LDR Brachytherapy Research Articles

Optical fiber dosimeter for real-time in-vivo dose monitoring during LDR brachytherapy.

An optical fiber sensor for monitoring low dose radiation is presented. The sensor, based on radiation sensitive scintillation material, terbium doped gadolinium oxysulphide (Gd2O2S:Tb), is embedded in a cavity of 700µm diameter within a 1mm plastic optical fiber. The sensor is compared with the treatment planning system for repeatability, angular dependency, distance and accumulated radiation activity. The sensor demonstrates a high sensitivity of 152 photon counts/Gy with a temporal resolution of 0.1 seconds, with the largest repeatability error of 4.1%, to 0.361mCi of Iodine-125 the radioactive source most commonly used in LDR brachytherapy for treating prostate cancer.

Validation of biochemical definition of cure after low-dose rate prostate brachytherapy.

322 Background: Prospectively collected outcome data for 14,196 patients with localized prostate cancer treated with LDR brachytherapy (BT) from 7 institutions were analyzed. For the 80% of patients with a 4 year PSA < 0.2 ng/ml, 99% were free of clinical failure at 10 years and 96% at 15 years. We sought to validate this result with 2 independent data sets from mature prospective clinical trials. Methods: In the initial analysis, patients were treated with either BT alone (61%), or in combination with external beam radiotherapy (EBRT:8%), androgen deprivation (ADT:22%) or both (9%). 42% were low risk, 50% intermediate (IR) and 8% high risk(HR). KM analysis was carried out using clinical failure (local, distant, regional or biochemical triggering salvage) as endpoints for each of 4 PSA categories: PSA<0.2 ng/ml, PSA >0.2 to < 0.5, PSA > 0.5 to < 1.0, and PSA>1.0 ng/ml. Results were compared to 12 year follow up data on a phase 2 trial of BT for IR prostate cancer (n=223; MDAnderson Cohort 1) and 10-year data from the BT arm of the phase 3 randomized ASCENDE RT trial (n=160, Cohort 2) for upper tier IR and HR prostate cancer. Results: The results of the initial KM analysis showed that for the 80% of patients with PSA < 0.2 ng/ml at 4 years, 99% were free of recurrence at 10 years (95% CI: 98.4-99.1) and 96% at 15 years (95% CI: 95-97). The association of treatment success with PSA range was highly significant (p<0.0005). Independent validation against BT alone in IR patients (Cohort 1) confirmed that 99% of patients with PSA at 4 years < 0.2 ng/ml were NED at 10 years (CI: 95.8-99.9). For the unfavorable IR and HR patients receiving 12 months ADT + pelvic EBRT and BT in ASCENDE-RT (Cohort 2), PSA < 0.2 ng/ml at 4 years was associated with 96.7% (CI: 89.9-98.9) being failure free at 10 years. Conclusions: As over 80% of patients achieve a PSA < 0.2 ng/ml at 4 years post-LDR BT, and this is associated with 97%-99% being disease free beyond 10 years, we suggest that this biochemical definition of cure be adopted for LDR brachytherapy patients with ≥ 4 years’ follow-up.

Validation of the NCCN prostate cancer favorable- and unfavorable-intermediate risk groups among men treated with I-125 low dose rate brachytherapy monotherapy

PurposeTo validate the 2019 NCCN subgroups of favorable- and unfavorable-intermediate risk (IR) prostate cancer among patients treated with brachytherapy, who are underrepresented in the studies used to develop the 2019 NCCN classification. MethodsWe included all 2,705 men treated with I-125 LDR brachytherapy monotherapy at a single institution, and who could be classified into the 2019 NCCN risk groups. Biochemical failure and distant metastasis rates were calculated using cumulative incidence analysis. ResultsOf 1,510 IR patients, 756 (50%) were favorable-IR, and 754 (50%) were unfavorable-IR. Median follow up was 48 months (range, 3–214). As compared to favorable-IR, the unfavorable-IR group was associated with significantly higher rates of biochemical failure (HR, 2.87; 95% CI, 2.00–4.10; p < 0.001) and distant metastasis (HR, 3.14; 95% CI, 1.78–5.50, p < 0.001). For favorable-IR vs. unfavorable-IR groups, 5-year estimates of biochemical failure were 4.3% (95% CI, 2.6–6.1%) vs. 17.0% (95% CI, 13.6–20.5%; p < 0.001), and for distant metastasis were 1.6% (95% CI, 0.5–2.6%) vs. 5.4% (95% CI, 3.3–7.4%; p < 0.001), respectively. Patients with one unfavorable-intermediate risk factor (unfavorable-IRF; HR, 2.27; 95% CI, 1.54–3.36; p < 0.001) and 2–3 unfavorable-IRFs (HR, 4.42; 95% CI, 2.89–6.76; p < 0.001) had higher biochemical failure rates; similar findings were observed for distant metastasis (1 unfavorable-IRF: HR, 2.46; 95% CI, 1.34–4.53, p = 0.004; 2–3 unfavorable-IRFs: HR, 4.76; 95% CI, 2.49–9.10, p < 0.001). ConclusionsThese findings validate the prognostic utility of the 2019 NCCN favorable-IR and unfavorable-IR prostate cancer subgroups among men treated with brachytherapy. Androgen deprivation was not beneficial in any subgroup. Alternative treatment intensification strategies for unfavorable-IR patients are warranted.

Prospective Observational Trial of an Absorbable Hydrogel Spacer in Prostate Cancer Radiotherapy: Quality of Life and Dosimetric Outcomes

A hydrogel spacer is an FDA approved medical device designed to increase the distance between the rectum and the prostate during radiotherapy to minimize morbidity. Its use provides favorable dosimetry for conventional radiotherapy and has become a standard at our institution. We therefore sought to prospectively observe the quality of life (QOL) outcomes and dosimetric profiles for patients receiving hydrogel spacers. We prospectively enrolled 30 patients between 10/2016 and 10/2018. Inclusion criteria required low risk or favorable-intermediate risk patients as defined by clinical stage T1-T2, Gleason ≤ 3+3 or select 3+4 with low volume disease. Patients completed baseline Expanded Prostate Cancer Index Composite (EPIC-26) and American Urological Association symptom index (AUA-SI) questionnaires. A hydrogel spacer was placed for all patients who then received stereotactic body radiation therapy, low dose rate brachytherapy, conventionally fractionated radiation therapy, or moderately hypofractionated radiation therapy. We evaluated post-implant dosimetry to critical structures, and prospectively collected follow-up surveys. For inferential statistics we performed a repeated measures analysis of variance to compare patient specific response and correlated survey data with dosimetric metrics by generating linear regression models. During two years, thirty patients are evaluable for study: 17 patients received prostate SBRT, 5 LDR brachytherapy, 7 moderately hypofractionated IMRT, and one with conventionally fractionated IMRT. Data was collected at median intervals of 30, 95, and 294 days after therapy. Median bowel QOL scores at first, second and third follow-up time points for EPIC-26 bowel score 100, 95, and 100 respectively. For EPIC-26 urinary incontinence score was were 100, 90, and 90. There was no difference across survey participants for EPIC-26 bowel (p=0.52) or urinary bother (p=0.58) or AUA-SI total score (p=0.44) across all time points. Dosimetric variables were not associated with any decline in QOL scores at these time points. We achieved favorable dosimetry for all patients. Within the SBRT patients, dose to 50% of the rectum was a median of 656 cGy (IQR 727) and dose to 50% of the bladder was 215 cGy (245) which far exceeds the recommended constraints. Dose to 25% of the rectum for SBRT patients was 1153 (IQR 869). Within the hypofractionated group dose to 50% of the rectum the median was 2301(IQR 519). A hydrogel spacer results in relatively favorable dosimetry for all prostate radiotherapy modalities given to patients with favorable-intermediate or low risk prostate cancer. Hydrogel spacer placement also portends stable good long-term QOL outcomes.

Evaluation of Rectal Dose in Prostate Cancer Patients Having Hydrogel Spacer Insertion in LDR Brachytherapy and EBRT Radiotherapy

Evaluation of Rectal Dose in Prostate Cancer Patients Having Hydrogel Spacer Insertion in LDR Brachytherapy and EBRT Radiotherapy

Proposed Hydrogel Implant Quality Score (HIQS) for Prostate Radiotherapy

A hydrogel spacer has been FDA-approved to reduce rectal toxicity in prostate radiotherapy. Training and certification for this procedure is currently performed by the manufacturer, without independent measures of quality. The technique has been associated with toxicity including rectal fistula. While quality has not reported, variability in spacing and distribution is described by clinicians. In the absence of validated instruments, the wider implementation of hydrogel spacer implants may lead to an emergence in unexpected complications creating negative consequences for the field of radiation oncology. The purpose of the current retrospective clinical study is to develop a simple robust Hydrogel Implant Quality Score (HIQS) system as a quality surrogate to assist clinicians in tracking proficiency and to support quality improvement. Between May 2018 and February 2019, 50 subjects with prostate cancer, undergoing IMRT and/or LDR brachytherapy, had hydrogel spacer implantation under standard supervision and certification from the manufacturer. No acute complications were noted. Post-procedure CT simulation and T2 MRI were performed for radiation planning. Prostate and rectal dosimetry were performed and qualitatively analyzed to identify hydrogel placement characteristics influencing dosimetry. A novel scoring system was created with criteria domains including implanted hydrogel volume, left-right symmetry (LR), cranio-caudad symmetry (CC), mid prostate spacing, distortion of prostate anatomy and distortion of rectal anatomy. HIQS scores were calculated for the patients in the series and domains were analyzed for influence on hydrogel placement quality. The average hydrogel spacer volume was 16.3 cc (SD=2.7 cc). The average mid-prostate spacing was 14.2 mm (SD=3.4 mm). Rectal anatomical distortions, including disruption of serosal and/or submucosal layers, was seen in 12 cases (24%). Overall, the HIQS ranged from 43-92 with an average of 78.5 (std dev=9.8). The HIQS was higher in patients without rectal distortion, 80 vs. 74 (NS). The HIQS was also higher with implant volume greater than 15 mL, 81 vs. 73 (NS). Over the duration of the clinical series the HIQS improved with a linear trend from 74 to 82 suggesting improved quality with experience. The current study used retrospective data to propose a universal scoring system. In ongoing work, the HIQS will require larger samples for possible validation as a predictive instrument. The HIQS suggests a risk for rectal anatomy distortion despite careful final needle position implicating needle trauma to the rectal layers during pre-implantation position adjustments. This study and contribute to a safety culture around quality in hydrogel spacer implants to reduce the likelihood of severe complications.Abstract 2672; Table 1Score(Volume)Score (LR)Score (CC)Score(spacing)Total HIQSAverage16.314.814.414.278.5Standard Deviation2.74.64.93.49.8 Open table in a new tab

Overall Survival and Radiation Treatment Modality for Low-risk and Intermediate-risk Prostate Cancer: Analysis of a Hospital-based Big Database

Both external beam radiation therapy (EBRT), including proton beam therapy, and brachytherapy are used for treating low-risk and intermediate-risk prostate cancer (CaP) patients. While they are usually considered to be equally effective, there may be differential utilization based on availability of treatment modality or physician and/or patient’s preference. In this study, the practice pattern of modality used and the efficacy of radiation therapy (RT) modality in the survival of CaP patients has been evaluated. We have analyzed the National Cancer Database (NCDB) for stage T1-2B prostate cancer patients treated from 2004 to 2015. Patients were stratified according to the National Comprehensive Cancer Network (NCCN) guidelines: low-risk (clinical stage T1–T2a, GS of 6, and PSA < 10), intermediate-risk (clinical stageT2b or T2c, GS of 7, or PSA of 10–20). Considered non-surgical patients who were treated either with EBRT (3DCRT, IMRT, SBRT, or Proton) or brachytherapy (LDR or HDR). Included patients (n=194,214) received primary/initial treatment as well as boost with the same EBRT modality, i.e. IMRT or 3DCRT or Proton; no boost was considered for SBRT, LDR and HDR. Considered total dose was 70-81Gy for IMRT, 3DCRT and Proton; 30-40Gy for SBRT; monotherapy was considered for LDR and HDR. Kaplan-Meier analysis was used for determining the survival probability. Software was used for statistical analysis; p-value < 0.05 was considered statistically significant. The median age of the selected patients was 68 years (range: 29-90). The median follow-up was 72.6 months (range: 0-157.4months). Mean overall survival (OS) are provided in the table below (table 1). Observed marginal differences in OS of patients treated with IMRT and 3DCRT; brachytherapy performed better than photons (3DCRT, IMRT and SBRT). No difference in OS was noticed between LDR or HDR brachytherapy. Patient treated with Proton had highest OS for both low- and intermediate-risk CaP. All these differences in OS were statistically significant (p<0.05). This study indicates that IMRT is most commonly used modality followed by brachytherapy for treating low- and intermediate-risk CaP patients. Photon beam therapy appears to be superior to other modalities of RT for far the overall survival is concerned. Brachytherapy performed better than 3DCRT and IMRT. Multivariable risk model analysis is underway.Abstract 2694; Table 1Overall survival (OS) of Low-risk and Intermediate-risk prostate cancer patients.Treatment modality3DCRTIMRTSBRTProtonLDRHDRp-valueNumber of patients (n=194,214)3,683 (1.9%)99,231 (51.1%)7,750 (4.0%)5,386 (2.8%)51,508 (26.5%)26,656 (13.7%)Mean OS for Low-risk pts (mo)123.5127.5129.5139.6136.0135.8< 0.001Mean OS for Interm-risk pts (mo)115.0117.6122.1132.8127.0128.4< 0.00110-yr OS for combined Low-risk and Intermediate-risk pts71.2%80.6%91.3%93.8%86.1%86.3%<0.05 Open table in a new tab

Comparison of Long-term Outcomes for Patients with High-Risk Prostate Cancer Treated with EBRT Alone Versus Combination EBRT with a LDR Brachytherapy Boost

Comparison of Long-term Outcomes for Patients with High-Risk Prostate Cancer Treated with EBRT Alone Versus Combination EBRT with a LDR Brachytherapy Boost

OA42 - Concurrent Chemoradiation for Cervical Cancer: Comparison of LDR and HDR Brachytherapy

OA42 - Concurrent Chemoradiation for Cervical Cancer: Comparison of LDR and HDR Brachytherapy

OC-0079 Expanding Calibration Service for LDR Brachytherapy Seeds by Photon Fluence Determination

OC-0079 Expanding Calibration Service for LDR Brachytherapy Seeds by Photon Fluence Determination

A Monte Carlo investigation of the dose distribution for new I-125 Low Dose Rate brachytherapy source in water and in different media

Abstract Permanent and temporary implantation of I-125 brachytherapy sources has become an official method for the treatment of different cancers. In this technique, it is essential to determine dose distribution around the brachytherapy source to choose the optimal treatment plan. In this study, the dosimetric parameters for a new interstitial brachytherapy source I-125 (IrSeed-125) were calculated with GATE/GEANT4 Monte Carlo code. Dose rate constant, radial dose function and 2D anisotropy function were calculated inside a water phantom (based on the recommendations of TG-43U1 protocol), and inside several tissue phantoms around the IrSeed-125 capsule. Acquired results were compared with MCNP simulation and experimental data. The dose rate constant of IrSeed-125 in the water phantom was about 1.038 cGy·h−1U−1 that shows good consistency with the experimental data. The radial dose function at 0.5, 0.9, 1.8, 3 and 7 cm radial distances were obtained as 1.095, 1.019, 0.826, 0.605, and 0.188, respectively. The results of the IrSeed-125 is not only in good agreement with those calculated by other simulation with MCNP code but also are closer to the experimental results. Discrepancies in the estimation of dose around IrSeed-125 capsule in the muscle and fat tissue phantoms are greater than the breast and lung phantoms in comparison with the water phantom. Results show that GATE/GEANT4 Monte Carlo code produces accurate results for dosimetric parameters of the IrSeed-125 LDR brachytherapy source with choosing the appropriate physics list. There are some differences in the dose calculation in the tissue phantoms in comparison with water phantom, especially in long distances from the source center, which may cause errors in the estimation of dose around brachytherapy sources that are not taken account by the TG43-U1 formalism.

Impact of a dominant intraprostatic lesion (DIL) boost defined by sextant biopsy in permanent I-125 prostate implants on biochemical disease free survival (bDFS) and toxicity outcomes

Background and purposeTo compare bDFS and toxicity outcomes in a population of intermediate risk prostate cancer patients treated using I-125 LDR brachytherapy with or without DIL boost based on multiple core biopsy maps. Materials and methodsBetween January 2005 and December 2013, all our intermediate risk prostate cancer patients treated with LDR I-125 brachytherapy were reviewed. All patients were given 144 Gy to the prostate. A pathologic DIL distribution (defined by sextant biopsy) was contoured prospectively prior to planning, to be covered by the 150% isodose line. Of the 165 patients treated, 55 received a DIL boost. Patients completed prospectively the IPSS questionnaire, a sexual and bowel function questionnaire. Gastro-intestinal toxicities were graded according to CTCAE v4.03. A patient was considered to have erectile dysfunction if he was unable to achieve erection to perform intercourse. BDFS was determined according to the Phoenix consensus definitions. ResultsThe median follow-up was 78 months. The estimated 7-year bDFS rate was 96% (95% CI, 74–99%) in the DIL group versus 89% (95% CI, 79–94%) in the control group (p = 0.188). There was no difference between groups in urinary, gastro-intestinal or sexual toxicities up to 5 years of follow-up. There was no difference in urinary obstruction with catheterization between DIL versus control groups (3,6 vs 2,8 %, p = 1.00). Only 1 patient in the DIL group had ≥grade 3 toxicity (TURP) and none in the control group. ConclusionsBoost to DIL defined by sextant biopsy with permanent seed prostate implant shows a trend toward improvement of biochemical control in intermediate risk prostate cancer patient without increasing toxicity.

A comparison of six fractions per week chemoradiation versus five fractions per week of conventional chemoradiation in carcinoma cervix: A prospective controlled study.

The standard of care for carcinoma cervix stage IB2-IVA is five fractions per week of radiotherapy (RT) with concurrent cisplatin. We compared the standard treatment with six fractions per week of RT with concurrent Cisplatin to see whether the later had improved survival outcomes with comparable toxicities. 46 patients of carcinoma cervix with stage IB2-IVAwere randomized into two arms. Study arm: 46 Gy/23 fractions/26 days, 6 fractions/week with injection CDDP 40 mg/m2 and Control arm: 46 Gy/23 fractions/31 days, 5 fractions/week with injection Cisplatin 40mg/m2. Patients in both the arms received LDR brachytherapy to a dose of 29 Gy at point A. The primary end points were disease-free survival (DFS) and overall survival (OS). Compliance to treatment and treatment toxicities were the secondary end points. P value ≤0.05 were considered significant. The study was carried out during June, 2014-April, 2015. Statistical analysis was done in May, 2019. Of 46 patients, 39 patients completed the treatment. The study and control arms had 17 and 22 patients, respectively. Median follow-up period is 45 months (range: 1-54 months). 3-year DFS rates and OS was 69.5% vs. 72.7% (P = 0.73) and 63% vs. 68% (P = 0.45) in study and in control arm, respectively. There was no significant difference in acute and late radiation toxicities between two arms. Chemoradiotherapy with six fractions per week seems feasible and equally efficacious in terms of survival outcomes and toxicity profile. Further prospective randomized controlled study is required to prove the merit of altered fractionation with concurrent cisplatin.

Initial Clinical Experience with Uni-Directional LDR Brachytherapy in the Treatment of Retroperitoneal Sarcoma

Retroperitoneal sarcomas (RPS)s constitute 10%-15% of patients diagnosed with soft tissue sarcomas. Despite advances in cancer care and aggressive management, the 5-year overall survival rate is 47%-67%. The crude cumulative incidence of local recurrence (LR) is 26%. A previous trial combining preoperative external beam radiation therapy with post-operative brachytherapy found substantial toxicity and treatment related death. This report demonstrates the utility of unidirectional LDR brachytherapy for treatment of RPS. In this study, the unidirectional device employed is a permanent, Pd-103 brachytherapy device designed to be implanted during surgical resection for the treatment of anticipated positive or close surgical margins. The device consists of a plane of sources with an unidirectional gold shield backing to protect normal tissues yet direct radiation to the target margin(s). The sources are embedded in a bio-absorbable matrix membrane that may be cut to size to allow for conformal targeting of the surgical tumor bed. At surgery, patients were assessed and determined to have close or positive margins. The prescribed LDR brachytherapy dose averaged 34.7 Gy (range: 20 – 60 Gy) and covered an average area of 6060 mm2 (∼58 sources). Pd-103 has a half-life of 16.99 days and delivers therapeutic radiation dose over several weeks. The device was attached with sutures and tacks. Seven RPS patients have been implanted with the CivaSheet at 4 medical centers. Six patients had recurrent sarcoma in the retroperitoneum or pelvic side wall. One patient had locally advanced leiomyosarcoma with no previous treatment. Three patients had prior EBRT at first diagnosis (45 – 57.5 Gy). Five patients received neoadjuvant EBRT (35 – 57.5 Gy) prior to surgery plus brachytherapy. The patients tolerated the implant well with no complications following surgery. There have been 0 reports of source movement in RPS patients. At median 15 months (8-24 months) follow-up, 0/7 patients have demonstrated local recurrence as defined as the targeted field of brachytherapy radiation. One patient (1/7) recurred outside of the surgical field and subsequent brachytherapy radiation. There were 0 reported incidences of acute or late radiation toxicity despite the surrounding organs at risk, inclusive of the small intestine, ureter and kidneys. Unidirectional, planar Pd-103 LDR brachytherapy has demonstrated a 100% local recurrence free survival with no acute or late-term toxicities at a median of 15 months in our patient cohort. Application of uni-directional, planar Pd-103 LDR brachytherapy technology is very safe and easy, and should be considered to escalate dose or retreat to the high risk margins of RPS after resection.

Salvage Brachytherapy in Prostate Cancer after Radiation Failure: HDR vs LDR

To evaluate efficacy and toxicity of HDR and LDR brachytherapy (BT) as salvage modalities in prostate cancer (PCa) patients after primary radiotherapy failure. Between 2001 and 2016, 126 patients were treated with BT as salvage local treatment, 47 with LDR and 79 with HDR. All patients had biopsy proven local relapse. A total of 31 patients (25%) received androgen deprivation therapy at the time of BT. Post-salvage BT progression and cause-specific-mortality of both treatment modalities (LDR and HDR) were analyzed. Toxicity was evaluated by RTOG scale. Median follow-up was 52 months (4-186) from BT. In 23 patients, HDR was used as a salvage modality because LDR-BT was already used as initial treatment. A total of 39 patients progressed after salvage BT, 15 (32%) in LDR and 24 (30%) in HDR group. The 5-yr cause-specific survival was 97% with LDR and 94% with HDR (p=ns). On multivariate analysis, factors associated to progression were initial score Gleason ≥7 (p=0.02), time to BF from initial RT < 30 months (p=0.00) and nadir PSA post-salvage BT (p=0.00). A total of 14 patients had urethral stenosis, 18 urinary incontinence and 13 haematuria. Grade ≥3 toxicity was observed in 22%. Salvage BT in PCa patients who have local failure after radiation therapy can achieve local control > 70% with an adequate toxicity profile. There were not significant differences observed neither in efficacy nor in toxicity between HDR and LDR modalities.

Widening the Therapeutic Window using an Implantable, Unidirectional LDR Brachytherapy Sheet as a Boost in Pancreatic Cancer

Patients with borderline resectable pancreatic cancer are typically treated with neoadjuvant therapy including chemotherapy followed by chemoradiation with the goal of becoming surgical candidates. Unfortunately, due to inflammatory changes after treatment, the pre-operative imaging is not reliable in determining resectability and many patients still have concern for close or positive retroperitoneal margins given the proximity to major vasculature. Post-operatively, an external beam RT (EBRT) boost is difficult given bowel constraints and difficulty in identifying the area at highest risk. The purpose of this study is to demonstrate the ability of the LDR brachytherapy CivaSheet to deliver a focal high-dose boost, targeted to the area at highest risk in patients who received neoadjuvant chemoradiation. Three patients with borderline resectable pancreatic cancer received neoadjuvant FOLFIRINOX followed by gemcitabine-based chemoRT to 50.4Gy in 28 fractions with dose prescribed to the gross tumor plus a 1 cm margin. After neoadjuvant therapy, the multidisciplinary team was concerned for close or positive margin resection. CivaSheet® is an FDA-cleared product from CivaTech Oncology® consisting of a matrix of uni-directional Pd-103 radiation sources on a bio-absorbable membrane. Dose is prescribed to 5mm depth and in these patients was 38Gy EQD2 to bring the total dose of radiation to 88.4Gy to the targeted tissue. Post-operatively, patients had a CT scan. The tumor bed and organs at risk were contoured. Small bowel (SB) was contoured as the bowel bag and included the entire peritoneal cavity. Brachytherapy plans as well as EBRT boost plans were created for each patient. DVH from initial 3D treatment plans for all patients showed the SB volume receiving 45Gy (V45) was a median of 78.2 cc (range 61.7-107.1 ccs) and maximum bowel doses were a median of 53.2, range 53.1-53.6 Gy. Per Quantec and current pancreatic protocols, the V45 for SB should be <195 cc with a max of ≤58 Gy to prevent SB obstruction, fistula and perforation. With these fixed constraints, we were left with about an additional 5-10 Gy boost possible with EBRT. With the sheet, the boost dose can be dramatically increased and the dose to the SB was marginal at about 1/10th of the prescription dose. For the target, the brachytherapy sheet delivers prescription dose to 5 mm depth with a large inhomogeneous dose throughout the tumor bed with the minimum dose of 38 Gy. These are the first patients in the world to be treated with the LDR implantable brachytherapy sheet at the time of surgery as a boost for pancreatic cancer after neoadjuvant therapy. This dosimetric study shows that applying this uni-directional source to the area at highest risk can serve to improve the therapeutic index by improving the local control and minimizing toxicities in this deadly disease.

First Report of the Permanently Implantable Uni-Directional Planar LDR Brachytherapy for Patients with Locally Advanced Pancreatic Cancer

First Report of the Permanently Implantable Uni-Directional Planar LDR Brachytherapy for Patients with Locally Advanced Pancreatic Cancer

Long-term outcomes analysis of low-dose-rate brachytherapy in clinically T3 high-risk prostate cancer

PurposeThe available data demonstrating that superiority of LDR brachytherapy (LDR-BT) boost in high-risk prostate cancer patients under represents patients with extracapsular extension (T3a) and/or seminal vesicle invasion (T3b) have been limited. We report long-term clinical outcomes data for patients with cT3a/b disease receiving LDR-BT. Methods and MaterialsNinety-nine men (median age: 69.4 years) with cT3a/bN0M0 high-risk prostate adenocarcinoma received definitive LDR-BT or LDR-BT boost after external beam radiation therapy (EBRT) at a single institution between 1998 and 2007. About 86% of patients received androgen deprivation therapy. Freedom from biochemical failure (FFBF), prostate cancer–specific survival (PCSS), and overall survival (OS) was calculated using the Kaplan–Meier method with the Phoenix definition used as definition of failure. Cox regression analysis was used to compare outcomes between clinical stage, initial PSA, Gleason Score, and percent core positive rate. ResultsWith a median followup of 7 years, 7-year rate of FFBF, PCSS, and OS for the entire cohort was 65.2% (±5.6%), 90.1% (±3.6%), and 77.9% (±4.7%), respectively. LDR-BT boost patients achieved a 7-year FFBF rate of 73.5 (±6.5%). No significant difference in outcomes was present between T3a or T3b disease, Gleason score, iPSA stratification and percent core positive rates. ConclusionsLDR-BT, primarily as a boost in conjunction with ADT and EBRT, is not only feasible, but also highly effective in men with cT3a and cT3b high-risk prostate cancer resulting in excellent biochemical control and survival outcomes. LDR-BT boost implantation of patients should be strongly considered for cT3 patients given the merits of trimodality care.

Comparison of LDR Brachytherapy Combined with Conventionally Fractionated EBRT or SBRT in High Risk Node Negative Prostate Cancer Patients: Early Toxicity and Tumor Control Outcomes

One of the most effective radiotherapeutic interventions for the treatment of high-risk prostate is the combination of brachytherapy with supplemental external beam radiotherapy directed to the prostate and regional nodes. While conventionally fractionated external beam radiotherapy has been a standard approach to supplement the brachytherapy boost, we have recently treated such patients with supplemental SBRT using an ultra-hypofractionated regimen. In this study we compare the early toxicity and tumor control outcomes of high risk, node negative patients treated with combination of brachytherapy and SBRT versus brachytherapy and conventionally fractionation RT (CFRT).

Mature Results using an Automated Prostate Brachytherapy System

As healthcare increasingly moves to value-based treatment decisions, LDR brachytherapy represents a cost effective option for the treatment of selected prostate cancers. Brachytherapy outcomes are governed by dosimetric quality. Automated prostate brachytherapy with intraoperative planning and mechanical delivery of seeds may be more amenable to widescale implementation over manual systems dependent on user expertise. This study presents the updated dosimetric and mature clinical outcomes of an automated brachytherapy program.