Beyond surgical resection: evaluating stereotactic brachytherapy iodine-125 for low-grade gliomas: a systematic review and meta-analysis.

Stereotactic Brachytherapy Iodine-125 (SBT I-125) has been investigated by some studies for the treatment of lowgrade gliomas. We performed a meta-analysis to assess the efficacy and safety of SBT I-125 Brachytherapy for treatment of patients with Low-Grade Gliomas. PubMed, Cochrane, Web of Science, and EMBASE databases were searched for randomized and observational studies. This systematic review and meta-analysis was conducted according to the Cochrane Collaboration and the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement guidelines. We used relative risk (RR) with 95% confidence intervals and random effects model to compare the effects of I-125 SBT treatment on the interest outcomes. We evaluated heterogeneity using I2 statistics; we considered heterogeneity to be significant if the p-value was less than 0.05 and I2 was higher than 35%. We performed statistical analysis using the software R (version 4.2.3). A total of 20 studies with a cohort of 988 patients with low grade gliomas who received SBT I-125 as a treatment option. The pooled analysis evidenced: (1) Complication rate of 10% (95% CI: 7-12%; I² = 60%); (2) 5-year PFS of 66% (99% CI: 45-86%; I²= 98%); (3) 10-year PFS was 66% (99% CI: 45-86%; I²= 98%); (4) Malignant transformation rate of 26% (95% CI: 8-45%; I²=0); (5) Mortality of 33% (95% CI: 15-51%; I² = 0%). Our systematic review and meta-analysis of SBT I-125 for low-grade gliomas have revealed significant concerns regarding its safety and efficacy. Despite a proportion of patients remaining progression-free, elevated rates of complications and mortality cast doubt on the intervention's reliability. Future research should prioritize long-term follow-up studies, standardized protocols, and comparative effectiveness research.

Commissioning of MRI-guided gynaecological brachytherapy using an MR-linac.

Purpose. To evaluate the feasibility of use of an 1.5 T magnetic resonance (MR)-linear accelerator MR-linac for imaging in gynaecologic high-dose-rate (HDR) brachytherapy.Method. Commissioning measurements for MR images quality control, geometric distortion, dwell position accuracy, applicator reconstruction and end-to-end test for a tandem-and-ring applicator were performed following the recommendations of American Brachytherapy Society, International Commission on Radiation Units and Measurements and Report of the Brachytherapy Working Group of the Spanish Society of Medical Physics. The values for MR-based IGABT were compared to the corresponding values with computed tomography (CT).Results. Measured distorsions for the MR images were less than 0.50 mm compared to the CT images. The differences between 3D displacements for all dwell positions were 0.66 mm and 0.62 mm for the tandem and ring, respectively. The maximum difference is 0.64 mm for the distances from the applicator tip obtained using the films. The CT and MR dose differences for the right and left 'A' points were 0.9% and -0.7%, respectively. Similar results were observed in terms of dose distribution for CT and Mr The gamma passing rate was 99.3% and 99.5%, respectively.Conclusion. The use of MR images from an MR-linac used in a radiotherapy service for gynaecological brachytherapy was proved to be feasible, safe and precise as the geometrical differences were less than 1 mm, and the dosimetric differences were less than 1% when comparing to the use of CT images for the same purpose.

Calibration system correction factor for measuring the reference air kerma rate (RAKR) applied to high dose rate192Ir sources (HDR).

The aim of this study was to use computer simulation to analyze the impact of the aluminum fixing support on the Reference Air Kerma (RAK), a physical quantity obtained in a calibration system that was experimentally developed in the Laboratory of Radiological Sciences of the University of the State of Rio de Janeiro (LCR-UERJ). Correction factors due to scattered radiation and the geometry of the192Ir sources were also sought to be determined. The computational simulation was validated by comparing some parameters of the experimental results with the computational results. These parameters were: verification of the inverse square law of distance, determination of (RAKR), analysis of the source spectrum with and without encapsulation, and the sensitivity curve of the Sourcecheck 4PI ionization chamber response, as a function of the distance from the source along the axial axis, using the microSelectron-v2 (mSv2) and GammaMedplus (GMp) sources. Kerma was determined by activity in the Reference air, with calculated values of 1.725 × 10-3U. Bq-1and 1.710 × 10-3U. Bq-1for the ionization chamber NE 2571 and TN 30001, respectively. The expanded uncertainty for these values was 0.932% and 0.919%, respectively, for a coverage factor (k = 2). The correction factor due to the influence of the aluminum fixing support for measurements at 1 cm and 10 cm from the source was 0.978 and 0.969, respectively. The geometric correction factor of the sources was ksg= 1.005 with an expanded uncertainty of 0.7% for a coverage factor (k = 2). This value has a difference of approximately 0.2% compared to the experimental values.

Enhanced outcomes in residual or recurrent craniopharyngioma: evaluating combined gamma knife and phosphorus-32 brachytherapy.

BACKGROUND: Managing residual and recurrent craniopharyngioma effectively is crucial for improving patient outcomes. This study evaluates the combined use of gamma knife and phosphorus-32 brachytherapy, offering insights into alternative, less invasive treatment strategies. METHODS: We conducted a retrospective analysis of 97 patients treated from 2010 to 2016 for residual and recurrent craniopharyngioma using gamma knife and phosphorus-32 brachytherapy. We classified these patients into three groups: superficial solid (Group A), simple cystic (Group B), and mixed cystic-solid (Group C). We assessed the treatment's effectiveness by the tumor control rates and evaluated safety by monitoring vision, endocrine function improvements, and complication rates. RESULTS: The treatment achieved complete and adequate control rates of 49.5% and 87.6%, respectively. We observed improvements in vision or visual fields in 55.1% of the patients. The morbidity rate was 15.5%. The study found no significant differences in tumor control rates among the various lesion types. CONCLUSION: The combination of gamma knife and phosphorus-32 brachytherapy presents a viable, minimally invasive alternative for treating residual and recurrent craniopharyngioma. It offers high tumor control and functional improvement rates, suggesting its potential as a preferred strategy in some instances.

Selective Internal Radiation Therapy Using Y-90 Resin Microspheres for Metastatic Colorectal Cancer: An Updated Systematic Review and Network Meta-Analysis.

INTRODUCTION: This literature review and exploratory network meta-analysis (NMA) aimed to compare the clinical effectiveness and tolerability of selective internal radiation therapy (SIRT) using yttrium-90 (Y-90) resin microspheres, regorafenib (REG), trifluridine-tipiracil (TFD/TPI), and best supportive care (BSC) in adult patients with chemotherapy-refractory or chemotherapy-intolerant metastatic colorectal cancer (mCRC). METHODS: In light of recently published data, the literature was searched to complement and update a review published in 2018. Studies up to December 2022 comparing two or more of the treatments and reporting overall survival (OS), progression-free survival (PFS), or incidence of adverse events (AE) were included. The NMA compared hazard ratios (HRs) for OS and PFS using Markov chain Monte Carlo techniques. RESULTS: Fifteen studies were included, with eight studies added (none addressing SIRT). All active treatments improved OS in relation to BSC. SIRT had the longest OS among all treatments, although without statistically significant differences (HR [95% credible interval] for SIRT, 0.48 [0.27, 0.87]; TFD/TPI, 0.62 [0.46, 0.83]; REG, 0.78 [0.57, 1.05]) in a fixed effects model. Information regarding SIRT was insufficient for PFS analysis, and TFD/TPI was the best intervention (HR 2.26 [1.6, 3.18]). One SIRT study reported radioembolization-induced liver disease in > 10% of the sample; this was symptomatically managed. Non-haematological AEs (hand-foot skin reaction, fatigue, diarrhoea, hypertension, rash or desquamation) were more common with REG, while haematological events (neutropoenia, leukopenia, and anaemia) were more common with TFD/TPI. CONCLUSION: Current evidence supports SIRT treatment in patients with chemotherapy-refractory or chemotherapy-intolerant mCRC compared to newer oral agents, with comparable OS and low incidence of AEs.

Reirradiation salvage radiotherapy for recurrent prostate cancer after primary low-dose brachytherapy.

PURPOSE: Local recurrence of prostate cancer after low-dose rate brachytherapy is a clinical problem with limited salvage treatment options. This prospective study evaluated the tolerability and outcome of salvage external beam radiation therapy (S-EBRT) for locally recurrent prostate cancer after primary low-dose rate prostate brachytherapy (LDR-BT). MATERIALS AND METHODS: Between October 2012 and 2022, 18 patients with biopsy-proven locally recurrent prostate cancer after primary LDR-BT and received S-EBRT. We evaluated biochemical failure (BF), overall survival (OS) and acute/late gastrointestinal and urinary toxicities (CTCAE v5.0 or CTCAE v4, only before 2017). RESULTS: Median follow-up was 32 months (range, 5-124). The median age was at S-EBRT 68 years (range 59-79). 34% (6/18) were low risk, 44% (8/18) intermediate risk, 5% (1/18) high risk, and 17% (3/18) not specified. All patients were treated with IMRT/VMAT and received 60 Gy (2.5 Gy/fraction) to the prostate and 40% (7/18) 55.2 Gy (2,3 Gy/fx) to the seminal vesicles. 56% received ADT The 3-year OS and biochemical relapse-free survival after S-EBRT were 100% and 89%, respectively, with a median PSA nadir 0,035 ng/mL (0,01-0,34). Acute cystitis was present in 72% (13/18) of patients (27% of Grade > 2). Urethritis was present in 78% (14/18) patients (16% of cases Grade > 3), and acute rectitis occurred in 22% (4/18) of patients (no cases Grade > 3). CONCLUSIONS: Our data suggest that the treatment of locally recurrent prostate cancer with S-EBRT could provide adequate disease control safely and be used as an additional treatment in the natural history of prostate cancer patients. However, the results are still early and the sample is small; larger studies with longer follow-up would be mandatory.

Redefining bladder neck dose in low-dose-rate prostate brachytherapy-Can we improve urinary toxicity without impacting disease control?

BACKGROUND: We sought to assess the impact of bladder neck dose (BND) on patient reported urinary toxicity, and feasibility of relative urethral sparing technique in prostate brachytherapy (PB). METHODS AND MATERIALS: We retrospectively identified bladder neck as a point dose on post-implant CT scans in patients treated with 131Cs PB. Urinary symptoms were assessed through EPIC questionnaires. Patient cohorts were identified based on mean BND as a percentage of prescription dose with toxicity assessment at each time point. RESULTS: In our cohort of 542 patients, BND was associated with clinically significant acute urinary symptoms and chronic symptoms, as patients receiving >70% of the prescription dose had significantly worse overall EPIC scores than patients receiving ≤70% of prescription dose. There was no difference in bDFS between patients receiving BND ≤70% (96% bDFS) and >70% (94% bDFS) at a median follow up of 57 months. CONCLUSIONS: BND has a significant impact on both acute and chronic urinary symptoms, with reduced symptoms reported with BND <70% of prescription dose. With a median follow up of 4.7 years, excellent bDFS has thus far been achieved with relative urethral and bladder neck sparing. Utilizing this constraint should improve urinary symptoms without impacting disease control.

Status of head and neck brachytherapy in Spain in 2022.

PURPOSE: Brachytherapy (BT) has been used for many years for disease control in tumours of the head and neck area (H&N). It is currently performed with high dose rate (HDR) or pulsed dose rate (PDR), but its use has been reduced due to the implementation of new non-invasive external beam radiotherapy techniques such as intensity modulation (IMRT) and volumetric modulated arc therapy (VMAT) and the improvement of surgical techniques. METHODS: The Spanish Brachytherapy Group (GEB) has carried out a survey to find out the number of centres in Spain that continue to use BT in H&N and its indications and expectations for the future. RESULTS: The results were presented at the XX GEB Consensus Meeting held on October 21, 2022, in Valencia (Spain) and it was confirmed that, although there are fewer and fewer centres that use BT in H&N, there are still units with extensive experience in this technique that should be positioned as referral centres. CONCLUSION: It is necessary to carry out continuous work with other specialities involved, such as H&N surgeons, and other radiation oncologists, to improve the training of residents, both oncologists and medical physicists.

Comparison of partial-breast irradiation and intraoperative radiation to whole-breast irradiation in early-stage breast cancer patients: a Kaplan-Meier-derived patient data meta-analysis.

PURPOSE: Partial breast irradiation (PBI) and intraoperative radiation (IORT) represent alternatives to whole breast irradiation (WBI) following breast conserving surgery. However, data is mixed regarding outcomes. We therefore performed a pooled analysis of Kaplan-Meier-derived patient data from randomized trials to evaluate the hypothesis that PBI and IORT have comparable long-term rates of ipsilateral breast tumor recurrence as WBI. METHODS: In February, 2023, PubMed, EMBASE and Cochrane Central were systematically searched for randomized phase 3 trials of early-stage breast cancer patients undergoing breast-conserving surgery with PBI or IORT as compared to WBI. Time-to-event outcomes of interest included ipsilateral breast tumor recurrence (IBTR), overall survival (OS) and distant disease-free survival (DDFS). Statistical analysis was performed with R Statistical Software. RESULTS: Eleven randomized trials comprising 15,460 patients were included; 7,675 (49.6%) patients were treated with standard or moderately hypofractionated WBI, 5,413 (35%) with PBI and 2,372 (15.3%) with IORT. Median follow-up was 9 years. PBI demonstrated comparable IBTR risk compared with WBI (HR 1.20; 95% CI 0.95-1.52; p = 0.12) with no differences in OS (HR 1.02; 95% CI 0.90-1.16; p = 0.70) or DDFS (HR 1.15; 95% CI 0.81-1.64; p = 0.43). In contrast, patients treated with IORT had a higher IBTR risk (HR 1.46; 95% CI 1.23-1.72; p < 0.01) compared with WBI with no difference in OS (HR 0.98; 95% CI 0.84-1.14; p = 0.81) or DDFS (HR 0.91; 95% CI 0.76-1.09; p = 0.31). CONCLUSION: For patients with early-stage breast cancer following breast-conserving surgery, PBI demonstrated no difference in IBTR as compared to WBI while IORT was inferior to WBI with respect to IBTR.

Cs-131 prostate brachytherapy boost and effect of hydrogel rectal spacer on long-term patient-reported rectal bleeding and bowel quality of life.

PURPOSE: This study evaluates long-term patient-reported bowel quality of life (QOL), rectal bleeding, and bleeding bother in patients with prostate cancer treated with external beam radiation therapy (EBRT) and Cesium-131 LDR brachytherapy (LDR-BT) boost with and without hydrogel rectal spacer. METHODS AND MATERIALS: This is a retrospective analysis of prostate cancer patients treated between 2007 and 2022 with 45 Gy EBRT followed by 85 Gy Cs-131 LDR-BT boost with or without hydrogel rectal spacer. Expanded Prostate Cancer Index Composite (EPIC) QOL questionnaires pre-treatment and at each follow-up were collected. Patient-reported rectal bleeding occurring more than "rarely" and bother from rectal bleeding occurring more than a "very small problem" were deemed clinically significant. Fisher's exact test was used to test the association of rectal spacer use and the incidence of clinically significant rectal bleeding and bleeding bother. Paired samples t-test was used to analyze mean bowel scores at each time point. RESULTS: Three hundred and forty-one patients were included in the analysis. The rectal spacer was used in 108 patients. Overall median follow-up was 48 months (IQR, 24-72), with a median follow-up of 24 months (IQR, 12-37.5) for the hydrogel group and 60 months (IQR, 36-84) for the non-hydrogel group. EPIC questionnaire response rates at median follow-up were 33% and 37% for the hydrogel and non-hydrogel groups, respectively. A clinically significant decrease in mean bowel domain scores was seen in the bowel bother domain at 6 and 12 months for patients who did not receive a rectal spacer. At the last follow-up of 60 months, the prevalence of clinically significant rectal bleeding and bleeding bother were 2.2% and 2.2%, respectively. The cumulative incidence of clinically significant long-term rectal bleeding was 2.8% and 18.9% in the hydrogel group and non-hydrogel group, respectively (Fisher's exact test, p < 0.0001). The cumulative incidence of clinically significant long-term bowel bother was 4.6% and 19.7% in the hydrogel group and non-hydrogel group, respectively (Fisher's exact test, p < 0.001). CONCLUSIONS: Use of hydrogel rectal spacer with EBRT and Cs-131 LDR-BT boost was significantly associated with a lower incidence of patient-reported rectal bleeding and bother from rectal bleeding, and better long-term bowel QOL. Cumulative incidence was 2.8% (hydrogel group) versus 18.9% (non-hydrogel group) and 4.6% (hydrogel group) versus 19.7% (non-hydrogel group) for clinically significant long-term rectal bleeding and long-term bleeding bother, respectively.

Vaginal dilator use more than 9 months is a main prognostic factor for reducing G2­late vaginal complications in 3D­vaginal­cuff brachytherapy (interventional radiotherapy)?

PURPOSE: Analyse the impact of different prognostic factors on G2-late vaginal complications after vaginal brachytherapy (VBT) ± external beam radiotherapy (EBRT) in postoperative endometrial cancer (PEC). METHODS: One hundred and twenty-six PEC patients treated with VBT ± EBRT were retrospectively analysed considering age, body mass index, applicator diameter, clinical target volume (CTV), use of dilators, chemotherapy and EQD2(α/ß=3) at the most exposed 2 cm3 of the CTV as prognostic factors for vaginal complications. Late vaginal complications were evaluated using objective LENT-SOMA criteria. STATISTICS: descriptive analysis, Chi-square, Fisher and Student tests were applied. Univariate and multivariate analyses were performed with the Baptista-Pike exact method and multiple logistic regression. RESULTS: Mean age was 65 years (SD ± 10), and median follow-up was 66 months (8-104). 19/126 patients (15%) showed G2-late vaginal complications, and 107/126 (85%) G0-G1. Univariate analysis showed: CTV ≤ 9 cm3 (p = 0.036), use of dilators < 9 months (p = 0.015), and total ≥ 68 Gy EQD2 received by 2 cm3 of CTV (p = 0.039) were associated with G2-late vaginal toxicity. Multivariate analysis showed the use of dilators < 9 months as an independent prognostic factor for G2-late vaginal toxicity (p = 0.043, OR 8.59, CI 1.59-159.9). CONCLUSION: The use of dilators < 9 months in VBT ± EBRT for PEC was an independent prognostic factor for G2-late vaginal toxicity. The use of vaginal dilators ≥ 9 months requires further analysis in studies evaluating late vaginal toxicity.

Recommendations of the Spanish brachytherapy group of the Spanish Society of Radiation Oncology and the Spanish Society of Medical Physics for interstitial high-dose-rate brachytherapy for gynaecologic malignancies.

The present document includes consensus-based recommendations from the Brachytherapy Group (GEB) of the Spanish Society of Radiation Oncology (SEOR) and the Spanish Society of Medical Physics (SEFM) for interstitial high-dose-rate (HDR) brachytherapy (BT) for gynaecologic malignancies. A nine-item survey-which included questions on experience with interstitial BT; indications and technique; applicator type; magnetic resonance imaging (MRI)-based planning; dose; fractionation schedule; and treatment planning-was sent to all radiation oncology departments (n = 174) in Spain in 2021. Responses were received from 36 centres (50% of all centres [n = 72] with a BT unit). The consensus-based recommendations presented here are based on a review of the available literature, professional experience among the group of experts, and in-person discussions held during the annual meeting of these two societies. We describe the results of the survey and the following: indications; contraindications; patient selection; description of applicators; role of imaging in planning; contouring; dose prescription; dosimetric reconstruction; optimisation; and dose indications for cancers of the cervix, vagina, and vulva. The various clinical scenarios in which interstitial BT is used in the treatment of gynaecological tumours are described in detail, including cervix intracavitary/interstitial hybrid HDR-BT; cervix perineal templates/freehand implants; primary vaginal malignancies/vaginal recurrences; and vulvar interstitial implants.

Outcomes of 3D MRI based HDR brachytherapy with hybrid multichannel vaginal cylinder applicator and freehand needles for treatment of vaginal disease.

Freehand needles can be used with multichannel vaginal cylinders (MCVC) to cover vaginal cancer >7 mm thick or with supra-vaginal extension. We report our institutional outcomes using this novel hybrid technique. Patients with vaginal malignancies treated with HDR BT using MCVC plus freehand needles from 2014-2021 at our institution were identified. Clinical characteristics, details of brachytherapy, initial response, and overall local control (LC) outcomes were recorded. LC was analyzed via Kaplan-Meier method. 34 patients were identified with median follow-up 1.9 years. 19 patients had primary endometrial cancer with vaginal recurrence/disease, and remaining had primary vaginal cancer or other primaries. 7 patients had recurrence after previous RT course. 25 patients received EBRT with median dose 45 Gy in 25 fractions, and rest received BT alone. Median HR-CTV D90 for patients treated with EBRT plus BT was 77.4 Gy. 30 patients had complete local response to BT on initial examination and/or follow-up imaging. 1 and 2-year LC rates in patients without prior RT treated with EBRT + BT were 94.1% and 94.1%, respectively. 1 and 2-year LC rates for those without prior RT were 88.1% and 76.4%, respectively. 1 and 2-year LC rates for those with prior RT were 68.6% and 34.3%, respectively. 1 patient had vaginal laceration requiring surgical repair, and 1 patient developed small bowel obstruction 1 month after BT, with no additional acute grade 3+ toxicities identified. Our approach with MCVC plus freehand needles with MRI-based planning was feasible and safe, with excellent initial local response and low rate of serious toxicities.

The Kelowna template for combined intracavitary and interstitial brachytherapy for gynecologic malignancies: Design, application, treatment planning, dosimetric and treatment outcomes.

PURPOSE: We report the feasibility, experience, and early outcomes of the combined intracavitary and interstitial dedicated applicator using the Kelowna GYN template (Varian, Palo Alto, CA). METHODS AND MATERIALS: The Kelowna GYN template is CT compatible and used for the treatment of gynecologic cancers. In cases with patients that have an intact uterus, a modified applicator system using the Kelowna GYN template and a 3D printed adapter piece allows for compatibility with an intrautaerine tandem. RESULTS: We reviewed the treatment course of 23 patients comprising of 86 fractions of HDR treatment. Median D90 for cervical tumors (n = 7) was 82.4 Gy (range 77.7-92.6); for postoperative cervical tumors (n = 2) was 73.9 Gy (range 72.0-5.8); for vaginal tumors (n = 4) was 85.8 Gy (range 79.8-88.1); for recurrent endometrial (n = 10) was 86.9 Gy (range 74.8-103.2). Median EQD2 D2cc for bladder was 72.4 Gy (range 47.7-99.4), for rectum was 61.2 Gy (range 52.4-80.6), and for sigmoid colon of 50.5 Gy (44.3-66.9). At a median follow-up of 12 months, 2 patients had a local recurrence. Two patients had distant recurrence: one with carcinomatosis at 6 months, and one with pulmonary metastases at 3 months. No patients had late grade three toxicities. CONCLUSIONS: Our single institutional experience supports the use of the Kelowna template as a robust system as a combined IC-IS applicator resulting in versatile and reproducible implants for a variety of gynecologic malignancies.

Comparison of AUA and phoenix definitions of biochemical failure following permanent brachytherapy for prostate cancer.

PURPOSE: To compare biochemical recurrence free survival (BCRFS) and cancer-specific survival (CSS) after brachytherapy using the AUA and the Phoenix definitions. METHODS AND MATERIALS: 2634 men with T1-T4N0M0 prostate cancer were treated with brachytherapy with or without neoadjuvant hormonal therapy or external beam radiation therapy. Five, 10, and 15- year BCRFS and CSS were estimated with Kaplan-Meier estimates with log rank. Multivariate analysis of survival was performed with Cox regression analysis. RESULTS: Median age was 66, follow-up was 8.6 years, and prostate specific antigen was 6.9. Overall, 11.1% (n = 293) of patients experienced Phoenix BCR and 17.48% (n = 457) experienced AUA BCR. The rates of AUA BCR and Phoenix BCR were significantly different at 5 and 10-years but not at 15 years. Patients treated with BED ≤ 200 Gy were more likely to experience AUA BCR (22.5% vs. 12.4%, OR 1.44, p < 0.001) and Phoenix BCR (14.3% and 8.3%, OR 1.37, p < 0.001) than patients treated with a BED > 200 Gy. CONCLUSIONS: Compared to the Phoenix definition, the AUA definition of BCR after brachytherapy is associated with significantly worse BCRFS for the first 15 years after treatment. Receiving a BED > 200, which cannot be achieved without the addition of brachytherapy, is associated with better BCRFS and CSS. Our findings reaffirm the importance of dose in the management of prostate cancer.

System-Level Capacity of High-Dose Rate (HDR) Brachytherapy for Management of Cervical Cancer in an Upper-Middle Income Country: A Case Study From Brazil.

PURPOSE: Ensuring optimal access to radiation therapy (RT) facilities is challenging for many countries. External beam RT and brachytherapy (BCT) are required to treat advanced cervical cancer. In this analysis, we evaluated the system-level capacity of BCT in Brazil and its relationship with access to complete cervix cancer radiation treatment with both external beam RT and BCT. METHODS AND MATERIALS: We used official government reports to compile data on BCT and linear accelerator (LINAC) numbers, geographic distribution and coverage, cervical cancer annual incidence, and prevalence in Brazil. We also evaluated changes in national BCT capacity between 2001 and 2021. The 2020 relationship between cervical cancer cases for RT per BCT unit, LINAC per BCT unit, and the LINAC supply for each Brazilian state and region were evaluated. For comparison, the LINAC per BCT unit ratio in Brazil was compared with Europe using International Atomic Energy Agency data. RESULTS: Eighty-five percent (23/27) of Brazilian states have at least 1 BCT unit; nationally, there are 117 cervical cancer cases for RT per BCT unit. Compared with the benchmark of 200 cervical cancer cases per BCT device per year, there are enough BCT units to fill capacity in Brazil nationally and regionally. The ratio of total cervix cancer cases per BCT unit decreased substantially over time from 142 in 2013 to 117 in 2021 (P < .0001). Nationally, there are 252 LINAC units in the public system with a ratio of 1985 new cancer cases/LINAC. Brazilian regions have a LINAC shortage ranging from 15 to 141 units. There were 2.55 LINACs per BCT unit in Brazil, compared with 3.25 in Europe (P = .012). CONCLUSIONS: Over 20 years, BCT capacity in Brazil has increased to meet the cervical cancer demand. However, the LINAC shortage has persisted over the decades, affecting access to complete treatment and possibly the oncological outcomes. These data can help organize the patient treatment flow, avoid treatment delays, and improve survival.

A Monte Carlo study of the relative biological effectiveness in surface brachytherapy.

PURPOSE: This work aims to simulate clustered DNA damage from ionizing radiation and estimate the relative biological effectiveness (RBE) for radionuclide (rBT)- and electronic (eBT)-based surface brachytherapy through a hybrid Monte Carlo (MC) approach, using realistic models of the sources and applicators. METHODS: Damage from ionizing radiation has been studied using the Monte Carlo Damage Simulation algorithm using as input the primary electron fluence simulated using a state-of-the-art MC code, PENELOPE-2018. Two 192 Ir rBT applicators, Valencia and Leipzig, one 60 Co source with a Freiburg Flap applicator (reference source), and two eBT systems, Esteya and INTRABEAM, have been included in this study implementing full realizations of their geometries as disclosed by the manufacturer. The role played by filtration and tube kilovoltage has also been addressed. RESULTS: For rBT, an RBE value of about 1.01 has been found for the applicators and phantoms considered. In the case of eBT, RBE values for the Esteya system show an almost constant RBE value of about 1.06 for all depths and materials. For INTRABEAM, variations in the range of 1.12-1.06 are reported depending on phantom composition and depth. Modifications in the Esteya system, filtration, and tube kilovoltage give rise to variations in the same range. CONCLUSIONS: Current clinical practice does not incorporate biological effects in surface brachytherapy. Therefore, the same absorbed dose is administered to the patients independently on the particularities of the rBT or eBT system considered. The almost constant RBE values reported for rBT support that assumption regardless of the details of the patient geometry, the presence of a flattening filter in the applicator design, or even significant modifications in the photon energy spectra above 300 keV. That is not the case for eBT, where a clear dependence on the eBT system and the characteristics of the patient geometry are reported. A complete study specific for each eBT system, including detailed applicator characteristics (size, shape, filtering, among others) and common anatomical locations, should be performed before adopting an existing RBE value.

The American Brachytherapy Society consensus statement for permanent implant brachytherapy using Yttrium-90 microsphere radioembolization for liver tumors.

PURPOSE: To develop a multidisciplinary consensus for high quality multidisciplinary implementation of brachytherapy using Yttrium-90 (90Y) microspheres transarterial radioembolization (90Y TARE) for primary and metastatic cancers in the liver. METHODS AND MATERIALS: Members of the American Brachytherapy Society (ABS) and colleagues with multidisciplinary expertise in liver tumor therapy formulated guidelines for 90Y TARE for unresectable primary liver malignancies and unresectable metastatic cancer to the liver. The consensus is provided on the most recent literature and clinical experience. RESULTS: The ABS strongly recommends the use of 90Y microsphere brachytherapy for the definitive/palliative treatment of unresectable liver cancer when recommended by the multidisciplinary team. A quality management program must be implemented at the start of 90Y TARE program development and follow-up data should be tracked for efficacy and toxicity. Patient-specific dosimetry optimized for treatment intent is recommended when conducting 90Y TARE. Implementation in patients on systemic therapy should account for factors that may enhance treatment related toxicity without delaying treatment inappropriately. Further management and salvage therapy options including retreatment with 90Y TARE should be carefully considered. CONCLUSIONS: ABS consensus for implementing a safe 90Y TARE program for liver cancer in the multidisciplinary setting is presented. It builds on previous guidelines to include recommendations for appropriate implementation based on current literature and practices in experienced centers. Practitioners and cooperative groups are encouraged to use this document as a guide to formulate their clinical practices and to adopt the most recent dose reporting policies that are critical for a unified outcome analysis of future effectiveness studies.

Effect of short-term corticosteroid usage on acute urinary toxicity following Cs-131 prostate brachytherapy.

PURPOSE: To evaluate short-term patient reported urinary quality of life scores in patients with prostate cancer treated at our institution with and without perioperative prednisone following Cesium-131 (131Cs) prostate LDR brachytherapy. METHODS AND MATERIALS: We started routinely using a perioperative 7-day course of prednisone at a dose of 5 mg per day, beginning 1 day prior to 131Cs prostate LDR brachytherapy from 2013 with goal of improving acute urinary symptomatology. One hundred consecutive patients treated with prednisone were selected, with comparison to 100 consecutive patients who were not treated with prednisone. We analyzed for differences in mean change with standard deviation (SD) in EPIC and AUA scores at 0.5-1 month and 3 months with or without prednisone by Mann-Whitney U Test. Binary logistic regression was performed to assess for impact of prednisone on postoperative urinary catheter use. RESULTS: Pretreatment EPIC and AUA scores were available in 197 patients. Less reduction in EPIC US score was noted at 0.5-1.0 month in the group who received prednisone with mean change of -22.9 (SD 15.4) when compared to the group who did not receive prednisone with mean change of -31.7 (SD 19.3), p < 0.01, with significance lost at 3 months. There was no significant difference in acute urinary retention requiring postoperative urinary catheter placement with perioperative prednisone (OR 1.13, p = 0.71). CONCLUSIONS: A short course of perioperative low-dose prednisone was associated with less severe worsening in urinary symptoms by the EPIC questionnaire at the 0.5-1.0-month timepoint suggesting some improvement in acute urinary quality of life, although differences did not remain statistically significant at 3 months.