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1.
JCO Oncol Pract ; 20(5): 732-738, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38330252

RESUMO

PURPOSE: Clinical efficiency is a key component of value-based health care. Our objective here was to identify workflow inefficiencies by using time-driven activity-based costing (TDABC) and evaluate the implementation of a new clinical workflow in high-volume outpatient radiation oncology clinics. METHODS: Our quality improvement study was conducted with the Departments of GI, Genitourinary (GU), and Thoracic Radiation Oncology at a large academic cancer center and four community network sites. TDABC was used to create process maps and optimize workflow for outpatient consults. Patient encounter metrics were captured with a real-time status function in the electronic medical record. Time metrics were compared using Mann-Whitney U tests. RESULTS: Individual patient encounter data for 1,328 consults before the intervention and 1,234 afterward across all sections were included. The median overall cycle time was reduced by 21% in GI (19 minutes), 18% in GU (16 minutes), and 12% at the community sites (9 minutes). The median financial savings per consult were $52 in US dollars (USD) for the GI, $33 USD for GU, $30 USD for thoracic, and $42 USD for the community sites. Patient satisfaction surveys (from 127 of 228 patients) showed that 99% of patients reported that their providers spent adequate time with them and 91% reported being seen by a care provider in a timely manner. CONCLUSION: TDABC can effectively identify opportunities to improve clinical efficiency. Implementing workflow changes on the basis of our findings led to substantial reductions in overall encounter cycle times across several departments, as well as high patient satisfaction and significant financial savings.


Assuntos
Pacientes Ambulatoriais , Radioterapia (Especialidade) , Fluxo de Trabalho , Humanos , Radioterapia (Especialidade)/economia , Radioterapia (Especialidade)/métodos , Radioterapia (Especialidade)/normas , Masculino , Feminino , Encaminhamento e Consulta , Pessoa de Meia-Idade
2.
J Cancer Educ ; 38(1): 344-348, 2023 02.
Artigo em Inglês | MEDLINE | ID: mdl-35013900

RESUMO

Subspecialty exposure during medical school can be limited. Moreover, the COVID19 pandemic prevented most onsite elective medical student (MS) rotations during 2020. Therefore, we sought to create and assess the efficacy of an informal virtual elective (IVE) for MSs to explore radiation oncology (RO) at our institution. We created IVE activities including invitations to resident didactics, a faculty lecture series, and interactive virtual events with residents and faculty. MSs were offered RO resident and faculty mentors and the opportunity to deliver a lecture. Pre- and post-IVE evaluation surveys were sent to 27 4th year MSs. Surveys utilized importance ordering (1=most important; reported as median (interquartile range), free response, and Likert-type questions (5 = extremely, 1=not at all). Our IVE, held from July to October 2020, had a median of 11 students (range 7-18) attend each activity. Pre- and post-IVE surveys were completed by 22/27 (81%) and 20/27 (74%) MSs, respectively. In pre-IVE, MSs reported participating in the IVE for faculty/resident interaction (1.5 [1, 2]), networking (3 [2, 3]), and learning (4 [3-5]). In post-IVE, MSs reported benefit from faculty mentors (5 [4, 5]), delivering a presentation (5 [3-5]), and faculty lectures (4.5 [4, 5]). In post-IVE, MSs preferred a full onsite away elective (16, 80%) over an official virtual elective (1, 5%) or IVE (3, 15%). Overall, MSs reported that the IVE provided an adequate introduction to RO at our institution (4 [4, 5]). Alternative virtual elective experiences allow MSs to informally evaluate medical subspecialties and could be offered even if formal elective opportunities are available.


Assuntos
COVID-19 , Educação de Graduação em Medicina , Radioterapia (Especialidade) , Estudantes de Medicina , Humanos , Radioterapia (Especialidade)/educação , Pandemias
3.
Cancer Res ; 83(3): 441-455, 2023 02 03.
Artigo em Inglês | MEDLINE | ID: mdl-36459568

RESUMO

Pancreatic ductal adenocarcinoma (PDAC) has been classified into classical and basal-like transcriptional subtypes by bulk RNA measurements. However, recent work has uncovered greater complexity to transcriptional subtypes than was initially appreciated using bulk RNA expression profiling. To provide a deeper understanding of PDAC subtypes, we developed a multiplex immunofluorescence (mIF) pipeline that quantifies protein expression of six PDAC subtype markers (CLDN18.2, TFF1, GATA6, KRT17, KRT5, and S100A2) and permits spatially resolved, single-cell interrogation of pancreatic tumors from resection specimens and core needle biopsies. Both primary and metastatic tumors displayed striking intratumoral subtype heterogeneity that was associated with patient outcomes, existed at the scale of individual glands, and was significantly reduced in patient-derived organoid cultures. Tumor cells co-expressing classical and basal markers were present in > 90% of tumors, existed on a basal-classical polarization continuum, and were enriched in tumors containing a greater admixture of basal and classical cell populations. Cell-cell neighbor analyses within tumor glands further suggested that co-expressor cells may represent an intermediate state between expression subtype poles. The extensive intratumoral heterogeneity identified through this clinically applicable mIF pipeline may inform prognosis and treatment selection for patients with PDAC. SIGNIFICANCE: A high-throughput pipeline using multiplex immunofluorescence in pancreatic cancer reveals striking expression subtype intratumoral heterogeneity with implications for therapy selection and identifies co-expressor cells that may serve as intermediates during subtype switching.


Assuntos
Carcinoma Ductal Pancreático , Neoplasias Pancreáticas , Humanos , Neoplasias Pancreáticas/patologia , Carcinoma Ductal Pancreático/genética , Carcinoma Ductal Pancreático/patologia , Prognóstico , Fenótipo , RNA , Regulação Neoplásica da Expressão Gênica , Claudinas
4.
Med Phys ; 49(1): 497-509, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34800037

RESUMO

PURPOSE: The main purpose of this work was to generate and validate the dosimetric accuracy of proton beams of dimensions that are appropriate for in vivo small animal and in vitro ultrahigh dose rate (FLASH) radiotherapy experiments using a synchrotron-based treatment delivery system. This study was performed to enable future investigations of the relevance of a spread-out Bragg peak (SOBP) under FLASH conditions. METHODS: The spill characteristics of the small field fixed horizontal beam line were modified to deliver accelerated protons in times as short as 2 ms and to control the dose delivered. A Gaussian-like transverse beam profile was transformed into a square uniform one at FLASH dose rates, while avoiding low-dose regions, a crucial requirement to protect normal tissue during FLASH irradiation. Novel beam-shaping devices were designed using Monte Carlo techniques to produce up to about 6 cm3 of uniform dose in SOBPs while maximizing the dose rate. These included a scattering foil, a conical flattening filter to maximize the flux of protons into the region of interest, energy filters, range compensators, and collimators. The shapes, sizes, and positions of the components were varied to provide the required field sizes and SOBPs. RESULTS: The designed and fabricated devices were used to produce 10-, 15-, and 20-mm diameter, circular field sizes and 10-, 15-, and 20-mm SOBP modulation widths at uniform physical dose rates of up to 375 Gy/s at the center of the SOBP and a minimum dose rate of about 255 Gy/s at the entrance, respectively, in cylindrical volumes. The flatness of lateral dose profiles at the center could be adjusted to within ±1.5% at the center of the SOBP. Assessment of systematic uncertainties, such as impact of misalignments and positioning uncertainties, was performed using simulations, and the results were used to provide appropriate adjustments to ensure high-accuracy FLASH beam delivery for both in vitro and in vivo preclinical experiments. CONCLUSIONS: It is feasible to use synchrotron-generated proton beams of sufficient dimensions for FLASH radiobiology experiments. We expect to use the system we developed to acquire in vitro and in vivo small animal FLASH radiobiology data as a function of dose, dose rate, oxygen content, and linear energy transfer to help us understand the underlying mechanisms of the FLASH phenomenon.


Assuntos
Terapia com Prótons , Prótons , Animais , Método de Monte Carlo , Dosagem Radioterapêutica , Síncrotrons
6.
Radiat Oncol ; 14(1): 154, 2019 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-31470860

RESUMO

BACKGROUND: Target localization in radiation therapy is affected by numerous sources of uncertainty. Despite measures to minimize the breathing motion, the treatment of hypofractionated liver radiation therapy is further challenged by residual uncertainty coming from involuntary organ motion and daily changes in the shape and location of abdominal organs. To address the residual uncertainty, clinics implement image-guided radiation therapy at varying levels of soft-tissue contrast. This study utilized the treatment records from the patients that have received hypofractionated liver radiation therapy using in-room computed tomography (CT) imaging to assess the setup uncertainty and to estimate the appropriate planning treatment volume (PTV) margins in the absence of in-room CT imaging. METHODS: We collected 917 pre-treatment daily in-room CT images from 69 patients who received hypofractionated radiation therapy to the liver with the inspiration breath-hold technique. For each treatment, the daily CT was initially aligned to the planning CT based on the shape of the liver automatically using a CT-CT alignment software. After the initial alignment, manual shift corrections were determined by visual inspection of the two images, and the corrections were applied to shift the patient to the physician-approved treatment position. Considering the final alignment as the gold-standard setup, systematic and random uncertainties in the automatic alignment were quantified, and the uncertainties were used to calculate the PTV margins. RESULTS: The median discrepancy between the final and automatic alignment was 1.1 mm (0-24.3 mm), and 38% of treated fractions required manual corrections of ≥3 mm. The systematic uncertainty was 1.5 mm in the anterior-posterior (AP) direction, 1.1 mm in the left-right (LR) direction, and 2.4 mm in the superior-inferior (SI) direction. The random uncertainty was 2.2 mm in the AP, 1.9 mm in the LR, and 2.2 mm in the SI direction. The PTV margins recommended to be used in the absence of in-room CT imaging were 5.3 mm in the AP, 3.5 mm in the LR, and 5.1 mm in the SI direction. CONCLUSIONS: Manual shift correction based on soft-tissue alignment is substantial in the treatment of the abdominal region. In-room CT can reduce PTV margin by up to 5 mm, which may be especially beneficial for dose escalation and normal tissue sparing in hypofractionated liver radiation therapy.


Assuntos
Suspensão da Respiração , Tomografia Computadorizada de Feixe Cônico/métodos , Processamento de Imagem Assistida por Computador/métodos , Neoplasias Hepáticas/radioterapia , Planejamento da Radioterapia Assistida por Computador/métodos , Radioterapia Guiada por Imagem/métodos , Humanos , Neoplasias Hepáticas/diagnóstico por imagem , Neoplasias Hepáticas/patologia , Prognóstico , Hipofracionamento da Dose de Radiação , Radioterapia de Intensidade Modulada/métodos , Incerteza
7.
J Natl Cancer Inst ; 111(12): 1358-1360, 2019 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-31165160

RESUMO

Two decades following the creation of the Office of Cancer Complementary and Alternative Medicine at the National Cancer Institute, the status of complementary and alternative medicine (CAM) research within oncology remains opaque. To better understand the landscape of CAM studies in oncology, we identified CAM-related phase III randomized controlled trials (RCTs) through ClinicalTrials.gov and compared these CAM trials to all non-CAM oncologic RCTs. Pearson χ2 testing was used to compare proportions across groups; all tests were two-sided. Comparing the 25 identified CAM RCTs with 739 non-CAM RCTs, CAM studies were more likely to be sponsored by a cooperative group (64.0% vs 28.6%, P < .001) and less likely to be industry funded (8.0% vs 76.5%, P < .001). CAM trials disproportionately excluded disease-related outcomes as endpoints (8.0% vs 84.6%, P < .001), were unsupported by prior early-phase data (55.0% vs 96.1%, P < .001), and did not meet the primary endpoint (8.7% vs 53.0%, P < .001). Given the observed relationship between encouraging pilot data and subsequent phase III trial success, we contend that future CAM RCTs may yield more promising findings if better supported by appropriately designed and well-characterized early-phase signals.


Assuntos
Terapias Complementares/estatística & dados numéricos , Neoplasias/terapia , Distribuição de Qui-Quadrado , Ensaios Clínicos Fase III como Assunto , Terapias Complementares/economia , Humanos , Oncologia , National Cancer Institute (U.S.) , Intervalo Livre de Progressão , Ensaios Clínicos Controlados Aleatórios como Assunto , Apoio à Pesquisa como Assunto , Resultado do Tratamento , Estados Unidos
8.
JAMA Oncol ; 5(12): 1769-1773, 2019 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-31158272

RESUMO

Importance: Seminal investigation 2 decades ago alerted the oncology community to age disparities in participation in cooperative group trials; less is known about whether these disparities persist in industry-funded research. Objective: To characterize the age disparities among trial enrollees on randomized clinical trials (RCTs) of common cancers in clinical oncology and identify factors associated with wider age imbalances. Data Sources: Phase 3 clinical oncology RCTs were identified through ClinicalTrials.gov. Study Selection: Multiarm RCTs assessing a therapeutic intervention for patients with breast, prostate, colorectal, or lung cancer (the 4 most common cancer disease sites) were included. Data Extraction and Synthesis: Trial data were extracted from ClinicalTrials.gov. Trial screening and parameter identification were independently performed by 2 individuals. Data were analyzed in 2018. Main Outcomes and Measures: The difference in median age (DMA) between the trial participant median age and the population-based disease-site-specific median age was determined for each trial. Results: Three hundred two trials met inclusion criteria. The trials collectively enrolled 262 354 participants; 249 trials (82.5%) were industry-funded. For all trials, the trial median age of trial participants was a mean of 6.49 years younger than the population median age (95% CI, -7.17 to -5.81 years; P < .001). Age disparities were heightened among industry-funded trials compared with non-industry-funded trials (mean DMA, -6.84 vs -4.72 years; P = .002). Enrollment criteria restrictions based on performance status or age cutoffs were associated with age disparities; however, industry-funded trials were not more likely to use these enrollment restrictions than non-industry-funded trials. Age disparities were also larger among trials that evaluated a targeted systemic therapy and among lung cancer trials. Linear regression modeling revealed a widening gap between trial and population median ages over time at a rate of -0.19 years annually (95% CI, -0.37 to -0.01 years; P = .04). Conclusions and Relevance: Age disparities between trial participants and the incident disease population are pervasive across trials and appear to be increasing over time. Industry sponsorship of trials is associated with heightened age imbalances among trial participants. With an increasing role of industry funding among cancer trials, efforts to understand and address age disparities are necessary to ensure generalizability of trial results as well as equity in trial access.


Assuntos
Neoplasias/terapia , Fatores Etários , Ensaios Clínicos Fase III como Assunto/economia , Humanos , Modelos Lineares , Ensaios Clínicos Controlados Aleatórios como Assunto , Medição de Risco
9.
J Oncol Pract ; 13(12): e992-e1001, 2017 12.
Artigo em Inglês | MEDLINE | ID: mdl-29035618

RESUMO

PURPOSE: Drivers of variation in the cost of care after chemoradiotherapy for the management of anal squamous cell carcinoma (SCC) have not been fully elucidated. We sought to characterize the direct and indirect impact of radiotherapy modality on health care costs among patients with anal SCC. PATIENTS AND METHODS: A retrospective cohort study was performed using the 2014 linkage of the SEER-Medicare database. We identified 1,025 patients with anal SCC diagnosed between 2001 and 2011 and treated with chemoradiotherapy. Propensity score matching was used to balance baseline differences between patients treated with intensity-modulated radiotherapy (IMRT) and those treated with three-dimensional conformal radiotherapy (3D-CRT). Differences in total, cancer-attributable, and procedure-specific costs between groups were measured. RESULTS: Radiation-related, patient out-of-pocket, and total costs in the 1-year period after radiotherapy start were all higher for the IMRT group than the 3D-CRT group (median total cost, $35,890 v $27,262, respectively; P < .001). Patients who received IMRT had lower cumulative costs associated with urgent hospitalizations and emergency department visits at both 9 months and 1 year after treatment start compared with a matched cohort of patients who received 3D-CRT (median, $711 v $4,957 at 1 year, respectively; P = .021). CONCLUSION: Although total costs of care were higher for IMRT compared with 3D-CRT, primarily as a result of higher radiotherapy-specific costs, IMRT was associated with decreased unplanned health care utilization costs starting at 9 months after treatment start. Radiotherapy-centered episodes of care may need to encompass a longer time horizon to capture the full cost savings associated with more advanced radiation modalities.


Assuntos
Neoplasias do Ânus/economia , Neoplasias do Ânus/radioterapia , Carcinoma de Células Escamosas/economia , Carcinoma de Células Escamosas/radioterapia , Radioterapia de Intensidade Modulada/economia , Idoso , Quimiorradioterapia/economia , Feminino , Custos de Cuidados de Saúde , Humanos , Masculino , Medicare/economia , Dosagem Radioterapêutica , Radioterapia Conformacional/economia , Estudos Retrospectivos , Estados Unidos
10.
Int J Radiat Oncol Biol Phys ; 98(1): 177-185, 2017 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-28258896

RESUMO

PURPOSE: We examined the impact of intensity modulated radiation therapy (IMRT) on hospitalization rates in the Surveillance, Epidemiology, and End Results (SEER)-Medicare population with anal squamous cell carcinoma (SCC). METHODS AND MATERIALS: We performed a retrospective cohort study using the SEER-Medicare database. We identified patients with nonmetastatic anal SCC diagnosed between 2001 and 2011 and treated with chemoradiation therapy. We assessed the relation between IMRT and first hospitalization by use of a multivariate competing-risk model, as well as instrumental variable analysis, using provider IMRT affinity as our instrument. RESULTS: Of the 1165 patients included in our study, 458 (39%) received IMRT. IMRT use increased over time and was associated more with regional and provider characteristics than with patient characteristics. The 3- and 6-month cumulative incidences of first hospitalization were 41.9% (95% confidence interval [CI], 37.3%-46.4%) and 47.6% (95% CI, 43.0%-52.2%), respectively, for the IMRT cohort and 46.7% (95% CI, 43.0%-50.4%) and 52.1% (95% CI, 48.4%-55.7%), respectively, for the non-IMRT cohort. IMRT was associated with a decreased hazard of first hospitalization compared with 3-dimensional radiation techniques (hazard ratio, 0.70; 95% CI, 0.58-0.84; P=.0002). Instrumental variable analysis suggested an even greater reduction in hospitalizations with IMRT after controlling for unmeasured confounders. There was a trend toward improved overall survival with IMRT, with an adjusted hazard ratio of 0.77 (95% CI, 0.59-1.00; P=.05). CONCLUSIONS: The use of IMRT is associated with reduced hospitalizations in elderly patients with anal SCC. Further work is warranted to understand the long-term health and cost impact of IMRT, particularly for patient subgroups most at risk of toxicity and hospitalization.


Assuntos
Neoplasias do Ânus/radioterapia , Carcinoma de Células Escamosas/radioterapia , Hospitalização/estatística & dados numéricos , Medicare/estatística & dados numéricos , Radioterapia de Intensidade Modulada/estatística & dados numéricos , Programa de SEER/estatística & dados numéricos , Idoso , Neoplasias do Ânus/mortalidade , Neoplasias do Ânus/patologia , Carcinoma de Células Escamosas/mortalidade , Carcinoma de Células Escamosas/patologia , Intervalos de Confiança , Fatores de Confusão Epidemiológicos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Modelos de Riscos Proporcionais , Radioterapia de Intensidade Modulada/mortalidade , Radioterapia de Intensidade Modulada/tendências , Estudos Retrospectivos , Taxa de Sobrevida , Resultado do Tratamento , Estados Unidos
11.
Pract Radiat Oncol ; 7(3): 173-182, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28343896

RESUMO

PURPOSE: This study aims to determine how the albumin-bilirubin (ALBI) score compares with the Child-Pugh (CP) score for assessing liver function following stereotactic body radiation therapy (SBRT). METHODS AND MATERIALS: In total, 60 patients, 40 with hepatocellular carcinoma (HCC) and 20 with cholangiocarcinoma (CCA), were treated with SBRT. Liver function panels were obtained before and at 1, 3, 6, and 12 months after SBRT. Laboratory values were censored after locoregional recurrence, further liver-directed therapies, or liver transplant. RESULTS: A significant decline in hepatic function occurred after SBRT for HCC patients only (P = .001 by ALBI score; P < .0001 by CP score). By converting radiation doses to biologically equivalent doses by using a standard linear quadratic model using α/ß of 10, the strongest dosimetric predictor of liver function decline for HCC was the volume of normal liver irradiated by a dose of 40 Gy when assessing liver function by the ALBI score (P = .07), and the volume of normal liver irradiated by a dose of 20 Gy by using the CP score (P= .0009). For CCA patients, the volume of normal liver irradiated by a dose of 40 Gy remained the strongest dosimetric predictor when using the ALBI score (P = .002), but no dosimetric predictor was significant using the CP score. Hepatic function decline correlated with worse overall survival for HCC (by ALBI, P = .0005; by CP, P < .0001) and for CCA (by ALBI, P = NS; by CP, P = .008). CONCLUSIONS: ALBI score was similarly able to predict hepatic function decline compared with CP score, and both systems correlated with survival.


Assuntos
Bilirrubina/sangue , Neoplasias Hepáticas/radioterapia , Fígado/fisiologia , Radiocirurgia/efeitos adversos , Albumina Sérica Humana/análise , Idoso , Neoplasias dos Ductos Biliares/mortalidade , Neoplasias dos Ductos Biliares/fisiopatologia , Neoplasias dos Ductos Biliares/radioterapia , Biomarcadores , Carcinoma Hepatocelular/mortalidade , Carcinoma Hepatocelular/fisiopatologia , Carcinoma Hepatocelular/radioterapia , Colangiocarcinoma/mortalidade , Colangiocarcinoma/fisiopatologia , Colangiocarcinoma/radioterapia , Relação Dose-Resposta à Radiação , Feminino , Humanos , Fígado/efeitos da radiação , Neoplasias Hepáticas/mortalidade , Neoplasias Hepáticas/fisiopatologia , Masculino , Pessoa de Meia-Idade , Lesões por Radiação/etiologia , Lesões por Radiação/fisiopatologia , Radiocirurgia/métodos , Dosagem Radioterapêutica
12.
Radiology ; 283(2): 460-468, 2017 05.
Artigo em Inglês | MEDLINE | ID: mdl-28045603

RESUMO

Purpose To assess the cost-effectiveness of stereotactic body radiation therapy (SBRT) versus radiofrequency ablation (RFA) for patients with inoperable localized hepatocellular carcinoma (HCC) who are eligible for both SBRT and RFA. Materials and Methods A decision-analytic Markov model was developed for patients with inoperable, localized HCC who were eligible for both RFA and SBRT to evaluate the cost-effectiveness of the following treatment strategies: (a) SBRT as initial treatment followed by SBRT for local progression (SBRT-SBRT), (b) RFA followed by RFA for local progression (RFA-RFA), (c) SBRT followed by RFA for local progression (SBRT-RFA), and (d) RFA followed by SBRT for local progression (RFA-SBRT). Probabilities of disease progression, treatment characteristics, and mortality were derived from published studies. Outcomes included health benefits expressed as discounted quality-adjusted life years (QALYs), costs in U.S. dollars, and cost-effectiveness expressed as an incremental cost-effectiveness ratio. Deterministic and probabilistic sensitivity analysis was performed to assess the robustness of the findings. Results In the base case, SBRT-SBRT yielded the most QALYs (1.565) and cost $197 557. RFA-SBRT yielded 1.558 QALYs and cost $193 288. SBRT-SBRT was not cost-effective, at $558 679 per QALY gained relative to RFA-SBRT. RFA-SBRT was the preferred strategy, because RFA-RFA and SBRT-RFA were less effective and more costly. In all evaluated scenarios, SBRT was preferred as salvage therapy for local progression after RFA. Probabilistic sensitivity analysis showed that at a willingness-to-pay threshold of $100 000 per QALY gained, RFA-SBRT was preferred in 65.8% of simulations. Conclusion SBRT for initial treatment of localized, inoperable HCC is not cost-effective. However, SBRT is the preferred salvage therapy for local progression after RFA. © RSNA, 2017 Online supplemental material is available for this article.


Assuntos
Carcinoma Hepatocelular/economia , Carcinoma Hepatocelular/mortalidade , Ablação por Cateter/economia , Neoplasias Hepáticas/economia , Neoplasias Hepáticas/mortalidade , Radiocirurgia/economia , Ablação por Cateter/mortalidade , Ablação por Cateter/estatística & dados numéricos , Simulação por Computador , Análise Custo-Benefício/economia , Custos de Cuidados de Saúde/estatística & dados numéricos , Humanos , Cadeias de Markov , Modelos Econômicos , Complicações Pós-Operatórias/economia , Complicações Pós-Operatórias/mortalidade , Prevalência , Prognóstico , Modelos de Riscos Proporcionais , Lesões por Radiação/economia , Lesões por Radiação/mortalidade , Radiocirurgia/mortalidade , Radiocirurgia/estatística & dados numéricos , Reprodutibilidade dos Testes , Medição de Risco/métodos , Sensibilidade e Especificidade , Taxa de Sobrevida , Estados Unidos/epidemiologia
13.
Med Phys ; 42(4): 1606-13, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25832051

RESUMO

PURPOSE: To measure radiation dose in a water-equivalent medium from very high-energy electron (VHEE) beams and make comparisons to Monte Carlo (MC) simulation results. METHODS: Dose in a polystyrene phantom delivered by an experimental VHEE beam line was measured with Gafchromic films for three 50 MeV and two 70 MeV Gaussian beams of 4.0-6.9 mm FWHM and compared to corresponding MC-simulated dose distributions. MC dose in the polystyrene phantom was calculated with the EGSnrc/BEAMnrc and DOSXYZnrc codes based on the experimental setup. Additionally, the effect of 2% beam energy measurement uncertainty and possible non-zero beam angular spread on MC dose distributions was evaluated. RESULTS: MC simulated percentage depth dose (PDD) curves agreed with measurements within 4% for all beam sizes at both 50 and 70 MeV VHEE beams. Central axis PDD at 8 cm depth ranged from 14% to 19% for the 5.4-6.9 mm 50 MeV beams and it ranged from 14% to 18% for the 4.0-4.5 mm 70 MeV beams. MC simulated relative beam profiles of regularly shaped Gaussian beams evaluated at depths of 0.64 to 7.46 cm agreed with measurements to within 5%. A 2% beam energy uncertainty and 0.286° beam angular spread corresponded to a maximum 3.0% and 3.8% difference in depth dose curves of the 50 and 70 MeV electron beams, respectively. Absolute dose differences between MC simulations and film measurements of regularly shaped Gaussian beams were between 10% and 42%. CONCLUSIONS: The authors demonstrate that relative dose distributions for VHEE beams of 50-70 MeV can be measured with Gafchromic films and modeled with Monte Carlo simulations to an accuracy of 5%. The reported absolute dose differences likely caused by imperfect beam steering and subsequent charge loss revealed the importance of accurate VHEE beam control and diagnostics.


Assuntos
Simulação por Computador , Elétrons , Dosimetria Fotográfica , Método de Monte Carlo , Imagens de Fantasmas , Doses de Radiação , Poliestirenos , Incerteza , Água
14.
Ann Surg Oncol ; 20(12): 3999-4007, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-23800897

RESUMO

PURPOSE: The optimal combination and timing of therapy for esophageal cancer remains controversial. The Surveillance, Epidemiology, and End Results (SEER)-Medicare registry was used to assess neoadjuvant and adjuvant therapy. METHODS: Patients diagnosed with nonmetastatic T3+ or N1+ esophageal adenocarcinoma (ACA) or squamous cell carcinoma (SCC) from 1995 to 2002 who underwent surgical resection within 6 months of diagnosis were studied. Medicare data defined preoperative chemoradiotherapy (preCRT), preoperative radiotherapy (preRT), postoperative CRT (postCRT), chemotherapy and surgery (CT + S), and surgery alone. RESULTS: Of 419 eligible patients, 126 received preCRT, 55 preRT, 40 postCRT, 29 CT + S, and 169 surgery alone. PreCRT yielded median overall survival (OS) of 37 months, greater than surgery alone (17 months, p = 0.002) and postCRT (17 months, p = 0.06). PreRT (20 months, p = 0.20), postCRT (p = 0.88), and CT + S (20 months, p = 0.42) were not associated with OS benefit versus surgery alone. For SCC, preCRT improved survival versus surgery alone (p = 0.01), with a trend for ACA (p = 0.07). ACA (22 months) had greater OS than SCC (17 months) (p = 0.03). ACA, younger age, and married status were associated with increased OS. Adjusting for these, preCRT had longer OS versus surgery alone (p = 0.02) and postCRT (p = 0.03). Chemotherapy agents and surgical approach did not affect OS. CONCLUSIONS: In the SEER-Medicare cohort, preCRT significantly improved survival versus surgery alone and postCRT for locally advanced esophageal cancer, particularly for SCC. PreRT, postCRT, and CT + S were not associated with longer survival.


Assuntos
Adenocarcinoma/terapia , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Carcinoma de Células Escamosas/terapia , Quimiorradioterapia , Neoplasias Esofágicas/terapia , Esofagectomia , Adenocarcinoma/mortalidade , Idoso , Carcinoma de Células Escamosas/mortalidade , Estudos de Coortes , Terapia Combinada , Neoplasias Esofágicas/mortalidade , Feminino , Seguimentos , Humanos , Masculino , Medicare , Terapia Neoadjuvante , Prognóstico , Programa de SEER , Taxa de Sobrevida , Estados Unidos
15.
Cancer ; 118(4): 1119-29, 2012 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-21773972

RESUMO

BACKGROUND: Radiotherapy may improve the outcome of patients with pancreatic cancer but at an increased cost. In this study, the authors evaluated the cost-effectiveness of modern radiotherapy techniques in the treatment of locally advanced pancreatic cancer. METHODS: A Markov decision-analytic model was constructed to compare the cost-effectiveness of 4 treatment regimens: gemcitabine alone, gemcitabine plus conventional radiotherapy, gemcitabine plus intensity-modulated radiotherapy (IMRT); and gemcitabine with stereotactic body radiotherapy (SBRT). Patients transitioned between the following 5 health states: stable disease, local progression, distant failure, local and distant failure, and death. Health utility tolls were assessed for radiotherapy and chemotherapy treatments and for radiation toxicity. RESULTS: SBRT increased life expectancy by 0.20 quality-adjusted life years (QALY) at an increased cost of $13,700 compared with gemcitabine alone (incremental cost-effectiveness ratio [ICER] = $69,500 per QALY). SBRT was more effective and less costly than conventional radiotherapy and IMRT. An analysis that excluded SBRT demonstrated that conventional radiotherapy had an ICER of $126,800 per QALY compared with gemcitabine alone, and IMRT had an ICER of $1,584,100 per QALY compared with conventional radiotherapy. A probabilistic sensitivity analysis demonstrated that the probability of cost-effectiveness at a willingness to pay of $50,000 per QALY was 78% for gemcitabine alone, 21% for SBRT, 1.4% for conventional radiotherapy, and 0.01% for IMRT. At a willingness to pay of $200,000 per QALY, the probability of cost-effectiveness was 73% for SBRT, 20% for conventional radiotherapy, 7% for gemcitabine alone, and 0.7% for IMRT. CONCLUSIONS: The current results indicated that IMRT in locally advanced pancreatic cancer exceeds what society considers cost-effective. In contrast, combining gemcitabine with SBRT increased clinical effectiveness beyond that of gemcitabine alone at a cost potentially acceptable by today's standards.


Assuntos
Neoplasias Pancreáticas/patologia , Neoplasias Pancreáticas/radioterapia , Radiocirurgia/economia , Radioterapia de Intensidade Modulada/economia , Radioterapia/economia , Índice de Gravidade de Doença , Idoso , Idoso de 80 Anos ou mais , Antimetabólitos Antineoplásicos/uso terapêutico , Terapia Combinada , Análise Custo-Benefício , Desoxicitidina/análogos & derivados , Desoxicitidina/uso terapêutico , Humanos , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Neoplasias Pancreáticas/tratamento farmacológico , Qualidade de Vida , Anos de Vida Ajustados por Qualidade de Vida , Taxa de Sobrevida , Resultado do Tratamento , Gencitabina
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