Journal of Contemporary Brachytherapy最新文献

Purpose: Intra-cavitary brachytherapy is an integral component of cervical cancer management, and uterine perforation is the most significant complication, which may lead to prolonged overall treatment time and decreased local control in these patients.

Material and methods: A retrospective analysis of cervical cancer patients who completed radiotherapy (external beam radiotherapy and brachytherapy) in our department was conducted to determine the incidence, effect on overall treatment time, and final outcome in patients with uterine perforation during brachytherapy procedure.

Results: Among 55 women, of the 398 applications, 85 (21.36%) resulted in uterine perforation. Out of these 85 applications, treatment time was extended among 3 (3.5%) applications only, as re-insertion was done nearly after one week, while the remaining 82 (96.5%) applications were completed in time. At the time of analysis, the median follow-up was 12 months, and 32 patients were disease-free, 3 had distant metastatic disease, 2 had residual disease, and 18 were lost to follow-up.

Conclusions: In our study, uterine perforation incidence was found to be comparable with other centers worldwide. In asymptomatic and uncomplicated uterine perforation, treatment can be continued with computer-based optimized treatment plans without loading a specific dwell position and without affecting overall treatment time.

Purpose: To analyze the effects of different bladder and rectal volumes on the dose of organ at risks (OARs) and primary tumors following uniform preparation procedure.

Material and methods: In this retrospective study, a total of 60 patients with cervical cancer treated with external beam radiation therapy (EBRT) combined with chemotherapy and brachytherapy (BT) during 2019-2022 were included (300 insertions). Then, tandem-ovoid applicators were placed and computed tomography (CT) scanning was performed after each insertion. Delineation of OARs and clinical target volumes (CTVs) were done according to GEC-ESTRO group recommendations. Finally, doses of high-risk clinical target volume (HR-CTV) and OARs were obtained from dose volume histogram (DVH) automatically generated by BT treatment planning system.

Results: Following a uniform preparation procedure, the median bladder volume of 68.36 cc (range, 29.9-235.68 cc) was in optimal agreement with the recommended bladder volume of ≤ 70 ml, which avoided more manipulation and possible risk of adverse events during general anesthesia. As the bladder filling volume increased, there was no corresponding increase in rectal, HR-CTV, and small bowel volumes, while the sigmoid colon volume decreased. The median rectal volume was 54.95 cc (range, 24.92-168.1 cc), and as the rectal volume increased, HR-CTV, sigmoid colon, and rectum volumes increased, and conversely, small bowel volume decreased. HR-CTV changes with volume affected the rectum, bladder, and HR-CTV, but not the sigmoid colon and small intestine.

Conclusions: Following a uniform preparation procedure, the bladder and rectum can also be controlled to an optimal volume (B ≤ 70 cc, R ≈ 40 cc), which is related to the dose of the bladder, rectum, and sigmoid colon.

Purpose: To apply a deep learning approach to automatically detect implanted seeds on a fluoroscopy image in prostate brachytherapy.

Material and methods: Forty-eight fluoroscopy images of patients, who underwent permanent seed implant (PSI) were used for this study after our Institutional Review Boards approval. Pre-processing procedures that were used to prepare for the training data, included encapsulating each seed in a bounding box, re-normalizing seed dimension, cropping to a region of prostate, and converting fluoroscopy image to PNG format. We employed a pre-trained faster region convolutional neural network (R-CNN) from PyTorch library for automatic seed detection, and leave-one-out cross-validation (LOOCV) procedure was applied to evaluate the performance of the model.

Results: Almost all cases had mean average precision (mAP) greater than 0.91, with most cases (83.3%) having a mean average recall (mAR) above 0.9. All cases achieved F1-scores exceeding 0.91. The averaged results for all the cases were 0.979, 0.937, and 0.957 for mAP, mAR, and F1-score, respectively.

Conclusions: Although there are limitations shown in interpreting overlapping seeds, our model is reasonably accurate and shows potential for further applications.

Purpose: Pain control techniques during high-dose-rate hybrid intracavitary-interstitial brachytherapy (HBT) for cervical cancer vary widely, with many centers opting for general anesthesia (GA) or conscious sedation (CS). Here, we describe a single-institutional series of patients treated with HBT and ASA-defined minimal sedation, utilizing oral analgesic and anxiolytic medications in substitution for GA or CS.

Material and methods: The charts of patients who underwent HBT treatments for cervical cancer from June 2018 to May 2020 were retrospectively reviewed. Prior to HBT, all patients underwent an exam under anesthesia (EUA), and Smit sleeve placement under general anesthesia or deep sedation. Oral lorazepam and oxycodone/acetaminophen were administered between 30-90 minutes before HBT procedure for minimal sedation. HBT placement was performed on computed tomography (CT) table, with needle advancement under CT-guidance.

Results: Treatments with minimal sedation were attempted in 63 patients. A total of 244 interstitial implants with 453 needles were placed via CT-guidance. Sixty-one patients (96.8%) tolerated the procedure without any additional intervention, while two patients (3.2%) required the use of epidural anesthesia. None of the patients in the series required a transition to general anesthesia for the procedure. Bleeding, which resolved with short-term vaginal packing, occurred in 22.1% of insertions.

Conclusions: In our series, the treatment of HBT for cervical cancer with minimal sedation was feasible at a high percentage (96.8%). The ability to perform HBT without GA or CS could be a reasonable option to provide image-guided adaptive brachytherapy (IGABT) with limited resources, allowing for more widespread use. Further investigations using this technique are warranted.

Purpose: We assessed prognostic factors of local control and progression-free survival (PFS) of patients treated for AJCC stages T1 and T2 cervical cancer using utero-vaginal brachytherapy after chemoradiotherapy.

Material and methods: This retrospective single-institution analysis included patients who underwent brachytherapy after radiochemotherapy between 2005 and 2015 at the Institut de Cancérologie de Lorraine. Adjuvant hysterectomy was optional. A multivariate analysis of prognostic factors was carried out.

Results: Of 218 patients, 81 (37.2%) were AJCC stage T1, and 137 (62.8%) were AJCC stage T2. 167 (76.6%) patients had squamous cell carcinoma, 97 (44.5%) patients had pelvic nodal disease, and 30 (13.8%) patients had para-aortic nodal disease. One hundred eighty-four patients (84.4%) underwent concomitant chemotherapy, while adjuvant surgery was performed in 91 patients (41.9%) and 42 (46.2%) patients had pathological complete response. Median follow-up was 4.2 years, and local control was reported in 87.8% (95% CI: 83.0-91.8) and 87.2% (95% CI: 82.3-91.3) of patients at 2 and 5 years, respectively. In multivariate analysis, T stage (hazard ratio [HR] = 3.65, 95% CI: 1.27-10.46, p = 0.016) was associated with local control. PFS was reported in 67.6% (95% CI: 60.9-73.4) and 57.4% (95% CI: 49.3-64.2) of patients at 2 and 5 years, respectively. In multivariate analysis, para-aortic nodal disease (HR = 2.03, 95% CI: 1.16-3.54, p = 0.012), pathological complete response (HR = 0.33, 95% CI: 0.15-0.73, p = 0.006), and intermediate-risk clinical tumor volume of > 60 cc (HR = 1.90, 95% CI: 1.22-2.98, p = 0.005) were associated with PFS.

Conclusions: Lower dose brachytherapy may benefit AJCC stages T1 and T2 tumors, whereas higher doses are required for larger tumors and para-aortic nodal disease involvement, respectively. Pathological complete response should be associated with better local control and not surgery.

Purpose: Suitable commissioning and quality control (QC) tests for high-dose-rate brachytherapy (HDR-BT) is necessary to ensure dosimetric and geometric accuracy of the treatment. This study aimed to present the methodology of developing a novel multi-purpose QC phantom (AQuA-BT) and examples of its' application in 3D image-based (particularly magnetic resonance imaging [MRI]-based) planning for cervix BT.

Material and methods: Design criteria led to a phantom with sufficient size waterproof box for dosimetry and capability for inserting other components inside the phantom for: (A) Validating dose calculation algorithms in treatment planning systems (TPSs) using a small-volume ionization chamber; (B) Testing volume calculation accuracy in TPSs for bladder, rectum, and sigmoid organs at risk (OARs) constructed by 3D printing; (C) Quantification of MRI distortions using 17 semi-elliptical plates with 4,317 control points to mimic a realistic female's pelvis size; and (D) Quantification of image distortions and artifacts induced by MRI-compatible applicators using a specific radial fiducial marker. The utility of the phantom was tested in various QC procedures.

Results: The phantom was successfully implemented for examples of intended QC procedures. The maximum deviation between the absorbed doses to water assessed with our phantom and those calculated by SagiPlan TPS was 1.7%. The mean discrepancy in volumes of TPS-calculated OARs was 1.1%. The differences between known distances within the phantom on MR imaging were within 0.7 mm compared with computed tomography.

Conclusions: This phantom is a promising useful tool for dosimetric and geometric quality assurance (QA) in MRI-based cervix BT.

Purpose: To compare the effectivity and toxicity of monotherapy with computed tomography-guided high-dose-rate brachytherapy (CT-HDRBT) vs. combination therapy of transarterial chemoembolization with irinotecan (irinotecan-TACE) and CT-HDRBT in patients with large unresectable colorectal liver metastases (CRLM) with a diameter of > 3 cm.

Material and methods: Forty-four retrospectively matched patients with unresectable CRLM were treated either with mono-CT-HDRBT or with a combination of irinotecan-TACE and CT-HDRBT (n = 22 in each group). Matching parameters included treatment, disease, and baseline characteristics. National Cancer Institute Common Terminology Criteria for Adverse Events (version 5.0) were used to evaluate treatment toxicity and the Society of Interventional Radiology classification was applied to analyze catheter-related adverse events. Statistical analysis involved Cox regression, Kaplan-Meier estimator, log-rank test, receiver operating characteristic curve analysis, Shapiro-Wilk test, Wilcoxon test, paired sample t-test, and McNemar test. P-values < 0.05 were deemed significant.

Results: Combination therapy ensued longer median progression-free survival (PFS: 5/2 months, p = 0.002) and significantly lower local (23%/68%, p < 0.001) and intrahepatic (50%/95%, p < 0.001) progress rates compared with mono-CT-HDRBT after a median follow-up time of 10 months. Additionally, tendencies for longer local tumor control (LTC: 17/9 months, p = 0.052) were found in patients undergoing both interventions. After combination therapy, aspartate and alanine aminotransferase toxicity levels increased significantly, while total bilirubin toxicity levels showed significantly higher increases after monotherapy. No catheter-associated major or minor complications were identified in each cohort.

Conclusions: Combining irinotecan-TACE with CT-HDRBT can improve LTC rates and PFS compared with mono-CT-HDRBT in patients with unresectable CRLM. The combination of irinotecan-TACE and CT-HDRBT shows satisfying safety profiles.

Purpose: To compare dosimetric parameters of brachytherapy (BT) treatment plans made with or without active source positions of the ring/ovoid (R/O) applicator in locally advanced cervical cancer patients.

Material and methods: Sixty patients with cervical cancer without vaginal involvement were selected for the study, who received intra-cavitary/interstitial BT. For each patient, two plans with and without active source dwell positions in R/O were created, using the same dose-volume constraints. EQD₂ total doses from external beam and BT of target volumes and organs at risk (OARs) between the competing plans were compared.

Results: There was no significant difference in the dose of high-risk clinical target volume (HR-CTV) and gross tumor volume (GTV) between the plans with inactive vs. active R/O. The mean D₉₈ of intermediate-risk clinical target volume (IR-CTV) was significantly lower with inactive R/O; however, the GEC-ESTRO (EMBRACE II study) and ABS criteria were fulfilled in 96% in both plans. There was no difference in dose homogeneity, but conformity of the plans with inactive R/O was higher. Doses to all OARs were significantly lower in plans without R/O activation. While all the plans without R/O activation fulfilled the recommended dose criteria for OARs, it was less achievable with R/O activation.

Conclusions: Inactivation of R/O applicator results in similar dose coverage of the target volumes with lower doses to all OARs, as activation of R/O in cervix cancer patients when HR-CTV does not extend to R/O applicator. The use of active source positions in R/O shows worse performance regarding the fulfilment of the recommended criteria for OARs.

Purpose: High-dose-rate electronic brachytherapy (eBx) is a non-surgical treatment option for non-melanoma skin cancer (NMSC) patients. This study assessed long-term effectiveness and safety of eBx for the treatment of NMSC.

Material and methods: A chart review was conducted to identify subjects who had five or more years since their last eBx treatment fraction. Subjects meeting these criteria were contacted to determine their interest in participating in a long-term follow-up study. Those who agreed, underwent a follow-up visit where consent was obtained, and their lesions were clinically assessed for recurrence and long-term skin toxicities. History and demographic data were retrospectively collected, and treatment method was verified.

Results: 183 subjects with 185 lesions were enrolled into this study at four dermatology centers in two practices in California. Three subjects in the analysis were less than 5 years from the last treatment to follow-up visit. All lesions were stage 1 basal cell carcinoma, squamous cell carcinoma, or squamous cell carcinoma in situ. Recurrence rate for the 183 subjects was 1.1%. Long-term skin toxicities were reported in 70.0% of the subjects. Hypopigmentation grade 1 was observed in 65.9% of the lesions, telangiectasia grade 1 was seen in 22.2%, scarring grade 1 in two subjects (1.1%), hyperpigmentation grade 1 in two subjects (1.1%), and induration grade 2 in one patient (0.5%). The induration grade 2 was located on the upper back and did not limit instrumental activities of daily living (ADLs).

Conclusions: Electronic brachytherapy for the treatment of non-melanoma skin cancer is safe and effective, showing excellent long-term 98.9% local control through a median follow-up of 7.6 years (n = 183), with minimal long-term toxicities.

Purpose: We investigated the long-term oncological outcome of high-dose-rate (HDR) multicatheter interstitial brachytherapy (MIB) for adjuvant accelerated partial breast irradiation (APBI) after breast conserving surgery in Japanese patients.

Material and methods: Between June 2002 and October 2011, 86 breast cancer patients were treated at National Hospital Organization Osaka National Hospital (trial number of the local institutional review board, 0329). Median age was 48 years (range, 26-73 years). Eighty patients had invasive and 6 patients non-invasive ductal carcinoma. Tumor stage distribution was pT0 in 2, pTis in 6, pT1 in 55, pT2 in 22, and pT3 in one patient, respectively. Twenty-seven patients had close/positive resection margins. Total physical HDR dose was 36-42 Gy in 6-7 fractions.

Results: At a median follow-up of 119 months (range, 13-189 months), the 10-year local control (LC) and overall survival rate was 93% and 88%, respectively. Concerning the 2009 Groupe Européen de Curiethérapie-European Society for Therapeutic Radiology and Oncology risk stratification scheme, the 10-year LC rate was 100%, 100%, and 91% for patients considered as low-risk, intermediate-risk, and high-risk, respectively. According to the 2018 American Brachytherapy Society risk stratification scheme, the 10-year LC rate was 100% and 90% for patients 'acceptable' and 'unacceptable' for APBI, respectively. Wound complications were observed in 7 patients (8%). Risk factors for wound complications were the omission of prophylactic antibiotics during MIB, open cavity implantation, and V₁₀₀ ≥ 190 cc. No grade ≥ 3 late complications (CTCVE version 4.0) were observed.

Conclusions: Adjuvant APBI using MIB is associated with favorable long-term oncological outcomes in Japanese patients for low-risk, intermediate-risk, and acceptable groups of patients.