Radiotherapy in localized prostate cancer: a multicenter analysis evaluating tumor control and late toxicity after brachytherapy and external beam radiotherapy in 1293 patients

BACKGROUND AND PURPOSE

Comparing oncological outcomes and toxicity after primary treatment of localized prostate cancer using HDR- or LDR-mono-brachytherapy (BT), or conventionally (CF) or moderately hypofractionated (HF) external beam radiotherapy.

MATERIALS AND METHODS

Retrospectively, patients with low- (LR) or favorable intermediate-risk (IR) prostate cancer treated between 03/2000 and 09/2022 in two centers were included. Treatment was performed using either CF with total doses between 74 and 78 Gy, HF with 2.4-2.6 Gy per fraction in 30 fractions, or LDR- or HDR-BT. Biochemical control (BC) according to the Phoenix criteria, and late gastrointestinal (GI), and genitourinary (GU) toxicity according to RTOG/EORTC criteria were assessed.

RESULTS

We identified 1293 patients, 697 with LR and 596 with IR prostate cancer. Of these, 470, 182, 480, and 161 were treated with CF, HF, LDR-BT, and HDR-BT, respectively. For BC, we did not find a significant difference between treatments in LR and IR (p = 0.31 and 0.72). The 5‑year BC for LR was between 93 and 95% for all treatment types. For IR, BC was between 88% in the CF and 94% in the HF group. For CF and HF, maximum GI and GU toxicity grade ≥ 2 was between 22 and 27%. For LDR-BT, we observed 67% grade ≥ 2 GU toxicity. Maximum GI grade ≥ 2 toxicity was 9%. For HDR-BT, we observed 1% GI grade ≥ 2 toxicity and 19% GU grade ≥ 2 toxicity.

CONCLUSION

All types of therapy were effective and well received. HDR-BT caused the least late toxicities, especially GI.

Transrectal ultrasound for intraoperative interstitial needle guidance in cervical cancer brachytherapy

OBJECTIVE

This study aimed to prospectively assess the visibility of interstitial needles on transrectal ultrasound (TRUS) in cervical cancer brachytherapy patients and evaluate its impact on implant and treatment plan quality.

MATERIAL AND METHODS

TRUS was utilized during and after applicator insertion, with each needle's visibility documented through axial images at the high-risk clinical target volume's largest diameter. Needle visibility on TRUS was scored from 0 (no visibility) to 3 (excellent discrimination, margins distinct). Quantitative assessment involved measuring the distance between tandem and each needle on TRUS and comparing it to respective magnetic resonance imaging (MRI) measurements. Expected treatment plan quality based on TRUS images was rated from 1 (meeting all planning objectives) to 4 (violation of High-risk clinical target volume (CTVHR) and/or organ at risk (OAR) hard constraints) and compared to the final MRI-based plan.

RESULTS

Analysis included 23 patients with local FIGO stage IB2-IVA, comprising 41 applications with a total of 230 needles. A high visibility rate of 99.1% (228/230 needles) was observed, with a mean visibility score of 2.5 ± 0.7 for visible needles. The maximum and mean difference between MRI and TRUS measurements were 8 mm and -0.1 ± 1.6 mm, respectively, with > 3 mm discrepancies in 3.5% of needles. Expected treatment plan quality after TRUS assessment exactly aligned with the final MRI plan in 28 out of 41 applications with only minor deviations in all other cases.

CONCLUSION

Real-time TRUS-guided interstitial needle placement yielded high-quality implants, thanks to excellent needle visibility during insertion. This supports the potential of TRUS-guided brachytherapy as a promising modality for gynecological indications.

Association between Regular Vaginal Dilation and/or Sexual Activity and Long-Term Vaginal Morbidity in Cervical Cancer Survivors

PURPOSE/OBJECTIVE(S)

To evaluate the association between regular vaginal dilation and/or sexual activity and vaginal morbidity in locally advanced cervical cancer patients after definitive radiochemotherapy and image-guided adaptive brachytherapy from the EMBRACE I study.

MATERIALS/METHODS

Physician-assessed vaginal morbidity (CTCAE v.3), vaginal dilation and patient-reported sexual activity (EORTC QLQ CX24) were assessed at baseline, every 3 months in the 1st year, every 6 months in the 2nd and 3rd year and yearly thereafter. For this longitudinal analysis, a subgroup of patients was selected with at least 3 follow-ups with information on vaginal dilation and/or sexual activity. Vaginal penetration summarized either the use of vaginal dilators or sexual activity or both. Regular vaginal penetration was defined if reported in ≥50%, infrequent if reported in <50% and absent if reported in 0% of follow-ups. Actuarial estimates of vaginal morbidity were calculated with Kaplan-Meier method and included the individual symptoms: vaginal dryness, stenosis, mucositis and bleeding. Group comparisons were evaluated with the log-rank test.

RESULTS

The EMBRACE I study included 1416 patients overall (2008-2015); the subgroup of patients for this longitudinal evaluation consists of 882 patients, with a median follow-up of 60 months (IQR 47-77). Of those, 565 (64%) reported regular, 205 (23%) infrequent and 112 (13%) no penetration. Reporting regular penetration was associated with a significantly lower risk of vaginal stenosis G≥2 of 23% at 5 years, compared to reporting of infrequent (37%) and no penetration (36%, p≤0.001). However, reporting regular penetration was associated with a significantly higher risk for vaginal dryness G≥1 (72% vs. 69% vs. 62%, respectively, p = 0.038) and bleeding G≥1 (61% vs. 40% vs. 25%, respectively, p≤0.001). No associations were seen for G≥1 vaginal stenosis, G≥2 dryness, G≥2 bleeding and G≥1/G≥2 mucositis.

CONCLUSION

Regular penetration (defined as vaginal dilation and/or sexual activity) was associated with lower risk for vaginal stenosis G≥2, but higher risk for vaginal dryness G≥1 and bleeding G≥1. Mild vaginal dryness seems to become apparent in particular for patients experiencing vaginal penetration. Minor vaginal blood loss during dilation and/or sexual activity is commonly reported by patients, resulting from atrophy of the vaginal mucosa and/or telangiectasia. While both of these G≥1 symptoms can be managed with lubricants, moisturizer and/or hormonal replacement therapy, G≥2 vaginal stenosis represents an irreversible fibrotic adverse event that can cause dyspareunia in many cancer patients. These long-term data support clinical recommendations for dilation and/or sexual activity after radiotherapy.

EviGUIDE - a tool for evidence-based decision making in image-guided adaptive brachytherapy for cervical cancer

PURPOSE

To develop a novel decision-support system for radiation oncology that incorporates clinical, treatment and outcome data, as well as outcome models from a large clinical trial on magnetic resonance image-guided adaptive brachytherapy (MR-IGABT) for locally advanced cervical cancer (LACC).

METHODS

A system, called EviGUIDE, was developed that combines dosimetric information from the treatment planning system, patient and treatment characteristics, and established tumor control probability (TCP), and normal tissue complication probability (NTCP) models, to predict clinical outcome of radiotherapy treatment of LACC. Six Cox Proportional Hazards models based on data from 1341 patients of the EMBRACE-I study have been integrated. One TCP model for local tumor control, and five NTCP models for OAR morbidities.

RESULTS

EviGUIDE incorporates TCP-NTCP graphs to help users visualize the clinical impact of different treatment plans and provides feedback on achievable doses based on a large reference population. It enables holistic assessment of the interplay between multiple clinical endpoints and tumour and treatment variables. Retrospective analysis of 45 patients treated with MR-IGABT showed that there exists a sub-cohort of patients (20%) with increased risk factors, that could greatly benefit from the quantitative and visual feedback.

CONCLUSION

A novel digital concept was developed that can enhance clinical decision- making and facilitate personalized treatment. It serves as a proof of concept for a new generation of decision support systems in radiation oncology, which incorporate outcome models and high-quality reference data, and aids the dissemination of evidence-based knowledge about optimal treatment and serve as a blueprint for other sites in radiation oncology.

Implementation of online workshops on image-guided adaptive brachytherapy (interventional radiotherapy) in locally advanced cervical cancer: Experience of BrachyAcademy

PURPOSE

To provide educational support to brachytherapy users during the COVID-19 pandemic, online workshops were developed and implemented by BrachyAcademy, non-profit peer-to-peer educational initiative in Elekta.

METHODS AND MATERIALS

In 2021-2022 two online workshops were organized. Participating teams had to send a clinical case of locally advanced cervical cancer (LACC) including brachytherapy Digital Imaging and Communications in Medicine (DICOM) files and questions to the faculty. During the workshop, feedback was given to each clinical case by five faculty members (two Radiation Oncologists, one Radiologist, two Medical Physicists). Participants competed a post-workshop questionnaire which included combination of qualitative and quantitative questions via yes/no responses, Likert scale, and 1 to 10 scale.

RESULTS

Twenty-one teams from eight countries (Europe, Asia, Latin America) participated in two online workshops. The total number of participants was 49. The clinical cases represented LACC with The International Federation of Gynecology and Obstetrics (FIGO) stages from IB3 to IVA. During both, Workshop1 (W1) and Workshop 2 (W2) the following areas of improvement were identified: familiarity with the GEC ESTRO and The International Commission on Radiation Units & Measurements, Report 89 (ICRU 89) recommendations for contouring and planning based on clinical drawings and MRI sequencing choice; appropriate applicator selection; experience with interstitial needles; appropriate applicator reconstruction; dose optimization. The participants rated both workshops with overall scores 8,3 for W1, and 8,5 for W2. In 82% participants the training course fully met expectations for W1, and in 76% in W2.

CONCLUSIONS

We successfully implemented the online workshops on image-guided adaptive brachytherapy (IGABT) in LACC. Main performance issues and areas for improvement were identified based on multidisciplinary discussion of participant's clinical cases through all steps of the brachytherapy procedure. We encourage teams to consider online workshops in addition to hands-on training.

Brachytherapy boost in anal canal cancer - A GEC ESTRO PDR task force meta-analysis

Purpose

A meta-analysis is presented comparing clinical outcomes and toxicities between high dose rate (HDR) and pulsed dose rate (PDR) brachytherapy (BT) for anal cancer.

Methods and material

Retrospective or prospective clinical trials were identified on electronical databases. Data were collected per Preferred Reporting Items for Systematic Reviews and meta-Analyses guidelines. Pooled effect size for HDR and PDR BT were compared using subgroup analyses.

Results

Nine retrospective studies with a total of 481 patients treated were included of which 219 with HDR and 262 with PDR. Significant differences were observed between the two groups for baseline characteristics and treatment. The cumulative proportion of stage T3-T4 was lower in the HDR group, 0.15 [95 % confidence interval (CI) 0.07-0.29] vs 0.27 [95 %CI 0.09-0.57] in the LDR group, p < 0.001. Lower BT doses (in equivalent 2-Gy fraction dose) were given for patients in the HDR group, 11.9 Gy [95 %CI 8.2-15.5] vs 19.5 Gy [95 %CI 15.0-24.0] in the PDR group, p < 0.001. No significant differences were found for clinical outcomes or toxicities. The pooled effect size of the overall survival at 5 years for HDR and PDR was respectively 0.82 [95 %CI 0.70-0.94] and 0.82 [95 %CI 0.73-0.91], p > 0.99. The 5 years local control was 0.86 [95 % confidence interval (CI) 0.81-0.91] and 0.83 [95 %CI 0.77-0.89], p = 0.62. Cumulative toxicity-related colostomy proportion was 0.04 [95 %CI 0.02-0.09] and 0.03 [95 %CI 0.02-0.07], p = 0.85.

Conclusion

Both modalities provided a good profile of tolerance and are effective organ conservative strategies for patients with anal canal cancer. In parallel with ongoing developments to better determine the optimal fractionation and dose for HDR-BT treatments, especially in large tumors, PDR BT still has a crucial role for dose escalation strategy in advanced cases.

Overall Severe Morbidity After Chemo-Radiation Therapy and Magnetic Resonance Imaging-Guided Adaptive Brachytherapy in Locally Advanced Cervical Cancer: Results From the EMBRACE-I Study

PURPOSE

To evaluate overall severe late morbidity (grade ≥3) in patients with locally advanced cervical cancer treated with chemo-radiation therapy and magnetic resonance image guided adaptive brachytherapy within the prospective EMBRACE-I study, and to compare the results with published literature after standard radiograph based brachytherapy (BT).

METHODS AND MATERIALS

From 2008 to 2015 the EMBRACE-I study enrolled 1416 patients. Morbidity was assessed (Common Terminology Criteria for Adverse Events version 3.0) every 3 months the 1st year, every 6 months the second and third year, and yearly thereafter and 1251 patients had available follow-up on late morbidity. Morbidity events (grade 3-5) were summarized as the maximum grade during follow-up (crude incidence rates) and actuarial estimates at 3 and 5 years. To compare with the published literature on standard radiograph based BT, Common Terminology Criteria for Adverse Events scores from the EMBRACE-I study were retrospectively converted into a corresponding score in the Radiation Therapy Oncology Group and European Organization for Research and Treatment of Cancer system.

RESULTS

In total, 534 severe events occurred in 270 patients; 429 events were grade 3 and 105 were grade 4 events. Actuarial estimates for grade ≥3 gastrointestinal (GI), genitourinary (GU), vaginal and fistula events at 5 years were 8.5% (95% confidence interval [CI], 6.9%-10.6%), 6.8% (95% CI, 5.4%-8.6%), 5.7% (95% CI, 4.3%-7.6%), and 3.2% (95% CI, 2.2%-4.5%), respectively. The 5-year actuarial estimate for organ-related events (GI, GU, vaginal, or fistula) was 18.4% (95% CI, 16.0%-21.2%). The 5-year actuarial estimate when aggregating all G≥3 endpoints (GI, GU, vaginal, fistulas, and non-GI/GU/vaginal) was 26.6% (95% CI, 23.8%-29.6%). Thirteen patients had a treatment-related death, 8 of which were associated with GI morbidity.

CONCLUSIONS

This report assesses severe morbidity from the largest prospective study on chemo-radiation therapy and image guided adaptive brachytherapy for locally advanced cervical cancer to date. Severe late morbidity was limited per endpoint and organ category, but considerable when aggregated across organs and all endpoints. The late morbidity results in the EMBRACE-I study compare favorably with published literature on standard radiograph based BT for GI morbidity, vaginal morbidity, and fistulas.

Risk Factors for Local Failure Following Chemoradiation and Magnetic Resonance Image-Guided Brachytherapy in Locally Advanced Cervical Cancer: Results From the EMBRACE-I Study

PURPOSE

To report clinical and treatment characteristics, remission and failure patterns, and risk factors for local failure (LF) from the EMBRACE-I study.

MATERIALS AND METHODS

EMBRACE-I was a prospective, observational, multicenter cohort study on magnetic resonance imaging-based image-guided adaptive brachytherapy (MR-IGABT) in locally advanced cervical cancer. Treatment consisted of external beam radiotherapy, concurrent chemotherapy, and MR-IGABT. LF was defined as progressive or recurrent disease in the cervix, uterus, parametria, pelvic wall, or vagina. Competing risk analysis was used to estimate local tumor control (LC) and Cox proportional regression models for multivariable analysis and dose-response analysis.

RESULTS

One thousand three hundred eighteen patients with a median follow-up of 52 months were available for this analysis. Eighty-one patients had persistent disease 3 months after end of treatment. Of those, 60 patients achieved LC at 6-9 months without further treatment, whereas 21 patients had progressive disease. In addition, 77 patients developed a local recurrence after complete remission comprising a total number of 98 LFs. LFs were located inside the MR-IGABT target volumes in 90% of patients with LF. In multivariable analysis, histology, minimal dose to 90% of high-risk clinical target volume (CTV_HR), maximum tumor dimension, CTV_HR > 45 cm³, overall treatment time, tumor necrosis on magnetic resonance imaging at diagnosis, uterine corpus infiltration at diagnosis and at MR-IGABT, and mesorectal infiltration at MR-IGABT had significant impact on LF. Dose-response analysis showed that a minimal dose to 90% of 85 Gy to the CTV_HR led to 95% (95% CI, 94 to 97) LC 3 years postintervention for squamous cell in comparison to 86% (95% CI, 81 to 90) for adeno/adenosquamous carcinoma histology.

CONCLUSION

The present study demonstrates the safety and validity of the GYN GEC-ESTRO/ICRU-89 target concept and provides large-scale evidence for dose prescription and new risk factors for LF in MR-IGABT in locally advanced cervical cancer.

The Effect of Land-Use Categories on Traffic Noise Annoyance

Land-use categories are often used to define the exposure limits of national environmental noise policies. Often different guideline values for noise are applied for purely residential areas versus residential areas with mixed-use. Mixed-use includes living plus limited activities through crafts, commerce, trade, agriculture, and forestry activities. This differentiation especially when rating noise from road, railway, and air traffic might be argued by different expectations and therefore noise annoyance in those two categories while scientific evidence is missing. It should be tested on empirically derived data. Surveys from two studies in the state of Tyrol in urban and rural areas were retrospectively matched with spatial data to analyze the potential different influences on noise effects. Using non-parametric tests, the correlation between land-use category on self-reported noise sensitivity and noise annoyance was investigated. Exposure-response for the two analyzed land-use categories showed no significant impact on noise sensitivity and exposure-response relationships for the three traffic noise sources. Including only noise annoyance, there is not sufficient evidence to define different noise policies for those two land-use categories.

Neural network-assisted automated image registration for MRI-guided adaptive brachytherapy in cervical cancer

PURPOSE

In image-guided adaptive brachytherapy (IGABT) a quantitative evaluation of the dosimetric changes between fractions due to anatomical variations, can be implemented via rigid registration of images from subsequent fractions based on the applicator as a reference structure. With available treatment planning systems (TPS), this is a manual and time-consuming process. The aim of this retrospective study was to automate this process. A neural network (NN) was trained to predict the applicator structure from MR images. The resulting segmentation was used to automatically register MR-volumes.

MATERIAL AND METHODS

DICOM images and plans of 56 patients treated for cervical cancer with high dose-rate (HDR) brachytherapy were used in the study. A 2D and a 3D NN were trained to segment applicator structures on clinical T2-weighted MRI datasets. Different rigid registration algorithms were investigated and compared. To evaluate a fully automatic registration workflow, the NN-predicted applicator segmentations (AS) were used for rigid image registration with the best performing algorithm. The DICE coefficient and mean distance error between dwell positions (MDE) were used to evaluate segmentation and registration performance.

RESULTS

The mean DICE coefficient for the predicted AS was 0.70 ± 0.07 and 0.58 ± 0.04 for the 3D NN and 2D NN, respectively. Registration algorithms achieved MDE errors from 8.1 ± 3.7 mm (worst) to 0.7 ± 0.5 mm (best), using ground-truth AS. Using the predicted AS from the 3D NN together with the best registration algorithm, an MDE of 2.7 ± 1.4 mm was achieved.

CONCLUSION

Using a combination of deep learning models and state of the art image registration techniques has been demonstrated to be a promising solution for automatic image registration in IGABT. In combination with auto-contouring of organs at risk, the auto-registration workflow from this study could become part of an online-dosimetric interfraction evaluation workflow in the future.

AAPM Task Group Report 303 endorsed by the ABS: MRI Implementation in HDR Brachytherapy-Considerations from Simulation to Treatment

The Task Group (TG) on Magnetic Resonance Imaging (MRI) Implementation in High Dose Rate (HDR) Brachytherapy - Considerations from Simulation to Treatment, TG 303, was constituted by the American Association of Physicists in Medicine's (AAPM's) Science Council under the direction of the Therapy Physics Committee, the Brachytherapy Subcommittee, and the Working Group on Brachytherapy Clinical Applications. The TG was charged with developing recommendations for commissioning, clinical implementation, and on-going quality assurance (QA). Additionally, the TG was charged with describing HDR brachytherapy (BT) workflows and evaluating practical consideration that arise when implementing MR imaging. For brevity, the report is focused on the treatment of gynecologic and prostate cancer. The TG report provides an introduction and rationale for MRI implementation in BT, a review of previous publications on topics including available applicators, clinical trials, previously published BT related TG reports, and new image guided recommendations beyond CT based practices. The report describes MRI protocols and methodologies, including recommendations for the clinical implementation and logical considerations for MR imaging for HDR BT. Given the evolution from prescriptive to risk-based QA,¹ an example of a risk-based analysis using MRI-based, prostate HDR BT is presented. In summary, the TG report is intended to provide clear and comprehensive guidelines and recommendations for commissioning, clinical implementation, and QA for MRI-based HDR BT that may be utilized by the medical physics community to streamline this process. This report is endorsed by the American Brachytherapy Society (ABS). This article is protected by copyright. All rights reserved.

Prognostic Implications of Uterine Cervical Cancer Regression During Chemoradiation Evaluated by the T-Score in the Multicenter EMBRACE I Study

PURPOSE

A simple scoring system (T-score, TS) for integrating findings from clinical examination and magnetic resonance imaging (MRI) of the primary tumor at diagnosis has shown strong prognostic capability for predicting local control and survival in locally advanced cervical cancer treated with chemoradiation and MRI-guided brachytherapy (BT). The aim was to validate the performance of TS using the multicenter EMBRACE I study and to evaluate the prognostic implications of TS regression obtained during initial chemoradiation.

METHODS AND MATERIALS

EMBRACE I recruited 1416 patients, of whom 1318 were available for TS. Patients were treated with chemoradiation followed by MRI-guided BT. A ranked ordinal scale of 0 to 3 points was used to assess 8 anatomic locations typical for local invasion of cervical cancer. TS was calculated separately at diagnosis (TSD) and at BT (TSBT) by the sum of points obtained from the 8 locations at the 2 occasions.

RESULTS

Median TSD and TSBT was 5 and 4, respectively. TS regression was observed in 71% and was an explanatory variable for BT technique (intracavitary vs intracavitary/interstitial) and major dose-volume histogram parameters for BT, such as high-risk clinical target (CTVHR), CTVHR D90 (minimal dose to 90% of the target volume), D2cm3 bladder (minimal dose to the most exposed 2 cm3 of the bladder), and D2cm3 rectum. TS regression (TSBT≤5) was associated with improved local control and survival and with less morbidity compared with patients with TSBT remaining high (>5) despite initial chemoradiation. TS regression was significant in multivariate analysis for both local control and survival when analyzed in consort with already established prognostic parameters related to the patient, disease, and treatment.

CONCLUSIONS

TS was validated in a multicenter setting and proven to be a strong multidisciplinary platform for integration of clinical findings and imaging with the ability to quantitate local tumor regression and its prognostic implications regarding BT technique, dose-volume histogram parameters, local control, survival, and morbidity.

Dosimetric impact of target definition in brachytherapy for cervical cancer – Computed tomography and trans rectal ultrasound versus magnetic resonance imaging

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This study evaluated the dosimetric impact of target volume delineation in Computed Tomography (CT) with assistance from Trans Rectal Ultrasound (TRUS) as compared to Magnetic Resonance Imaging (MRI) image-based brachytherapy for cervical cancer.

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No statistically significant systematic difference was found between MRI and CT for target structures.

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However, considerable variations were seen on individual patient level which needs to be considered during clinical practice, which also needs further investigations.

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Current findings provide useful information to optimally utilize various imaging modalities for brachytherapy planning.

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Although, CT + TRUS based delineation of target volume, appear promising, MRI remains the gold standard.

Background and Purpose

Magnetic Resonance Imaging (MRI) based target definition in cervix brachytherapy is limited by its availability, logistics and financial implications, therefore, use of computed tomography (CT) and Trans Rectal UltraSonography (TRUS) has been explored. The current study evaluated the dosimetric impact of CT + TRUS based target volumes as compared to gold standard MRI.

Methods and Materials

Images of patients (n = 21) who underwent TRUS followed by MRI and CT, were delineated with High-Risk Clinical Target Volume in CT (CTV_HR-CT) and in MRI (CTV_HR-MR). CTV_HR-CT was drawn on CT images with TRUS assistance. For each patient, two treatment plans were made, on MRI and CT, followed by fusion and transfer of CTV_HR-MR to the CT images, referred as CTV_HR-MRonCT. The agreement between CTV_HR-MRonCT and CTV_HR-CT was evaluated for dosimetric parameters (D₉₀, D₉₈ and D₅₀; Dose received by 90%, 98% and 50% of the volumes) using Bland-Altman plots, linear regression, and Pearson correlation.

Results

No statistically significant systematic difference was found between MRI and CT. Mean difference (±1.96 SD) of D₉₀, D₉₈ and D₅₀ between CTV_HR-MRonCT and CTV_HR-CT was 2.0, 1.2 and 5.6 Gy respectively. The number of patients who have met the dose constraints of D₉₀ > 85 Gy were 90% and 80% in MR and in CT respectively, others were in the borderline, with a minimum dose of 80 Gy. The mean ± SD dose-difference between MR and CT plans for bladder was significant (5 ± 13 Gy; p = 0.12) for D_0.1cm3, while others were statistically insignificant.

Conclusion

CT + TRUS based delineation of CTV_HR appear promising, provide useful information to optimally utilize for brachytherapy planning, however, MRI remains the gold standard.

Toward 3D-TRUS image-guided interstitial brachytherapy for cervical cancer

PURPOSE

To qualitatively and quantitatively analyze needle visibility in combined intracavitary and interstitial cervical cancer brachytherapy on 3D transrectal ultrasound (TRUS) in comparison to gold standard MRI.

METHODS AND MATERIALS

Image acquisition was done with a customized TRUS stepper unit and software (Medcom, Germany; Elekta, Sweden; ACMIT, Austria) followed by an MRI on the same day with the applicator in place. Qualitative assessment was done with following scoring system: 0 = no visibility 1 (= poor), 2 (= fair), 3 (= excellent) discrimination, quantitative assessment was done by measuring the distance between each needle and the tandem two centimeters (cm) above the ring and comparing to the respective measurement on MRI.

RESULTS

Twenty-nine implants and a total of 188 needles (132 straight, 35 oblique, 21 free-hand) were available. Overall, 79% were visible (87% straight, 51% oblique, 76% free-hand). Mean visibility score was 1.4 ± 0.5 for all visible needles. Distance of the visible needles to tandem was mean ± standard deviation (SD) 21.3 millimeters (mm) ± 6.5 mm on MRI and 21.0 mm ± 6.4 mm on TRUS, respectively. Difference between MRI and TRUS was max 14 mm, mean ± SD -0.3 mm ± 2.6 mm. 11% differed more than 3 mm.

CONCLUSIONS

Straight needles were better detectable than oblique needles (87% vs. 51%). Detectability was impaired by insufficient rotation of the TRUS probe, poor image quality or anatomic variation. As needles show a rather indistinct signal on TRUS, online detection with a standardized imaging protocol in combination with tracking should be investigated, aiming at the development of real time image guidance and online treatment planning.

Comparison of EBRT and I-125 seed brachytherapy concerning outcome in intermediate-risk prostate cancer

PURPOSE

This study's objective was the comparison of external beam radiotherapy (EBRT) and I‑125 seed brachytherapy regarding clinical outcome and development of side effects.

PATIENTS AND METHODS

In all, 462 localized intermediate-risk prostate cancer patients treated between 2000 and 2019 at our department using either I‑125 seed brachytherapy or EBRT with a dose of 74 or 78 Gy were included: 297 patients were treated with EBRT and 165 with seeds. Biochemical no evidence of disease (bNED) rates according to Phoenix definition as well as late gastrointestinal and urogenital side effects (EORTC/RTOG) were assessed.

RESULTS

Patients were followed up yearly with a median follow-up of 54 (3-192) months. Observed bNED rates for 74 Gy, 78 Gy and seeds were 87, 92, and 88% after 5 years and 71, 85, and 76% after 9 years, respectively. No significant differences were found comparing seeds with 74 Gy (p = 0.81) and 78 Gy (p = 0.19), as well as between 74 and 78 Gy (p = 0.32). Concerning gastrointestinal side effects, EBRT showed significantly higher rates of RTOG grade ≥ 2 toxicity compared to seeds, but at no point of the follow-up more than 10% of all patients. However, genitourinary side effects were significantly more prevalent in patients treated with seeds, with 33% RTOG grade ≥ 2 toxicity 12 months after treatment. Nevertheless, both types of side effects decreased over time.

CONCLUSION

Favorable intermediate-risk prostate cancer patients can be treated either by external beam radiotherapy (74/78 Gy) or permanent interstitial seed brachytherapy.

Severity and persistency of late gastrointestinal morbidity in locally advanced cervical cancer: lessons learned from EMBRACE-I and implications for the future

PURPOSE

To evaluate patient- and treatment-related risk factors for physician-assessed and patient-reported gastrointestinal (GI) symptoms after radio(chemo)therapy and image guided adaptive brachytherapy (IGABT) in locally advanced cervical cancer (LACC).

MATERIAL AND METHODS

Of 1416 patients from the XXX study, 1199 and 1002 were prospectively evaluated using physician-assessed (CTCAE) and patient-reported (EORTC) GI symptoms, respectively. CTCAE severe grade (G≥3) events were pooled according to the location in the GI tract (anus/rectum, sigmoid and colon/small bowel). CTCAE G≥2 and EORTC "very much" and "quite a bit"+"very much" scores (≥"quite a bit") were analyzed for individual symptoms with Cox regression. Logistic regression was used for persistent G≥1 and EORTC ≥"quite a bit" symptoms, defined if present in at least half of follow-ups.

RESULTS

Incidence of G≥3 events was 2.8%, 1.8% and 2.3% for G≥3 anus/rectum, sigmoid and colon/small bowel events, respectively. Among G≥2 symptoms, diarrhea and flatulence were the most prevalent (8.4% and 9.9%, respectively). Among patient-related factors, baseline morbidity, increasing age, smoking status and low body-mass-index were associated to GI symptoms with different impact. Among treatment-related factors, rectum D_2cm3 and ICRU recto-vaginal reference point (RV-RP) correlated with G≥3 anus/rectum events, and moderate/persistent diarrhea, proctitis, bleeding, abdominal cramps and difficulty in bowel control. Bowel D_2cm3 correlated with G≥3 sigmoid and colon/small bowel events, and moderate/persistent diarrhea and flatulence. For external beam radiotherapy (EBRT), prescription dose correlated with G≥3 anus/rectum, diarrhea and difficulty in bowel control. Patients with large lymph-node boost (V57Gy) were at higher risk for G≥3 sigmoid events, moderate/persistent diarrhea, proctitis and cramps.

CONCLUSION

The analysis showed that both EBRT and IGABT contribute to GI symptoms after LACC treatment. Rectum D_2cm3, ICRU RV-RP and bowel D_2cm3 are risk factors for GI morbidity. The risk for various symptoms was lower with an EBRT prescription of 45Gy than 50Gy, and increased with larger V57Gy.

Low-Dose-Rate versus High-Dose-Rate intracavitary brachytherapy in cervical cancer - Final Results of a Phase III randomized trial

PURPOSE

Intracavitary brachytherapy using High-Dose-Rate (HDR) and Low-dose-rate (LDR) in cervical cancer has been utilized. We report the long-term final results of a large randomized trial in terms of toxicities and efficacy.

METHODS AND MATERIALS

Between 1996 to 2005, 816 patients were randomized to LDR (n = 441 patients) or HDR brachytherapy (n = 369 patients) stratified by FIGO Stage grouping. Patients with Stage I-II received external irradiation of 40 Gy in 20 fractions (with midline block (MLB)) followed by either 2 LDR Intracavitary applications of 30 Gy to point A (2-3 weeks apart) or 5 HDR Intracavitary applications of 7 Gy to point A once weekly. Patients with Stage III received 50 Gy in 25 fractions (with MLB after 40 Gy) followed by either one application of LDR 30 Gy to point A or three applications of HDR 7 Gy to point A once weekly.

RESULTS

With a median follow-up was 64 months (interquartile range [IQR]: 21 - 111), moderate to severe rectal and bladder complications were higher in LDR arm as compared to HDR arm (9.7% vs. 3.6%; p = 0.02) and (10.5% vs. 5.5%; p = 0.06) for Stage I-II. No difference in rectal or bladder complications for Stage III patients. Disease free and overall survivals were similar in both the arms for all stages.

CONCLUSIONS

HDR intracavitary brachytherapy with 7 Gy per fraction weekly is superior to LDR in terms of late rectal and bladder complications. Local control rates and survivals are similar irrespective of stages.

Risk factors for nodal failure after radiochemotherapy and image guided brachytherapy in locally advanced cervical cancer: An EMBRACE analysis

OBJECTIVE

To assess risk factors for nodal failure (NF) after definitive (chemo)radiotherapy and image-guided brachytherapy for locally advanced cervical cancer (LACC) for patients treated in the EMBRACE I study.

MATERIALS AND METHODS

Data for pelvic NF and para-aortic (PAO) NF (NF_PAO) were analysed. After multiple imputation, univariable and multivariable Cox-regression was performed for clinical and treatment-related variables. For patients with affected pelvic nodes but no PAO nodes at diagnosis, additional analyses were performed for two subgroups: 1. 'small pelvis' nodes in internal and external iliac, obturator, parametrial, presacral and/or common iliac (CI) region and 2. any CI nodes (subgroup of 1).

RESULTS

1338 patients with 152 NF and 104 NF_PAO events were analysed with a median follow-up of 34.2 months (IQR 16.4-52.7). For the entire group, larger tumour width, nodal risk groups (in particular any CI nodes without PAO nodes), local failure, and lower Hb-nadir increased the risk of NF. Elective PAO-irradiation was independently associated with a decreased risk of NF_PAO (HR 0.53, 95%-CI 0.28-1.00, p = 0.05). For subgroup 1, having 'any CI nodes without PAO nodes' and local failure significantly increased NF risk. Additionally, elective PAO-irradiation was associated with less risk of NF_PAO (HR 0.38, 95%-CI 0.17-0.86, p = 0.02). For subgroup 2 only local failure was associated with higher risk of NF.

CONCLUSION

In this patient cohort, nodal disease and tumour width at diagnosis, as well as local failure, are risk factors for NF after definitive treatment. Having either 'any PAO nodes' (with or without pelvic nodes) or 'any CI nodes' (without PAO nodes) are stronger risk factors than involvement of nodes in the small pelvis alone. Elective PAO-irradiation was associated with significantly less NF_PAO, particularly in patients with nodal disease in the 'small pelvis' and/or CI region at time of diagnosis.

Nomogram Predicting Overall Survival in Patients With Locally Advanced Cervical Cancer Treated With Radiochemotherapy Including Image-Guided Brachytherapy: A Retro-EMBRACE Study

PURPOSE

To present a nomogram for prediction of overall survival (OS) in patients with locally advanced cervical cancer (LACC) undergoing definitive radiochemotherapy including image-guided adaptive brachytherapy (IGABT).

METHODS AND MATERIALS

Seven hundred twenty patients with LACC treated with radiochemotherapy including IGABT in 12 institutions (median follow-up 56 months) were analyzed; 248 deaths occurred. Thirteen candidate predictors for OS were a priori chosen on the basis of the literature and expert knowledge. Missing data (7.2%) were imputed using multiple imputation and predictive mean matching. Univariate analysis with a multivariable Cox regression model for OS stratified by center was performed. Stepwise selection of predictive factors with the Akaike Information Criterion was used to obtain a predictive model and construct a nomogram for OS predictions 60 months from diagnosis; this was internally validated by concordance probability as a measure of discrimination and a calibration plot.

RESULTS

Thirteen potential predictive factors were evaluated; 10 factors reached statistical significance in univariate analysis (age, Hemoglobin, FIGO Stage₂₀₀₉, tumor width, corpus involvement, lymph node involvement, concurrent chemotherapy, dose to 90% of the high-risk clinical target volume_, volume of CTV at the first brachytherapy [CTV_HRVolumeBT], overall treatment time [OTT]). Four factors were confirmed significant within the multivariable Cox regression model (FIGO Stage₂₀₀₉, lymph node involvement, concurrent chemotherapy, CTV_HRVolumeBT). The predictive model and corresponding nomogram were based on 7 Akaike Information Criterion-selected factors (age, corpus involvement, FIGO Stage₂₀₀₉, lymph node involvement, concurrent chemotherapy, CTV_HRVolumeBT, OTT) and showed promising calibration and discrimination (cross-validated concordance probability c = 0.73).

CONCLUSIONS

This is the first nomogram to predict OS in patients with LACC treated with IGABT. In addition to previously reported factors (age, FIGO₂₀₀₉ stage, corpus involvement, chemotherapy delivery, OTT, lymph node involvement), status of primary tumor at the time of brachytherapy seems to be an essential outcome predictor. These results can facilitate individualized tailoring of treatment and patient counseling during the treatment.

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.

Risk factors and dose-effects for bladder fistula, bleeding and cystitis after radiotherapy with imaged-guided adaptive brachytherapy for cervical cancer: An EMBRACE analysis

PURPOSE

To identify patient- and treatment-related risk factors for fistula, bleeding, cystitis, pain and difficulty in voiding in locally advanced cervical cancer patients treated with radio(chemo)therapy and image-guided adaptive brachytherapy (IGABT).

MATERIAL AND METHODS

Morbidity within the EMBRACE-I study was prospectively reported for physician-assessed (CTCAE) fistula, bleeding and cystitis and patient-reported (EORTC) pain and difficulty in voiding. Analysis of risk factors was performed in patients without bladder infiltration. Risk factors were tested with Cox regression for grade (G) ≥ 3 cystitis, for G ≥ 2 fistula, bleeding and cystitis, and for EORTC "very much" and "quite a bit" or worse.

RESULTS

Of 1416 patients enrolled, 1153 and 884 patients without bladder infiltration were evaluable for the analysis of CTCAE and EORTC items, respectively. Median follow-up was 48[3-120] months. Crude incidence rates for G ≥ 2 fistula, bleeding and cystitis were 0.7%, 2.7% and 8.8%, respectively, and 16% and 14% for "quite a bit" or worse pain and difficulty in voiding, respectively. Baseline urinary morbidity and overweight/obesity were significant risk factors for most endpoints. Bladder D_2cm3 correlated with G ≥ 2 fistula, bleeding and cystitis, while ICRU bladder point dose correlated with EORTC pain "quite a bit" or worse. An increase from 75 Gy to 80 Gy in bladder D_2cm3 resulted in an increase from 8% to 13% for 4-year actuarial estimate of G ≥ 2 cystitis.

CONCLUSION

Clinical and treatment-related risk factors for bladder fistula, bleeding and cystitis were identified within a prospective and multi-institutional setting. A dose-effect was established with bladder D_2cm3, reinforcing the importance of continued optimization during individualized IGABT planning.

Combined annoyance response from railroad and road traffic noise in an alpine valley

Context

The aim of this study was to verify the contributing effect in the cases of combined road traffic noise and railroad traffic noise on total noise annoyance.

Materials and Methods

After opening the four-track railway of the Lower Inn Valley Route in Austria, an evaluation study was conducted by an interview survey (n=1003). The data of this survey included answers on annoyance caused by railroad, road traffic noise and total annoyance as well as self-evaluated noise sensitivity.

Results

When annoyance is only related to one of these sources, a 10% share of highly annoyed persons was observed at 59 dB for road noise and 60 dB for railroad noise. The annoyance model including both noise sources with a coefficient of 0.145 for road noise, 0.034 for railroad noise and 0.431 for noise sensitivity (all p-values < 0.01) showed a regression coefficient R² of 0.299. The presence of road background noise did not influence the annoyance on railway noise.

Conclusion

The combined influence of road and railway noise showed an increase of total annoyance.

Importance of the ICRU bladder point dose on incidence and persistence of urinary frequency and incontinence in locally advanced cervical cancer: An EMBRACE analysis

PURPOSE

To identify patient- and treatment-related risk factors and dose-effects for urinary frequency and incontinence in locally advanced cervical cancer (LACC) treated with radio(chemo)therapy and image-guided adaptive brachytherapy (IGABT).

MATERIAL AND METHODS

Physician-assessed (CTCAE) and patient-reported (EORTC) frequency and incontinence recorded in the EMBRACE-I study were analysed. Risk factors analysis was performed in patients without bladder infiltration and with baseline morbidity available. Cox regression was used for CTCAE grade (G) ≥ 3 and G ≥ 2 and for EORTC "very much" and "quite a bit" or worse. Logistic regression was used for late persistent morbidity defined when CTCAE G ≥ 1 or EORTC ≥ "quite a bit" were scored in at least half of follow-ups.

RESULTS

Longitudinal data on 1153 and 884 patients were available for CTCAE and EORTC analysis, respectively. Median follow-up was 48[3-120] months. Crude incidence rates of G≥2 were 13% and 11% for frequency and incontinence, respectively. Baseline morbidity and overweight-obesity were risk factors for both symptoms. Elderly patients were at higher risk for incontinence. Patients receiving conformal-radiotherapy were at higher risk for frequency. ICRU bladder point (ICRU-BP) dose was a stronger predictor for incontinence than bladder D_2cm3. The 5-year actuarial estimate of G ≥ 2 incontinence increased from 11% to 20% with ICRU-BP doses > 75 Gy compared to ≤ 65 Gy. Frequency showed weaker associations with dose.

CONCLUSION

ICRU-BP dose, in addition to clinical parameters, is a risk factor for urinary incontinence and shows a dose-effect after radio(chemo)therapy and IGABT. ICRU-BP dose should be monitored during treatment planning alongside volumetric parameters. Frequency seems associated with larger irradiated volumes.

Dose-Volume Effects and Risk Factors for Late Diarrhea in Cervix Cancer Patients After Radiochemotherapy With Image Guided Adaptive Brachytherapy in the EMBRACE I Study

PURPOSE

To evaluate patient- and treatment-related risk factors associated with incidence and persistence of late diarrhea after radiochemotherapy and image guided adaptive brachytherapy (IGABT) in locally advanced cervical cancer.

MATERIALS AND METHODS

Of 1416 patients from the EMBRACE I study, 1199 were prospectively evaluated using physician-reported (Common Terminology Criteria for Adverse Events version 3 [CTCAEv3]) assessment for diarrhea; median follow-up 48 months. Patient-reported outcome (EORTC) was available in 900 patients. Incidence of CTCAE G≥2, G≥3, and EORTC "very much" diarrhea was analyzed with Cox proportional hazards regression. Binary logistic regression was used for analysis of persistent G≥1 and EORTC "quite a bit" - "very much" (≥"quite a bit") diarrhea, defined if present in at least half of all follow-ups.

RESULTS

Crude incidences of G≥2 and G≥3 diarrhea were 8.3% and 1.5%, respectively, and 8% of patients reported "very much" diarrhea. Persistent G≥1 and ≥"quite a bit" diarrhea was present in 16% and 7%, respectively. Patient-related risk factors were baseline diarrhea, smoking, and diabetes with hazard ratios of 1.4 to 7.3. Treatment-related risk factors included prescribed dose, V43 Gy, V57 Gy (lymph node boost), and para-aortic irradiation for external beam radiation therapy (EBRT). G≥2 diarrhea at 3 years increased from 9.5% to 19.9% with prescribed dose 45 Gy versus 50 Gy, 8.7% to 14.0% with V43 Gy <2500 cm³ versus >3000 cm³ and 9.4% to 19.0% with V57 Gy <165 cm³ versus ≥165 cm³. Brachytherapy-related bowel and rectum D_2cm3 were also associated with diarrhea.

CONCLUSION

Dose and volume effects have been established for late diarrhea after radiochemotherapy and IGABT in both CTCAE and EORTC reporting. The risk of diarrhea was lower with a pelvic EBRT prescription of 45 Gy, and higher with larger lymph node boosts volumes (ie, ≥165 cm³). The importance of EBRT volumes as determinants of late toxicity underline the need for continuous quality assurance of target contouring, dose planning, and conformity. The findings of brachytherapy dosimetric factors related to the intestines may become more important with highly conformal EBRT.

Clinical and imaging findings in cervical cancer and their impact on FIGO and TNM staging - An analysis from the EMBRACE study

OBJECTIVE

To investigate differences in local tumour staging between clinical examination and MRI and differences between FIGO 2009, FIGO 2018 and TNM in patients with primary cervical cancer undergoing definitive radio-chemotherapy.

METHODS

Patients from the prospective observational multi-centre study "EMBRACE" were considered for analysis. All patients had gynaecological examination and pelvic MRI before treatment. Nodal status was assessed by MRI, CT, PET-CT or lymphadenectomy. For this analysis, patients were restaged according to the FIGO 2009, FIGO 2018 and TNM staging system. The local tumour stage was evaluated for MRI and clinical examination separately. Descriptive statistics were used to compare local tumour stages and different staging systems.

RESULTS

Data was available from 1338 patients. For local tumour staging, differences between MRI and clinical examination were found in 364 patients (27.2%). Affected lymph nodes were detected in 52%. The two most frequent stages with FIGO 2009 are IIB (54%) and IIIB (16%), with FIGO 2018 IIIC1 (43%) and IIB (27%) and with TNM T2b N0 M0 (27%) and T2b N1 M0 (23%) in this cohort.

CONCLUSIONS

MRI and clinical examination resulted in a different local tumour staging in approximately one quarter of patients. Comprehensive knowledge of the differential value of clinical examination and MRI is necessary to define one final local stage, especially when a decision about treatment options is to be taken. The use of FIGO 2009, FIGO 2018 and TNM staging system leads to differences in stage distributions complicating comparability of treatment results. TNM provides the most differentiated stage allocation.

Initiatives for education, training, and dissemination of morbidity assessment and reporting in a multiinstitutional international context: Insights from the EMBRACE studies on cervical cancer

In 2008, the GEC ESTRO Gyn network launched the first multiinstitutional, observational, and prospective international study on MRI-guided brachytherapy in locally advanced cervical cancer patients (EMBRACE-I). EMBRACE-I was followed by EMBRACE-II from 2016 and ongoing. Among the aims of the EMBRACE studies are to benchmark morbidity outcomes and develop dose-volume effects and predictive models for morbidity. The EMBRACE studies collect both physician (CTCAE v.3) and patient (EORTC QLQ-C30/CX24) reported outcomes, including baseline information, in a regular follow-up schedule. The EMBRACE studies feature high numbers of patients (EMBRACE-I N = 1416, EMBRACE-II N = 1500 expected) enrolled from many institutions worldwide (EMBRACE-I n = 23, EMBRACE-II n = 45). This large-scale multiinstitutional approach offers a unique opportunity to investigate and develop new strategies for improving the quality of assessment and reporting of morbidity. This report presents an overview of the challenges and pitfalls regarding the assessment and reporting of morbidity encountered during more than a decade of development and research activities within the EMBRACE consortium. This includes the recognition and evaluation of inconsistencies in the morbidity assessment, and consequently, the provision of assistance and training in the scoring procedure to reduce systematic assessment bias. In parallel, a variety of methodological approaches were tested to comprehensively summarize morbidity outcomes, and a novel approach was developed to refine dose-effect models and risk factor analyses. The purpose of this report is to present an overview of these findings, describe the learning process, and the strategies that have consequently been implemented regarding educational activities, training, and dissemination.

Hybrid TRUS/CT with optical tracking for target delineation in image-guided adaptive brachytherapy for cervical cancer

Objective

To prospectively compare the interobserver variability of combined transrectal ultrasound (TRUS)/computed tomography (CT)- vs. CT only- vs. magnetic resonance imaging (MRI) only-based contouring of the high-risk clinical target volume (CTV_HR) in image-guided adaptive brachytherapy (IGABT) for locally advanced cervical cancer (LACC).

Methods

Five patients with LACC (FIGO stages IIb–IVa) treated with radiochemotherapy and IGABT were included. CT, TRUS, and T2-weighted MRI images were performed after brachytherapy applicator insertion. 3D-TRUS image acquisition was performed with a customized ultrasound stepper device and software. Automatic applicator reconstruction using optical tracking was performed in the TRUS dataset and TRUS and CT images were fused with rigid image registration with the applicator as reference structure. The CTV_HR (based on the GEC-ESTRO recommendations) was contoured by five investigators on the three modalities (CTV_HR_CT, CTV_HR_TRUS-CT, and CTV_HR_MRI). A consensus reference CTV_HR_MRI (MRIref) was defined for each patient. Descriptive statistics and overlap measures were calculated using RTslicer (SlicerRT Community and Percutaneous Surgery Laboratory, Queen’s University, Canada), comparing contours of every observer with one another and with the MRIref.

Results

The interobserver coefficient of variation was 0.18 ± 0.05 for CT, 0.10 ± 0.04 for TRUS-CT, and 0.07 ± 0.03 for MRI. Interobserver concordance in relation to the MRIref expressed by the generalized conformity index was 0.75 ± 0.04 for MRI, 0.51 ± 0.10 for TRUS-CT, and 0.48 ± 0.06 for CT. The mean CTV_HR_CT volume of all observers was 71% larger than the MRIref volume, whereas the mean CTV_HR_TRUS-CT volume was 15% larger.

Conclusion

Hybrid TRUS-CT as an imaging modality for contouring the CTV_HR in IGABT for LACC is feasible and reproducible among multiple observers. TRUS-CT substantially reduces overestimation of the CTV_HR volume of CT alone while maintaining similar interobserver variability.

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.

GEC-ESTRO/ACROP recommendations for quality assurance of ultrasound imaging in brachytherapy

Ultrasound (US) is an important imaging modality in brachytherapy (BT). In particular for low-dose-rate (LDR) and high-dose-rate (HDR) prostate implants transrectal ultrasound (TRUS) is widespread. Besides the common use of US for prostate implants, US can also be applied in gynecological and anal cancer therapies as examples amongst others. The BRAPHYQS (BRAchytherapy PHYsics Quality assurance System) and UroGEC (urology) working groups of GEC-ESTRO (GEC: Groupe Européen de Curiethérapie, committee of ESTRO: European SocieTy for Radiotherapy & Oncology) elaborated upon guidelines describing quality assurance (QA) methods for US in BT. The total quality management (QM) for the unit includes acceptance testing, commissioning and periodic image testing. In 2008, the AAPM (American Association of Physicists in Medicine) published the TG (Task group) 128 report. Whereas the TG 128 focuses on US systems and prostate BT, the current recommendations also cover tests for stepping devices and include other interstitial or intracavitary treatment sites in BT, such as anal implants and gynecological BT. The recommendations presented herein do not replace regular maintenance for the US devices performed by the vendor. They are the QA of US in BT but are not sufficient for the whole maintenance of medical US devices. Moreover, national regulations and recommendations should also be followed. For the tests presented in this report tolerances or action limits are given. These recommendations explain practical test procedures of US devices in BT. They will help the clinics to perform a high level of quality in the use of US for BT in Europe.

Importance of Technique, Target Selection, Contouring, Dose Prescription, and Dose-Planning in External Beam Radiation Therapy for Cervical Cancer: Evolution of Practice From EMBRACE-I to II

PURPOSE

To describe the evolution of external beam radiation therapy (EBRT) from EMBRACE-I (general guidelines for EBRT) to the initial phase of the EMBRACE-II study (detailed protocol for EBRT).

METHODS AND MATERIALS

EMBRACE-I enrolled 1416 locally advanced cervical cancer patients treated with chemoradiation including image-guided adaptive brachytherapy during 2008 to 2015. From March 2016 until March 2018, 153 patients were enrolled in the ongoing EMBRACE-II study, which involves a comprehensive detailed strategy and accreditation procedure for EBRT target contouring, treatment planning, and image guidance. EBRT planning target volumes (PTVs), treated volumes (V43 Gy), and conformity index (CI; V43 Gy/PTV) were evaluated in both studies and compared.

RESULTS

For EMBRACE-I, conformal radiation therapy (60% of patients) or intensity-modulated radiation therapy (IMRT) and volumetric arc therapy (VMAT; 40%) was applied with 45 to 50 Gy over 25 to 30 fractions to the elective clinical target volume (CTV). For pelvic CTVs (82%), median PTV and V43 Gy volumes were 1549 and 2390 mL, respectively, and CI was 1.54. For pelvic plus paraortic nodal (PAN) CTVs (15%), median PTV and V43 Gy volumes were 1921 and 2895 mL, and CI was 1.51. For pelvic CTVs treated with 45 to 46 Gy, the use of conformal radiation therapy was associated with a median V43 Gy volume that was 546 mL larger than with IMRT/VMAT. For pelvic CTVs treated with IMRT, the use of a dose prescription ≥48 Gy was associated with a median V43 Gy volumes that was 428 mL larger than with a dose prescription of 45 to 46 Gy. For EMBRACE-II, all patients were treated with: IMRT/VMAT, daily IGRT, 45 Gy over 25 fractions for the elective CTV, and simultaneously integrated boost for pathologic lymph nodes. For pelvic CTVs (61%), median PTV and V43 Gy volumes were 1388 and 1418 mL, and CI was 1.02. For pelvic plus PAN CTVs (32%), median PTV and V43 Gy volumes were 1720 and 1765 mL, and CI was 1.03. From EMBRACE-I to initial II, median V43 Gy was decreased by 972 mL (41%) and 1130 mL (39%), and median CI decreased from 1.54 to 1.02 and 1.51 to 1.03 for pelvic and pelvic plus PAN irradiation, respectively.

CONCLUSIONS

Application of IMRT/VMAT, IGRT, and a 45-Gy dose provides the potential of higher conformality inducing significant reduction of treated volume. Adherence to a detailed protocol including comprehensive accreditation, as in EMBRACE-II, reduces considerably V43 Gy and V50 Gy and improves conformality and interinstitutional consistency.