Mass-manufacturable scintillation-based optical fiber dosimeters for brachytherapy

Scintillation-based fiber dosimeters are a powerful tool for minimally invasive localized real-time monitoring of the dose rate during Low Dose Rate (LDR) and High Dose Rate (HDR) brachytherapy (BT). This paper presents the design, fabrication, and characterization of such dosimeters, consisting of scintillating sensor tips attached to polymer optical fiber (POF). The sensor tips consist of inorganic scintillators, i.e. Gd2O2S:Tb for LDR-BT, and Y2O3:Eu+4YVO4:Eu for HDR-BT, dispersed in a polymer host. The shape and size of the tips are optimized using non-sequential ray tracing simulations towards maximizing the collection and coupling of the scintillation signal into the POF. They are then manufactured by means of a custom moulding process implemented on a commercial hot embossing machine, paving the way towards series production. Dosimetry experiments in water phantoms show that both the HDR-BT and LDR-BT sensors feature good consistency in the magnitude of the average photon count rate and that the photon count rate signal is not significantly affected by variations in sensor tip composition and geometry. Whilst individual calibration remains necessary, the proposed dosimeters show great potential for in-vivo dosimetry for brachytherapy.

MRI-based volumetric tumor parameters before and during chemoradiation predict tumor recurrence and patient survival in locally advanced cervical cancer: a subgroup analysis of a phase II prospective trial

BACKGROUND

This subgroup analysis of a prospective phase II trial aimed to identify valuable and accessible prognostic factors for overall survival (OS) and progression-free survival (PFS) of patients with locally advanced cervical cancer (LACC).

METHODS

Patients with FIGO II to IVA cervical cancer were assessed in this study. All patients underwent concurrent chemoradiotherapy (CCRT) followed by brachytherapy. Tumor parameters based on MRI scans before and during CCRT were evaluated for Overall survival (OS) and Progression-free survival (PFS).

RESULTS

A total of 86 patients were included in this analysis with a median follow-up period of 31.7 months. Three-year OS and PFS rates for all patients were 87.1% and 76.5%, respectively. Univariate Cox regression analysis showed that restaging tumor size (rTS) over 2.55 cm (p < 0.001), initial tumor volume (iTV) over 55.99 cc (p < 0.001), downstaging (p = 0.042), and restaging tumor volume (rTV) over 6.25 cc (p = 0.006) were significantly associated with OS. rTS (p < 0.001), iTV (p < 0.001), downstaging (p = 0.027), and rTV (p < 0.001) were identified as significant prognostic factors for PFS. In the stepwise multivariable analysis, only rTS > 2.55 cm showed statistically significant with OS (HR: 5.47, 95% CI 1.80-9.58, p = 0.035) and PFS (HR: 3.83, 95% CI 1.50-11.45; p = 0.025).

CONCLUSIONS

Initial tumor size and restaging tumor volume that are easily accessible during radiotherapy provide valuable prognostic information for cervical cancer. MRI-based measurable volumetric scoring system can be readily applied in real-world practice of cervical cancer.

CLINICAL TRIAL INFORMATION

This study is a subgroup analysis of prospective trial registered at ClinicalTrials.gov Identifier: NCT02993653.

Interstitial round needles should not be used for cervical cancer patient treated with intracavitary/ interstitial brachytherapy using a Venezia applicator : a case report

BACKGROUND

Image-guided adaptive brachytherapy (IGABT) demonstrates an excellent local control rate and low toxicity while treating cervical cancer. For intracavitary/interstitial (IC/IS) brachytherapy (BT), several applicators are commercially available. Venezia (Elekta, Sweden), an advanced gynecological applicator, is designed for IC/IS BT for treating locally advanced cervical cancer. There are two types of interstitial needles for the Venezia applicator: the round needle and sharp needle. Generally, a round needle is safer because it has less risk of damaging the organ at risk than a sharp needle. However, there is currently no evidence to suggest that a round needle is better than a sharp needle for the Venezia applicator in IC/IS BT. Herein, we documented our experience of using both round and sharp needles with the Venezia applicator in IC/IS BT for cervical cancer.

CASE PRESENTATION

A 71-year-old woman was diagnosed with clinical stage T2bN0M0 and the International Federation of Gynecology and Obstetrics stage IIB cervical squamous cell carcinoma. Definitive therapy, including a high-dose-rate BT boost, was planned using a round needle with the Venezia applicator in IC/IS BT. After inserting four interstitial round needles during the first and second BT sessions, an unexpectedly large gap (1.5 cm) was detected between the cervix and ovoid. We therefore used a sharp needle with the Venezia applicator for IC/IS BT during the third and fourth BT sessions. Three sharp needles were firmly inserted during the third and fourth BT sessions.

CONCLUSIONS

The study findings suggest that the interstitial round needle should not be used for cervical cancer patients undergoing IC/IS BT using the Venezia applicator.

The influence of Gleason score ≤ 6 histology on the outcome of high-risk localized prostate cancer after modern radiotherapy

We aimed to retrospectively review outcomes in patients with high-risk prostate cancer and a Gleason score ≤ 6 following modern radiotherapy. We analyzed the outcomes of 1374 patients who had undergone modern radiotherapy, comprising a high-risk low grade [HRLG] group (Gleason score ≤ 6; n = 94) and a high-risk high grade [HRHG] group (Gleason score ≥ 7, n = 1125). We included 955 patients who received brachytherapy with or without external beam radio-therapy (EBRT) and 264 who received modern EBRT (intensity-modulated radiotherapy [IMRT] or stereotactic body radiotherapy [SBRT]). At a median follow-up of 60 (2-177) months, actuarial 5-year biochemical failure-free survival rates were 97.8 and 91.8% (p = 0.017), respectively. The frequency of clinical failure in the HRLG group was less than that in the HRHG group (0% vs 5.4%, p = 0.012). The HRLG group had a better 5-year distant metastasis-free survival than the HRHG group (100% vs 96.0%, p = 0.035). As the HRLG group exhibited no clinical failure and better outcomes than the HRHG group, the HRLG group might potentially be classified as a lower-risk group.

Equivalent uniform RBE-weighted dose in eye plaque brachytherapy

BACKGROUND

Brachytherapy for ocular melanoma is based on the application of eye plaques with different spatial dose nonuniformity, time-dependent dose rates and relative biological effectiveness (RBE).

PURPOSE

We propose a parameter called the equivalent uniform RBE-weighted dose (EUDRBE) that can be used for quantitative characterization of integrated cell survival in radiotherapy modalities with the variable RBE, dose nonuniformity and dose rate. The EUDRBE is applied to brachytherapy with 125I eye plaques designed by the Collaborative Ocular Melanoma Study (COMS).

METHODS

The EUDRBE is defined as the uniform dose distribution with RBE = 1 that causes equal cell survival for a given nonuniform dose distribution with the variable RBE > 1. The EUDRBE can be used for comparison of cell survival for nonuniform dose distributions with different RBE, because they are compared to the reference dose with RBE = 1. The EUDRBE is applied to brachytherapy with 125I COMS eye plaques that are characterized by a steep dose gradient in tumor base-apex direction, protracted irradiation during time intervals of 3-8 days, and variable dose-rate dependent RBE with a maximum of about 1.4. The simulations are based on dose of 85 Gy prescribed to the farthest intraocular extent of the tumor (tumor apex). To compute the EUDRBE in eye plaque brachytherapy and correct for protracted irradiation, the distributions of physical dose have been converted to non-uniform distributions of biologically effective dose (BED) to include the biological effects of sublethal cellular repair, Our radiobiological analysis considers the combined effects of different time-dependent dose rates, spatial dose non-uniformity, dose fractionation and different RBE and can be used to derive optimized dose regimens brachytherapy.

RESULTS

Our simulations show that the EUDRBE increases with the prescription depths and the maximum increase may achieve 6% for the tumor height of 12 mm. This effect stems from a steep dose gradient within the tumor that increases with the prescription depth. The simulations also show that the EUDRBE increase may achieve 12% with increasing the dose rate when implant duration decreases. The combined effect of dose nonuniformity and dose rate may change the EUDRBE up to 18% for the same dose prescription of 85 Gy to tumor apex. The absolute dose range of 48-61 Gy (RBE) for the EUDRBE computed using 4 or 5 fractions is comparable to the dose prescriptions used in stereotactic body radiation therapy (SBRT) with megavoltage X-rays (RBE = 1) for different cancers. The tumor control probabilities in SBRT and eye plaque brachytherapy are very similar at the level of 80% or higher that support the hypothesis that the selected approximations for the EUDRBE are valid.

CONCLUSIONS

The computed range of the EUDRBE in 125I COMS eye plaque brachytherapy suggests that the selected models and hypotheses are acceptable. The EUDRBE can be useful for analysis of treatment outcomes and comparison of different dose regimens in eye plaque brachytherapy.

External beam radiotherapy boost versus surgical debulking followed by radiotherapy for the treatment of metastatic lymph nodes in cervical cancer: A systematic review and meta-analysis

OBJECTIVE

We aimed to assess disease-free survival (DFS), overall survival (OS) and treatment-related toxicity of two therapeutic strategies for treating bulky lymph nodes on imaging in patients with locally advanced cervical cancer (LACC): radiotherapy boost versus surgical debulking followed by radiotherapy.

METHODS

We performed a systematic review of studies published up to October 2023. We selected studies including patients with LACC treated by external beam radiotherapy (EBRT) boost or lymph node debulking followed by EBRT (with or without boost).

RESULTS

We included two comparative (included in the meta-analysis) and nine non-comparative studies. The estimated 3-year recurrence rate was 28.2% (95%CI:18.3-38.0) in the EBRT group and 39.9% (95%CI:22.1-57.6) in the surgical debulking plus EBRT group. The estimated 3-year DFS was 71.8% and 60.1%, respectively (p = 0.19). The estimated 3-year death rate was 22.2% (95%CI:11.2-33.2) in the EBRT boost group and 31.9% (95%CI:23.3-40.5) in the surgical debulking plus EBRT group. The estimated 3-year OS was 77.8% and 68.1%, respectively (p = 0.04). No difference in lymph node recurrence between the two comparative studies (p = 0.36). The meta-analysis of the two comparative studies showed no DFS difference (p = 0.13) but better OS in the radiotherapy boost group (p = 0.006). The incidence of grade≥3 toxicities (ranging 0-50%) was not different between the two approaches in the two comparative studies (p = 0.31).

CONCLUSION

No DFS and toxicity difference when comparing EBRT boost with surgical debulking of enlarged lymph nodes and EBRT in patients with cervical cancer was evident. Radiotherapy boost had better OS. Further investigation is required to better understand the prognostic role of surgical lymph node debulking in light of radiotherapy developments.

Assessment of Eligibility and Utilization of Accelerated Partial Breast Irradiation in Korean Breast Cancer Patients (KROG 22-15)

PURPOSE

We investigated the proportions of patients eligible for accelerated partial breast irradiation (APBI) among those with pT1-2N0 breast cancer, based on the criteria set by the American Society for Radiation Oncology (ASTRO), the Groupe Européen de Curiethérapie and the European Society for Radiotherapy and Oncology (GEC-ESTRO), the American Brachytherapy Society (ABS), and the American Society of Breast Surgeons (ASBS). Additionally, we analyzed the rate of APBI utilization among eligible patients.

MATERIALS AND METHODS

Patients diagnosed with pT1-2N0 breast cancer in 2019 were accrued in four tertiary medical centers in Korea. All patients had undergone breast conserving surgery followed by radiotherapy, either whole breast irradiation or APBI. To determine which guideline best predicts the use of APBI in Korea, the F1 score and Matthews Correlation Coefficient (MCC) were determined for each guideline.

RESULTS

A total of 1,251 patients were analyzed, of whom 196 (15.7%) underwent APBI. The percentages of eligible patients identified by the ASTRO, GEC-ESTRO, ABS, and ASBS criteria were 13.7%, 21.0%, 50.5%, and 63.5%, respectively. APBI was used to treat 54.4%, 37.2%, 27.1%, and 23.7% of patients eligible by the ASTRO, GEC-ESTRO, ABS, and ASBS criteria, respectively. The ASTRO guideline exhibited the highest F1 score (0.76) and MCC (0.67), thus showing the best prediction of APBI utilization in Korea.

CONCLUSION

The proportion of Korean breast cancer patients who are candidates for APBI is substantial. The actual rate of APBI utilization among eligible patients may suggest there is a room for risk-stratified optimization in offering radiation therapy.

National Trends in Management of Newly Diagnosed Prostate Cancer

BACKGROUND

Deciding whether to treat or conservatively manage patients with prostate cancer is challenging. Recent changes in guidelines, advances in treatment technologies, and policy can influence decision making surrounding management, particularly for those for whom the decision to treat is discretionary. Contemporary trends in management of newly diagnosed prostate cancer are unclear.

METHODS

Using national Medicare data, men with newly diagnosed prostate cancer were identified between 2014 and 2019. Patients were classified by 5- and 10-year noncancer mortality risk. Multinomial logistic regression models were fit to assess adjusted trends in management over time. The primary outcome was management of prostate cancer: local treatment (inclusive of surgery, radiation, brachytherapy, or cryotherapy), hormone therapy, or observation.

RESULTS

Local treatment was the most common form of management and stable across years (68%). Use of observation increased (21%-23%, P < .001) and use of hormone therapy decreased (11%-8%, P < 0.001). After stratifying by 10-year non-cancer mortality risk, observation increased among men with low (22.3%-26.1%, P < .001) and moderate (19.9%-23.5%, P < .001) mortality risk. Conversely, use of treatment increased among those with high (62.8%-68.0%, P = .004) and very high (45.5%-54.1%, P < .001) risk of noncancer mortality. These trends were similar across groups when stratified by 5-year noncancer mortality risk.

CONCLUSION

Nationally, use of local treatment remains common and was stable throughout the study period. However, while local treatment declined among men with a lower risk of noncancer mortality, it increased among men with a higher risk of non-cancer mortality.

Medication-based Comorbidity Measures and Prostate Cancer Treatment Selection

INTRODUCTION

We aimed to assess the association between comorbidities and prostate cancer management.

PATIENTS AND METHODS

We studied 12,603 South Australian men diagnosed with prostate cancer between 2003 and 2019. Comorbidity was measured one year prior to prostate cancer diagnosis using a medication-based comorbidity index (Rx-Risk). Binomial logistic regression analyses were used to assess the association between comorbidities and primary treatment selection (active surveillance, radical prostatectomy (RP), external beam radiotherapy (EBRT) with or without androgen deprivation therapy (ADT), brachytherapy, ADT alone, and watchful waiting (WW)). Certain common comorbidities within Rx-Risk (cardiac disorders, diabetes, chronic airway diseases, depression and anxiety, thrombosis, and chronic pain) were also assessed. All models were adjusted for sociodemographic and tumor characteristics.

RESULTS

Likelihood of receiving RP was lower among men with Rx-Risk score ≥3 (odds ratio (OR) 0.62, 95%CI:0.56-0.69) and Rx-Risk 2 (OR 0.80, 95%CI:0.70-0.92) compared with no comorbidity (Rx-Risk ≤0). Men with high comorbidity (Rx-Risk ≥3) were more likely to have received ADT alone (OR 1.76, 95%CI:1.40-2.21), EBRT (OR 1.30, 95%CI:1.17-1.45) or WW (OR 1.49, 95%CI:1.19-1.88) compared with Rx-Risk ≤0. Pre-existing cardiac and respiratory disorders, thrombosis, diabetes, depression and anxiety, and chronic pain were associated with lower likelihood of selecting RP and higher likelihood of EBRT (except chronic airway disease) or WW (except diabetes and depression and anxiety). Cardiac disorders and thrombosis were associated with higher likelihood of selecting ADT alone. Furthermore, age had greater effect on treatment choice than the level of comorbidity.

CONCLUSION

High comorbidity burden was associated with primary treatment choice, with significantly less RP and more EBRT, WW and ADT alone among men with higher levels of comorbidity. Each of the individual comorbid conditions also influenced treatment selection.

Simultaneous catheter and multicriteria optimization for HDR cervical cancer brachytherapy with a complex intracavity/interstitial applicator

BACKGROUND

Complex intracavity and interstitial (IC/IS) applicators, such as the Venezia applicator, can improve the HR-CTV coverage while adequately protecting organs at risk in the treatment of cervical cancer with high-dose-rate (HDR) brachytherapy. Although the Venezia applicator offers more choice for catheter selection, commercially available catheter and dose optimization algorithms are still missing for complex applicators. Moreover, studies on catheter and dose optimization for IC/IS implants in the treatment of cervical cancer are still limited.

PURPOSE

This work aims to combine a GPU-based multi-criteria optimization (gMCO) algorithm with a sparse catheter (SC) optimization algorithm for the Venezia applicator.

METHODS

Fifty-eight cervical cancer patients who received 28 Gy in 4 fx of HDR brachytherapy with the Venezia applicator (combination to external beam radiation therapy) are retrospectively revisited. The modelization of the applicator is done by virtually reconstructing all the IS catheters passing through the ring. Template catheters are reconstructed using an in-house python script. To perform simultaneous MCO and SC optimization (SC+MCO), the objective function includes aggregated dose objectives in a weighted sum and a group sparsity term that individually penalizes the contribution of IS catheters. Plans generated with the SC+MCO algorithm are compared with plans generated with MCO using clinical catheters (CC+MCO) and the clinical plans (CP). The EMBRACE II soft constraints (planning aims) and hard constraints (limits for prescribed dose) are used as plan evaluation criteria.

RESULTS

CC+MCO gives the most important gain with an increase up to 20.7% in meeting all EMBRACE II soft constraints compared with CP. The SC+MCO algorithm (adding catheter optimization to MCO) provides a second order increase (up to 12.1% with total acceptance rate of 60.3% or 35/58) in the acceptance rate versus CC+MCO (total increase of 32.8% vs. CP). Acceptance rate in EMBRACE II hard constraints is 98.3% (57/58) for both CC+MCO and SC+MCO versus 91.4% (53/58) for CP. The median SC+MCO optimization time is 11 s to generate a total of 5000 Pareto-optimal plans with different catheter configurations (position and number) for each fraction.

CONCLUSIONS

Simultaneous catheter and MCO optimization is clinically feasible for HDR cervical cancer brachytherapy using the Venezia applicator. Clinical catheter configurations could be improved and/or the catheter number could be reduced without decreasing plan quality using SC+MCO compared with the CP.

Treatment of node-positive endometrial cancer: chemotherapy, radiation, immunotherapy, and targeted therapy

OPINION STATEMENT

The standard of treatment for node-positive endometrial cancer (FIGO Stage IIIC) in North America has been systemic therapy with or without additional external beam radiation therapy (RT) given as pelvic or extended field RT. However, this treatment paradigm is rapidly evolving with improvements in systemic chemotherapy, the emergence of targeted therapies, and improved molecular characterization of these tumors. The biggest question facing providers regarding management of stage IIIC endometrial cancer at this time is: what is the best management strategy to use with regard to combinations of cytotoxic chemotherapy, immunotherapy, other targeted therapeutics, and radiation that will maximize clinical benefit and minimize toxicities for the best patient outcomes? While clinicians await the results of ongoing clinical trials regarding combined immunotherapy/RT as well as management based on molecular classification, we must make decisions regarding the best treatment combinations for our patients. Based on the available literature, we are offering stage IIIC patients without measurable disease postoperatively both adjuvant chemotherapy and IMRT with carboplatin, paclitaxel, and with or without pembrolizumab/dostarlimab as primary adjuvant therapy. Patients with measurable disease post operatively, high risk histologies, or stage IV disease receive chemoimmunotherapy, and vaginal brachytherapy is added for those with uterine risk factors for vaginal recurrence. In the setting of endometrioid EC recurrence more than 6 months after treatment, patients with pelvic nodal and vaginal recurrence are offered IMRT and brachytherapy without chemotherapy. For measurable recurrence not suitable for pelvic radiation alone, chemoimmunotherapy is preferred as standard of care.

Development of patient and catheter specific error thresholds for high dose rate prostate brachytherapy

BACKGROUND

In-vivo source tracking has been an active topic of research in the field of high-dose rate brachytherapy in recent years to verify accuracy in treatment delivery. Although detection systems for source tracking are being developed, the allowable threshold of treatment error is still unknown and is likely patient-specific due to anatomy and planning variation.

PURPOSE

The purpose of this study was to determine patient and catheter-specific shift error thresholds for in-vivo source tracking during high-dose-rate prostate brachytherapy (HDRPBT).

METHODS

A module was developed in the previously described graphical processor unit multi-criteria optimization (gMCO) algorithm. The module generates systematic catheter shift errors retrospectively into HDRPBT treatment plans, performed on 50 patients. The catheter shift model iterates through the number of catheters shifted in the plan (from 1 to all catheters), the direction of shift (superior, inferior, medial, lateral, cranial, and caudal), and the magnitude of catheter shift (1-6 mm). For each combination of these parameters, 200 error plans were generated, randomly selecting the catheters in the plan to shift. After shifts were applied, dose volume histogram (DVH) parameters were re-calculated. Catheter shift thresholds were then derived based on plans where DVH parameters were clinically unacceptable (prostate V100 < 95%, urethra D0.1cc > 118%, and rectum Dmax > 80%). Catheter thresholds were also Pearson correlated to catheter robustness values.

RESULTS

Patient-specific thresholds varied between 1 to 6 mm for all organs, in all shift directions. Overall, patient-specific thresholds typically decrease with an increasing number of catheters shifted. Anterior and inferior directions were less sensitive than other directions. Pearson's correlation test showed a strong correlation between catheter robustness and catheter thresholds for the rectum and urethra, with correlation values of -0.81 and -0.74, respectively (p < 0.01), but no correlation was found for the prostate.

CONCLUSIONS

It was possible to determine thresholds for each patient, with thresholds showing dependence on shift direction, and number of catheters shifted. Not every catheter combination is explorable, however, this study shows the feasibility to determine patient-specific thresholds for clinical application. The correlation of patient-specific thresholds with the equivalent robustness value indicated the need for robustness consideration during plan optimization and treatment planning.

Partial Breast Irradiation for Patients With Early-Stage Invasive Breast Cancer or Ductal Carcinoma In Situ: An ASTRO Clinical Practice Guideline

PURPOSE

This guideline provides evidence-based recommendations on appropriate indications and techniques for partial breast irradiation (PBI) for patients with early-stage invasive breast cancer and ductal carcinoma in situ.

METHODS

ASTRO convened a task force to address 4 key questions focused on the appropriate indications and techniques for PBI as an alternative to whole breast irradiation (WBI) to result in similar rates of ipsilateral breast recurrence (IBR) and toxicity outcomes. Also addressed were aspects related to the technical delivery of PBI, including dose-fractionation regimens, target volumes, and treatment parameters for different PBI techniques. The guideline is based on a systematic review provided by the Agency for Healthcare Research and Quality. Recommendations were created using a predefined consensus-building methodology and system for grading evidence quality and recommendation strength.

RESULTS

PBI delivered using 3-dimensional conformal radiation therapy, intensity modulated radiation therapy, multicatheter brachytherapy, and single-entry brachytherapy results in similar IBR as WBI with long-term follow-up. Some patient characteristics and tumor features were underrepresented in the randomized controlled trials, making it difficult to fully define IBR risks for patients with these features. Appropriate dose-fractionation regimens, target volume delineation, and treatment planning parameters for delivery of PBI are outlined. Intraoperative radiation therapy alone is associated with a higher IBR rate compared with WBI. A daily or every-other-day external beam PBI regimen is preferred over twice-daily regimens due to late toxicity concerns.

CONCLUSIONS

Based on published data, the ASTRO task force has proposed recommendations to inform best clinical practices on the use of PBI.

Review of brachytherapy clinical trials: a cross-sectional analysis of ClinicalTrials.gov

INTRODUCTION

Characterizing the landscape of clinical trials including brachytherapy can provide an overview of the current status and research trends which may guide further areas of investigation.

METHOD

We queried 449,849 clinical trials from the ClinicalTrials.gov registry using brachytherapy-related keywords from 1980 to 2023, yielding 245 multi-arm and 201 single-arm, brachytherapy trials. Multi-arm and single-arm brachytherapy trials were compared using 12 trial protocol elements.

RESULTS

The number of trials including brachytherapy has increased over time, with over 60% of trials registered in 2010 onwards. The majority of clinical trials were Phase 2 or 3, evaluated both safety and efficacy, and were funded by academic sponsors. The most common tumor sites evaluated in brachytherapy clinical trials include prostate, cervix, liver, endometrium, and breast.

CONCLUSION

There remains continued interest in clinical trials including brachytherapy focused on evaluation of novel delivery systems, treatment planning, and new indications. More brachytherapy clinical trials are needed to define the optimal clinical utilization and advance prospective research in this field.

The Effect of Music on Anxiety, Pain Levels, and Physiological Parameters in Women Undergoing Brachytherapy: A Randomized Controlled Trial

OBJECTIVES

This study was conducted to investigate the effect of music on anxiety, pain, and physiologic parameters in women undergoing brachytherapy.

DATA SOURCES

The study was conducted with a randomized controlled design between June and December 2022. Music intervention was practiced to the patients in the experimental group (n = 30), while no practice was given to the control group (n = 25). In the study, the data were collected using the Descriptive Information Form, Hospital Anxiety and Depression Scale, visual analog scale, and vital signs (temperature, pulse rate, blood pressure, respiratory rate, SpO2) recording form. Intergroup and intragroup averages were evaluated by the mixed-design analysis of variance. Variables with pre-post intervention designs were evaluated with the one-way analysis of covariance. There was no significant difference in physiological parameters between the groups (P > . 05). Although the mean anxiety scores decreased in the music group and increased in the control group, there was no statistically significant difference (P > .05). A significant difference was found in the pain levels of the patients in repeated measurements made in intragroup evaluations (P < .001). The depression mean of the music intervention group was significantly lower than the control group (P ≤ .05).

CONCLUSION

It was concluded that the music played during the brachytherapy process had positive effects on feeling less pain and management of depressive symptoms but did not affect anxiety and physiological parameters. Since each patient is different, the effects of music therapy can vary individually.

IMPLICATIONS FOR NURSING PRACTICE

Nurses should apply different strategies to investigate session frequencies and durations for different patient groups and treatment stages in cancer care.

Challenges and opportunities in the implementation of advanced brachytherapy programs for cervical cancer in the Philippines

Cervical cancer is the second most common cancer cause of morbidity and mortality in Filipino women; the age-standardized annual incidence is 15.2 as of March 2023. The majority are diagnosed at a locally advanced stage and in the reproductive and working age group. This results in important treatment and productivity costs. The importance of image-guided and interstitial brachytherapy (BRT) in local control and toxicity outcomes has been shown in recent meta-analyses. We review the status of advanced BRT program training and implementation in the Philippines and important challenges and opportunities to move forward.

CT-guided High-Dose-Rate Brachytherapy versus Transarterial Chemoembolization in Patients with Unresectable Hepatocellular Carcinoma

Background CT-guided high-dose-rate (HDR) brachytherapy (hereafter, HDR brachytherapy) has been shown to be safe and effective for patients with unresectable hepatocellular carcinoma (HCC), but studies comparing this therapy with other local-regional therapies are scarce. Purpose To compare patient outcomes of HDR brachytherapy and transarterial chemoembolization (TACE) in patients with unresectable HCC. Materials and Methods This multi-institutional retrospective study included consecutive treatment-naive adult patients with unresectable HCC who underwent either HDR brachytherapy or TACE between January 2010 and December 2022. Overall survival (OS) and progression-free survival (PFS) were compared between patients matched for clinical and tumor characteristics by propensity score matching. Not all patients who underwent TACE had PFS available; thus, a different set of patients was used for PFS and OS analysis for this treatment. Hazard ratios (HRs) were calculated from Kaplan-Meier survival curves. Results After propensity matching, 150 patients who underwent HDR brachytherapy (median age, 71 years [IQR, 63-77 years]; 117 males) and 150 patients who underwent TACE (OS analysis median age, 70 years [IQR, 63-77 years]; 119 male; PFS analysis median age, 68 years [IQR: 63-76 years]; 119 male) were analyzed. Hazard of death was higher in the TACE versus HDR brachytherapy group (HR, 4.04; P < .001). Median estimated PFS was 32.8 months (95% CI: 12.5, 58.7) in the HDR brachytherapy group and 11.6 months (95% CI: 4.9, 22.7) in the TACE group. Hazard of disease progression was higher in the TACE versus HDR brachytherapy group (HR, 2.23; P < .001). Conclusion In selected treatment-naive patients with unresectable HCC, treatment with CT-guided HDR brachytherapy led to improved OS and PFS compared with TACE. © RSNA, 2024 Supplemental material is available for this article. See also the editorial by Chapiro in this issue.

GammaTile® (GT) as a brachytherapy platform for rapidly proliferating glioblastomas: from case series to clinical trials

PURPOSE

Radiation plays a central role in glioblastoma treatment. Logistics related to coordinating clinic visits, radiation planning, and surgical recovery necessitate delay in radiation delivery from the time of diagnosis. Unimpeded tumor growth occurs during this period, and is associated with poor clinical outcome. Here we provide a pilot experience of GammaTile ® (GT), a collagen tile-embedded Cesium-131 (131Cs) brachytherapy platform for such aggressive tumors.

METHODS

We prospectively followed seven consecutive patients (2019-2023) with newly diagnosed (n = 3) or recurrent (n = 4) isocitrate dehydrogenase wild-type glioblastoma that grew > 100% in volume during the 30 days between the time of initial diagnosis/surgery and the radiation planning MRI. These patients underwent re-resection followed by GT placement.

RESULTS

There were no surgical complications. One patient developed right hemiparesis prior to re-resection/GT placement and was discharged to rehabilitation, all others were discharged home-with a median hospital stay of 2 days (range: 1-5 days). There was no 30-day mortality and one 30-day readmission (hydrocephalus, requiring ventriculoperitoneal shunting (14%)). With a median follow-up of 347 days (11.6 months), median progression free survival of ≥ 320 days (10.6 months) was achieved for both newly and recurrent glioblastoma patients. The median overall survival (mOS) was 304 and 347 days (10 and 11.5 mo) for recurrent and newly diagnosed glioblastoma patients, respectively.

CONCLUSION

Our pilot experience suggests that GT offers favorable local control and safety profile for patients afflicted with rapidly proliferating glioblastomas and lay the foundation for future clinical trial design.

The organization of care in pediatric radiotherapy across SIOP Europe affiliated centers: A multicenter survey in the framework of the 'Joint Action on Rare Cancers' project

BACKGROUND/PURPOSE

To reduce inequalities among SIOPE-affiliated countries, standard and optional levels to deliver 'Good Clinical Practice' compliant treatment in pediatric radiation oncology have been published. The aim of this project was to map the availability of pediatric radiotherapy resources across SIOPE-affiliated radiotherapy departments.

MATERIALS/METHODS

An online survey with 34 questions was distributed to 246 radiotherapy departments across 35 SIOPE-affiliated countries. In addition to demographic data, 15 general items related to the organization of the radiotherapy process, and 10 radiotherapy-specific items were defined. For each of the 25 items, sum scores were calculated per center and country. Mann-Whitney U tests were used to analyze associations.

RESULTS

Between March-June 2019, 121 departments (49 %) out of 31 countries (89 %) completed the survey. At center level, involvement of core disciplines in tumor boards (28 %), and integration of dedicated pediatric radiation therapy technologists (24 %) are limited, while rare & complex brachytherapy procedures are performed in many centers (23 %). For general and radiotherapy-specific items respectively, a relevant variation of sum scores was observed across countries (Δgeneral: ≤10 points; ΔRT_specific: ≤5 points) and among centers within a country (Δgeneral: ≤9 points; ΔRT_specific: ≤6 points). Sum scores for general and radiotherapy-specific items were higher in countries with a high-income (p < 0.01) and higher health development index (p < 0.01). A larger annual number of irradiated pediatric patients was associated with higher sum scores for general items (p < 0.01).

CONCLUSION

This survey demonstrates the disparities in organization of pediatric radiotherapy departments between SIOPE-affiliated countries and centers within the same country. Investment is needed to reduce inequalities in pediatric radiotherapy care.

A robust evaluation of 49 high-dose-rate prostate brachytherapy treatment plans including all major uncertainties

BACKGROUND

Uncertainties in radiotherapy cause deviation from the planned dose distribution and may result in delivering a treatment that fails to meet clinical objectives. The impact of uncertainties is unique to the patient anatomy and the needle locations in HDR prostate brachytherapy. Evaluating this impact during treatment planning is not common practice, relying on margins around the target or organs-at-risk to account for uncertainties.

PURPOSE

A robust evaluation framework for HDR prostate brachytherapy treatment plans was evaluated on 49 patient plans, measuring the range of possible dosimetric outcomes to the patient due to 14 major uncertainties.

METHODS

Patient plans were evaluated for their robustness to uncertainties by simulating probable uncertainty scenarios. Five-thousand probabilistic and 1943 worst-case scenarios per patient were simulated by changing the position and size of structures and length of dwell times from their nominal values. For each uncertainty scenario, the prostate D90 and maximum doses to the urethra, D0.01cc , and rectum, D0.1cc , were calculated.

RESULTS

The D90 was an average 1.16 ± 0.51% (mean ± SD) below nominal values for the probabilistic scenarios; the D0.01cc metric was 2.24 ± 0.90% higher; and D0.1cc was greater by 0.48 ± 0.30%. The D0.01cc and D90 metrics were more sensitive to uncertainties than D0.1cc , with a median of 79.0% and 84.9% of probabilistic scenarios passing the constraints, compared to 96.5%. The median pass-rate for scenarios that passed all three metrics simultaneously was 63.4%.

CONCLUSIONS

Assessing treatment plan robustness improves plan quality assurance, is achievable in less than 1-min, and identifies treatment plans with poor robustness, allowing re-optimization before delivery.

International multidisciplinary consensus on the integration of radiotherapy with new systemic treatments for breast cancer: European Society for Radiotherapy and Oncology (ESTRO)-endorsed recommendations

Novel systemic therapies for breast cancer are being rapidly implemented into clinical practice. These drugs often have different mechanisms of action and side-effect profiles compared with traditional chemotherapy. Underpinning practice-changing clinical trials focused on the systemic therapies under investigation, thus there are sparse data available on radiotherapy. Integration of these new systemic therapies with radiotherapy is therefore challenging. Given this rapid, transformative change in breast cancer multimodal management, the multidisciplinary community must unite to ensure optimal, safe, and equitable treatment for all patients. The aim of this collaborative group of radiation, clinical, and medical oncologists, basic and translational scientists, and patient advocates was to: scope, synthesise, and summarise the literature on integrating novel drugs with radiotherapy for breast cancer; produce consensus statements on drug-radiotherapy integration, where specific evidence is lacking; and make best-practice recommendations for recording of radiotherapy data and quality assurance for subsequent studies testing novel drugs.

Locoregional Therapies for Primary and Metastatic Breast Cancer: AJR Expert Panel Narrative Review

Minimally invasive locoregional therapies have a growing role in the multidisciplinary treatment of primary and metastatic breast cancer. Factors contributing to the expanding role of ablation for primary breast cancer include earlier diagnosis, when tumors are small, and increased longevity of patients whose condition precludes surgery. Cryoablation has emerged as the leading ablative modality for primary breast cancer owing to its wide availability, the lack of need for sedation, and the ability to monitor the ablation zone. Emerging evidence suggests that in patients with oligometastatic breast cancer, use of locoregional therapies to eradicate all disease sites may confer a survival advantage. Evidence also suggests that transarterial therapies-including chemoembolization, chemoperfusion, and radioembolization-may be helpful to some patients with advanced liver metastases from breast cancer, such as those with hepatic oligoprogression or those who cannot tolerate systemic therapy. However, the optimal modalities for treatment of oligometastatic and advanced metastatic disease remain unknown. Finally, locoregional therapies may produce tumor antigens that in combination with immunotherapy drive anti-tumor immunity. Although key trials are ongoing, additional prospective studies are needed to establish the inclusion of interventional oncology in societal breast cancer guidelines to support further clinical adoption and improved patient outcomes.

Place of radiotherapy for treatment of metastatic cervical, vaginal and endometrial uterine cancer

Beyond classical palliative-intent irradiation schemes, there are increasing data suggesting a benefit for intensive locoregional treatments in metastatic gynecological cancers. Such approach aims at avoiding local symptoms related to tumor progression, but may also improve survival outcome by shrinking tumor burden to a microscopic state. This strategy is rarely considered upfront (in highly selected patients with very limited oligometastatic disease), but rather after systemic treatment. In case of tumor response (especially if complete response) of the metastatic sites, pelvic±para-aortic radiotherapy can be considered in combination with a brachytherapy boost to obtain long-term local control, in particular in cervical or vaginal cancer patients. Such approach seems particularly relevant when there is isolated persistence or progression of macroscopic disease within the pelvis. In parallel, there is also an increasing place for radiotherapy of oligo-metastatic sites. We review the literature on the place of radiotherapy in the management of cancers of the cervix and metastatic endometrial cancer.

Impact of technological advances in treatment planning, image guidance, and treatment delivery on target margin design for prostate cancer radiotherapy: an updated review

Recent innovations in image guidance, treatment delivery, and adaptive radiotherapy (RT) have created a new paradigm for planning target volume (PTV) margin design for patients with prostate cancer. We performed a review of the recent literature on PTV margin selection and design for intact prostate RT, excluding post-operative RT, brachytherapy, and proton therapy. Our review describes the increased focus on prostate and seminal vesicles as heterogenous deforming structures with further emergence of intra-prostatic GTV boost and concurrent pelvic lymph node treatment. To capture recent innovations, we highlight the evolution in cone beam CT guidance, and increasing use of MRI for improved target delineation and image registration and supporting online adaptive RT. Moreover, we summarize new and evolving image-guidance treatment platforms as well as recent reports of novel immobilization strategies and motion tracking. Our report also captures recent implementations of artificial intelligence to support image guidance and adaptive RT. To characterize the clinical impact of PTV margin changes via model-based risk estimates and clinical trials, we highlight recent high impact reports. Our report focusses on topics in the context of PTV margins but also showcase studies attempting to move beyond the PTV margin recipes with robust optimization and probabilistic planning approaches. Although guidelines exist for target margins conventional using CT-based image guidance, further validation is required to understand the optimal margins for online adaptation either alone or combined with real-time motion compensation to minimize systematic and random uncertainties in the treatment of patients with prostate cancer.

Paediatric radiotherapy in the United Kingdom: an evolving subspecialty and a paradigm for integrated teamworking in oncology

Many different malignancies occur in children, but overall, cancer in childhood is rare. Survival rates have improved appreciably and are higher compared with most adult tumour types. Treatment schedules evolve as a result of clinical trials and are typically complex and multi-modality, with radiotherapy an integral component of many. Risk stratification in paediatric oncology is increasingly refined, resulting in a more personalized use of radiation. Every available modality of radiation delivery: simple and advanced photon techniques, proton beam therapy, molecular radiotherapy, and brachytherapy, have their place in the treatment of children's cancers. Radiotherapy is rarely the sole treatment. As local therapy, it is often given before or after surgery, so the involvement of the surgeon is critically important, particularly when brachytherapy is used. Systemic treatment is the standard of care for most paediatric tumour types, concomitant administration of chemotherapy is typical, and immunotherapy has an increasing role. Delivery of radiotherapy is not done by clinical or radiation oncologists alone; play specialists and anaesthetists are required, together with mould room staff, to ensure compliance and immobilization. The support of clinical radiologists is needed to ensure the correct interpretation of imaging for target volume delineation. Physicists and dosimetrists ensure the optimal dose distribution, minimizing exposure of organs at risk. Paediatric oncology doctors, nurses, and a range of allied health professionals are needed for the holistic wrap-around care of the child and family. Radiographers are essential at every step of the way. With increasing complexity comes a need for greater centralization of services.

Magnetic hybrid Pd/Fe-oxide nanoparticles meet the demands for ablative thermo-brachytherapy

OBJECTIVE

To investigate the potential of hybrid Pd/Fe-oxide magnetic nanoparticles designed for thermo-brachytherapy of breast cancer, considering their specific loss power (SLP) and clinical constraints in the applied magnetic field.

METHODS

Hybrid nanoparticles consisting of palladium-core and iron oxide shell of increasing thickness, were suspended in water and their SLPs were measured at varying magnetic fields (12-26 mT peak) and frequencies (50-730 kHz) with a commercial alternating magnetic field generator (magneTherm™ Digital, nanoTherics Ltd.).

RESULTS

Validation of the heating device used in this study with commercial HyperMag-C nanoparticles showed a small deviation (±4%) over a period of 1 year, confirming the reliability of the method. The integration of dual thermometers, one in the center and one at the bottom of the sample vial, allowed monitoring of homogeneity of the sample suspensions. SLPs measurements on a series of nanoparticles of increasing sizes showed the highest heating for the diameter of 21 nm (SLP = 225 W/g) at the applied frequencies of 346 and 730 kHz. No heating was observed for the nanoparticles with the size <14 nm, confirming the importance of the size-parameter. The heating ability of the best performing Pd/Fe-oxide-21 was calculated to be sufficient to ablate tumors with a radius ±4 and 12 mm using 10 and 1 mg/mL nanoparticle concentration, respectively.

CONCLUSIONS

Nanoparticles consisting of non-magnetic palladium-core and magnetic iron oxide shell are suitable for magnetic hyperthermia/thermal ablation under clinically safe conditions of 346 kHz and 19.1 mT, with minimal eddy current effects in combination with maximum SLP.

The role of GammaTile in the treatment of brain tumors: a technical and clinical overview

Malignant and benign brain tumors with a propensity to recur continue to be a clinical challenge despite decades-long efforts to develop systemic and more advanced local therapies. GammaTile (GT Medical Technologies Inc., Tempe AZ) has emerged as a novel brain brachytherapy device placed during surgery, which starts adjuvant radiotherapy immediately after resection. GammaTile received FDA clearance in 2018 for any recurrent brain tumor and expanded clearance in 2020 to include upfront use in any malignant brain tumor. More than 1,000 patients have been treated with GammaTile to date, and several publications have described technical aspects of the device, workflow, and clinical outcome data. Herein, we review the technical aspects of this brachytherapy treatment, including practical physics principles, discuss the available literature with an emphasis on clinical outcome data in the setting of brain metastases, glioblastoma, and meningioma, and provide an overview of the open and pending clinical trials that are further defining the efficacy and safety of GammaTile.

B-scan measurements of intraocular tumor heights intraoperatively, before and after radioactive plaque application: A comparative prospective study

PURPOSE

To assess the difference in intraocular tumors height measurements intraoperatively before and after radioactive plaque application.

METHODOLOGY

Twenty-four eyes of 24 patients with intraocular tumors, candidates for radioactive therapy, were included. Each tumor was measured at the same setting before and after plaque application independently by 3 sonographers, using a 20-MHz B-scan transducer. Mean pre-plaque and post-plaque measurements were calculated and recorded. An A-scan vector aided in identification of the inner and outer tumor surfaces.

RESULTS

Each patient was examined independently three times by three experienced ultrasonographers within the same setting to assess interobserver variability. There was no statistically significant difference between the 3 examiners' readings, with P-value 0.99 for pre-plaque height and 0.97 for post-plaque height. Mean pre-plaque height was 5.16±2.11mm, while post-plaque height was 5.51±2.1mm (P-value 0.001). The Spearman correlation test showed that initial tumor height was negatively correlated with the difference between both heights, but with no statistical significance.

CONCLUSION

Intraocular tumor height measurement differs significantly before and after plaque application. Use of the pre-plaque height is advised until further studies are performed to assess the effect of this difference on treatment outcomes.

Generation and comparison of 3D dosimetric reference datasets for COMS eye plaque brachytherapy using model-based dose calculations

PURPOSE

A joint Working Group of the American Association of Physicists in Medicine (AAPM), the European Society for Radiotherapy and Oncology (ESTRO), and the Australasian Brachytherapy Group (ABG) was created to aid in the transition from the AAPM TG-43 dose calculation formalism, the current standard, to model-based dose calculations. This work establishes the first test cases for low-energy photon-emitting brachytherapy using model-based dose calculation algorithms (MBDCAs).

ACQUISITION AND VALIDATION METHODS

Five test cases are developed: (1) a single model 6711 125 I brachytherapy seed in water, 13 seeds (2) individually and (3) in combination in water, (4) the full Collaborative Ocular Melanoma Study (COMS) 16 mm eye plaque in water, and (5) the full plaque in a realistic eye phantom. Calculations are done with four Monte Carlo (MC) codes and a research version of a commercial treatment planning system (TPS). For all test cases, local agreement of MC codes was within ∼2.5% and global agreement was ∼2% (4% for test case 5). MC agreement was within expected uncertainties. Local agreement of TPS with MC was within 5% for test case 1 and ∼20% for test cases 4 and 5, and global agreement was within 0.4% for test case 1 and 10% for test cases 4 and 5.

DATA FORMAT AND USAGE NOTES

Dose distributions for each set of MC and TPS calculations are available online (https://doi.org/10.52519/00005) along with input files and all other information necessary to repeat the calculations.

POTENTIAL APPLICATIONS

These data can be used to support commissioning of MBDCAs for low-energy brachytherapy as recommended by TGs 186 and 221 and AAPM Report 372. This work additionally lays out a sample framework for the development of test cases that can be extended to other applications beyond eye plaque brachytherapy.

Optimisation of Organ Preservation treatment strategies in patients with rectal cancer with a good clinical response after neoadjuvant (chemo)radiotherapy: Additional contact X-ray brachytherapy versus eXtending the observation period and local excision (OPAXX) - protocol for two multicentre, parallel, single-arm, phase II studies

INTRODUCTION

Standard treatment for patients with intermediate or locally advanced rectal cancer is (chemo)radiotherapy followed by total mesorectal excision (TME) surgery. In recent years, organ preservation aiming at improving quality of life has been explored. Patients with a complete clinical response to (chemo)radiotherapy can be managed safely with a watch-and-wait approach. However, the optimal organ-preserving treatment strategy for patients with a good, but not complete clinical response remains unclear. The aim of the OPAXX study is to determine the rate of organ preservation that can be achieved in patients with rectal cancer with a good clinical response after neoadjuvant (chemo)radiotherapy by additional local treatment options.

METHODS AND ANALYSIS

The OPAXX study is a Dutch multicentre study that investigates the efficacy of two additional local treatments aiming at organ preservation in patients with a good, but not complete response to neoadjuvant treatment (ie near-complete response or a small residual tumour mass <3 cm). The sample size will be 168 patients in total. Patients will be randomised (1:1) between two parallel single-arm phase II studies: study arm 1 involves additional contact X-ray brachytherapy (an intraluminal radiation boost), while in study arm 2 the observation period is extended followed by a second response evaluation and optional transanal local excision. The primary endpoint of the study is the rate of successful organ preservation at 1 year following randomisation. Secondary endpoints include toxicity, morbidity, oncological and functional outcomes at 1 and 2 years of follow-up. Finally, an observational cohort study for patients who are not eligible for randomisation is conducted.

ETHICS AND DISSEMINATION

The trial protocol has been approved by the medical ethics committee of the Netherlands Cancer Institute (METC20.1276/M20PAX). Informed consent will be obtained from all participants. The trial results will be published in an international peer-reviewed journal.

TRIAL REGISTRATION NUMBER

NCT05772923.

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

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

Treatment outcomes of early-stage endometrial cancer patients: A propensity score matching of vaginal brachytherapy versus pelvic radiotherapy

OBJECTIVES

This study aimed to report the treatment outcomes of radiation therapy for early-stage endometrial cancer patients. In addition, this study intended to identify high-risk factors that require pelvic radiotherapy (PRT) in addition to vaginal brachytherapy (VBT) for intermediate-risk endometrial cancer patients.

METHODS

Patients with early-stage endometrial cancer receiving postoperative VBT alone or with PRT were included. Propensity score matching was used to balance the two study groups. The primary endpoint was locoregional recurrence (LRR). Age-adjusted Charlson comorbidity index and substantial lymphovascular space invasion were selected for subgroup analyses to identify the benefits of PRT over VBT alone.

RESULTS

From 2005 to 2017, a total of 288 patients underwent analysis following propensity score matching. Of these, 144 received VBT and 144 received PRT. There was no significant difference in 5-year LRR between VBT and PRT for both intermediate (0% vs. 0%) and high-intermediate risk patients (3.5% VBT vs. 5.4% PRT; HR 0.54: 0.05-6.00; p = 0.616). The subgroup analyses revealed no significant factors favoring PRT over VBT. Patients with high comorbidities may have higher risks of non-cancer death after receiving PRT.

CONCLUSIONS

Postoperative VBT alone is sufficient for early-stage intermediate-risk endometrial cancer patients.

Risk of prostate cancer death after radical radiotherapy with neoadjuvant and adjuvant therapy with bicalutamide or gonadotropin-releasing hormone agonists

BACKGROUND

Oncological outcome after radical radiotherapy (RRT) combined with neoadjuvant and adjuvant androgen suppression therapy (AST) may differ according to type of AST. The aim of this nationwide register-based study was to investigate risk of prostate cancer (Pca) death after different neoadjuvant and adjuvant ASTs; (i) bicalutamide, (ii) gonadotropin-releasing hormone agonists (GnRH) or (iii) combined bicalutamide and GnRH (CAB), together with RRT.

MATERIALS AND METHODS

Data for 6882 men diagnosed with high-risk Pca between 2007 and 2020 and treated with primary RRT was retrieved from Prostate Cancer data Base Sweden (PCBaSe) 5.0. Time to Pca death according to type of neoadjuvant and adjuvant AST was assessed by use of Kaplan-Meier plots and Cox proportional hazard models adjusted for putative confounders.

RESULTS

Data were stratified by RRT type since the effect of AST in risk of Pca death differed according to type of RRT. Compared with the reference RRT combined with neoadjuvant CAB/adjuvant GnRH, risk of Pca death for men treated with CAB/bicalutamide and conventionally fractionated external beam radiotherapy (CF-EBRT) was hazard ratio (HR) 0.73 (95% CI: 0.50-1.04), hypofractionated EBRT (HF-EBRT), HR 1.35 (95% CI: 0.65-2.81) and EBRT with high dose rate brachytherapy (EBRT-HDRBT), HR 0.85 (95% CI: 0.37-1.95). Risk of Pca death for men treated with bicalutamide/bicalutamide and: (i) CF-EBRT was HR 2.35 (95% CI: 1.42-3.90), (ii) HF-EBRT, HR 0.70 (95% CI: 0.26-1.85), (iii) HF-EBRT, HR 4.07 (95% CI: 1.88-8.77) vs the reference.

CONCLUSION

In this observational study, risk of Pca death between men receiving different combinations of AST varied according to RRT type. No difference was found in risk of Pca death for men treated with bicalutamide or GnRH as adjuvant therapy to RRT following neoadjuvant CAB. Risk of Pca death was increased for men with monotherapy neo-/adjuvant bicalutamide in combination with CF-EBRT or EBRT-HDRBT.

A single centre intercomparison between commercial treatment planning systems for 90Y radioembolization using virtual and experimental phantoms

INTRODUCTION

Dedicated Treatment Planning Systems (TPSs) were developed to personalize 90Y-transarterial radioembolization. This study evaluated the agreement among four commercial TPSs assessing volumes of interest (VOIs) volumes and dose metrics.

METHODS

A homogeneous (EH) and an anthropomorphic phantom with hot and cold inserts (EA) filled with 99mTc-pertechnetate were acquired with a SPECT/CT scanner. Their virtual versions (VH and VA, respectively) and a phantom with activity inside a single voxel (VK) were generated by an in-house MATLAB script. Images and delineated VOIs were imported into the TPSs to compute voxel-based absorbed dose distributions with various dose deposition approaches: local deposition method (LDM) and dose kernel convolution (DKC) with/without local density correction (LDC). VOI volumes and mean absorbed doses were assessed against their median value across TPSs. Dose-volume histograms (DVHs) and VK-derived dose profiles were evaluated.

RESULTS

Small (<2.1 %) and large (up to 42.4 %) relative volume differences were observed on large (>500 ml) and small VOIs, respectively. Mean absorbed doses relative differences were < 3 % except for small VOIs with steep dose gradients (up to 89.1 % in the VA Cold Sphere VOI). Within the same TPS, LDC negligibly affected the mean absorbed dose, while DKC and LDM showed differences up to 63 %. DHVs were mostly overlapped in experimental phantoms, with some differences in the virtual versions. Dose profiles agreed within 1 %.

CONCLUSION

TPSs showed an overall good agreement except for small VOI volumes and mean absorbed doses of VOIs with steep dose gradients. These discrepancies should be considered in the dosimetry uncertainty assessment, thus requiring an appropriate harmonization.

Isolated vaginal recurrence in women with stage I endometrial cancer

OBJECTIVE

To compare clinical and pathologic characteristics of women with surgical stage I endometrial carcinoma by location of first recurrence and describe characteristics of isolated vaginal recurrence.

METHODS

Patients with 2009 International Federation of Obstetrics and Gynecology (FIGO) stage I endometrial carcinoma treated at two large cancer centers from 1/1/2009-12/31/2017 were identified. Sarcoma histology was excluded. Recurrences were grouped into isolated vaginal or extravaginal. Isolated vaginal recurrences were localized by anatomic location within the vaginal vault. Clinical and pathologic variables were compared with chi-square analysis, and Kaplan-Meier curves with log-rank tests.

RESULTS

Of 2815 women identified, 278 (10%) experienced a recurrence. Sixty-one patients (2%) had an isolated vaginal recurrence, including 42 (69%) at the vaginal apex; 217 (8%) had an extravaginal recurrence, including 18 with a vaginal component. Median time to recurrence was 11 months (range, 1-68) for isolated vaginal recurrence and 20 months (range, 1-98) for extravaginal recurrence (P < .004). Of 960 patients (34%) treated with adjuvant vaginal brachytherapy (VBT), 156 (16%) recurred; 19 (2%) had an isolated vaginal recurrence, including 16 (84%) at the vaginal apex. Three-year PFS rates for isolated vaginal recurrence were 97.6% (SE ± 0.4%) with minimally invasive surgery (MIS) versus 96.9% (SE ± 1.1%) with open (P = .8), and for extravaginal recurrence were 91.8% (SE ± 0.7%) with MIS versus 90.8% (SE ± 1.8%) with open (P = .8).

CONCLUSIONS

Isolated vaginal recurrences in stage I endometrial cancer are detected earlier than non-vaginal recurrences. Surgical approach does not appear to impact recurrence. Adjuvant VBT after primary surgery carries a 1%-2% risk of isolated vaginal apex recurrence.

A scintillation dosimeter with real-time positional tracking information for in vivo dosimetry error detection in HDR brachytherapy

PURPOSE

To evaluate the performance of an electromagnetic (EM)-tracked scintillation dosimeter in detecting source positional errors of IVD in HDR brachytherapy treatment.

MATERIALS AND METHODS

Two different scintillator dosimeter prototypes were coupled to 5 degrees-of-freedom (DOF) EM sensors read by an Aurora V3 system. The scintillators used were a 0.3 × 0.4 × 0.4 mm3 ZnSe:O and a BCF-60 plastic scintillator of 0.5 mm diameter and 2.0 mm in length (Saint-Gobain Crystals). The sensors were placed at the dosimeter's tip at 20.0 mm from the scintillator. The EM sampling rate was 40/s while the scintillator signal was sampled at 100 000/s using two photomultiplier tubes from Hamamatsu (series H10722) connected to a data acquisition board. A high-pass filter and a low-pass filter were used to separate the light signal into two different channels. All measurements were performed with an afterloader unit (Flexitron-Elekta AB, Sweden) in full-scattered (TG43) conditions. EM tracking was further used to provide distance/angle-dependent energy correction for the ZnSe:O inorganic scintillator. For the error detection part, lateral shifts of 0.5 to 3 mm were induced by moving the source away from its planned position. Indexer length (longitudinal) errors between 0.5 to 10 mm were also introduced. The measured dose rate difference was converted to a shift distance, with and without using the positional information from the EM sensor.

RESULTS

The inorganic scintillator had both a signal-to-noise-ratio (SNR) and signal-to-background-ratio (SBR) close to 70 times higher than those of the plastic scintillator. The mean absolute difference from the dose measurement to the dose calculated with TG-43U1 was 1.5% ±0.7%. The mean absolute error for BCF-60 detector was 1.7%± 1.2 % $\pm 1.2\%$ when compared to TG-43 calculations formalism. With the inorganic scintillator and EM tracking, a maximum area under the curve (AUC) gain of 24.0% was obtained for a 0.5-mm lateral shift when using the EMT data with the ZnSe:O. Lower AUC gains were obtained for a 3-mm lateral shifts with both scintillators. For the plastic scintillator, the highest gain from using EM tracking information occurred for a 0.5-mm lateral shift at 20 mm from the source. The maximal gain (17.4%) for longitudinal errors was found at the smallest shifts (0.5 mm).

CONCLUSIONS

This work demonstrates that integrating EM tracking to in vivo scintillation dosimeters enables the detection of smaller shifts, by decreasing the dosimeter positioning uncertainty. It also serves to perform position-dependent energy correction for the inorganic scintillator,providing better SNR and SBR, allowing detection of errors at greater distances from the source.

[Combination of internal and external beam radiotherapy]

External beam radiation therapy and internal vectorized radiation therapy are two types of radiotherapy that can be used to treat cancer. They differ in the way they are administered, and the type of radiation used. Although they can be effective in treating cancer, they each have their own advantages and disadvantages, and their combination could be synergistic. Preclinical studies on combined internal and external beam radiation therapy have mainly used radiolabelled antibodies, whose bone marrow toxicity remains the limiting factor in increasing the administered activities. The use of small radioligands in clinical trials has shown to be better tolerated and more effective, which explains their rapid development. The results of preclinical studies on combined internal and external beam radiation therapy appear heterogeneous, making it impossible to determine an ideal therapeutic sequencing scheme, and complicating the transposition to clinical studies. The few clinical studies on combined internal and external beam radiation therapy available to date have demonstrated feasibility and tolerability. More work remains to be done in the fields of dosimetry and radiobiology, as well as in the sequencing of these two irradiation modalities to optimize their combination.

CAD/CAM-assisted ablative surgery and intraoperative brachytherapy for pediatric skull-base sarcomas

BACKGROUND

Head and neck (H&N) sarcomas in children can poise numerous challenges to the surgical oncologist and require multidisciplinary input and meticulous surgical planning. The application of computer-assisted design/computer-assisted manufacturing (CAD/CAM) has been extensively examined in H&N reconstruction in adults, but its utility in ablative oncologic surgery in children warrants further examination. We present preliminary results utilizing CAD/CAM techniques to assist in planning tumor resections and the application of intra-operative radiation in children with skull-base sarcomas.

METHODS

A retrospective cohort review of all pediatric patients who presented to a tertiary care cancer center for surgical resection of a skull-base malignancy was performed between 1980 and 2021. All children under 18 years of age with diagnosis of a skull-base sarcoma as confirmed with imaging and pathology were analyzed.

RESULTS

A total of 21 children were identified but only four children with skull-base sarcomas had diagnostic imaging available in whom computer-assisted volumetric analyses were generated. In these cases, CAD/CAM was used to plan surgical approaches and intraoperative radiotherapy, significantly aiding in treatment for these complicated pediatric cases.

CONCLUSION

CAD/CAM planning for oncologic resection has huge potential. Here we have shown its utility in pre-operative surgical planning and for administration of intraoperative radiation therapy. Future studies are needed to examine its value in facilitating intraoperative surgical management and patient outcomes, as well as cost effectiveness.