Try a new search

Format these results:

Searched for:

person:djb506

in-biosketch:true

Total Results:

36


Strict bladder filling and rectal emptying during prostate SBRT: Does it make a dosimetric or clinical difference?

Byun, David J; Gorovets, Daniel J; Jacobs, Lauren M; Happersett, Laura; Zhang, Pengpeng; Pei, Xin; Burleson, Sarah; Zhang, Zhigang; Hunt, Margie; McBride, Sean; Kollmeier, Marisa A; Zelefsky, Michael J
BACKGROUND:To evaluate inter-fractional variations in bladder and rectum during prostate stereotactic body radiation therapy (SBRT) and determine dosimetric and clinical consequences. METHODS:Eighty-five patients with 510 computed tomography (CT) images were analyzed. Median prescription dose was 40 Gy in 5 fractions. Patients were instructed to maintain a full bladder and empty rectum prior to simulation and each treatment. A single reviewer delineated organs at risk (OARs) on the simulation (Sim-CT) and Cone Beam CTs (CBCT) for analyses. RESULTS:Bladder and rectum volume reductions were observed throughout the course of SBRT, with largest mean reductions of 86.9 mL (19.0%) for bladder and 6.4 mL (8.7%) for rectum noted at fraction #5 compared to Sim-CT (P < 0.01). Higher initial Sim-CT bladder volumes were predictive for greater reduction in absolute bladder volume during treatment (ρ = - 0.69; P < 0.01). Over the course of SBRT, there was a small but significant increase in bladder mean dose (+ 4.5 ± 12.8%; P < 0.01) but no significant change in the D2cc (+ 0.8 ± 4.0%; P = 0.28). The mean bladder trigone displacement was in the anterior direction (+ 4.02 ± 6.59 mm) with a corresponding decrease in mean trigone dose (- 3.6 ± 9.6%; P < 0.01) and D2cc (- 6.2 ± 15.6%; P < 0.01). There was a small but significant increase in mean rectal dose (+ 7.0 ± 12.9%, P < 0.01) but a decrease in rectal D2cc (- 2.2 ± 10.1%; P = 0.04). No significant correlations were found between relative bladder volume changes, bladder trigone displacements, or rectum volume changes with rates of genitourinary or rectal toxicities. CONCLUSIONS:Despite smaller than expected bladder and rectal volumes at the time of treatment compared to the planning scans, dosimetric impact was minimal and not predictive of detrimental clinical outcomes. These results cast doubt on the need for excessively strict bladder filling and rectal emptying protocols in the context of image guided prostate SBRT and prospective studies are needed to determine its necessity.
PMCID:7565753
PMID: 33066781
ISSN: 1748-717x
CID: 5275082

Prognostic potential of mid-treatment nodal response in oropharyngeal squamous cell carcinoma

Byun, David J; Tam, Moses M; Jacobson, Adam S; Persky, Mark S; Tran, Theresa T; Givi, Babak; DeLacure, Mark D; Li, Zujun; Harrison, Louis B; Hu, Kenneth S
BACKGROUND:We examine the prognostic implications of mid-course nodal response in oropharyngeal cancer (OPX) to radiation therapy. METHODS:In 44 patients with node-positive OPX undergoing concurrent chemoradiation, nodal volumes were measured on cone beam CTs from days 1, 10, 20, and 35. Nodal decrease (ND) was based on percent shrinkage from day 1. RESULTS:At a median follow-up of 17 months, the 2-year disease-free survival (DFS), locoregional control (LRC), distant metastasis-free survival (DMFS), and overall survival (OS) were 87%, 92%, 89%, and 92%, respectively. Patients with ND ≥43% at D20 had improved LRC (100% vs 78.4%, P = .03) compared to D20 ND <43%. On multivariate analysis, D20 ≥43% was independently prognostic for LRC (HR 1.17, P = .05). CONCLUSION/CONCLUSIONS:Patients with low-risk oropharynx cancer with ND of ≥43% by treatment day 20 had significantly improved LRC. The prognostic benefit of ND may assist in identifying candidates for treatment de-escalation.
PMID: 32964574
ISSN: 1097-0347
CID: 4605742

Cancer immunotherapy - immune checkpoint blockade and associated endocrinopathies

Byun, David J; Wolchok, Jedd D; Rosenberg, Lynne M; Girotra, Monica
Advances in cancer therapy in the past few years include the development of medications that modulate immune checkpoint proteins. Cytotoxic T-lymphocyte antigen 4 (CTLA4) and programmed cell death protein 1 (PD1) are two co-inhibitory receptors that are expressed on activated T cells against which therapeutic blocking antibodies have reached routine clinical use. Immune checkpoint blockade can induce inflammatory adverse effects, termed immune-related adverse events (IRAEs), which resemble autoimmune disease. In this Review, we describe the current data regarding immune-related endocrinopathies, including hypophysitis, thyroid dysfunction and diabetes mellitus. We discuss the clinical management of these endocrinopathies within the context of our current understanding of the mechanisms of IRAEs.
PMCID:5629093
PMID: 28106152
ISSN: 1759-5037
CID: 5275022

Risk and Prognostics of Second Primary Cancer after Prostate Radiation Therapy

Liu, Elisa K.; Daniels, Thomas B.; Lischalk, Jonathan W.; Oh, Cheongeun; Haas, Jonathan A.; Evans, Andrew J.; Byun, David J.
Introduction:As overall survival in prostate cancer increases due to advances in early detection and management, there is a growing need to understand the long-Term morbidity associated with treatment, including secondary tumors. The significance of developing radiation-Associated secondary cancers in an elderly population remains unknown.Methods:Patients diagnosed with prostate cancer between 1975 and 2016 in one of 9 Surveillance, Epidemiology, and End Results registries were included in this study. Risk of second primary pelvic malignancies (SPPMs) were assessed with death as a competing risk using the Fine-Gray model. Time-varying Cox proportional hazard models were employed to analyze risk to overall mortality based on secondary tumor status.Results:A total of 569,167 primary prostate cancers were included in analysis with an average follow-up of 89 months. Among all prostate cancer patients, 4956 SPPMs were identified. After controlling for differences in age, year of diagnosis, and surgery at time of prostate cancer treatment, radiation receipt was associated with a significantly higher incidence of SPPMs (1.1% vs 1.8% at 25 years). Among those who received radiation during initial prostate cancer treatment (n = 195,415), developing an SPPM is significantly associated with worse survival (adjusted hazard ratio = 1.76), especially among younger patients (under age 63, adjusted hazard ratio = 2.36).Conclusions:While developing a secondary malignancy carries a detrimental effect on overall survival, the absolute risk of developing such tumors is exceedingly low regardless of radiation treatment.
SCOPUS:85181833354
ISSN: 2352-0779
CID: 5630052

Risk and Prognostics of Second Primary Cancer After Prostate Radiation Therapy

Liu, Elisa K; Daniels, Thomas B; Lischalk, Jonathan W; Oh, Cheongeun; Haas, Jonathan A; Evans, Andrew J; Byun, David J
INTRODUCTION/UNASSIGNED:As overall survival in prostate cancer increases due to advances in early detection and management, there is a growing need to understand the long-term morbidity associated with treatment, including secondary tumors. The significance of developing radiation-associated secondary cancers in an elderly population remains unknown. METHODS/UNASSIGNED:Patients diagnosed with prostate cancer between 1975 and 2016 in one of 9 Surveillance, Epidemiology, and End Results registries were included in this study. Risk of second primary pelvic malignancies (SPPMs) were assessed with death as a competing risk using the Fine-Gray model. Time-varying Cox proportional hazard models were employed to analyze risk to overall mortality based on secondary tumor status. RESULTS/UNASSIGNED:A total of 569,167 primary prostate cancers were included in analysis with an average follow-up of 89 months. Among all prostate cancer patients, 4956 SPPMs were identified. After controlling for differences in age, year of diagnosis, and surgery at time of prostate cancer treatment, radiation receipt was associated with a significantly higher incidence of SPPMs (1.1% vs 1.8% at 25 years). Among those who received radiation during initial prostate cancer treatment (n = 195,415), developing an SPPM is significantly associated with worse survival (adjusted hazard ratio = 1.76), especially among younger patients (under age 63, adjusted hazard ratio = 2.36). CONCLUSIONS/UNASSIGNED:While developing a secondary malignancy carries a detrimental effect on overall survival, the absolute risk of developing such tumors is exceedingly low regardless of radiation treatment.
PMID: 37917577
ISSN: 2352-0787
CID: 5612762

A Tool to Integrate Electrophysiological Mapping for Cardiac Radioablation of Ventricular Tachycardia

Wang, Hesheng; Barbhaiya, Chirag R; Yuan, Ye; Barbee, David; Chen, Ting; Axel, Leon; Chinitz, Larry A; Evans, Andrew J; Byun, David J
PURPOSE/UNASSIGNED:Cardiac radioablation is an emerging therapy for recurrent ventricular tachycardia. Electrophysiology (EP) data, including electroanatomic maps (EAM) and electrocardiographic imaging (ECGI), provide crucial information for defining the arrhythmogenic target volume. The absence of standardized workflows and software tools to integrate the EP maps into a radiation planning system limits their use. This study developed a comprehensive software tool to enable efficient utilization of the mapping for cardiac radioablation treatment planning. METHODS AND MATERIALS/UNASSIGNED:After the scar area is outlined on the mapping surface, the tool extracts and extends the annotated patch into a closed surface and converts it into a structure set associated with the anatomic images. The tool then exports the structure set and the images as The Digital Imaging and Communications in Medicine Standard in Radiotherapy for a radiation treatment planning system to import. Overlapping the scar structure on simulation CT, a transmural target volume is delineated for treatment planning. RESULTS/UNASSIGNED:The tool has been used to transfer Ensite NavX EAM data into the Varian Eclipse treatment planning system in radioablation on 2 patients with ventricular tachycardia. The ECGI data from CardioInsight was retrospectively evaluated using the tool to derive the target volume for a patient with left ventricular assist device, showing volumetric matching with the clinically used target with a Dice coefficient of 0.71. CONCLUSIONS/UNASSIGNED:HeaRTmap smoothly fuses EP information from different mapping systems with simulation CT for accurate definition of radiation target volume. The efficient integration of EP data into treatment planning potentially facilitates the study and adoption of the technique.
PMCID:10320498
PMID: 37415904
ISSN: 2452-1094
CID: 5539402

Impact of Dosimetric Factors on Local Failure in Patients with Spine Metastasis after Stereotactic Body Radiotherapy: A Multi-Institutional Study [Meeting Abstract]

LeCompte, M C; Chen, X; Tseng, C L; Campbell, M; Balagamwala, E H; Hanan, J; Byun, D J; Silverman, J S; Foote, M C; Gatt, N; Mahadevan, A; Grimm, J; Redmond, K J
Purpose/Objective(s): Stereotactic body radiotherapy (SBRT) is increasingly utilized in the treatment of spine metastasis. Preliminary data suggest that higher doses may improve local control, but may also increase risk of toxicity including vertebral compression fracture (VCF). Our single institution study recently found that a minimum dose of at least 21 Gy to 80% of planning target volume (PTV D80%) in 2 fractions was associated with higher risk of VCF. The purpose of this study is to assess this variable's relationship with local failure (LF) and VCF in an international, multi-institutional cohort. Materials/Methods: Patients with radiation naive solid tumor spine metastases treated with SBRT at 5 international institutions from 2010 - 2020 were included. Patients with surgical stabilization were excluded. LF was defined per spine response assessment in neuro-oncology criteria. Variables examined included spinal instability neoplastic score (SINS) factors and dosimetric/volumetric characteristics of radiation planning. All fractionation scheme doses were converted to 2-fraction equivalent doses (2fxED) using the linear quadratic model with an alpha/beta of 3 and used in analyses of PTV D80%. Univariate and multivariate Cox proportional hazard models for LF and VCF were constructed using the Fine and Gray competing risk method.
Result(s): 357 vertebral segments from 234 patients were treated with SBRT. Common primary tumor types were prostate (n = 50, 22%), non-small cell lung cancer (n = 42, 18%), breast (n = 35, 15%), and kidney (n = 25, 11%). Most (n = 199 pts, 242 segments) were treated with 2 or 3 fractions with a median prescription dose of 24 Gy or 27 Gy, respectively (range: 14-45 Gy in 1-5 fractions). Median follow was 21.1 months (0.6-88.4 mo). LF was 12.6% and 18.1% at 1- and 2-years, respectively. Variables associated with increased LF on univariate analysis were lower PTV D80% at 2fxED <=21 Gy (HR 0.36, 95% CI 0.20-0.65, p = 0.001) and lower prescription dose BED3 (HR 0.98 as continuous variable, CI 0.97-0.99, p = 0.03). On multivariate analysis, only PTV D80% at 2fxED <=21 Gy remained associated with increased risk of LF (HR 0.46, CI 0.24-0.85, p = 0.01). VCF incidence was low, at 4.2% and 6.7% at 1- and 2-years, respectively. Higher SINS was predictive of VCF (HR 1.22, CI 1.1-1.36, p <0.001). Patients with higher PTVD80% at 2fxED>21 Gy had a higher, albeit non-significant, risk of VCF (HR 3.30, CI 0.80-13.6, p = 0.10), consistent with our previous single institution study.
Conclusion(s): This multi-institutional, international study suggests that a PTV D80% at 2fxED <=21 Gy may increase the risk of LF, while >21 Gy may increase the likelihood of VCF. Prospective studies are needed to further explore this complex relationship and identify the dose/fractionation schedule that best balances local control with normal tissue toxicity including VCF.
Copyright
EMBASE:2020265669
ISSN: 1879-355x
CID: 5366232

Pulmonary Toxic Effects After Myeloablative Conditioning With Total Body Irradiation Delivered via Volumetric Modulated Arc Therapy With Fludarabine

Modrek, Aram S; Karp, Jerome M; Byun, David; Gerber, Naamit K; Abdul-Hay, Maher; Al-Homsi, Ahmad Samer; Galavis, Paulina; Teruel, Jose; Yuan, Ye
We present the case of a 56-year-old female with a diagnosis of acute T-cell lymphoblastic leukemia who received myeloablative conditioning for bone marrow transplant with total body irradiation (TBI) using volumetric modulated arc therapy (VMAT) to the upper body and anterior-posterior/posterior-anterior (AP/PA) open fields to the lower body followed by hematopoietic stem cell transplant. Her clinical course was complicated by high-grade pulmonary toxic effects 55 days after treatment that resulted in death. We discuss the case, planning considerations by radiation oncologists and radiation physicists, and the multidisciplinary medical management of this patient.
PMID: 35598860
ISSN: 1879-8519
CID: 5275182

Early-onset osteoradionecrosis following adjuvant volumetric-modulated arc therapy to an osteocutaneous free fibula flap with customized titanium plate [Case Report]

Daar, David A; Byun, David J; Spuhler, Karl; Anzai, Lavinia; Witek, Lukasz; Barbee, David; Hu, Kenneth S; Levine, Jamie P; Jacobson, Adam S
BACKGROUND:Computerized surgical planning (CSP) in osseous reconstruction of head and neck cancer defects has become a mainstay of treatment. However, the consequences of CSP-designed titanium plating systems on planning adjuvant radiation remains unclear. METHODS:Two patients underwent head and neck cancer resection and maxillomandibular free fibula flap reconstruction with CSP-designed plates and immediate placement of osseointegrated dental implants. Surgical treatment was followed by adjuvant intensity modulated radiation therapy (IMRT). RESULTS:Both patients developed osteoradionecrosis (ORN), and one patient had local recurrence. The locations of disease occurred at the areas of highest titanium plate burden, possibly attributed to IMRT dosing inaccuracy caused by the CSP-designed plating system. CONCLUSION/CONCLUSIONS:Despite proven benefits of CSP-designed plates in osseous free flap reconstruction, there may be an underreported risk to adjuvant IMRT treatment planning leading to ORN and/or local recurrence. Future study should investigate alternative plating methods and materials to mitigate this debilitating outcome.
PMID: 34906727
ISSN: 2468-7855
CID: 5109702

Osteoradionecrosis following radiation to reconstructed mandible with titanium plate and osseointegrated dental implants

Byun, David J; Daar, David A; Spuhler, Karl; Anzai, Lavinia; Witek, Lukasz; Barbee, David; Jacobson, Adam S; Levine, Jamie P; Hu, Kenneth S
PMID: 34706296
ISSN: 1879-8519
CID: 5042562