development of a Machine Learning Model for Optimal Applicator Selection in High-Dose-Rate Cervical Brachytherapy

Purpose

To develop and validate a preliminary machine learning (ML) model aiding in the selection of intracavitary (IC) versus hybrid interstitial (IS) applicators for high-dose-rate (HDR) cervical brachytherapy.

Methods

From a dataset of 233 treatments using IC or IS applicators, a set of geometric features of the structure set were extracted, including the volumes of OARs (bladder, rectum, sigmoid colon) and HR-CTV, proximity of OARs to the HR-CTV, mean and maximum lateral and vertical HR-CTV extent, and offset of the HR-CTV centre-of-mass from the applicator tandem axis. Feature selection using an ANOVA F-test and mutual information removed uninformative features from this set. Twelve classification algorithms were trained and tested over 100 iterations to determine the highest performing individual models through nested 5-fold cross-validation. Three models with the highest accuracy were combined using soft voting to form the final model. This model was trained and tested over 1,000 iterations, during which the relative importance of each feature in the applicator selection process was determined.

Results

Feature selection indicated that the mean and maximum lateral and vertical extent, volume, and axis offset of the HR-CTV were the most informative features and were thus provided to the ML models. Relative feature importances indicated that the HR-CTV volume and mean lateral extent were most important for applicator selection. From the comparison of the individual classification algorithms, it was found that the highest performing algorithms were tree-based ensemble methods – AdaBoost Classifier (ABC), Gradient Boosting Classifier (GBC), and Random Forest Classifier (RFC). The accuracy of the individual models was compared to the voting model for 100 iterations (ABC = 91.6 ± 3.1%, GBC = 90.4 ± 4.1%, RFC = 89.5 ± 4.0%, Voting Model = 92.2 ± 1.8%) and the voting model was found to have superior accuracy. Over the final 1,000 evaluation iterations, the final voting model demonstrated a high predictive accuracy (91.5 ± 0.9%) and F1 Score (90.6 ± 1.1%).

Conclusion

The presented model demonstrates high discriminative performance, highlighting the potential for utilization in informing applicator selection prospectively following further clinical validation.

Prognostic Significance of Tumor Regression Rate during Concurrent Chemoradiotherapy in Locally Advanced Cervix Cancer: Analysis by Radiation Phase and Histologic Type

This study aimed to evaluate the prognostic significance of tumor regression rate according to radiation phase and histologic subtype in patients with locally advanced cervical cancer (LACC) treated with chemoradiation. We retrospectively reviewed the medical records of 398 patients with FIGO stage IIB-IVA cervical cancer treated with concurrent chemoradiotherapy (CCRT) between 2001 and 2019. Tumor response was assessed using serial magnetic resonance imaging (MRI) at three time points: pre-treatment, post-external beam radiotherapy (EBRT), and post-intracavitary radiotherapy (ICR). Tumor regression pattern according to histologic subtype and radiation phase (EBRT and ICR) was evaluated. Overall survival (OS) and progression-free survival (PFS) were the primary outcomes. Of 398 patients, 44 patients had adenocarcinoma/adenosquamous carcinoma (AC/ASC) and 354 patients had squamous cell carcinoma (SCC). AC/ASC was associated with significantly worse PFS and OS than SCC (p < 0.001). AC/ASC had a relatively poorer regression rate in response to EBRT than SCC (p < 0.001), whereas there was no significant difference in overall tumor regression rate after completion of RT (EBRT and ICR) between the two histologic subtypes. Multivariable analysis demonstrated AC/ASC histology to be an independent prognostic factor of decreased PFS and OS. Moreover, tumor regression rate after completion of EBRT (post-EBRT tumor regression rate (EBRT_regression ≤ 26%) and proportion of tumor regression during EBRT to overall tumor regression (EBRT_proportion ≤ 40%) were independent predictors of poor survival in patients with LACC. Tumor regression pattern of LACC in response to CCRT differs according to histologic subtype. AC/ASC histology and poor tumor response to EBRT are independent prognostic factors for worse survival in patients with LACC. Further studies are needed to develop a CCRT protocol that is specialized for patients with AC/ASC.

Stereotactic Body Radiation Therapy (SBRT) in Pelvic Lymph Node Oligometastases

The role of stereotactic body radiation therapy (SBRT) in achieving durable local control and palliation of pain in pelvic lymph node oligometastatic disease is not well-studied. We performed a retrospective analysis of 30 patients with 43 pelvic lymph node oligometastases from various primary cancers all but one with non-prostate primaries treated at our institution with SBRT. The median follow-up time was 21 months. The median SBRT dose was 24 Gy in four fractions. The one-, two-, and five-year local control was 74%, 71%, and 70% and one-, two-, and five-year overall survival was 70%, 47%, and 31%. Toxicities were mild with no grade 3 or higher.

Aiming for 100% Local Control in Locally Advanced Cervical Cancer: The Role of Complex Brachytherapy Applicators and Intraprocedural Imaging

The use of brachytherapy for the treatment of gynecologic malignancies, particularly cervical cancer, has a long and rich history that is nearly as long as the history of radiation oncology itself. From the first gynecologic brachytherapy treatments in the early 20th century to the modern era, significant transformation has occurred driven largely by advancements in technology. The development of high-dose rate sources, remote afterloaders, novel applicators, and 3-dimensional image guidance has led to improved local control, and thus improved survival, solidifying the role of brachytherapy as an integral component in the treatment of locally advanced cervical cancer. Current research efforts examining novel magnetic resonance imaging sequences, active magnetic resonance tracking, and the application of hydrogel aim to further improve local control and reduce treatment toxicity.

Comparison of computed tomography- and magnetic resonance imaging-based target delineation for cervical cancer brachytherapy

Purpose

The objective of this study was to compare and assess the accuracy of computed tomography (CT)-based target delineation with that of magnetic resonance imaging (MRI)-based on high-dose-rate brachytherapy (HDR-BT) for patients with cervical cancer.

Material and methods

Data of 20 patients with locally advanced cervical cancer were collected and evaluated. Dimensions, conformity, and dose parameters of high-risk clinical target volume (CTV_HR) as well as D_0.1cc, D_1cc, and D_2cc of organs at risk (OARs) based on MRI were compared with those based on CT.

Results

Average age of 20 patients included was 57.8 years. Width, thickness, and volumes of CT-based CTV_HR (CTV_HR-CT) were significantly overestimated compared with those of MRI-based CTV_HR (CTV_HR-MR). Mean values of dice similarity coefficient (DSC), Hausdorff distance (HD), and centroid distance (ΔV) of CTV_HR were 0.82 cm, 0.96 cm, and 0.35 cm, respectively. Dose values of CTV_HR-CT were significantly lower compared with those of CTV_HR-MR. Concerning OARs, geometrical and dosimetric values on CT were comparable to those on MRI.

Conclusions

The delineated ranges of CTV_HR were significantly over-estimated on CT compared with MRI. D₉₈ and D₉₀ of CTV_HR-CT were lower than CTV_HR-MR. DSC and ΔV of CTV_HR and CTV_IR were similar to each other; however, there was a difference in terms of HD. CT images regarding pre-BT MR images for delineating were not enough and MRI fusion is still required.

#ThisIsBrachytherapy: Increasing awareness of brachytherapy

PURPOSE

The use of brachytherapy continues to be a vital application of radiation oncology for various cancers. Despite this, there has been a decrease in the utilization of brachytherapy in many cancers. Social media in medicine facilitates engagement and advocacy. We launched a social media campaign to bring awareness of brachytherapy throughout the world with #ThisIsBrachytherapy hashtag on July 17, 2019.

METHODS AND MATERIALS

#ThisIsBrachytherapy hashtag was registered with Symplur Healthcare Hashtag Project. We collected total tweet counts, retweet counts, impression counts, geolocation, top 10 influencers, associated hashtags, associated words, and word sentiment score.

RESULTS

The campaign launched on July 17, 2019, had a total of 145 tweets on that day with 213,416 impressions. Twenty-seven accounts (45%) were identified as physicians. Top countries which tweeted, among those with information available, included the United States, United Kingdom, and Australia. Since July 17, 2019, there has been an increase in tweets using #ThisIsBrachytherapy, with 1990 total tweets with 1,999,248 impressions. Fifty-four percent (1030) of the tweets contained photos and 319 contained links. This was from 462 unique users. Word sentiment was overwhelmingly positive. Associated hashtags with #ThisIsBrachytherapy included most commonly #radonc, #brachytherapy, #brachy, #prostatecancer, and #pcsm.

CONCLUSIONS

The #ThisIsBrachytherapy inaugural campaign was successful and has continued to grow throughout the months after the initiation. By continuing to advocate for brachytherapy through the social media campaign #ThisIsBrachytherapy, we can empower radiation oncologists, especially trainees, and patients to address underutilization.

Hypnosedation for endocavitary uterovaginal applications: A pilot study

PURPOSE

Implantations for uterovaginal brachytherapy are usually performed under general or spinal anesthesia, which are not without risk. As it is a rather short procedure and since postoperative pain is minimal, hypnosedation was proposed to selected patients requiring endocavitary applications as part of their routine treatment.

METHODS AND MATERIALS

Consecutive patients requiring intracavitary uterovaginal brachytherapy from January to October 2019 were included if they accepted the procedure. A premedication was systematically administered. Hypnosedation was based on an Ericksonian technique. The procedure was immediately interrupted if the patient requested it, in cases of extreme anxiety or pain. Procedure was in that case rescheduled with a "classical" anesthesia technique.

RESULTS

A total of 20 patients were included. Four patients had to be converted toward a general anesthesia: one because of a fibroma on the probe's way and three young patients with a very anteverted/retroverted uterus that was painful at every mobilization. Mean and maximum pain scores during implant were 2.9/10 and 5.1/10, respectively. The most painful maneuver was cervical dilation for 45% of the patients, followed by mold insertion in 40% of cases. About 85% of the patients declared that hypnosis helped them relax; 90% of the patients would recommend the technique. No procedure-related complication occurred.

CONCLUSION

With a 70% success rate (correct implant with mean pain and anxiety scores < 5), one can conclude that uterovaginal brachytherapy implantation under hypnosedation is feasible and received a high satisfaction rate from the patients. This technique may reduce overall treatment time in a context of difficult access to the OR and to anesthesiologists, while reducing anesthetic drugs resort and postoperative nausea.

Ring Versus Ovoids and Intracavitary Versus Intracavitary-Interstitial Applicators in Cervical Cancer Brachytherapy: Results From the EMBRACE I Study

PURPOSE

The aim of this study was to investigate the influence of brachytherapy technique and applicator type on target dose, isodose surface volumes, and organ-at-risk (OAR) dose.

METHODS AND MATERIALS

Nine hundred two patients treated with tandem/ovoids (T&O) (n = 299) and tandem/ring (T&R) (n = 603) applicators from 16 EMBRACE centers were analyzed. Patients received external beam radiation therapy and magnetic resonance imaging guided brachytherapy with dose prescription according to departmental practice. Centers were divided into 4 groups, according to applicator/technique: Ovoids and ring centers treating mainly with the intracavitary (IC) technique and ovoids and ring centers treating routinely with the intracavitary/interstitial (IC/IS) technique. V85Gy EQD210, CTVHR D90% (EQD210), and bladder, rectum, sigmoid, and vaginal 5-mm lateral-point doses (EQD23) were evaluated among center groups. Differences between T&O and T&R were tested with multivariable analysis.

RESULTS

For similar point A doses, mean CTVHR D90% was 3.3 Gy higher and V85Gy was 23% lower for ring-IC compared with ovoids-IC centers (at median target volumes). Mean bladder/rectum doses (D2cm3 and ICRU-point) were 3.2 to 7.7 Gy smaller and vaginal 5-mm lateral-point was 19.6 Gy higher for ring-IC centers. Routine use of IC/IS technique resulted in increased target dose, whereas V85Gy was stable (T&R) or decreased (T&O); reduced bladder and rectum D2cm3 and bladder ICRU-point by 3.5 to 5.0 Gy for ovoids centers; and similar OAR doses for ring centers. CTVHR D90% was 2.8 Gy higher, bladder D2cm3 4.3 Gy lower, rectovaginal ICRU-point 4.8 Gy lower, and vagina 5-mm lateral-point 22.4 Gy higher for ring-IC/IS versus ovoids-IC/IS centers. The P values were <.002 for all comparisons. Equivalently, significant differences were derived from the multivariable analysis.

CONCLUSIONS

T&R-IC applicators have better target dose and dose conformity than T&O-IC in this representative patient cohort. IC applicators fail to cover large target volumes, whereas routine application of IC/IS improves target and OAR dose considerably. Patients treated with T&R show a more favorable therapeutic ratio when evaluating target, bladder/rectum doses, and V85Gy. A comprehensive view on technique/applicators should furthermore include practical considerations and clinical outcome.

The Impact of High-Dose-Rate Brachytherapy: Measuring Clinical Outcomes in the Primary Treatment of Cervical Cancer

Purpose

Radical concurrent chemoradiotherapy with combined external beam radiotherapy (EBRT) and brachytherapy is used to treat locally advanced cervical cancer. Our institution has transitioned to high-dose-rate (HDR) intracavitary brachytherapy (ICBT) from low-dose-rate (LDR) brachytherapy in 2008, and a review was conducted on the effect of this change on patient outcomes.

Methods and Materials

A single-arm retrospective chart review was performed on locally advanced (Fédération Internationale de Gynécologie et d’Obstétrique stage IB-IVA) patients with cervical cancer treated with combined external beam radiation therapy and HDR-ICBT with curative intent between 2008 and 2014. Clinical outcomes were evaluated, and multivariate analysis was performed to identify prognostic factors.

Results

Of the 76 patients selected, median age was 47.9 years and median follow-up was 5.2 years. Thirteen patients (17.1%) developed locoregional recurrence and 23 patients (30.3%) patients developed distant recurrence. Five-year progression-free survival and overall survival were 63.7% and 69.3%, respectively. A significant survival difference was found between stages (P < .001). Multivariate analysis found nodal involvement was strongly associated with poorer survival (P = .007).

Conclusions

Our experience with the transition to HDR-ICBT as part of concurrent chemoradiotherapy in treatment of locally advanced cervical cancer resulted in acceptable long-term outcomes and toxicity to that of LDR brachytherapy. Potential further improvement of treatment outcomes for patients may be possible with image guided brachytherapy and the addition of effective systemic therapy.