Sort by
Feasibility and clinical implementation of MRI-guided surface brachytherapy.

Best practices for high-dose-rate surface applicator brachytherapy treatment (SABT) have long relied on computed tomography (CT)-based imaging to visualize diseased sites for treatment planning. Compared with magnetic resonance (MR)-based imaging, CT provides insufficient soft tissue contrast. This work described the feasibility of clinical implementation of MR-based imaging in SABT planning to provide individualized treatment optimization. A 3D-printed phantom was used to fit Freiberg flap-style (Elekta, The Netherlands) applicator. Images were taken using an optimized pointwise encoding time reduction with radial acquisition (PETRA) MR sequence for catheter visualization, and a helical CT scan to generate parallel treatment plans. This clinical study included three patients undergoing SABT for Dupuytren's contracture/palmar fascial fibromatosis imaged with the same modalities.SABT planning was performed in Oncentra Brachy (Elekta Brachytherapy, The Netherlands) treatment planning software. A geometric analysis was conducted by comparing CT-based digitization with MR-based digitization. CT and MR dwell positions underwent a rigid registration, and average Euclidean distances between dwell positions were calculated. A dosimetric comparison was performed, including point-based dose difference calculations and volumetric segmentations with Dice similarity coefficient (DSC) calculations. Euclidean distances between dwell positions from CT-based and MR-based plans were on average 0.68 ±0.05 mm and 1.35 ±0.17 mm for the phantom and patients, respectively. The point dose difference calculations were on average 0.92% for the phantom and 1.98% for the patients. The D95 and D90 DSC calculations were both 97.9% for the phantom, and on average 93.6% and 94.2%, respectively, for the patients. The sub-millimeter accuracy of dwell positions and high DSC's (> 0.95) of the phantom demonstrated that digitization was clinically acceptable, and accurate treatment plans were produced using MR-only imaging. This novel approach, MRI-guided SABT, will lead to individualized prescriptions for potentially improved patient outcomes.

Open Access
Relevant
Brachytherapy in gynecological malignancies at a tertiary care hospital: An analysis.

Brachytherapy plays a crucial role in the standard of care for locally advanced gynecological malignancies. In this report, we present the experience from a tertiary teaching hospital, which is a referral center for image-guided brachytherapy (IGBT) in the management of locally advanced gynecological malignancies. This was a retrospective study of 130 patients referred to our hospital for IGBT after receiving initial external beam radiotherapy in their primary healthcare facilities, from January 2021 till January 2023. CT-based planning was done to delineate high-risk clinical target volume (HR-CTV). Dose of 6-7.5 Gy in 3-4 fractions was prescribed. Overall treatment time (OTT) was calculated, and patients were assessed for clinical response and toxicity after three months. All patients received IGBT using an intra-cavitary or interstitial technique. The D90 HR-CTV mean EQD2 dose was 28.34 ±2.78 Gy. The mean EQD2 dose to 2 cc of the bladder, rectum, and sigmoid was 18.31 ±5.19 Gy, 14.14 ±5.76 Gy, and 17.43 ±4.75 Gy, respectively. The median interval time between the last fraction of external beam radiation therapy (EBRT) and first evaluation in the hospital was 19 (range, 13-28) days (interquartile range [IQR]). The median time between the completion of chemoradiation and brachytherapy procedure was 25 (range, 19-33) days (IQR). The mean overall treatment time (OTT) was 63.5 ±14.7 days. This study highlights the established advantages of image-guided interstitial brachytherapy and associated challenges. To optimize the overall treatment duration, it is imperative to prioritize and update the referral processes for brachytherapy centers.

Open Access
Relevant
Clinical implementation of failure modes and effects analysis for gynecological high-dose-rate brachytherapy.

To use failure modes and effects analysis (FMEA) to identify failure modes for gynecological high-dose-rate (HDR) brachytherapy pathway and score with severity, occurrence, and detectability. A research team was organized to observe gynecological HDR brachytherapy pathway, and draw detailed process map to identify all potential failure modes (FMs). The whole team scored FMs based on three parameters, including occurrence (O), detectability (D), and severity (S), and then multiplied three scores to obtain risk priority number (RPN). All FMs were ranked according to RPNs and/or severity scores, and FMs with the highest RPN scores (> 100) and severity scores (> 8) were selected for in-depth analysis. Fault tree analysis (FTA) was applied to find progenitor causes of high-risk FMs and their propagation path, and determine which steps in the process need to be changed and optimized. Efficiency of each existing preventive methods to detect and stop FMs was analyzed, and proposals to improve quality management (QM) and ensure patient safety were suggested. The whole gynecological HDR brachytherapy pathway consisted of 5 sub-processes and 30 specific steps, in which 57 FMs were identified. Twelve high-risk FMs were found, including 7 FMs with RPNs > 100 and 5 FMs with severity scores > 8. For these FMs, 2 were in the insertion stage, 1 in the imaging stage, 4 in the treatment planning stage, and 5 in the final stage of treatment delivery. The most serious of these FMs was the change in organ at risk (OAR) during treatment delivery (RPN = 245.7). The FM that occurred most frequently was the applicator shift during patient transfer. Failure modes and effects analysis is a prospective risk-based tool that can identity high-risk steps before failures occur, provide preventive measures to stop their occurrence, and improve quality management system.

Open Access
Relevant
Adjuvant pulse-dose-rate brachytherapy for oral cavity and oropharynx carcinoma: Outcome and toxicity assessment of 66 patients.

Brachytherapy (BT) is a validated radiation technique for treatment of early stage tumors of oral cavity and oropharynx. This study aimed to analyze the results of our institute's patients after replacing low-dose-rate (LDR) with pulse-dose-rate (PDR) brachytherapy. We retrospectively collected data from all patients treated between 2009 and 2020 for squamous cell carcinoma (floor of the mouth, tongue, and oropharynx) using adjuvant interstitial BT with or without external RT. Primary outcome was local control. Secondary outcomes were regional control rate and toxicity. Statistical analysis of local and regional recurrences were described using Kaplan-Meier method. Prognostic value of each factor for recurrence or toxicity was evaluated with bivariate Fine-Gray model. Data from 66 patients were analyzed. Local and regional recurrences were reported in 11% and 20% of the patients, respectively. No significant factors were identified in the present study. Grade 2 and 3 acute mucositis were reported in 21% of patients, and were more frequent in the BT only group. Almost half (47%) of the patients described acute pain following BT, and 26% required stage 2 or 3 analgesics. Trophic disorders were observed in 16 patients. Five patients presented with soft tissue necrosis (STN) and required medical treatment, of whom one subsequently required hyperbaric oxygen therapy. No predictive factors were identified for STN risk. Two patients developed osteoradionecrosis. Oral and oropharyngeal PDR-BT as adjuvant treatment is safe and effective for well-defined indications.

Open Access
Relevant
Safety of high-dose-rate brachytherapy in patients with prostate cancer and inflammatory bowel disease: A case series.

Inflammatory bowel disease (IBD) is a relative contraindication to external beam radiation therapy (EBRT) for prostate cancer patients due to fear of increased risk of gastrointestinal (GI) toxicity. High-dose-rate (HDR) brachytherapy, capable of minimizing radiation dose to surrounding tissues, is a feasible alternative. Given limited data, this study examined the safety profile of HDR brachytherapy in this setting. We conducted a retrospective review of patients with localized prostate cancer and IBD treated with HDR brachytherapy at the University of California San Francisco (UCSF), between 2010 and 2022. Eligibility criteria included biopsy-proven prostate cancer, no distant metastases, absence of prior pelvic radiotherapy, IBD diagnosis, and at least one follow-up visit post-treatment. Eleven patients were included, with a median follow-up of 28.7 months. The median dose administered was 2700 cGy (range, 1500-3150 cGy) over 2 fractions (range, 1-3 fractions). Two patients also received EBRT. Rectal spacers (SpaceOAR) were applied in seven patients. All patients experienced acute genitourinary (GU) toxicity, ten of which were grade 1 and one was grade 2. Eight patients experienced late grade 1 GU toxicity, and three patients had late grade 2 GU toxicity. GI toxicities were similarly low-grade, with six grade 1 acute toxicity, no grade 2 or higher acute toxicity, six grade 1 late toxicity, and one late grade 2 GI toxicity. No grade 3 or higher acute or late GI or GU toxicities were reported. HDR brachytherapy appears to be a safe and tolerable treatment modality for patients with prostate cancer and IBD, with minimal acute and late GI and GU toxicity. These findings warrant multi-institutional validation due to small sample size.

Open Access
Relevant
Low-dose-rate brachytherapy and long-term treatment outcomes in patients younger than 60 years of age.

Low-dose-rate (LDR) brachytherapy in young men remains controversial amongst urologists due to their concerns regarding long-term biochemical control and treatment-related toxicities. The purpose of this study was to evaluate the treatment outcomes of men under 60 years of age who underwent LDR brachytherapy with iodine-125 (125I) for clinically localized low- to intermediate-risk prostate cancer. All consecutive patients with clinically localized prostate cancer treated at our institution from 2003 to 2016 with 125I monotherapy were included in the study. Prescription dose was 145.0 Gy modified peripheral loading (MPD). All patients were assessed for biochemical progression-free survival using Phoenix definition (nadir +2 ng/ml), clinical progression-free survival, overall survival (OS), and any associated treatment toxicity. A total of 161 patients were included, with a median follow-up of 6.8 years (range, 3-14.54 years). Median age at implant was 57 years (range, 53-59 years). Mean prostate specific antigen (PSA) level at diagnosis was 4.43 ng/ml (SD = 2.29). Majority of men had low-risk prostate cancer (70.2%). Biochemical progression-free survival at 8 years was 94% for the entire cohort. Median PSA at 4 years was 0.169 (IQR, 0.096-0.360), with 45% of patients having a PSA greater than 0.2. OS was 96.9%, with 5 deaths reported but only one was secondary to prostate cancer. Late grade > 2 genitourinary toxicities were reported in 18 patients (11.2%). Three patients (1.9%) developed secondary cancers, all considered unrelated to their LDR brachytherapy. With excellent long-term treatment outcomes and minimal associated toxicities, our results showed that LDR brachytherapy can be an effective treatment of choice in younger men.

Open Access
Relevant