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1.
J Cancer Educ ; 35(1): 105-111, 2020 02.
Artículo en Inglés | MEDLINE | ID: mdl-30467774

RESUMEN

Radiation therapy (RT) is an effective treatment modality for hepatocellular carcinoma (HCC), but globally, it is underutilized. In Russia, practice patterns with regard to liver-directed radiation are unknown. Under the auspices of Russian Society of Clinical Oncology (RUSSCO), our team conducted an IRB-approved contouring workshop for Russian radiation oncologists. Pre- and post-workshop surveys were analyzed to determine baseline clinical experience and patterns of care for liver-directed RT among Russian providers. The effect of the contouring workshop on participants' knowledge was tested using mixed effects model. Forty pre-workshop and 24 post-workshop questionnaires were analyzable with a 100% response rate. Sixty percent of respondents had never evaluated a patient with HCC and only 8% (3 out of 40) reported treating an HCC patient with liver-directed RT. Nonetheless, 73% of respondents were comfortable offering liver-directed RT prior to the workshop. After the workshop, 85% of respondents felt comfortable treating a patient with HCC with liver-directed RT and 50% were comfortable recommending stereotactic body radiation therapy (SBRT). Measures of knowledge pertaining to evaluation of HCC patients and selection for appropriate liver-directed therapies were dramatically improved after the workshop. Liver-directed RT is not commonly used in Russia in the management of patients with HCC, and few centers are equipped for motion management. Our contouring workshop resulted in dramatically improved understanding of the evaluation and management of HCC patients. We recommend starting with a more protracted fractionated RT and building experience through attendance of additional educational activities, participation in multidisciplinary liver tumor boards, and prospective analysis of treatment toxicity and outcomes.


Asunto(s)
Carcinoma Hepatocelular/radioterapia , Competencia Clínica , Neoplasias Hepáticas/radioterapia , Guías de Práctica Clínica como Asunto/normas , Pautas de la Práctica en Medicina/normas , Oncología por Radiación/educación , Carcinoma Hepatocelular/epidemiología , Carcinoma Hepatocelular/patología , Manejo de la Enfermedad , Humanos , Neoplasias Hepáticas/epidemiología , Neoplasias Hepáticas/patología , Oncólogos de Radiación , Radiocirugia/métodos , Federación de Rusia/epidemiología , Encuestas y Cuestionarios , Resultado del Tratamiento
2.
J Cancer Educ ; 34(5): 871-873, 2019 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-29938298

RESUMEN

Radiation oncologists in Russia face a number of unique professional difficulties including lack of standardized training and continuing medical education. To combat this, under the auspices of the Russian Society of Clinical Oncology (RUSSCO), our group has developed a series of ongoing in-person interactive contouring workshops that are held during the major Russian oncology conferences in Moscow, Russia. Since November 2016 during each workshop, we utilized a web-based open-access interactive three-dimensional contouring atlas as part of our didactics. We sought to determine the impact of this resource on radiation oncology practice in Russia. We distributed an IRB-approved web-based survey to 172 practicing radiation oncologists in Russia. We inquired about practice demographics, RUSSCO contouring workshop attendance, and the clinical use of open-access English language interactive contouring atlas (eContour). The survey remained open for 2 months until November 2017. Eighty radiation oncologists completed the survey with a 46.5% response rate. Mean number of years in practice was 13.7. Sixty respondents (75%) attended at least one RUSSCO contouring workshop. Of those who were aware of eContour, 76% were introduced during a RUSSCO contouring workshop, and 81% continue to use it in their daily practice. The greatest obstacles to using the program were language barrier (51%) and internet access (38%). Nearly 90% reported their contouring practices changed since they started using the program, particularly for delineation of clinical target volumes (57%) and/or organs at risk (46%). More than 97% found the clinical pearls/links to cooperative group protocols in the software helpful in their daily practice. The majority used the contouring program several times per month (43%) or several times per week (41%). Face-to-face contouring instruction in combination with open-access web-based interactive contouring resource had a meaningful impact on perceived quality of radiation oncology contours among Russian practitioners and has the potential to have applications worldwide.


Asunto(s)
Anatomía/educación , Internet/estadística & datos numéricos , Neoplasias/radioterapia , Órganos en Riesgo/anatomía & histología , Guías de Práctica Clínica como Asunto/normas , Oncólogos de Radiación/educación , Oncología por Radiación/educación , Competencia Clínica , Humanos , Neoplasias/diagnóstico por imagen , Neoplasias/patología , Órganos en Riesgo/diagnóstico por imagen , Pautas de la Práctica en Medicina/normas , Federación de Rusia , Encuestas y Cuestionarios
3.
J Chem Phys ; 140(16): 164508, 2014 Apr 28.
Artículo en Inglés | MEDLINE | ID: mdl-24784288

RESUMEN

In a wide range of P-T conditions, such fundamental characteristics as compressibility and thermoelastic properties remain unknown for most classes of organic compounds. Here we attempt to clarify this issue by the example of naphthalene as a model representative of polycyclic aromatic hydrocarbons (PAHs). The elastic behavior of solid naphthalene was studied by in situ synchrotron powder X-ray diffraction up to 13 GPa and 773 K and first principles computations to 20 GPa and 773 K. Fitting of the P-V experimental data to Vinet equation of state yielded T 0 = 8.4(3) GPa and T' = 7.2 (3) at V0 = 361 Å(3), whereas the thermal expansion coefficient was found to be extremely low at P > 3 GPa (about 10(-5) K(-1)), in agreement with theoretical estimation. Such a diminishing of thermal effects with the pressure increase clearly demonstrates a specific feature of the high-pressure behavior of molecular crystals like PAHs, associated with a low energy of intermolecular interactions.

4.
Int J Gynecol Cancer ; 23(8): 1520-7, 2013 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-24257567

RESUMEN

PURPOSE: In this prospective study, symptoms were assessed in patients with locally advanced cervical cancer undergoing concurrent chemoradiotherapy (CTRT) with either weekly cisplatin (WP) or every-3-week cisplatin/5-fluorouracil (PF). MATERIALS AND METHODS: Patients with 1994 International Federation of Gynecology and Obstetrics stage IIB to IVA disease, biopsy-proven involved pelvic nodes, or gross tumor size greater than 5 cm were eligible. Patients requiring paraaortic radiotherapy were excluded. With the use of a modified Edmonton Symptom Assessment Scale, patients reported symptom severity on an 11-point scale 3 times per week during CTRT and at the first follow-up. The Wilcoxon rank sum test and multilevel mixed-effects linear regression were used to assess the effect of chemotherapy regimen on symptoms. RESULTS: Among the 52 patients included in the final analysis, 37 received WP, 13 received PF, and 2 received 1 cycle of PF followed by WP. Overall compliance with completion of Edmonton Symptom Assessment Scale questionnaires was 75%. There were significant differences in symptom scores for well-being, anorexia, fatigue, diarrhea, and stomatitis favoring the WP regimen. All symptoms except diarrhea were stable and of low intensity in the WP group. In the PF group, symptoms had a cyclical pattern with an initial rise followed by a gradual fall during the 3-week period after chemotherapy. For the 29 patients (56%) who completed the follow-up surveys, scores for all symptoms improved to baseline levels 4 to 6 weeks after treatment. CONCLUSIONS: This analysis provides important patient-reported data regarding the rates and timing of acute symptoms during CTRT that can help clinicians better manage symptoms that impact patients' quality of life.


Asunto(s)
Antimetabolitos Antineoplásicos/efectos adversos , Carcinoma/tratamiento farmacológico , Cisplatino/efectos adversos , Fluorouracilo/efectos adversos , Neoplasias del Cuello Uterino/tratamiento farmacológico , Adulto , Anciano , Anorexia/inducido químicamente , Antimetabolitos Antineoplásicos/administración & dosificación , Ansiedad/inducido químicamente , Carcinoma/radioterapia , Quimioradioterapia/efectos adversos , Cisplatino/administración & dosificación , Depresión/inducido químicamente , Diarrea/inducido químicamente , Fatiga/inducido químicamente , Femenino , Fluorouracilo/administración & dosificación , Humanos , Persona de Mediana Edad , Náusea/inducido químicamente , Dolor/inducido químicamente , Estudios Prospectivos , Estomatitis/inducido químicamente , Neoplasias del Cuello Uterino/radioterapia , Adulto Joven
5.
Brachytherapy ; 22(6): 716-727, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37704540

RESUMEN

PURPOSE: The global cervical cancer burden is disproportionately high in low- and middle-income countries (LMICs), and outcomes can be governed by the accessibility of appropriate screening and treatment. High-dose-rate (HDR) brachytherapy plays a central role in cervical cancer treatment, improving local control and overall survival. The American Brachytherapy Society (ABS) and Indian Brachytherapy Society (IBS) collaborated to provide this succinct consensus statement guiding the establishment of brachytherapy programs for gynecological malignancies in resource-limited settings. METHODS AND MATERIALS: ABS and IBS members with expertise in brachytherapy formulated this consensus statement based on their collective clinical experience in LMICs with varying levels of resources. RESULTS: The ABS and IBS strongly encourage the establishment of HDR brachytherapy programs for the treatment of gynecological malignancies. With the consideration of resource variability in LMICs, we present 15 minimum component requirements for the establishment of such programs. Guidance on these components, including discussion of what is considered to be essential and what is considered to be optimal, is provided. CONCLUSIONS: This ABS/IBS consensus statement can guide the successful and safe establishment of HDR brachytherapy programs for gynecological malignancies in LMICs with varying levels of resources.


Asunto(s)
Braquiterapia , Neoplasias de los Genitales Femeninos , Neoplasias del Cuello Uterino , Femenino , Humanos , Estados Unidos , Braquiterapia/métodos , Neoplasias del Cuello Uterino/radioterapia , Neoplasias del Cuello Uterino/patología , Países en Desarrollo , Neoplasias de los Genitales Femeninos/radioterapia , Dosificación Radioterapéutica
6.
J Appl Crystallogr ; 55(Pt 5): 1368-1376, 2022 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-36249509

RESUMEN

This contribution shares experience of teaching an interdisciplinary university course in crystal growth with examples ranging from geology to biology. This is an attempt to combine teaching the basics of the classical and non-classical theories of crystallization with impressive examples of crystals growing around us and in the human body, as well as demonstration of the common phenomena in the growth of minerals in nature, crystalline materials in industry and the laboratory, and biomimetic and stimulus-responsive crystals. Lectures are supported by laboratory exercises. Students can also perform an individual research project and present an oral contribution at a mini-conference. Examples of the topics considered in the course are given, and an extensive list of references to papers and web resources is provided, which may be useful to those who want to implement anything from the authors' experience.

7.
Chemphyschem ; 12(13): 2476-84, 2011 Sep 12.
Artículo en Inglés | MEDLINE | ID: mdl-21717564

RESUMEN

Experimental data on the pressure dependence of unit cell parameters for the gas hydrates of ethane (cubic structure I, pressure range 0-2 GPa), xenon (cubic structure I, pressure range 0-1.5 GPa) and the double hydrate of tetrahydrofuran+xenon (cubic structure II, pressure range 0-3 GPa) are presented. Approximation of the data using the cubic Birch-Murnaghan equation, P=1.5B(0)[(V(0)/V)(7/3)-(V(0)/V)(5/3)], gave the following results: for ethane hydrate V(0)=1781 Å(3) , B(0)=11.2 GPa; for xenon hydrate V(0)=1726 Å(3) , B(0)=9.3 GPa; for the double hydrate of tetrahydrofuran+xenon V(0)=5323 Å(3) , B(0)=8.8 GPa. In the last case, the approximation was performed within the pressure range 0-1.5 GPa; it is impossible to describe the results within a broader pressure range using the cubic Birch-Murnaghan equation. At the maximum pressure of the existence of the double hydrate of tetrahydrofuran+xenon (3.1 GPa), the unit cell volume was 86% of the unit cell volume at zero pressure. Analysis of the experimental data obtained by us and data available from the literature showed that 1) the bulk modulus of gas hydrates with classical polyhedral structures, in most cases, are close to each other and 2) the bulk modulus is mainly determined by the elasticity of the hydrogen-bonded water framework. Variable filling of the cavities with guest molecules also has a substantial effect on the bulk modulus. On the basis of the obtained results, we concluded that the bulk modulus of gas hydrates with classical polyhedral structures and existing at pressures up to 1.5 GPa was equal to (9±2) GPa. In cases when data on the equations of state for the hydrates were unavailable, the indicated values may be recommended as the most probable ones.


Asunto(s)
Gases/química , Agua/química , Etano/química , Furanos/química , Presión , Temperatura , Xenón/química
8.
Curr Oncol Rep ; 13(3): 157-67, 2011 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-21365188

RESUMEN

The optimal treatment strategy for esophageal cancer continues to be a topic of debate. Improvements in chemotherapy drugs, surgical techniques, and radiotherapy planning and delivery have led to the design of treatment approaches that are specific to both the stage of the tumor and the overall performance status of the patient. Surgery continues to be the standard treatment option for localized disease, but multimodality treatments that include radiation and chemotherapy with surgery are increasingly used. The next few years will continue to see improvements in radiation techniques, especially proton beam treatment; the development of additional minimally invasive surgical approaches to minimize postoperative side effects; and the discovery of molecular biomarkers to help specifically target treatment of esophageal cancer in individual patients.


Asunto(s)
Neoplasias Esofágicas/terapia , Técnicas de Ablación/métodos , Quimioterapia Adyuvante/métodos , Ensayos Clínicos como Asunto , Terapia Combinada , Neoplasias Esofágicas/patología , Neoplasias Esofágicas/cirugía , Humanos , Ganglios Linfáticos/patología , Estadificación de Neoplasias , Terapia de Protones
9.
Brachytherapy ; 20(5): 1041-1052, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34229964

RESUMEN

Skin cancer is the most prevalent malignancy, and its incidence is rising. Surgery is the primary treatment, however, morbidity of surgical resection in certain parts of the body warrant alternate treatment options such as radiation therapy. Complex topology of the skin can pose a challenge for treatment with photon and electron external beam radiotherapy techniques. Brachytherapy can be an attractive radiotherapy technique for these regions. Furthermore, brachytherapy results in lower dose to the underlying deep organs. The goal of this manuscript is to provide a brief overview of the role of brachytherapy for skin malignancies and to outline potential acute and long-term toxicities.


Asunto(s)
Braquiterapia , Traumatismos por Radiación , Braquiterapia/métodos , Humanos , Incidencia , Traumatismos por Radiación/etiología , Dosificación Radioterapéutica
10.
Pract Radiat Oncol ; 10(1): 8-20, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-31831330

RESUMEN

PURPOSE: This guideline reviews the evidence for the use of definitive and postoperative radiation therapy (RT) in patients with basal cell carcinoma (BCC) and cutaneous squamous cell carcinoma (cSCC). METHODS: The American Society for Radiation Oncology convened a task force to address 5 key questions focused on indications for RT in the definitive and postoperative setting for BCC and cSCC, as well as dose-fractionation schemes, target volumes, basic aspects of treatment planning, choice of radiation modality, and the role of systemic therapy in combination with radiation. Recommendations were based on a systematic literature review and created using a predefined consensus-building methodology and system for grading evidence quality and recommendation strength. RESULTS: The guideline recommends definitive RT as primary treatment for patients with BCC and cSCC who are not surgical candidates while conditionally recommending RT with an emphasis on shared decision-making in those situations in which adequate resection can lead to a less than satisfactory cosmetic or functional outcome. In the postoperative setting, a number of indications for RT after an adequate resection are provided while distinguishing the strength of the recommendations between BCC and cSCC. One key question is dedicated to defining indications for regional nodal irradiation. The task force suggests a range of appropriate dose-fractionation schemes for treatment of primary and nodal volumes in definitive and postoperative scenarios. The guideline also recommends against the use of carboplatin concurrently with adjuvant RT and conditionally recommends the use of systemic therapies for unresectable primaries where treatment may need escalation. CONCLUSIONS: Defining the role of RT in the management of BCC and cSCC has been hindered by a lack of high-quality evidence. This document synthesizes available evidence to define practice guidelines for the most common clinical situations. We encourage practitioners to enroll patients in prospective trials and to approach care in a multidisciplinary fashion whenever possible.


Asunto(s)
Carcinoma Basocelular/terapia , Carcinoma de Células Escamosas/terapia , Medicina Basada en la Evidencia/normas , Oncología por Radiación/normas , Neoplasias Cutáneas/terapia , Fraccionamiento de la Dosis de Radiación , Medicina Basada en la Evidencia/métodos , Humanos , Selección de Paciente , Oncología por Radiación/métodos , Planificación de la Radioterapia Asistida por Computador/normas , Radioterapia Adyuvante/métodos , Radioterapia Adyuvante/normas , Sociedades Médicas/normas , Estados Unidos
11.
Appl Spectrosc ; 72(6): 847-852, 2018 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-29258321

RESUMEN

A pressure shift of Raman band of liquid water (H2O) may be an important tool for measuring residual pressures in mineral inclusions, in situ barometry in high-pressure cells, and as an indicator of pressure-induced structural transitions in H2O. However, there was no consensus as to how the broad and asymmetric water Raman band should be quantitatively described, which has led to fundamental inconsistencies between reported data. In order to overcome this issue, we measured Raman spectra of H2O in situ up to 1.2 GPa using a diamond anvil cell, and use them to test different approaches proposed for the description of the water Raman band. We found that the most physically meaningful description of water Raman band is the decomposition into a linear background and three Gaussian components, associated with differently H-bonded H2O molecules. Two of these components demonstrate a pronounced anomaly in pressure shift near 0.4 GPa, supporting ideas of structural transition in H2O at this pressure. The most convenient approach for pressure calibration is the use of "a linear background + one Gaussian" decomposition (the pressure can be measured using the formula P (GPa) = -0.0317(3)·ΔνG (cm-1), where ΔνG represents the difference between the position of water Raman band, fitted as a single Gaussian, in measured spectrum and spectrum at ambient pressure).

12.
JNCI Cancer Spectr ; 2(2): pky022, 2018 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-29905226

RESUMEN

Given the recent emphasis on the totality of the diet by national guidelines, we examined the relationship between the quality of diet and overall and cancer-specific mortality among cancer survivors. From the Third National Health and Nutrition Examination Survey (NHANES III), 1191 participants diagnosed with cancer were identified. Healthy Eating Index (HEI) scores were utilized; higher HEI score indicated better adherence to dietary recommendations. During a median follow-up of 17.2 years, a total of 607 cancer-specific deaths occurred. A high-quality diet (highest-quartile HEI score) was associated with decreased risk of overall (hazard ratio [HR] = 0.59, 95% confidence interval [CI] = 0.45 to 0.77) and cancer-specific (HR = 0.35, 95% CI = 0.19 to 0.63) mortality when compared with a poor-quality diet (lowest-quartile HEI score). Among individual dietary components, the highest-quartile score for saturated fat intake was associated decreased cancer-specific mortality (HR = 0.55, 95% CI = 0.36 to 0.86). Our results highlight the importance of a "total diet" approach to improving survival among cancer patients.

13.
Pract Radiat Oncol ; 8(5): e329-e336, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-29861349

RESUMEN

BACKGROUND: In this study, we sought to examine the variation in intensity modulated radiation therapy (IMRT) use among radiation oncology providers. METHODS AND MATERIALS: The Medicare Physician and Other Supplier Public Use File was queried for radiation oncologists practicing during 2014. Healthcare Common Procedural Coding System code 77301 was designated as IMRT planning with metrics including number of total IMRT plans, rate of IMRT utilization, and number of IMRT plans per distinct beneficiary. RESULTS: Of 2759 radiation oncologists, the median number of total IMRT plans was 26 (mean, 33.4; standard deviation, 26.2; range, 11-321) with a median IMRT utilization rate of 36% (mean, 43%; standard deviation, 25%; range, 4% to 100%) and a median number of IMRT plans per beneficiary of 1.02 (mean, 1.07; range, 1.00-3.73). On multivariable analysis, increased IMRT utilization was associated with male sex, academic practice, technical fee billing, freestanding practice, practice in a county with 21 or more radiation oncologists, and practice in the southern United States (P < .05). The top 1% of users (28 providers) billed a mean 181 IMRT plans with an IMRT utilization rate of 66% and 1.52 IMRT plans per beneficiary. Of these 28 providers, 24 had billed technical fees, 25 practiced in freestanding clinics, and 20 practiced in the South. CONCLUSIONS: Technical fee billing, freestanding practice, male sex, and location in the South were associated with increased IMRT use. A small group of outliers shared several common demographic and practice-based characteristics.


Asunto(s)
Medicare/economía , Neoplasias/radioterapia , Pautas de la Práctica en Medicina/estadística & datos numéricos , Oncología por Radiación/estadística & datos numéricos , Radioterapia de Intensidad Modulada/estadística & datos numéricos , Femenino , Humanos , Reembolso de Seguro de Salud/economía , Reembolso de Seguro de Salud/estadística & datos numéricos , Masculino , Neoplasias/economía , Pautas de la Práctica en Medicina/economía , Oncólogos de Radiación/economía , Oncólogos de Radiación/estadística & datos numéricos , Planificación de la Radioterapia Asistida por Computador , Radioterapia de Intensidad Modulada/economía , Factores Sexuales , Estados Unidos
14.
J Oncol Pract ; 14(8): e513-e516, 2018 08.
Artículo en Inglés | MEDLINE | ID: mdl-30059272

RESUMEN

PURPOSE: Shorter fractionation radiation regimens for palliation of bone metastases result in lower financial and social costs for patients and their caregivers and have similar efficacy as longer fractionation schedules, although practice patterns in the United States show poor adoption. We investigated whether prospective peer review can increase use of shorter fractionation schedules. METHODS: In June 2016, our practice mandated peer review of total dose and fractionation for all patients receiving palliative treatment during our weekly chart rounds. We used descriptive statistics and Fisher's exact test to compare lengths of treatment of uncomplicated bone metastases before and after implementation of the peer review process. RESULTS: Between July 2015 and December 2016, a total of 242 palliative treatment courses were delivered, including 105 courses before the peer review intervention and 137 after the intervention. We observed greater adoption of shorter fractionation regimens after the intervention. The use of 8 Gy in one fraction increased from 2.8% to 13.9% of cases postadoption. Likewise, the use of 20 Gy in five fractions increased from 25.7% to 32.8%. The use of 30 Gy in 10 fractions decreased from 55.2% to 47.4% ( P = .002), and the use of ≥ 11 fractions decreased from 16.2% before the intervention to 5.8% after ( P = .006). CONCLUSION: Prospective peer review of palliative regimens for bone metastases can lead to greater adoption of shorter palliative fractionation schedules in daily practice, in accordance with national guidelines. This simple intervention may therefore benefit patients and their caregivers as well as provide value to the health care system.


Asunto(s)
Neoplasias Óseas/radioterapia , Cuidados Paliativos , Revisión por Pares , Neoplasias Óseas/secundario , Fraccionamiento de la Dosis de Radiación , Humanos , Dolor/radioterapia , Dosificación Radioterapéutica
15.
Int J Radiat Oncol Biol Phys ; 68(5): 1402-9, 2007 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-17467921

RESUMEN

PURPOSE: To report a new technique for the spinal component of craniospinal irradiation (CSI) in the supine position, to describe a verification procedure for this method, and to compare this technique with conventional plans. METHODS AND MATERIALS: Twelve patients were treated between 1998 and 2006 with CSI using a novel technique. Sixteen children were treated with a conventional field arrangement. All patients were followed for outcomes and toxicity. CSI was delivered using a posteroanterior (PA) intensity-modulated radiation therapy (IMRT) spinal field matched to conventional, opposed lateral cranial fields. Treatment plans were generated for each patient using the IMRT technique and a standard PA field technique. The resulting dosimetry was compared to determine target homogeneity, maximum dose to normal tissues, and total monitor units delivered. RESULTS: Evaluation of the spinal IMRT technique compared with a standard PA technique reveals a 7% reduction in the target volume receiving > or =110% of the prescribed dose and an 8% increase in the target volume receiving > or =95% of the prescribed dose. Although target homogeneity was improved, the maximum dose delivered in the paraspinal muscles was increased by approximately 8.5% with spinal IMRT compared to the PA technique. Follow-up evaluations revealed no unexpected toxicity associated with the IMRT technique. CONCLUSIONS: A new technique of spine IMRT is presented in combination with a quality assurance method. This method improves target dose uniformity compared to the conventional CSI technique. Longer follow-up will be required to determine any benefit with regard to toxicity and disease control.


Asunto(s)
Neoplasias Encefálicas/radioterapia , Radioterapia de Intensidad Modulada/métodos , Neoplasias de la Columna Vertebral/radioterapia , Posición Supina , Adolescente , Adulto , Niño , Preescolar , Femenino , Humanos , Masculino , Dosificación Radioterapéutica , Radioterapia de Intensidad Modulada/normas , Médula Espinal/efectos de la radiación , Columna Vertebral/efectos de la radiación
16.
Appl Spectrosc ; 71(8): 1842-1848, 2017 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-28195496

RESUMEN

The increasing demand for use of polymers at extreme conditions makes important the exploration of their behavior in a wide pressure and temperature range, which remains unknown for polytetrafluoroethylene (PTFE), one of the most common materials. An in situ Raman spectroscopic study of PTFE shows that it is stable within the range of 2-6 GPa at 500 ℃ and up to 12 GPa at 400 ℃. At T > 500 ℃ and P > 3.5 GPa, the graphitization of PTFE is observed, but judging from the preservation of liquid run products, PTFE can be used as a material for sample container up to 600 ℃ at this pressure. The obtained data allow the suggestion that the triple point between liquid, solid, and decomposed (carbonized) PTFE is located between 3 and 4 GPa at about 550 ℃, by analogy with the behavior of polycyclic aromatic hydrocarbons.

17.
J Natl Cancer Inst ; 109(11)2017 11 01.
Artículo en Inglés | MEDLINE | ID: mdl-29059428

RESUMEN

Background: Early-stage breast cancer is among the most prevalent and costly malignancies treated in the American health care system. Adjuvant radiotherapy after lumpectomy represents a substantial portion of breast cancer expenditures. The relative value of novel radiotherapeutic approaches such as intraoperative radiotherapy (IORT) and hypofractionated whole breast irradiation (HF-WBI) compared with conventionally fractionated whole breast irradiation (CF-WBI) is unknown. Therefore, we used prospectively collected outcomes from randomized clinical trials (RCTs) to compare the cost-effectiveness of these approaches. Methods: We constructed a decision-analytic model that followed women who were treated with lumpectomy for early-stage breast cancer. Recurrence, mortality, complication rates, and utilities (five-year radiation-associated quality of life scores), were extracted from RCTs. Costs were based on Medicare reimbursement rates. Cost-effectiveness from societal and health care sector perspectives was estimated considering two scenarios-the first assumes that radiation-associated disutility persists five years after treatment, and the second assumes that disutility discontinues. Lifetime outcomes were summarized using incremental cost-effectiveness ratios (ICERs). Deterministic and probabilistic sensitivity analyses evaluated the robustness of the results. Results: HF-WBI dominated CF-WBI (ie, resulted in higher quality-adjusted life-years [QALYs] and lower cost) in all scenarios. HF-WBI also had a greater likelihood of cost-effectiveness compared with IORT; under a societal perspective that assumes that radiation-associated disutility persists, HF-WBI results in an ICER of $17 024 per QALY compared with IORT with a probability of cost-effectiveness of 80% at the $100 000 per QALY willingness-to-pay threshold. If radiation-associated disutility is assumed to discontinue, the ICER is lower ($11 461/QALY), resulting in an even higher (83%) probability of relative cost-effectiveness. The ICER was most sensitive to the probability of metastasis and treatment cost. Conclusions: For women with early-stage breast cancer requiring adjuvant radiotherapy, HF-WBI is cost-effective compared with CF-WBI and IORT.


Asunto(s)
Neoplasias de la Mama/patología , Neoplasias de la Mama/radioterapia , Análisis Costo-Beneficio , Años de Vida Ajustados por Calidad de Vida , Anciano , Neoplasias de la Mama/cirugía , Femenino , Humanos , Cuidados Intraoperatorios , Cadenas de Markov , Mastectomía Segmentaria , Persona de Mediana Edad , Estadificación de Neoplasias , Calidad de Vida , Hipofraccionamiento de la Dosis de Radiación , Radioterapia/economía , Radioterapia Adyuvante/economía , Ensayos Clínicos Controlados Aleatorios como Asunto , Sensibilidad y Especificidad
18.
Brachytherapy ; 16(1): 223-229, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-27908679

RESUMEN

PURPOSE: The aim of this study was to define current patterns of care among radiation oncologists who use skin surface brachytherapy for the treatment of cutaneous squamous cell carcinoma (cSCC) and basal cell carcinoma (BCC) in academic and community settings. METHODS AND MATERIALS: A 30-question electronic survey was administered to clinician members of the American Brachytherapy Society. The respondents were asked to provide details regarding their clinical practice and their approach to skin surface brachytherapy. RESULTS: A total of 16 surveys were returned. Among the respondents, aggregate experience varied from 8 to 1800 cases. Most preferred brachytherapy over external beam radiation because of shorter treatment course, conformality of treatment for irregular or curved targets, and shallow dose deposition. Of the total, 60% of respondents routinely estimated lesion depth via ultrasound before initiating treatment. Treatment margin on gross disease varied widely (range, 3-15 mm; median, 5 mm). Hypofractionation was the preferred dose schedule. Prescribed doses ranged from 30 Gy in five fractions to 64 Gy in 32 fractions (EQD2, 40 Gy-65 Gy). There was a tendency to increase the number of fractions for larger targets, although some used the same fractionation regardless of anatomic location or lesion size. There was no consensus on dosimetric constraints, and some respondents reported cases of severe toxicity, particularly when treating the pretibial skin. CONCLUSIONS: This pattern of care study suggests that skin brachytherapy can be a convenient and safe tool for treatment of BCC and cSCC. Prospective trials and the development of expert consensus guidelines would be beneficial for optimizing skin surface brachytherapy and reducing practice variation.


Asunto(s)
Braquiterapia/métodos , Carcinoma Basocelular/radioterapia , Carcinoma de Células Escamosas/radioterapia , Pautas de la Práctica en Medicina/estadística & datos numéricos , Oncólogos de Radiación , Neoplasias Cutáneas/radioterapia , Braquiterapia/instrumentación , Fraccionamiento de la Dosis de Radiación , Humanos , Estudios Prospectivos , Encuestas y Cuestionarios
19.
Cancer Res ; 64(21): 8085-92, 2004 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-15520220

RESUMEN

In this study, we show that rodent albumin is expressed by and cell surface localized on at least some murine tumor cells. We have been able to purify this tumor-expressed albumin from in vivo grown tumor masses. The tumor-expressed albumin, unlike normal serum albumin purified from blood, is capable of inhibiting T-cell activation, proliferation, and function in both in vitro and in vivo settings. Tumor-expressed albumin does not appear to affect antigen processing or presentation by professional antigen-presenting cells. The activity appears to lie in relatively small, lipid-like moieties that are presumably cargo for tumor-expressed albumin, and that activity can be removed from the albumin by lipid removal or treatment with lipase. Thus, we herein report of a novel form of tumor-induced immune suppression attributable to lipid-like entities, cloaked by albumin produced by tumors.


Asunto(s)
Albúminas/farmacología , Inmunosupresores/farmacología , Activación de Linfocitos/efectos de los fármacos , Proteínas de Neoplasias/farmacología , Linfocitos T/inmunología , Albúminas/química , Albúminas/aislamiento & purificación , Animales , Lípidos/farmacología , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Factor de Crecimiento Transformador beta/inmunología
20.
Int J Radiat Oncol Biol Phys ; 95(2): 605-16, 2016 06 01.
Artículo en Inglés | MEDLINE | ID: mdl-27034179

RESUMEN

PURPOSE: Older women with early-stage disease constitute the most rapidly growing breast cancer demographic, yet it is not known which local therapy strategies are most favored by this population in the current era. Understanding utilization trends and cost of local therapy is important for informing the design of bundled payment models as payers migrate away from fee-for-service models. We therefore used the Surveillance, Epidemiology, and End Results Medicare database to determine patterns of care and costs for local therapy among older women with breast cancer. METHODS AND MATERIALS: Treatment strategy and covariables were determined in 55,327 women age ≥66 with Tis-T2N0-1M0 breast cancer who underwent local therapy between 2000 and 2008. Trends in local therapy were characterized using Joinpoint. Polychotomous logistic regression determined predictors of local therapy. The median aggregate cost over the first 24 months after diagnosis was determined from Medicare claims through 2010 and reported in 2014 dollars. RESULTS: The median age was 75. Local therapy distribution was as follows: 27,896 (50.3%) lumpectomy with external beam radiation, 18,356 (33.1%) mastectomy alone, 6159 (11.1%) lumpectomy alone, 1488 (2.7%) mastectomy with reconstruction, and 1455 (2.6%) lumpectomy with brachytherapy. Mastectomy alone declined from 39.0% in 2000 to 28.2% in 2008, and the use of breast conserving local therapies rose from 58.7% to 68.2%. Mastectomy with reconstruction was more common among the youngest, healthiest patients, whereas mastectomy alone was more common among patients living in rural low-income regions. By 2008, the costs were $36,749 for lumpectomy with brachytherapy, $35,030 for mastectomy with reconstruction, $31,388 for lumpectomy with external beam radiation, $21,993 for mastectomy alone, and $19,287 for lumpectomy alone. CONCLUSIONS: The use of mastectomy alone in older women declined in favor of breast conserving strategies between 2000 and 2008. Using these cost estimates, price points for local therapy bundles can be constructed to incentivize the treatment strategies that confer the highest value.


Asunto(s)
Neoplasias de la Mama/terapia , Costos de la Atención en Salud , Anciano , Anciano de 80 o más Años , Neoplasias de la Mama/economía , Terapia Combinada , Femenino , Humanos , Modelos Logísticos , Mastectomía/economía , Mastectomía Segmentaria/economía , Medicare , Receptores de Estrógenos/análisis , Programa de VERF , Estados Unidos
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