Brachytherapy最新文献

Purpose: The purpose of this work, a first-in-human randomized clinical trial, was to compare gMCO, a GPU-based multi criteria optimization (MCO) algorithm, to reference plans in terms of planning time and plan quality for prostate HDR brachytherapy.

Methods and materials: The brachytherapy procedure was as follows: (1) Patient installation, (2) Catheter implantation under transrectal ultrasound (US) guidance, (3) 3D US scan, (4) Contouring/catheter reconstruction on Oncentra Prostate (Elekta, Veenendaal, Netherlands), (5) Planning, (6) Treatment. Planning (step 5) was performed, after randomization, using either IPSA (Oncentra Prostate, Veenendaal, Netherlands) or gMCO. The planning times on IPSA or gMCO were recorded. Patients previously had a planning MR in order to identify whether a gross tumor volume (GTV, PIRADS 3 and above) was visible and, if present, the GTV was boosted to a minimum of 19 Gy of the prescription dose. Fifty-five patients were accrued and distributed randomly between both treatment arms. Dosimetric indices (Prostate V100, V150, V200, GTV D90, Urethra D10, Rectum and Bladder V75 and D1cc) of gMCO and Inverse-Planning Simulated Annealing algorithm (IPSA) plans were compared to determine if plan quality and planning times were statistically different.

Results: Results show that the optimization time is reduced by half when using gMCO as compared to IPSA, going from 10-5.2 minutes. Although no statistically significant difference is present between gMCO and IPSA plans when comparing pairs of individual dosimetric indices, gMCO plans exhibit a higher pass rate (higher by a factor ranging from 1.3 to 1.6), as compared to IPSA, when considering a basket of dosimetric indices simultaneously.

Conclusion: The use of gMCO halves the planning time for prostate HDR brachytherapy as compared to IPSA, without decreasing plan quality. The overall gain in efficiency related to the planning process has led to the use of gMCO for all of our HDR prostate cases.

Purpose: The purpose of this study is to evaluate clinical outcomes for medically inoperable endometrial cancer (MIEC) patients treated with triple tandem brachytherapy (TTB) ± external beam radiation therapy (EBRT).

Methods: This single institution retrospective review analyses MIEC patients treated definitively with TTB ± EBRT from 2014 to 2021. FIGO stage I-II with Grade 1-2 histology were considered low-risk endometrial cancer (LREC) and FIGO stage III-IVB and/or any Grade 3 endometrioid carcinoma, clear cell, or serous carcinoma were considered high-risk endometrial cancer (HREC). Planning parameters for target volume(s) and OARs (organs at risk) were per ABS guidelines. Overall survival (OS) and local failure-free survival (LFFS) were estimated by Kaplan-Meier analysis. Local control (LC), acute and late toxicities were evaluated clinically.

Results: Of 26 patients, 92.3% (n = 24) received TTB + EBRT. The median age at diagnosis was 66.5 years (40.5-88.7 years). Median follow up was 41.1 months (1.7-109.9 months). Median prescribed doses to the uterus were 45 Gy (0-50.4 Gy) for EBRT and 22.25 Gy (18-49.1 Gy) for TTB. 53.8% (n = 14) had LREC and 46.2% (n = 12) had HREC. 88.5% had endometrioid histology. The median OS for the entire cohort was 43.5 months with no difference for the LREC and HREC (p = 0.563). LC was superior (p = 0.032) in LREC patients (100% 4-year LFFS) with all recurrences occurring in the HREC cohort (1-/4-year LFFS 90.9%/62.3%). Late toxicities > Grade 2 were: Grade 2 GU (n = 2) and Grade 2 GI (n = 1).

Conclusions: Definitive TTB ± EBRT for MIEC patients was associated with excellent LFFS and acceptable toxicity rates.

Purpose: Rectal spacing has been shown to reduce toxicity following external beam radiation therapy for prostate cancer. However, real-world evidence of effectiveness for rectal spacers with brachytherapy (BT) monotherapy remains limited. This study used U.S. claims datasets to assess the association between rectal spacer use and bowel, urinary, and sexual function following BT.

Materials and methods: A retrospective study was conducted among patients treated with BT monotherapy for prostate cancer between 2015 and 2021, using Medicare 5% and 100% Files, MarketScan, and Premier Databases. Polyethylene glycol rectal spacer use was identified. Post-BT treatment diagnoses of bowel, urinary, and sexual dysfunction were evaluated using Cox proportional hazards models, adjusting for age, comorbidity, region, baseline dysfunction, secondary cancers, and BT modality (low-dose rate [LDR] or high-dose rate).

Results: Among 13,858 BT monotherapy patients, 1198 (8.6%) received a spacer. Patients with spacer were younger and had fewer baseline dysfunctions. At 5-year median follow-up, spacer use was associated with significantly lower incidence of bowel (adjusted hazard ratio, aHR: 0.76, p = 0.027) and urinary (aHR: 0.84, p = 0.008) dysfunction. Sexual dysfunction trended lower (aHR: 0.79, p = 0.120), although not significant. In LDR patients, spacer use remained significantly associated with reduced bowel (aHR: 0.74, p = 0.021) and urinary (aHR: 0.83, p = 0.005) dysfunction. Significant associations were not found in high-dose rate patients.

Conclusions: In this large real-world study, rectal spacing as a standard-of-care intervention showed sustained significant benefit in reducing bowel and urinary dysfunction, which appeared to be greatest in those treated with LDR BT.

Purpose: Accelerated partial breast irradiation (APBI) has emerged as an alternative to whole-breast irradiation (WBI) for selected patients with low-risk early breast cancer (EBC). While external beam APBI techniques are widely available, multicatheter interstitial brachytherapy (MIB) offers superior conformity and reduced normal tissue exposure. We evaluated the feasibility, toxicity, and early outcomes of an ultra-hypo fractionated approach using a single-fraction MIB-APBI in older patients.

Methods and materials: We conducted a single-institution retrospective study of 20 women (range, 69-88 years) with low-risk EBC treated with a single-fraction APBI (uAPBI) 16 Gy using MIB, between January 2023 and October 2024. All patients had undergone lumpectomy with sentinel lymph node biopsy. Eligibility criteria included age ≥65 years, tumor size ≤3 cm, unifocal disease, sentinel node-negative status and microscopically clear resection margins. Acute and late toxicities, cosmetic outcomes, oncological endpoints and dosimetric parameters were evaluated.

Results: Acute toxicity was limited to Grade 1/2 dermatitis in 25% of patients while no severe late toxicity was observed. Cosmetic outcomes were excellent to good in 100% of patients. At median follow-up of 18 months (range, 10-26), all patients remained alive with no locoregional recurrence or distant metastasis. Dosimetric parameters demonstrated excellent target coverage (median V100%: 97%, range 90-98%).

Conclusions: Single-fraction MIB-based APBI delivering 16 Gy appears to be a feasible, well-tolerated, and effective treatment approach for carefully selected older patients with EBC. This ultra-hypo fractionated approach significantly reduces treatment burden while maintaining excellent local control and favorable toxicity profiles.

Background: ¹²⁵I seed migration is a persistent safety concern in hepatic brachytherapy. Inflammatory and metabolic biomarkers may influence both tissue vulnerability and implantation strategies, contributing to migration risk.

Methods: In this retrospective study of 625 patients undergoing ¹²⁵I seed implantation for primary or metastatic liver tumors, clinical, laboratory, and procedural data were analyzed. Migration was assessed via follow-up chest radiography or CT. Univariate and multivariate Cox regression identified predictors of migration. Kaplan-Meier analysis evaluated seed migration-free survival (SMFS). Causal mediation analysis examined whether procedural factors-total number of seeds implanted (NSI) and maximum number per session (MAX)-mediated the effects of lactate dehydrogenase (LDH), neutrophil ratio, and lymphocyte ratio on migration.

Results: Seed migration occurred in 134 patients (21.4%). Elevated LDH, neutrophil ratio, MAX, and NSI were significantly associated with migration (all p < 0.01), while higher lymphocyte ratio was protective. Cox regression identified LDH, MAX, lymphocyte ratio, platelet count, and NSI as independent predictors. Kaplan-Meier analysis showed shorter SMFS in patients with high LDH or neutrophils and low lymphocytes. Mediation analysis revealed that LDH and neutrophils increased migration risk both directly and indirectly through procedural intensity (MAX, NSI), whereas lymphocytes had protective effects via both pathways.

Conclusion: Systemic inflammation and metabolic status influence both physiologic susceptibility and procedural factors associated with ¹²⁵I seed migration. Causal mediation analysis highlights modifiable indirect mechanisms, supporting personalized implantation planning to reduce migration risk.

Background: Brachytherapy boost in combination with external beam radiation therapy (EBRT-BT) improves biochemical progression-free survival in patients with intermediate- and high-risk prostate cancer. However, its adoption in routine clinical practice remains uncertain. We aimed to evaluate national trends and factors associated with the use of EBRT-BT following the publication of the ASCENDE-RT trial.

Methods: This retrospective cohort study used data from the Surveillance, Epidemiology, and End Results (SEER) database from 2015 to 2020. We included men with intermediate- or high-risk localized prostate cancer who received EBRT with or without brachytherapy boost as their sole initial treatment. The primary outcome was receipt of brachytherapy boost. Trends in use were assessed by year of diagnosis, and multivariable logistic regression was used to identify clinical and demographic factors associated with EBRT-BT.

Results: Among 507,327 men with prostate cancer, 48,777 (9.6%) met inclusion criteria. Of these, 6775 (13.9%) received EBRT-BT. Use increased modestly from 12.4% in 2015 to 14.6% in 2020 among patients with unfavorable intermediate-risk disease, and from 12.5% to 15.2% in those with high-risk disease. In multivariable analysis, use of EBRT-BT was significantly associated with younger age, higher Gleason grade group, and advanced T stage (all p < 0.001). Compared with 2015, EBRT-BT use was more likely in 2018-2020 (p < 0.05).

Conclusion: Despite level 1 evidence and guideline support, brachytherapy boost remains underutilized. These findings highlight a persistent gap between evidence and practice and underscore the need for strategies to expand access to EBRT-BT and promote its use where clinically appropriate.

Purpose: Accurate applicator reconstruction is a critical step in 3D image-guided brachytherapy (3D-IGBT) for cervical cancer, directly influencing tumor control and organ-at-risk sparing. This systematic review evaluates the accuracy, efficiency, and clinical impact of applicator reconstruction methods, focusing on AI's potential to overcome existing limitations.

Methods and materials: Following PRISMA guidelines, 23 studies from MEDLINE, PubMed, Scopus, Embase, Lilacs and Web of Science (up to May 2025) were analyzed. Evaluation metrics included geometric accuracy (tip error, Hausdorff distance), reconstruction time, and dosimetric parameters (D90 HR-CTV, D2cc OARs). Methods assessed spanned manual (e.g., MPR, scout-based), semi-automatic (library method, clustering algorithms), and AI-driven approaches (e.g., U-Net, Dilated-Supervised Deep U-Net, Attention-Gated networks). Special focus was placed on deep learning (DL) architectures and their ability to overcome metallic artifacts, partial-volume effects, and inter-operator variability.

Results: Manual methods exhibited significant limitations, with tip errors reaching 4.1 mm. Semi-automated approaches reduced variability (library-based methods: <0.5 mm mean deviation) but remained constrained by predefined applicator models. AI-driven workflows demonstrated superior precision, achieving submillimeter accuracy (median tip error: 0.64 mm; Dice Similarity Coefficient (DSC) > 0.89) and dosimetric consistency (D2cc deviations <3%). Notably, DL models like DSD-UNet and Attention-Gated U-Net reduced reconstruction time to <30 s per case while maintaining robustness against CT artifacts. However, challenges persist, including limited clinical validation (60% of studies used phantoms), data heterogeneity (slice thickness: 0.6-5 mm), and generalizability to novel applicator designs.

Conclusion: AI-driven reconstruction reduces human-dependent errors and enhances efficiency, but clinical validation remains a priority. Reducing CT slice thickness (≤1.5 mm) and combining scout images to mitigate metal artifacts are recommended. Future research should focus on generalizable AI models for nonlibrary applicators and large-scale clinical validation.