Journal of Contemporary Brachytherapy最新文献

Purpose: To compare the rectal and bladder doses using two different vaginal packing techniques among uterine cervical cancer patients receiving high-dose-rate (HDR) intracavitary brachytherapy (ICBT).

Material and methods: Forty-five patients with cervical cancer were randomized to receive two sessions of ICBT using tandem and ring applicator (Varian^©), following completion of pelvic external beam radiotherapy treatment. The procedure was performed with vaginal balloon plus gauze packing or vaginal gauze packing alone, each of which was used in one of two sessions. Sequence of the type of vaginal packing was chosen with computer-generated block randomization. A HDR dose of 8.5 Gy was prescribed to point A in all patients. Volumetric dose parameters, such as D_0.1cc, D_0.5cc, D_1cc, and D_2cc of the rectum and bladder were compared between the two techniques of vaginal packing.

Results: The mean age of patients was 51 years. Majority (88%) of patients had locally advanced stages of cancer at baseline (stage IIB or more). Rectal doses were significantly less in combined packing technique (D_0.1cc: 7.52 Gy vs. 9.02 Gy, p = 0.01; D_0.5cc: 6.46 Gy vs. 7.42 Gy, p < 0.01; D_1cc: 5.91 Gy vs. 6.7 Gy, p < 0.01; D_2cc: 5.29 Gy vs. 5.97 Gy, p < 0.01). Bladder doses were higher in the combined packing technique (D_0.1cc: 11.20 Gy vs. 10.76 Gy, p = 0.18; D_0.5cc: 9.64 Gy vs. 9.32 Gy, p = 0.56; D_1cc: 8.64 Gy vs. 8.36 Gy, p = 0.55; D_2cc: 7.56 vs. 7.33 Gy, p = 0.55).

Conclusions: Combined vaginal packing resulted in statistically significant reduction in rectal radiation dose compared with standard vaginal gauze packing in high-dose-rate brachytherapy of cervix cancer using tandem and ring applicators.

Purpose: A previous survey conducted in 2012 showed that 82% of radiation oncology residents felt they were not receiving optimal brachytherapy training. With almost 10 years of hindsight, the aim was to update these results.

Material and methods: An anonymized questionnaire based on the 2012 survey was submitted to the 161 French residents enrolled in the 2021 French Society of Young Radiation Oncologists (Société Française des Jeunes Radiothérapeutes Oncologues - SFJRO) national brachytherapy courses.

Results: With a participation rate of 73%, 86% of the residents were interested in brachytherapy, but 80% consider their training in brachytherapy insufficient. 88% and 69% of the residents stated that they knew gynecological and prostate brachytherapy indications correctly, respectively. The residents have achieved proficiency in the technique of brachytherapy of vaginal vault in 36% (compared with 21% in 2012), utero-vaginal in 13% (12% in 2012), including 4% with interstitial implants, and prostate in only 4% (4% in 2012). In their brachytherapy internships, 18% of the residents declared having no role or an observational role. The main obstacles to training were the need to go to several centers to see several indications (85%), lack of brachytherapy activity in the center (72%), and the difficulty of freeing themselves from hospital duties (71%).

Conclusions: With results globally stable compared with 2012, brachytherapy training needs improvement. In the absence of a mandatory internship in a reference center or dedicated fellowships, residents must have protected access to training sites by favoring inter-hospital exchanges.

Purpose: Biliary stents combined with percutaneous or endoscopic ultrasound-guided iodine-125 seed implantation into primary tumor have been confirmed to relieve malignant obstructive jaundice (MOJ), and prolong patient's stent patency. The aim of the study was to evaluate meaningful clinical application indications and better guide the application of this technology.

Material and methods: Patients with MOJ, who have received bile duct stenting combined with iodine-125 (¹²⁵I) seed implantation from October, 2010 to April, 2022, were retrospectively analyzed. Univariate and multivariate analyses were adopted to indicate factors of stent patency in MOJ and influencing factors of jaundice reduction at one week after surgery.

Results: A total of 90 patients were enrolled into the study, including 52 males (57.8%) and 38 females (42.2%), with a mean age of 68.66 ±12.53 years. The median stent patency was 8 months. No serious adverse events occurred during follow-up. Multivariate analysis showed that Child-Pugh score (HR = 2.221, 95% CI: 1.081-4.562), biliary infection (HR = 1.901, 95% CI: 1.084-3.335), and pre-operative jaundice duration (HR = 1.977, 95% CI: 1.106-3.533) were the independent risk factors for stent patency. Child-Pugh B/C (OR = 4.647, 95% CI: 1.080-19.982) and bile duct infection (OR = 3.583, 95% CI: 1.095-11.725) were the independent risk factors for jaundice reduction at one week after surgery.

Conclusions: MOJ patients treated with biliary stents combined with ¹²⁵I seed implantation, and patients with better pre-operative liver function and no biliary tract infection, present not only longer biliary stent patency, but also better early jaundice reduction.

Purpose: To report the clinical outcomes in patients treated with Martinez universal perineal interstitial template (MUPIT)-based interstitial brachytherapy boost for primary and recurrent vault and vaginal cancers, and to perform a comparative analysis with our previously published series of similar patients.

Material and methods: One hundred and seventeen patients treated between January, 2009 and December, 2015 were evaluated. Descriptive statistics for the patterns of relapse, local recurrence-free survival (LRFS), disease-free survival (DFS), overall survival (OS), and late toxicities were carried out. Kaplan-Meier curves were used for survival analysis. All variables with the potential to affect outcomes were tested using log-rank test for statistical significance.

Results: At a median follow-up of 63 months, LRFS, DFS, and OS at 3/5 years were 77.1%/74.7%, 61%/52%, and 72.3%/63.1%, respectively. Overall treatment time (OTT) of 56 days did not affect outcomes. Bulky tumors and OTT > 63 days adversely affected LRFS. Overall treatment time also significantly impacted DFS and OS. Grade 3-4 late bladder toxicities were observed in 1.7% patients, and grade 3-4 late rectal toxicities in 5% patients. Compared to our previous series, the outcome in the current series is better in terms of severe late toxicities (5% improvement in rectal toxicity, and 2.7% improvement in bladder toxicity) and OS by 10%. This could be attributed to the increasing use of concurrent chemotherapy and relative optimization strategies for organs at risk.

Conclusions: Patients with primary and recurrent vault and vaginal cancers treated with high-dose-rate interstitial brachytherapy boost using MUPIT resulted in modest clinical outcomes and acceptable late toxicities. OTT was the most important factor affecting the outcomes.

Purpose: Delineation of organs at risk (OARs) represents a crucial step for both tailored delivery of radiation doses and prevention of radiation-induced toxicity in brachytherapy. Due to lack of studies on auto-segmentation methods in head and neck cancers, our study proposed a deep learning-based two-step approach for auto-segmentation of organs at risk in parotid carcinoma brachytherapy.

Material and methods: Computed tomography images of 200 patients with parotid gland carcinoma were used to train and evaluate our in-house developed two-step 3D nnU-Net-based model for OARs auto-segmentation. OARs during brachytherapy were defined as the auricula, condyle process, skin, mastoid process, external auditory canal, and mandibular ramus. Auto-segmentation results were compared to those of manual segmentation by expert oncologists. Accuracy was quantitatively evaluated in terms of dice similarity coefficient (DSC), Jaccard index, 95^th-percentile Hausdorff distance (95HD), and precision and recall. Qualitative evaluation of auto-segmentation results was also performed.

Results: The mean DSC values of each OAR were 0.88, 0.91, 0.75, 0.89, 0.74, and 0.93, respectively, indicating close resemblance of auto-segmentation results to those of manual contouring. In addition, auto-segmentation could be completed within a minute, as compared with manual segmentation, which required over 20 minutes. All generated results were deemed clinically acceptable.

Conclusions: Our proposed deep learning-based two-step OARs auto-segmentation model demonstrated high efficiency and good agreement with gold standard manual contours. Thereby, this novel approach carries the potential in expediting the treatment planning process of brachytherapy for parotid gland cancers, while allowing for more accurate radiation delivery to minimize toxicity.

Purpose: The purpose of this study was to determine a comprehensive in vivo source tracking error thresholds in high-dose-rate (HDR) brachytherapy for cervical cancer. Achieving this enables the definition of an action level for imminent in vivo source tracking technologies and treatment monitoring devices, preventing clinically relevant changes to the applied dose.

Material and methods: Retrospective HDR interstitial (n = 10) and intra-cavitary (n = 20) cervical brachytherapy patients were randomly selected to determine the feasibility of implementing in vivo source tracking error thresholds. A script was developed to displace all dwell positions in each treatment plan, along all major axes from their original position. Dose-volume histogram (DVH) indices were calculated without re-optimization of modified plans to determine the appropriate in vivo source tracking error thresholds in each direction.

Results: In vivo source tracking error thresholds were directionally dependent; the smallest were found to be 2 mm in the anterior and posterior directions for both interstitial and intra-cavitary treatments. High-risk clinical treatment volume (HR-CTV) coverage was significantly impacted by displacements of 4 to 5 mm along each axis. Critically, there was a large variation in DVH metrics with displacement due to change in dwell weightings and patient anatomy.

Conclusions: Determining the dosimetric impact of dwell position displacement provides a clinical benchmark for the development of pre-treatment verification devices and an action level for real-time treatment monitoring. It was established that an in vivo source tracking error threshold needs to be patient-specific. In vivo source tracking error thresholds should be determined for each patient, and can be conducted with extension of the method established in this work.

Acute myeloid leukemia (AML) may extend to extra-medullary sites at diagnosis or at relapse, either isolated or associated with bone marrow disease. Granulocytic sarcoma of uterine cervix is rare, and there is no established treatment for this disease. Two cases of uterine cervix-limited AML relapse showed that brachytherapy may be an effective therapeutic option in this setting along with chemotherapy, with good tolerance.