Brachytherapy最新文献

Purpose: The quality of cervical cancer intracavitary brachytherapy (ICBT) depends on the training and experience of the radiation oncologist (RO). The present study was performed to establish primary learning curve for ICBT.

Materials and methods: Forty-three skill parameters were identified for performing ICBT and were included for Brachytherapy Proficiency Assessment and Scoring System (Brachy-PASS) questionnaire. Brachy-PASS score was first compared with blinded objective scoring of implant quality for 10 trainees by two ROs. Twenty eight consecutive trainees were scored with Brachy-PASS by two RO's. The impact of number of procedures and training years was ascertained using Mann Whitney-U test. Minimum number of intracavitary procedures to attain proficiency (score≥ 75%) were ascertained and learning curve plot of proficiency and procedures was generated.

Results: Between January, 2022 to September, 2023 38 trainees were evaluated (20: post graduate year (PGY) 1-3, and 18: PGY 4-5) after due consent for skill evaluation. Good congruence was reported of objective scoring and Brachy-PASS (83.4% vs 88%). Ten trainees had performed <15 ICBT, and 28 had performed ≥15 ICBT procedures. Overall 30/38 trainees (78.9%) achieved a Brachy-PASS score of ≥129 (75%). The average score for trainees with <15 procedures was 126.6 (73.6%) vs 148.8 (86.5%) in trainees who performed ≥15 procedures. PGY 4-5 trainees had higher score (153.8 (89.4%) vs 134 (77.9%)). Learning curve threshold of 15 ICBT was identified to attain 75% score (129/172) with no plateauing of learning curve even with ≥30 procedures.

Conclusion: Competency is established for independently performing intracavitary brachytherapy at 15 procedures and further increase in competency scores continues with increasing procedures.

Purpose: To retrospectively evaluate the efficacy of plaque brachytherapy for the treatment of retinoblastoma.

Methods: We retrospectively reviewed the clinical records of 163 patients (186 eyes, 333 tumors) treated with brachytherapy (¹⁰⁶Ru or ⁹⁰Sr plaques) for intraocular retinoblastoma between November 2007 and August 2023.

Results: Complete tumor control was achieved in 273 tumors (82%). Incomplete tumor control was observed in 44 tumors (13%). Thirteen tumors presented with tumor progression. Three tumors relapsed after brachytherapy. On multivariate statistical analysis apex dose ≤ 85 Gy (for ¹⁰⁶Ru) (p = 0.03), dark fundus pigmentation (p = 0.005) and intraarterial chemotherapy-brachytherapy period < 2 months (p = 0.001) demonstrated significant effect on brachytherapy insufficiency. Radiation-induced complications occurred in 62 eyes (33%). The most frequent complications were nonproliferative retinopathy (n = 39, 21%), optic neuropathy (n = 29, 16%) and vitreous hemorrhage (n = 29, 16%). Multivariate statistical analysis showed central localization (p = 0.005), tumor thickness > 2.7 mm (p = 0.04) and larger plaque diameter (>14 mm) (p = 0.035) to be the most significant variables for brachytherapy-associated complications. Eye retention was achieved in 91% of the treated eyes (n = 169). 17 eyes (9%) were enucleated. The reasons for enucleation were tumor recurrence or uncontrolled tumor growth (n = 7), anterior chamber involvement (n = 3), recurrent active vitreous seeding (n = 1), inability of adequate tumor monitoring due to opaque media (dense total vitreous hemorrhage or total retinal detachment) (n = 3), subatrophy of the eye with functional blindness (n = 3).

Conclusion: Overall, Beta-ray brachytherapy proved to be a highly effective method of retinoblastoma treatment with excellent local tumor control, eye preservation rate and acceptable incidence of curable radiation-induced complications.

Purpose: To compare the clinical outcomes of two different schedules of modern image-guided adaptive brachytherapy (IGABT) in patients underwent chemoradiotherapy (CCRT) and high-dose rate (HDR) brachytherapy (BT) for locally advanced cervical cancer treated (LACC) METHODS AND MATERIALS: Data from medical records of all consecutive patients with histologically proven cervical cancer (FIGO 2018 stage IB-IVA) treated by HDR-BT after CCRT at our institution between 2016 and 2021 were reviewed.

Results: Two hundred and 8 patients with LACC FIGO 2018 stages (IB 20.7%; II 26.5%, III 51%, IVA 1.9%) underwent brachytherapy at our institution. Depending on initial clinical features of disease and the clinical response to CCRT, HDR-BT was delivered with one implant (BT1i) or two implants (BT2i) in 39% and 61% of patients respectively. FIGO stages (≥IIB) were 63% vs. 78% for BT1i and BT2i patient group respectively. Combined brachytherapy technique [endocavitary/interstitial (IC/IS)] was required in 14.8% vs. 68.5% for BT1i and BT2i respectively. With a median follow-up of 32.5 months (95% confidence interval, [29.7-35.8]), local relapse was observed in sixteen patients: 8 patients (3.8%) had local (exclusive) relapse and 8 patients (3.8%) had locally persistent and progressive disease, without significant difference for each BT modality group (p = 0.27), even if BT2i group had more aggressive initial disease. The estimated 3-year disease free survival and overall survival for the entire population was 69% (95% confidence interval, [62-75%]) and 88% (95% confidence interval, [82-92%]) respectively. There was a significant difference in the incidence of global toxicity grade G≥2 in favour to the BT2i group (p = 0.026).

Conclusions: HDR brachytherapy delivered with a long time interval between fractions, two implants, and combined IC/IS brachytherapy is the best way to ensure local control and to perform IGABT with low toxicity, even in advanced stages of disease.

Background: To determine outcomes of MRI-assisted radiosurgery (MARS) for salvage brachytherapy using the radioisotope ¹⁰³Pd after various upfront treatments including surgery, external beam radiotherapy, and brachytherapy.

Methods: We retrospectively reviewed data for patients who underwent salvage MARS for intraprostatic lesions or prostate bed recurrences from 2016 to 2022. Biochemical recurrence, prostate cancer-specific, and overall survival, and the cumulative incidences of toxicities, were determined by Kaplan-Meier estimates. Cox proportional hazards models were used to determine associations between clinical and treatment variables and risk of toxicity.

Results: Study included 31 patients with local recurrence after initial definitive treatment. Four (13%) were initially treated with prostatectomy and salvage radiation, twenty-four (77%) with external beam radiation, and three with brachytherapy. Most had intermediate- or high-risk prostate cancer at the time of diagnosis. Twenty-two patients (71%) had focal-gland and nine (29%) had whole-gland MARS LDR salvage brachytherapy. Median follow-up was 35-28 months. By last follow-up, 5 patients (16%) experienced recurrence and started ADT, 3 patients started ADT before experiencing recurrence due to physician discretion, and 23 patients (74%) remained without recurrence. No patients died of prostate cancer. Median PSA nadir for recurrence-free patients was 0.2 ng/mL (range, 0-0.9 ng/mL). Grade 3 toxicities occurred in 4 patients (13%) including 3 patients (13%) with genitourinary events only and 1 patient (3%) with both a grade 3 genitourinary and a grade 3 gastrointestinal event.

Conclusions: In this modern series of patients undergoing salvage MARS with ¹⁰³Pd, we observed acceptable toxicity and early, promising biochemical disease control. These findings highlight the broader applicability of salvage MARS regardless of upfront treatment modality.

Purpose: Demonstrate quantitative characterization of 3D patient-specific absorbed dose distributions using Haralick texture analysis, and interpret measures in terms of underlying physics and radiation dosimetry.

Methods: Retrospective analysis is performed for 137 patients who underwent permanent implant prostate brachytherapy using two simulation conditions: "TG186" (realistic tissues including 0-3.8% intraprostatic calcifications; interseed attenuation) and "TG43" (water-model; no interseed attenuation). Five Haralick features (homogeneity, contrast, correlation, local homogeneity, entropy) are calculated using the original Haralick formalism, and a modified approach designed to reduce grey-level quantization sensitivity. Trends in textural features are compared to clinical dosimetric measures (D90; minimum absorbed dose to the hottest 90% of a volume) and changes in patient target volume % intraprostatic calcifications by volume (%IC).

Results: Both original and modified measures quantify the spatial differences in absorbed dose distributions. Strong correlations between differences in textural measures calculated under TG43 and TG186 conditions and %IC are observed for all measures. For example, differences between measures of contrast and correlation increase and decrease respectively as patients with higher levels of %IC are evaluated, reflecting the large differences across adjacent voxels (higher absorbed dose in voxels with calcification) when calculated under TG186 conditions. Conversely, the D90 metric is relatively weakly correlated with textural measures, as it generally does not characterize the spatial distribution of absorbed dose.

Conclusion: Patient-specific 3D dose distributions may be quantified using Haralick analysis, and trends may be interpreted in terms of fundamental physics. Promising future directions include investigations of novel treatment modalities and clinical outcomes.

Purpose: To compare dosimetric characteristics, clinical outcomes, and toxicity in patients with locally advanced cervical cancer(LACC) treated with transperineal interstitial brachytherapy(P-ISBT), using CT-based planning or MRI-based planning with a monoinstitutional MRI-compatible applicator, Template Benidorm(TB).

Materials and methods: We retrospectively analyzed 106 women treated with P-ISBT for LACC from 2006 to 2022. P-ISBT was CT-based, with Martinez Universal Perineal Interstitial Template(MUPIT) between 2006 and 2012, or MRI-based planning (TB) since 2013. Volumetric, clinical, and dosimetric parameters were compared between applicators.

Results: Forty-six (43.4%) patients were treated with MUPIT, and 60 (56.6%) with TB. Median follow-up was 42 months (4-188). No significant difference was observed in 5-year local control (LC), regional control (RC), distant failure (DF), overall survival (OS), and disease-specific survival (DSS) between applicators. The TB cohort had fewer needles (p = 0.001), halved median CTV volume (p < 0.001), increased median D_90%CTV dose (p < 0.005), and lower D_2cc values in rectum/bladder (p < 0.001). G3 chronic toxicity was 15% in the MUPIT group and 6% in TB (p = 0.15), with no G4 toxicity reported. Rectal hemorrhage was lower in the TB group (p = 0.002). Larger CTV volumes correlated with higher rectal D2cc and rectal hemorrhage (p = 0.001; p = 0.029, respectively), and enterovaginal fistula (p = 0.03; p < 0.001, respectively). Median CTV volume was 152.82 cc (35.3-256.78) in patients with chronic rectal toxicity and 102.9 cc (21.4-329.41) in those without (p = 0.001).

Conclusion: MRI's superior CTV-volume definition results in smaller treatment volumes, lower D_2cc for rectum and bladder, and a trend towards higher CTV D_90%. Rectal hemorrhage was significantly lower in the MRI-based group. A significant correlation was observed between larger CTV-volumes, higher rectal D_2cc and rectal hemorrhage/enterovaginal fistula.

Purpose: This study evaluates the use of a biodegradable balloon rectal spacer in two prostate cancer patients undergoing low dose radiation (LDR) and salvage high dose radiation (HDR) brachytherapy. The spacer aims to reduce radiation dose to adjacent organs, particularly the rectum, in patients previously treated with radiation.

Methods: The balloon spacer was implanted transperineally under transrectal ultrasonography (TRUS) guidance in two patients. For the LDR case (73-year-old, intermediate-risk), the balloon was placed postimplant with 55 iodine-125 seeds delivering 145 Gy. For the HDR case (66-year-old, high-risk), the balloon was placed one week before treatment, which delivered 23 Gy in two weekly fractions using 16 channels.

Results: The balloon provided a 14-15mm separation between rectum and prostate. In the LDR case, prostate D90 was 149.1Gy (102.83%), V100 was 91.95%, and rectum D30 was 23.93Gy (16.50%). For the HDR case, prostate D90 was 11.63Gy (105.79%), V100 was 93.63%, and rectum D0.5cc was 8.04Gy (73.15%). Both patients tolerated the treatment well, with no observed postoperative complications at 6-month follow-up.

Conclusions: The use of a rectal balloon spacer in both salvage HDR and LDR brachytherapy is feasible and safe, allowing for controlled placement and providing rectal protection from high radiation doses.

Background: An update of the 2007 and 2014 surveys of the American Brachytherapy Society (ABS) will elucidate current practice patterns of cervical cancer brachytherapy.

Methods: A 40-question survey was sent to all ABS members in June-July 2023 and February 2024; 167 responses were received, with 140 used for analysis. Results were compared to the 2014 survey using chi-squared testing. Multivariable logistic regression was used to calculate adjusted odds ratios (aOR) with 95% confidence intervals (CI) for outcomes of interest.

Results: Compared to 2014, MRI use for treatment planning of the first brachytherapy fraction increased from 34% to 63% (p < 0.001), prescription to the high-risk clinical target volume (HR-CTV) increased from 52% to 94% (p < 0.001), while Point A prescription decreased from 42% to 16% (p < 0.001). Additionally, procedural guidance with ultrasound significantly increased (79% vs. 32%, p < 0.001) along with the use of interstitial needles (always or nearly always, >80%) (29% vs. 4%, p < 0.001). MRI availability around the time of procedure was the largest challenge to incorporating MRI into brachytherapy treatment planning. Compared to those with MRI access reserved specifically for Radiation Oncology, respondents with shared-access or out-of-department MRI were less likely to obtain treatment planning MRIs for each brachytherapy fraction (22% vs. 75%; aOR 0.10 [95% CI, 0.03-0.30], p < 0.001).

Conclusion: For cervix cancer brachytherapy there has been significant increase in the use of MRI-based volumetric brachytherapy treatment planning, ultrasound guidance during procedures and the addition of interstitial needles. These advancements in practice patterns are congruent with published consensus guidelines and ongoing training initiatives. However, MRI access and lack of easy availability continue to be significant challenges for optimizing cervix brachytherapy.

Background: Radical urethectomy ± cystectomy has long represented the standard of care for rare primary urethral cancer (PUC). With our analysis, we want to demonstrate the efficacy and safety of brachytherapy (BT) of urethra for organ preservation.

Materials and methods: We analyzed treatment procedures and results of 3 patients with PUC, which have been treated in our department between 2011 and 2020 with brachytherapy. One male patient underwent brachytherapy with chemoradiotherapy after transurethral resection (TUR). Brachytherapy has been performed as high-dose-rate (HDR) boost with a cumulative dose of 8 Gy (9.3 Gy _{EQD2-α/β = 10 Gy}). The 2 further female patients have been treated with sole pulsed-dose-rate (PDR) brachytherapy with a total dose of 49.9 Gy (50.3 Gy _{EQD2-α/β = 10 Gy}) and 62.2 Gy (64.6 Gy _{EQD2-α/β = 10 Gy}).

Results: Median follow-up was 103 months (41-153). No local recurrence occurred and all patients are still alive. For the male patient we documented Grade 3 cystitis. As late side effects the pre-existing Grade 2 incontinence worsened to Grade 3. Among female patients one developed Grade 3 vaginal synechiae. There was no Grade ≥4 toxicity.

Conclusion: Brachytherapy in PUC is a feasible and promising option with high local control rate and tolerable toxicity. It provides a good alternative to surgery for organ preservation in selected patients.

Purpose: Brachytherapy (BT) is a time and resource intensive treatment modality. Constraints to efficiency and throughput include resource, staff and physician availability. Herein, we introduce a daily BT procedure scorecard, designed to ensure adequate resource allocation based on the type of procedure(s) being performed.

Methods: Data on BT procedures, number of fractions, number of patients, and the average daily caseload from 2021 to 2024 in our clinic were collected. Each BT procedure was assigned a score from 1 to 3 based on complexity and labor intensity, with 1 representing the least and 3 the most complex procedures. This data was then used to evaluate the efficiency of the BT scoring system.

Results: Implementing the BT scorecard improved scheduling efficiency without compromising patient throughput. Despite the growth in case complexity, we demonstrated that the scoring system effectively prevents understaffing in our clinics. The goal is to limit the daily BT score to 10 per day when creating the schedule, ensuring balanced resource allocation.

Conclusion: The strategies presented can enhance scheduling by ensuring an equitable workload distribution based on the BT schedule. These approaches should be considered in all high-volume BT clinics to optimize patient scheduling and throughput. Additionally, the scoring system allows clinics to develop full-time equivalent (FTE) staffing models that account for patient volume and case types, ensuring optimal resource utilization.