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1.
Cancer ; 128(10): 1967-1975, 2022 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-35157302

RESUMO

BACKGROUND: Little is known about how screening facilities are meeting the requirements for the reimbursement of lung cancer screening from the Centers for Medicare & Medicaid Services (CMS), including 1) the collection and submission of data to the CMS-approved registry (American College of Radiology [ACR] Lung Cancer Screening Registry), 2) the verification of a counseling and shared decision-making (SDM) visit having occurred as part of the written order for lung cancer screening with low-dose computed tomography, and 3) the offering of smoking cessation interventions. METHODS: The authors identified facilities in a southwestern state that were listed by either the ACR Lung Cancer Screening Registry or the GO2 Foundation Centers of Excellence. To select facilities, they used 2 purposive sampling approaches: maximum variation sampling and snowball sampling. They surveyed facilities from February to November 2019. RESULTS: There were 87 facilities contacted, and a total of 63 facilities representing 32 counties across Texas completed the survey. Nearly all facilities used Lung-RADS to classify nodules (92%; n = 58) and submitted data to a CMS-approved registry (92%; n = 57). Most facilities verified that the counseling and SDM visit had occurred (86%; n = 54). Although slightly more than half of the facilities reported always providing self-help cessation materials (68%; n = 42), similar or higher proportions of facilities reported that they never referred smokers to onsite cessation services (68%; n = 42) or quitlines (77%; n = 47), provided cessation counseling (81%; n = 50), or recommended medications (85%; n = 52). CONCLUSIONS: In general, screening facilities are meeting CMS requirements for screening, but they are struggling to offer smoking cessation interventions other than providing self-help materials.


Assuntos
Neoplasias Pulmonares , Abandono do Hábito de Fumar , Idoso , Estudos Transversais , Detecção Precoce de Câncer/métodos , Humanos , Neoplasias Pulmonares/diagnóstico por imagem , Medicare , Abandono do Hábito de Fumar/métodos , Tomografia Computadorizada por Raios X/métodos , Estados Unidos/epidemiologia
2.
Int J Radiat Oncol Biol Phys ; 95(1): 505-516, 2016 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-27084663

RESUMO

Radiation dose escalation has been shown to improve local control and survival in patients with non-small cell lung cancer in some studies, but randomized data have not supported this premise, possibly owing to adverse effects. Because of the physical characteristics of the Bragg peak, proton therapy (PT) delivers minimal exit dose distal to the target volume, resulting in better sparing of normal tissues in comparison to photon-based radiation therapy. This is particularly important for lung cancer given the proximity of the lung, heart, esophagus, major airways, large blood vessels, and spinal cord. However, PT is associated with more uncertainty because of the finite range of the proton beam and motion for thoracic cancers. PT is more costly than traditional photon therapy but may reduce side effects and toxicity-related hospitalization, which has its own associated cost. The cost of PT is decreasing over time because of reduced prices for the building, machine, maintenance, and overhead, as well as newer, shorter treatment programs. PT is improving rapidly as more research is performed particularly with the implementation of 4-dimensional computed tomography-based motion management and intensity modulated PT. Given these controversies, there is much debate in the oncology community about which patients with lung cancer benefit significantly from PT. The Particle Therapy Co-operative Group (PTCOG) Thoracic Subcommittee task group intends to address the issues of PT indications, advantages and limitations, cost-effectiveness, technology improvement, clinical trials, and future research directions. This consensus report can be used to guide clinical practice and indications for PT, insurance approval, and clinical or translational research directions.


Assuntos
Carcinoma Pulmonar de Células não Pequenas/radioterapia , Consenso , Neoplasias Pulmonares/radioterapia , Terapia com Prótons/métodos , Carcinoma Pulmonar de Células não Pequenas/patologia , Ensaios Clínicos como Assunto , Humanos , Neoplasias Pulmonares/patologia , Movimento , Tratamentos com Preservação do Órgão , Órgãos em Risco/efeitos da radiação , Terapia com Prótons/economia , Lesões por Radiação/prevenção & controle , Planejamento da Radioterapia Assistida por Computador/métodos , Radioterapia de Intensidade Modulada/métodos , Espalhamento de Radiação , Carga Tumoral
3.
Int J Radiat Oncol Biol Phys ; 86(2): 380-6, 2013 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-23462423

RESUMO

PURPOSE: To quantify the impact of respiratory motion on the treatment of lung tumors with spot scanning proton therapy. METHODS AND MATERIALS: Four-dimensional Monte Carlo simulations were used to assess the interplay effect, which results from relative motion of the tumor and the proton beam, on the dose distribution in the patient. Ten patients with varying tumor sizes (2.6-82.3 cc) and motion amplitudes (3-30 mm) were included in the study. We investigated the impact of the spot size, which varies between proton facilities, and studied single fractions and conventionally fractionated treatments. The following metrics were used in the analysis: minimum/maximum/mean dose, target dose homogeneity, and 2-year local control rate (2y-LC). RESULTS: Respiratory motion reduces the target dose homogeneity, with the largest effects observed for the highest motion amplitudes. Smaller spot sizes (σ ≈ 3 mm) are inherently more sensitive to motion, decreasing target dose homogeneity on average by a factor 2.8 compared with a larger spot size (σ ≈ 13 mm). Using a smaller spot size to treat a tumor with 30-mm motion amplitude reduces the minimum dose to 44.7% of the prescribed dose, decreasing modeled 2y-LC from 87.0% to 2.7%, assuming a single fraction. Conventional fractionation partly mitigates this reduction, yielding a 2y-LC of 71.6%. For the large spot size, conventional fractionation increases target dose homogeneity and prevents a deterioration of 2y-LC for all patients. No correlation with tumor volume is observed. The effect on the normal lung dose distribution is minimal: observed changes in mean lung dose and lung V20 are <0.6 Gy(RBE) and <1.7%, respectively. CONCLUSIONS: For the patients in this study, 2y-LC could be preserved in the presence of interplay using a large spot size and conventional fractionation. For treatments using smaller spot sizes and/or in the delivery of single fractions, interplay effects can lead to significant deterioration of the dose distribution and lower 2y-LC.


Assuntos
Neoplasias Pulmonares/radioterapia , Movimento , Terapia com Prótons/métodos , Respiração , Fracionamento da Dose de Radiação , Humanos , Pulmão/fisiopatologia , Neoplasias Pulmonares/patologia , Método de Monte Carlo , Planejamento da Radioterapia Assistida por Computador/métodos , Eficiência Biológica Relativa , Estudos Retrospectivos , Fatores de Tempo , Carga Tumoral
4.
Int J Radiat Oncol Biol Phys ; 70(1): 253-61, 2008 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-17967513

RESUMO

PURPOSE: Water equivalent path length (WEL) variations due to respiration can change the range of a charged particle beam and result in beam overshoot to critical organs or beam undershoot to tumor. We have studied range fluctuations by analyzing four-dimensional computed tomography data and quantitatively assessing potential beam overshoot. METHODS AND MATERIALS: The maximal intensity volume is calculated by combining the gross tumor volume contours at each respiratory phase in the four-dimensional computed tomography study. The first target volume calculates the maximal intensity volume for the entire respiratory cycle (internal target volume [ITV]-radiotherapy [RT]), and the second target volume is the maximal intensity volume corresponding to gated RT (gated-RT, approximately 30% phase window around exhalation). A compensator at each respiratory phase is calculated. Two "composite" compensators for ITV-RT and gated-RT are then designed by selecting the minimal compensator depth at the respective respiratory phase. These compensators are then applied to the four-dimensional computed tomography data to estimate beam penetration. Analysis metrics include range fluctuation and overshoot volume, both as a function of gantry angle. We compared WEL fluctuations observed in treating the ITV-RT versus gated-RT in 11 lung patients. RESULTS: The WEL fluctuations were <21.8 mm-WEL and 9.5 mm-WEL for ITV-RT and gated-RT, respectively for all patients. Gated-RT reduced the beam overshoot volume by approximately a factor of four compared with ITV-RT. Such range fluctuations can affect the efficacy of treatment and result in an excessive dose to a distal critical organ. CONCLUSION: Time varying range fluctuation analysis provides information useful for determining appropriate patient-specific treatment parameters in charged particle RT. This analysis can also be useful for optimizing planning and delivery.


Assuntos
Neoplasias Pulmonares/radioterapia , Movimento , Radioterapia Conformacional/métodos , Respiração , Tomografia Computadorizada por Raios X/métodos , Idoso , Idoso de 80 Anos ou mais , Carcinoma de Células Grandes/patologia , Carcinoma de Células Grandes/radioterapia , Carcinoma Pulmonar de Células não Pequenas/patologia , Carcinoma Pulmonar de Células não Pequenas/radioterapia , Expiração , Feminino , Humanos , Pulmão , Neoplasias Pulmonares/patologia , Masculino , Pessoa de Meia-Idade , Planejamento da Radioterapia Assistida por Computador/métodos , Radioterapia Conformacional/instrumentação , Carga Tumoral
5.
Phys Med Biol ; 51(11): 2763-79, 2006 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-16723765

RESUMO

The purpose of this study is to accurately estimate the difference between the planned and the delivered dose due to respiratory motion and free breathing helical CT artefacts for lung IMRT treatments, and to estimate the impact of this difference on clinical outcome. Six patients with representative tumour motion, size and position were selected for this retrospective study. For each patient, we had acquired both a free breathing helical CT and a ten-phase 4D-CT scan. A commercial treatment planning system was used to create four IMRT plans for each patient. The first two plans were based on the GTV as contoured on the free breathing helical CT set, with a GTV to PTV expansion of 1.5 cm and 2.0 cm, respectively. The third plan was based on the ITV, a composite volume formed by the union of the CTV volumes contoured on free breathing helical CT, end-of-inhale (EOI) and end-of-exhale (EOE) 4D-CT. The fourth plan was based on GTV contoured on the EOE 4D-CT. The prescribed dose was 60 Gy for all four plans. Fluence maps and beam setup parameters of the IMRT plans were used by the Monte Carlo dose calculation engine MCSIM for absolute dose calculation on both the free breathing CT and 4D-CT data. CT deformable registration between the breathing phases was performed to estimate the motion trajectory for both the tumour and healthy tissue. Then, a composite dose distribution over the whole breathing cycle was calculated as a final estimate of the delivered dose. EUD values were computed on the basis of the composite dose for all four plans. For the patient with the largest motion effect, the difference in the EUD of CTV between the planed and the delivered doses was 33, 11, 1 and 0 Gy for the first, second, third and fourth plan, respectively. The number of breathing phases required for accurate dose prediction was also investigated. With the advent of 4D-CT, deformable registration and Monte Carlo simulations, it is feasible to perform an accurate calculation of the delivered dose, and compare our delivered dose with doses estimated using prior techniques.


Assuntos
Neoplasias Pulmonares/radioterapia , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador/métodos , Mecânica Respiratória , Tomografia Computadorizada por Raios X/métodos , Simulação por Computador , Humanos , Imageamento Tridimensional , Neoplasias Pulmonares/patologia , Método de Monte Carlo , Movimento/fisiologia
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