Salvage Brachytherapy Research Articles

PO0413: Salvage Brachytherapy for Locally Recurrent Prostate Cancer after Definitive Radiotherapy - A Multicentric French Cohort by the SFRO Brachytherapy Group

PO0413: Salvage Brachytherapy for Locally Recurrent Prostate Cancer after Definitive Radiotherapy - A Multicentric French Cohort by the SFRO Brachytherapy Group

Iodine-125 low-dose rate prostate brachytherapy.

Robotic-assisted laparoscopic radical prostatectomy and intensity-modulated radiation therapy are the most common radical treatments for localized prostate cancer, and brachytherapy (BT) also plays a role in this field. Iodine-125 (I-125) low-dose rate (LDR) prostate BT is an established treatment. However, it remains controversial. Specifically, there are a variety of issues, such as indications for combined treatment with external beam radiotherapy and androgen deprivation therapy, prostate-specific antigen follow-up, the significance of postimplant biopsy, the usefulness of salvage BT and focal therapy, reduction of toxicities, and bladder cancer after BT. In this review, we summarize the recent developments in I-125 LDR BT.

Salvage radiotherapy for locally recurrent cervical and endometrial carcinoma: clinical outcomes and toxicities

BackgroundThe management of locally recurrent gynecological carcinoma remains a challenge due to the limited availability of data. This study aims to share our institutional experience in using definitive radiotherapy (RT) for the treatment of locally recurrent cervical and endometrial carcinoma.MethodsThe study retrospectively reviewed 20 patients in our hospital completing salvage 3D image-based HDR brachytherapy, with or without EBRT, for locally recurrent cervical and endometrial carcinoma after surgery. The Kaplan–Meier method was applied to estimate the disease-free survival (DFS) and overall survival (OS). The toxicities were assessed by CTCAEv5.ResultsDuring a median observation period of 21 months, the study reported a tumor objective response rate of 95%. The 3-year DFS and OS rates were 89.4% and 90.9%, respectively. The EBRT combined with brachytherapy achieved a median cumulative dose of 88 Gy to CTV D90. 14 patients received concurrent and/or systemic chemotherapy. Two patients suffered locoregional recurrence after salvage treatment, one of whom only received salvage brachytherapy for prior RT history. The analysis identified significant predictors for DFS, including tumor histology and FIGO stage. 5 patients observed acute grade 1–2 rectal (15%) or genitourinary (10%) toxicities. Late toxicities including grade 1–2 rectal bleeding (10%) and grade 2 pelvic fracture (5%) were seen in 3 patients.Conclusions3D image-guided brachytherapy combined with EBRT shows effective tumor control and acceptable toxicity profile for women with locally recurrent gynecologic cancer. The success in managing vaginal recurrence is notably influenced by histologic subtype and FIGO staging.

Salvage low-dose-rate brachytherapy for locally recurrent prostate cancer after definitive irradiation

PurposeThe optimal management of locally recurrent prostate cancer after definitive irradiation is still unclear but local salvage treatments are gaining interest. A retrospective, single-institution analysis of clinical outcomes and treatment-related toxicity after salvage I-125 low-dose-rate (LDR) brachytherapy (BT) for locally-recurrent prostate cancer was conducted in a Comprehensive Cancer Center. Patients and methodsA total of 94 patients treated with salvage LDR-BT between 2006 and 2021 were included. The target volume was either the whole-gland +/- a boost on the GTV, the hemigland, or only the GTV. The prescribed dose ranged from 90 to 145 Gy. Toxicity was graded by Common Terminology Criteria for Adverse Events (CTCAE) v5.0. ResultsMedian follow-up was 34 months. Initial radiotherapy was external beam radiotherapy in 73 patients (78 %) with a median dose of 76 Gy and I-125 BT in 21 patients (22 %) with a prescribed dose of 145 Gy. Median PSA at salvage was 3.75 ng/ml with a median interval between first and salvage irradiation of 9.4 years. Salvage brachytherapy was associated with androgen deprivation therapy for 32 % of the patients. Only 4 % of the patients were castrate-resistant. Failure free survival was 82 % at 2 years and 66 % at 3 years. The only factors associated with failure-free survival on multivariate analysis were hormonosensitivity at relapse and European Association of Urology (EAU) prognostic group. Late grade 3 urinary and rectal toxicities occurred in 12 % and 1 % of the patients respectively.No significant difference in toxicity or efficacy was observed between the three implant volume groups. ConclusionThe efficacy and toxicity results are consistent with those in the LDR group of the MASTER meta-analysis. Salvage BT confirms to be an effective and safe option for locally recurrent prostate cancer. A focal approach could be interesting to reduce late severe toxicities, especially urinary.

280: Salvage brachytherapy in second ipsilateral breast tumor event: Relating dosimetry with late toxicity

280: Salvage brachytherapy in second ipsilateral breast tumor event: Relating dosimetry with late toxicity

557: Local salvage brachytherapy for recurrent prostate cancer: a mono-institutional experience.

557: Local salvage brachytherapy for recurrent prostate cancer: a mono-institutional experience.

Optimization and experimental characterization of the innovative thermo-brachytherapy seed for prostate cancer treatment.

Adjuvant administration of hyperthermia (HT) with radiation therapy in the treatment of cancer has been extensively studied in the past five decades. Concurrent use of the two modalities leads to both complementary and synergetic enhancements in tumor management, but presents a practical challenge. Their simultaneous administration using the same implantable thermo-brachytherapy (TB) seed source has been established theoretically through magnetically mediated heat induction with ferromagnetic materials. Careful consideration, however, showed that regular ferromagnetic alloys lack the required conductivity to generate enough power through eddy current to overcome heat dissipation due to blood perfusion at clinically measuredrates. We characterized the TB implant that combines a sealed radioactive source with a ferrimagnetic ceramic (ferrite) core, serving as a self-regulating HT source when placed in an alternating electromagnetic field. To increase the heat production and uniformity of temperature distribution the empty spacers between radioisotope seeds were replaced by hyperthermia-only (HT-only)seeds. The heat generation due to eddy currents circulating in the seed's thin metal shell, surrounding the core, depends drastically on the core permeability. We identified a soft ferrite material ( ) as the best candidate for the core, owing to its high permeability, the HT-range Curie temperature, adjustable through material composition, and a sharp Curie transition, leading to heat self-regulation, with no invasive thermometry required. The core permeability as a function of temperature was calculated based on measured resistor-inductor (RL) circuit parameters and material B-H curves. The thickness of the shell was optimized separately for TB and HT-only seeds, having slightly different dimensions. Heat generation was calculated using the power versus temperature approximation. Finally, the temperature distribution for a realistic prostate LDR brachytherapy plan was modeled with COMSOL Multiphysics for a set of blood perfusion rates found in theliterature. The small size of the investigated ferrite core samples resulted in demagnetization significantly decreasing the relative permeability from its intrinsic value of ∼5000 to about 11 in the range of magnetic field amplitude and frequency values relevant to HT. The power generated by the seed dropped sharply as the shell thickness deviated from the optimal value. The optimized TB and HT-only seeds generated 45 and 267 mW power, respectively, providing a HT source sufficient for >90% volume coverage even for the highest blood perfusion rates. The toxicity of the surrounding normal tissues was minimal due to the rapid temperature fall off within a few millimeters distance from aseed. The investigated TB and HT-only seed prototypes were shown to provide sufficient power for the concurrent administration of radiation and HT. In addition to being used as a source for both radiation and heat at the onset of cancer therapy, these implanted seeds would be available for treatment intensification in the setting of salvage brachytherapy for locally radiorecurrent disease, possibly as a sensitizer to systemic therapies or as a modulator of the immune response, without another invasive procedure. Experimentally determined parameters of the ferrite material cores provided in this study establish a mechanistic foundation for future pre-clinical and clinical validationstudies.

Comparison of salvage high dose-rate brachytherapy and external beam radiotherapy for treatment of prostate cancer local recurrence after radical prostatectomy

Aim. To compare clinical efficacy of salvage high dose-rate brachytherapy (HDR-BT) and external beam radiotherapy (EBR) in treatment of local recurrence of prostate cancer after radical prostatectomy (RP).Materials and methods. Between January 2017 and December 2020, 60 patients with local recurrence of prostate cancer after RP were treated at the Russian Scientific Center of Roentgenology and Radiology. Two groups were identified: group 1 included 30 patients who underwent salvage external beam radiation therapy (EBRT) according to the classical fractionation regimen; in group 2, within the framework of the scientific protocol, 30 patients underwent 2 fractions of salvage HDR-BT with single boost dose of 15 Gy for total boost dose of 30 Gy. All patients in group 2 underwent pelvic multiparametric magnetic resonance imaging and positron emission tomography-computed tomography with prostatespecific membrane antigen ligands. In the 2nd group, transrectal biopsy of the prostate bed was also performed. Overall and biochemical recurrence-free survival, as well as the profile of early and late radiation complications, were analyzed.Results. Mean age of the patients at the time of salvage radiation therapy was 67.5 years (95 % confidence interval 66.1–69). Median time before development of biochemical relapse after RP was 24 months (interquartile range 13–46 months). Median follow-up period for all patients was 45 months (interquartile range 36–63 months). There were no dropouts in this study. The overall survival rate was 100 % in both groups. Comparative analysis of prostate specific antigen (PSA)-specific recurrence-free survival showed a clear trend toward an increase in the brachytherapy group; however, with the number of observations, statistically significant differences could not be achieved (p = 0.075). Salvage EBRT is more toxic than salvage HDR-BT. Comparative assessment of radiation adverse effects revealed higher frequency of early genitourinary toxicity of grade I and intestinal toxicity of grades I and II in the salvage EBRT group than in the salvage brachytherapy group, as well as late gastrointestinal toxicity of grade I and II.Conclusion. Salvage HDR-BT with 15 Gy × 2 fractions with total boost dose of up to 30 Gy was proved to be a promising treatment for local recurrence of prostate cancer after RP with an acceptable toxicity profile. There was also a trend towards increased PSA-specific recurrence-free survival in the salvage brachytherapy group compared with the salvage EBRT group.

PO-2198 MRI guided nodular salvage Brachytherapy after Prostatectomy and EBRT. 3 years outcome

PO-2198 MRI guided nodular salvage Brachytherapy after Prostatectomy and EBRT. 3 years outcome

Salvage prostate brachytherapy in radiorecurrent prostate cancer: An international Delphi consensus study

Background and PurposeLocal recurrences after previous radiotherapy (RT) are increasingly being identified in biochemically recurrent prostate cancer. Salvage prostate brachytherapy (BT) is an effective and well tolerated treatment option. We sought to generate international consensus statements on the use and preferred technical considerations for salvage prostate BT. Materials and MethodsInternational experts in salvage prostate BT were invited (n = 34) to participate. A three-round modified Delphi technique was utilized, with questions focused on patient- and cancer-specific criteria, type and technique of BT, and follow-up. An a priori threshold for consensus of ≥ 75% was set, with a majority opinion being ≥ 50%. ResultsThirty international experts agreed to participate. Consensus was achieved for 56% (18/32) of statements. Consensus was achieved in several areas of patient selection: 1) A minimum of 2–3 years from initial RT to salvage BT; 2) MRI and PSMA PET should be obtained; and 3) Both targeted and systematic biopsies should be performed. Several areas did not reach consensus: 1) Maximum T stage/PSA at time of salvage; 2) Utilization/duration of ADT; 3) Appropriateness of combining local salvage with SABR for oligometastatic disease and 4) Repeating a second course of salvage BT. A majority opinion preferred High Dose-Rate salvage BT, and indicated that both focal and whole gland techniques could be appropriate. There was no single preferred dose/fractionation. ConclusionAreas of consensus within our Delphi study may serve as practical advice for salvage prostate BT. Future research in salvage BT should address areas of controversy identified in our study.

V10-07 AUTOLOGOUS FAT TRANSFER AS A PROSTATE-RECTAL SPACER FOR PROSTATE BRACHYTHERAPY

You have accessJournal of UrologyCME1 Apr 2023V10-07 AUTOLOGOUS FAT TRANSFER AS A PROSTATE-RECTAL SPACER FOR PROSTATE BRACHYTHERAPY Ezequiel Becher, Juan Fernandez Long, Marcelo Bou, Edgardo F Becher, Luis Montes de Oca, and Marcelo Borghi Ezequiel BecherEzequiel Becher More articles by this author , Juan Fernandez LongJuan Fernandez Long More articles by this author , Marcelo BouMarcelo Bou More articles by this author , Edgardo F BecherEdgardo F Becher More articles by this author , Luis Montes de OcaLuis Montes de Oca More articles by this author , and Marcelo BorghiMarcelo Borghi More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000003328.07AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Implanted rectal spacers (IRS) have been developed to increase the distance between the prostate and the rectum, thus optimizing dose escalation in prostate brachytherapy (BT). Cost is a disadvantage and there is a lack of availability worldwide. We have developed an autologous fat transfer (AFT) technique to use as an IRS immediately after the implant of the seeds in low-dose-rate BT. We aim to present the feasibility and durability this technique. METHODS: A total of 120 patients underwent AFT (21 were treated with primary BT, 79 with a combined primary treatment of external beam radiotherapy and BT, 20 with salvage BT). The isodose used for primary BT was 14400 cGy, 11,000 cGy after 4600 cGy of external beam radiotherapy in the combined group, and 14400 cGy for the salvage group. Patients underwent a CT scan at 3, 6 and 12 months to measure the distance between the rectum and the prostate. RESULTS: An average of 18 cc (10-40) of fat was transferred successfully in 100% of cases.The mean distance to the rectum at the level of the base, middle, and apex at 1 and 6 months were 11.2, 9.7, and 7.6 mm; 8.3, 8.1, and 5.9 mm, respectively. No rectal toxicity or major complications were reported. CONCLUSIONS: The use of fat as an IRS seems to be a valid alternative to reduce rectal toxicity after BT, achieving equivalent distances to synthetic IRS. It is feasible, safe, and the loss of distance at 6 months is small. Cost is lower than other alternatives. Source of Funding: None © 2023 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 209Issue Supplement 4April 2023Page: e928 Advertisement Copyright & Permissions© 2023 by American Urological Association Education and Research, Inc.MetricsAuthor Information Ezequiel Becher More articles by this author Juan Fernandez Long More articles by this author Marcelo Bou More articles by this author Edgardo F Becher More articles by this author Luis Montes de Oca More articles by this author Marcelo Borghi More articles by this author Expand All Advertisement PDF downloadLoading ...

Outcomes of salvage high dose-rate brachytherapy with or without pelvic external beam radiotherapy in patients with palpable local recurrence of prostate cancer after radical prostatectomy

PurposeThis study aims to evaluate the outcomes and toxicities in patients with palpable local recurrence of prostate cancer after radical prostatectomy (RP), who were treated with salvage high dose-rate brachytherapy (HDR-BT) with or without pelvic external beam radiotherapy (EBRT). MethodsThis retrospective review included patients with palpable local recurrence of prostate cancer after RP who underwent salvage HDR-BT at a single institution between 2002 and 2020. HDR-BT regimens included 950 cGy x 2 (N = 4) or 1500 cGy x 1 (N = 2) combined with EBRT; or monotherapy with 950 cGy x 4 (N = 1) or 800 cGy x 2 (N = 1). Toxicity was graded according to CTCAE Version 5.0. ResultsA total of 8 patients were included. Median follow-up was 49 months (range: 9–223 months). Median age at time of salvage brachytherapy was 68 years (range: 59–85 years). Seven out of 8 patients were alive at last follow-up. There have been no locoregional recurrences. Three patients developed distant metastatic disease. One patient developed acute grade 3 urinary obstruction requiring catheterization, which lasted for 1 day postbrachytherapy. One patient developed late grade 3 urinary incontinence 18 months after brachytherapy. There were no other grade 2+ toxicities. ConclusionsThis study demonstrates the safety and efficacy of salvage HDR-BT in the setting of palpable local recurrence of prostate cancer after RP, with durable locoregional control and acceptable rates of toxicity. HDR-BT should be further explored as an option for dose-escalated salvage radiotherapy after prior radical prostatectomy.

PP02 Presentation Time: 9:10 AM: Salvage Prostate Brachytherapy in Radiorecurrent Prostate Cancer: An International Delphi Consensus Study

<h3>Purpose</h3> Local recurrences after previous radiotherapy (RT) are increasingly being identified with increasing use of molecular imaging in biochemically recurrent prostate cancer. Salvage prostate brachytherapy (BT) is an effective and well tolerated treatment option for radiorecurrent prostate cancer. While supported by multiple prospective studies, limited comparative data exists to guide optimal patient selection and treatment technique. We sought to generate international consensus statements on the use and preferred technical considerations for salvage prostate BT. <h3>Materials and Methods</h3> International experts in salvage prostate BT were invited (n=34) to participate. A three-round modified Delphi technique was utilized, with questions focused on patient- and cancer-specific criteria, type and technique of BT, and follow-up after salvage. An a priori threshold for consensus of ≥ 75% was set, with a majority opinion being set at ≥ 50%. <h3>Results</h3> Thirty international experts agreed to participate, and the response rates were 100% (30/30), 93.3% (28/30) and 100% (30/30) for the first, second and third rounds of the survey respectively. Consensus was achieved for 56% (18 of 32) statements. Consensus was achieved in several areas of patient selection, including: 1) A minimum of 2-3 years from initial RT and consideration of salvage BT; 2) MRI and PSMA PET should be acquired prior to salvage; 3) Both a targeted and systematic prostate biopsy should be performed; 4) Salvage BT can be considered after any initial RT technique; and 5) Any Gleason Score at recurrence could be considered for salvage. Several areas did not reach consensus and were controversial: 1) Cut off for maximum T stage and PSA at time of salvage; 2) Whether ADT should be used with salvage BT (and duration); 3) Whether it was appropriate to combine local salvage with SBRT for oligometastatic disease and 4) Whether salvage BT may be repeated more than once. More than 50% of respondents preferred High Dose-Rate salvage BT, and indicated that both focal and whole gland salvage could be appropriate depending on the clinical situation. There was no single preferred dose fractionation for salvage prostate BT. <h3>Conclusions</h3> These findings will inform development of an international expert consensus statement for salvage prostate BT. Consensus was achieved on 56% of statements, though several controversial areas were identified. While our results highlight there is no single preferred approach for salvage BT, areas of controversy will be relevant for the design of future prospective studies and clinical trials of salvage BT.

PO50 Presentation Time: 10:00 AM: Long-Term Results of Salvage High Dose-Rate Brachytherapy with or without Pelvic External Beam Radiotherapy in Patients with Palpable Local Recurrence of Prostate Cancer After Radical Prostatectomy

<h3>Purpose</h3> This study aims to evaluate the long term outcomes and toxicities in patients with clinically apparent, gross local recurrence of prostate cancer after radical prostatectomy, treated with salvage high dose-rate brachytherapy (HDR-BT) with or without pelvic external beam radiotherapy (EBRT). <h3>Materials and Methods</h3> Retrospective chart review was performed to identify patients with clinically apparent, gross local recurrence of prostate cancer after radical prostatectomy who underwent salvage HDR-BT at a single institution between 2002 and 2020. HDR-BT regimens included 950 cGy x 2 (N=4), 1500 cGy x 1 (N=2), 950 cGy x 4 (N=1), and 800 cGy x 2 (N=1). Pelvic EBRT was allowed at the discretion of the treating physician. Treatment and clinical characteristics were obtained for each patient, and outcome and toxicity data were collected. Toxicity was graded according to Common Toxicity criteria for Adverse Events Version 5.0. Descriptive analysis was performed. <h3>Results</h3> A total of 8 patients were included in analysis with a median follow-up of 49 months (range: 9 to 223 months). Five (63%) patients presented with a biochemical recurrence, and 3 patients (38%) presented with symptoms including hematuria and urinary obstruction. Seven patients underwent TRUS-guided biopsy which confirmed recurrent adenocarcinoma. The remaining patient underwent a PSMA PET/CT scan revealing a PET-avid soft tissue lesion in the prostate bed, but declined biopsy and proceeded with treatment without pathologic confirmation. Median age at time of salvage brachytherapy was 68 years (range: 59 to 85 years). Median time from prostatectomy to salvage HDR-BT was 95 months (range: 19 to 207 months). Median PSA at time of HDR brachytherapy was 2.32 ng/ml (range: undetectable on ADT to 13 ng/ml). Median lesion size was 2.5 cm (range: 1 to 3.6 cm). Six patients (75%) received adjuvant pelvic EBRT, 45-50 Gy in 25 fractions. Seven out of 8 patients received ADT after salvage brachytherapy for a median duration of 12 months (range: 8 to 24 months). The remaining patient did not receive ADT due to cardiac comorbidities. Seven out of 8 patients were alive at last follow-up. There have been no locoregional recurrences. Three patients developed distant metastatic disease. One patient, who had negative conventional staging scans 3 months prior to brachytherapy, was found to have distant metastatic disease only 2 months after salvage brachytherapy and died due to metastatic prostate cancer 9 months after HDR-BT. The other 2 patients developed distant metastases at 14 and 27 months after brachytherapy. One patient developed late grade 3 urinary incontinence requiring artificial urinary sphincter (AUS) placement 18 months after brachytherapy. This patient had the largest tumor size, 3.6 cm in longest dimension, and received pelvic EBRT in addition to HDR-BT. He is now more than 10 years out from HDR-BT with undetectable PSA and doing well with his AUS. There were no other grade 2 or higher genitourinary or gastrointestinal toxicities. <h3>Conclusions</h3> This study demonstrates the long-term safety and efficacy of salvage HDR brachytherapy in the setting of clinically apparent local recurrence of prostate cancer after radical prostatectomy, with durable locoregional control and acceptable rates of toxicity. HDR-BT should be further explored as an option for dose-escalated salvage radiotherapy in patients with gross local recurrences after radical prostatectomy.

PL02 Presentation Time: 2:15 PM: Protocol-Based Re-Lumpectomy and Salvage Brachytherapy as Accelerated Partial Breast Re-Irradiation for In-Breast Tumor Recurrence After Whole Breast Irradiation: Long-Term Results

<h3>Purpose</h3> To analyze the clinical outcome of salvage lumpectomy and multi-catheter salvage brachytherapy for local recurrent breast tumor. <h3>Material and Methods</h3> Between 07/03 and 12/21, 76 patients with local recurrence after previous breast conserving surgery and whole breast irradiation underwent a protocol based re-lumpectomy and adjuvant salvage-brachytherapy as partial breast re-irradiation. We analyzed second local recurrent rates, distant metastasis rates, disease-free survival, and overall survival as primary objective, and late effects and cosmetic results as secondary objective. <h3>Results</h3> Median and mean follow-up after the salvage brachytherapy was 48 and 65 months, respectively [range: 8-198 months]. The 5y.- and 10y.-cumulative local 2^nd recurrence rates were 4.1% and 17.1%, respectively. Five and 10-year actuarial distant-metastasis rate were 7.7%. 5y.- and 10-year overall survival rates were 90.8% and 85.4%, respectively. As serious late side effects grade 3-4 we observed only fibrosis grade 3 by 8/76 patients (10.5%). <h3>Conclusion</h3> For patients with local in-breast recurrence after previous breast conserving surgery and whole breast irradiation is the re-lumpectomy plus salvage-brachytherapy as partial breast re-irradiation a reasonable and effective organ sparing treatment option, which is at least equivalent to results achieved with salvage mastectomy.

PP03 Presentation Time: 9:20 AM: Patterns of Failure for Salvage HDR Prostate Brachytherapy in the Prostate PET Imaging Era

<h3>Purpose</h3> Although some patients who undergo prostate re-irradiation achieve long-term biochemical control, the majority of patients ultimately experience a biochemical recurrence. Furthermore, a small, but significant percentage of patients may experience significant toxicities. Prostate positron emission tomography (PET) may improve the management of radiorecurrent prostate cancer, by better delineating the systemic extent of disease prior to treatment. Furthermore, PET may allow for a more precise understanding of the patterns of failure after treatment. The purpose of this study is to analyze oncologic outcomes including patterns-of-failure for a contemporary cohort of patients who underwent salvage high-dose rate (HDR) prostate brachytherapy in the prostate PET imaging era. <h3>Materials and Methods</h3> We conducted a retrospective analysis of all patients, who underwent salvage HDR brachytherapy from 2017 onwards. 18F-fluciclovine and 18F-DCFPyL became available in 2017 and 2021, respectively. We utilized the Kaplan-Meier method to measure oncologic endpoints including biochemical progression-free survival (bPFS), clinical progression free survival (cPFS), and metastasis-free survival (MFS). We also implemented Cox regression analysis to identify factors associated with the development of bPFS and MFS. <h3>Results</h3> The median follow-up was 16.6 months. Of the 50 patients included in this study, 48 patients had 18F-fluciclovine (Axumin) imaging and two had 18F-DCFPyL (PSMA) imaging prior to treatment initiation. Six patients (12%) had oligometastatic disease prior to treatment and were treated with SBRT to those sites. Six patients (12%) had castrate-resistant prostate cancer at the time of salvage brachytherapy. The median brachytherapy dose was 1150 cGy in two treatments, and the entire prostate was treated. 43 (86%) patients were concurrently treated with androgen deprivation therapy. Six patients (12%) patients experienced a biochemical recurrence, and four patients (8%) experienced a local-regional recurrence by post-salvage PSMA or Auxmin imaging. Two patients (4%) experienced distant metastatic progression. No initial covariates were statistically associated with bPFS survival (Figure 1). However, increasing time to recurrence trended towards negative association (HR 0.77| CI 0.56 - 1.04, p = 0.091). The bPFS was 100% (CI 100% - 100%), 94% (CI 87% - 100%), and 90% (CI 81% - 100%) at 6 months, 12 months, and 18 months, respectively. <h3>Conclusion</h3> Patients undergoing HDR prostate brachytherapy to salvage recurrent disease in the prostate PET imaging era have durable bPFS. In this cohort, HDR salvage was equally effective regardless of initial treatment covariates (i.e. initial risk group), status of disease immediately prior to salvage (i.e. castrate resistance or oligometastases), or use of androgen deprivation therapy (ADT) during salvage. Therefore, prostate PET may identify candidates for whom HDR salvage will be effective.

Salvage Prostate Brachytherapy in Radiorecurrent Prostate Cancer: An International Delphi Consensus Study

<h3>Purpose/Objective(s)</h3> Local recurrences after previous radiotherapy (RT) are increasingly being identified with increasing use of molecular imaging in biochemically recurrent prostate cancer. Salvage prostate brachytherapy (BT) is an effective and well tolerated treatment option for radiorecurrent prostate cancer. While supported by multiple prospective studies, limited comparative data exists to guide optimal patient selection and treatment technique. We sought to generate international consensus statements on the use and preferred technical considerations for salvage prostate BT. <h3>Materials/Methods</h3> International experts in salvage prostate BT were invited (n=34) to participate. A three-round modified Delphi technique was utilized, with questions focused on patient- and cancer-specific criteria, type and technique of BT, and follow-up after salvage. An a priori threshold for consensus of ≥ 75% was set, with a majority opinion being set at ≥ 50%. <h3>Results</h3> Thirty international experts agreed to participate, and the response rates were 100% (30/30), 93.3% (28/30) and 100% (30/30) for the first, second and third rounds of the survey respectively. Consensus was achieved for 56% (18 of 32) statements. Consensus was achieved in several areas of patient selection, including: 1) A minimum of 2-3 years from initial RT and consideration of salvage BT; 2) MRI and PSMA PET should be acquired prior to salvage; 3) Both a targeted and systematic prostate biopsy should be performed; 4) Salvage BT can be considered after any initial RT technique; and 5) Any Gleason Score at recurrence could be considered for salvage. Several areas did not reach consensus and were controversial: 1) Cut off for maximum T stage and PSA at time of salvage; 2) Whether ADT should be used with salvage BT (and duration); 3) Whether it was appropriate to combine local salvage with SBRT for oligometastatic disease and 4) Whether salvage BT may be repeated more than once. More than 50% of respondents preferred High Dose-Rate salvage BT, and indicated that both focal and whole gland salvage could be appropriate depending on the clinical situation. There was no single preferred dose fractionation for salvage prostate BT. <h3>Conclusion</h3> These findings will inform development of an international expert consensus statement for salvage prostate BT. Consensus was achieved on 56% of statements, though several controversial areas were identified. While our results highlight there is no single preferred approach for salvage BT, areas of controversy will be relevant for the design of future prospective studies and clinical trials of salvage BT.

Efficacy and toxicity following salvage high-dose-rate brachytherapy for locally recurrent prostate cancer after radiotherapy

INTRODUCTIONThe management of local relapse after prostate cancer radiotherapy is frequently based on androgen deprivation therapy. The aim of the study was to report Gustave Roussy's experience with salvage prostate brachytherapy. PATIENTS AND METHODSAll cases of localized prostate cancer presenting in an irradiated area who received salvage high dose rate (HDR) brachytherapy from 2013 to 2020 were retrospectively reviewed. RESULTSA total of 64 patients were included. Median follow up was 30.5 months. Median initial EBRT dose was 70 Gy [Q1-Q3: 70 – 74]. Median PSA at brachytherapy was 6.8 ng/mL [Q1-Q3: 4.4 – 8.7] with a median interval between first and salvage irradiation of 10 years [Q1-Q3: 6.9 – 12.6]. The modality of the first irradiation was an exclusive EBRT in 73% of the cases, mostly with a 3D technique (82%). Dose prescription was two fractions of 12 Gy or 13 Gy associated with androgen deprivation therapy for 63% of the patients. About 23% of the patients were castrate-resistant. Disease free survival at 2 years was 58% in the whole population and 66% in hormone sensitive patients. The only factors associated with disease free survival on multivariate analysis was a high-risk disease at initial diagnosis (HR = 3.59, IC95 [1.75; 7.39], p = 0.0005). Grade 3 urinary and rectal toxicities occurred in 1.5% and 1.5% of the patients, respectively. CONCLUSIONHDR salvage brachytherapy seems to be a safe option for patients presenting with an isolated local relapse of prostate cancer.

Clinical outcomes and dosimetric predictors of toxicity for re-irradiation of vaginal recurrence of endometrial cancer

To report clinical outcomes and dosimetric predictors of late toxicity for patients with vaginal recurrence of endometrial cancer treated with brachytherapy in the re-irradiation setting. On retrospective review, 32 patients with vaginal recurrence of endometrial cancer received salvage brachytherapy with or without pelvic radiotherapy (RT) from 06/2003-12/2017. Prior RT modalities were vaginal brachytherapy (19, 59%), pelvic RT (7, 22%) or both (6, 19%). Image-guided brachytherapy was performed with CT- (25, 78%) or MR-guidance (7, 22%). Vaginal control, recurrence-free survival (RFS) and overall survival (OS) were estimated by Kaplan-Meier method. Late toxicity was graded by Common Toxicity Criteria for Adverse Events. Median time from prior RT to re-irradiation was 22 months (range, 4-140). Salvage RT modalities were pelvic RT and brachytherapy (25, 78%) or brachytherapy alone (7, 22%). With median follow-up of 47 months, 3/5-year vaginal control, RFS and OS rates were 64/56%, 47/41% and 68/42%, respectively. Six patients (19%) had no evidence of disease at 85-155 months. Late grade 2/3 GI, GU and vaginal toxicity rates were 13%/16%, 19%/13%, and 9%/16%. Cumulative D2cc rectum (sum of prior and salvage RT courses) was predictive of grade 2+ and grade 3 GI toxicity. Cumulative D2cc rectum for an estimated 10% risk of late grade 2+ and 3 GI toxicity was 86 Gy and 92 Gy, respectively. Salvage image-guided brachytherapy in the re-irradiation setting results in modest local control and increased late toxicity for localized recurrent endometrial cancer. With long-term disease control, cumulative D2cc rectum may be used to reduce late GI complication risk.

Salvage brachytherapy for multiply recurrent metastatic brain tumors: A matched case analysis.

BackgroundPatients with recurrent brain metastases who have exhausted external radiation options pose a treatment challenge in the setting of advances in systemic disease control which have improved quality of life and survival. Brachytherapy holds promise as salvage therapy given its ability to enforce surgical cytoreduction and minimize regional toxicity. This study investigates the role of salvage brachytherapy in maintaining local control for recurrent metastatic lesions.MethodsWe retrospectively reviewed our institution’s experience with brachytherapy in patients with multiply recurrent cerebral metastases who have exhausted external radiation treatment options (14 cases). The primary outcome of the study was freedom from local recurrence (FFLR). To capture the nuances of tumor biology, we compared FFLR achieved by brachytherapy to the preceding treatment for each patient. We further compared the response to brachytherapy in patients with lung cancer (8 cases) against a matched cohort of maximally radiated lung brain metastases (10 cases).ResultsBrachytherapy treatment conferred significantly longer FFLR compared to prior treatments (median 7.39 vs 5.51 months, P = .011) for multiply recurrent brain metastases. Compared to an independent matched cohort, brachytherapy demonstrated superior FFLR (median 8.49 vs 1.61 months, P = .004) and longer median overall survival (11.07 vs 5.93 months, P = .055), with comparable side effects.ConclusionBrachytherapy used as salvage treatment for select patients with a multiply recurrent oligometastatic brain metastasis in the setting of well-controlled systemic disease holds promise for improving local control in this challenging patient population.