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Recent studies suggest cancer therapy may compromise bone integrity. What is the rate of vertebral fractures among patients who have received trimodality therapy (radiation, chemotherapy, and surgery) for locally advanced esophageal cancer? This single-institution, retrospective study attempted to answer this question, focusing on 337 patients who had received trimodality therapy for locally advanced esophageal cancer between 1996 and 2005. Reports of serial radiographs were reviewed to identify vertebral fractures. Duration of follow-up was gathered for all esophageal cancer patients with the intention of calculating fracture incidence rates. Fracture-related symptoms, types of intervention and fracture recurrence were also gleaned from the clinical records. First-time fractures were identified in 47 patients, and 45 of these were new since the cancer diagnosis. Thus, the first-time fracture incidence rate from the time of cancer diagnosis was 12 fractures per 100 patient years. The median time from cancer diagnosis to fracture was 9 months. Fifteen (33%) patients were symptomatic. Acknowledging that a retrospective study can inadvertently result in information omission, we report that pain medications were started in only seven patients (16%), and osteoporosis medication in only six (13%). Two patients were hospitalized, and two underwent vertebroplasty. The median survival after fracture diagnosis was 36 months. This report describes a seemingly high fracture incidence rate that requires confirmation. If confirmed, future studies should focus on identifying risk factors and optimal strategies for the prevention and treatment of vertebral fractures in patients with esophageal cancer. [ABSTRACT FROM AUTHOR]

Combining different treatment modalities – such as surgery, radiation, and chemotherapy – is often utilized to treat patients with locally advanced esophageal cancer. However, it remains controversial how best to combine these modalities to provide patients with the greatest chance of cure. This review discusses recent studies in this field and outlines promising versus less promising therapeutic strategies. [ABSTRACT FROM AUTHOR]

Intraoperative radiotherapy (IORT) allows delivery of radiotherapy doses in excess of those typically deliverable with conventional external beam radiotherapy. IORT has potential utility in clinical situations, such as treatment of esophageal and gastric malignancies, in which the radiation tolerance of normal organs limits the dose that can be given with conventional radiotherapy techniques. We reviewed the records of 50 patients who received IORT for locally advanced primary or recurrent gastric or esophageal adenocarcinomas deemed unresectable for cure. IORT was given as a single fraction of electron beam radiotherapy (10–25 Gy) after maximal tumor resection: R0 in 42%, R1 in 46%, and R2 in 12%. Forty-eight patients also received external beam radiotherapy (8–55 Gy), 46 received radiosensitizing chemotherapy, and nine received systemic chemotherapy after radiotherapy. Outcomes were estimated with Kaplan-Meier analysis. Median survival was 1.6 years. Overall survival at 1, 2, and 3 years was 70%, 40%, and 27%. Of 42 patients who died, 37 died from cancer progression and three from multifactorial treatment toxicity. Median survival for patients with recurrent disease versus primary disease was 3.0 years versus 1.3 years ( P < 0.05), with a delay of metastatic failure in patients with recurrent tumors ( P = 0.06). At 3 years, distant metastatic failure was 79%, local failure was 10%, and regional failure was 15%. IORT for locally advanced primary or recurrent gastric malignancies effectively decreases the risk of local failure. For patients with isolated local recurrences, IORT may be effective salvage therapy. However, more effective systemic therapy is needed as a component of treatment. [ABSTRACT FROM AUTHOR]

Purpose: Occupational exposure to neutrons typically includes significant doses of low-energy neutrons, with energies below 100keV. In addition, the normal-tissue dose from boron neutron capture therapy will largely be from low-energy neutrons. Microdosimetric theory predicts decreasing biological effectiveness for neutrons with energies below about 350keV compared with that for higher-energy neutrons; based on such considerations, and limited biological data, the current radiation weighting factor (quality factor) for neutrons with energies from 10keV to 100keV is less than that for higher-energy neutrons. By contrast, some reports have suggested that the biological effectiveness of low-energy neutrons is similar to that of fast neutrons. The purpose of the current work is to assess the relative biological effectiveness of low-energy neutrons for an endpoint of relevance to carcinogenesis: in vitro oncogenic transformation. Methods: Oncogenic transformation induction frequencies were determined for C3H10T1/2 cells exposed to two low-energy neutron beams, respectively, with dose-averaged energies of 40 and 70keV, and the results were compared with those for higher-energy neutrons and X-rays. Results: These results for oncogenic transformation provide evidence for a significant decrease in biological effectiveness for 40keV neutrons compared with 350keV neutrons. The 70 keV neutrons were intermediate in effectiveness between the 70 and 350keV beams. Conclusions: A decrease in biological effectiveness for low-energy neutrons is in agreement with most (but not all) earlier biological studies, as well as microdosimetric considerations. The results for oncogenic transformation were consistent with the currently recommended decreased values for low-energy neutron radiation weighting factors compared with fast neutrons. [ABSTRACT FROM AUTHOR]

Low-temperature excitation and photoluminescence spectra are described for single GaAs/Al0.37Ga0.63As quantum wells grown by molecular beam epitaxy with and without a 2-min interruption of growth at the heterointerfaces. The spectra from samples grown with interruption include well-resolved multiple sharp peaks which are due to changes in well thickness of one monolayer and to bound excitons. These peaks are as narrow as 1.0, 1.7, and 6.0 meV for single wells of width 57, 28, and 17 Å, respectively. [ABSTRACT FROM AUTHOR]

High quality GaAs/AlxGa1-xAs single and multiquantum well heterostructures were grown for the first time by chemical beam epitaxy. Studies using low-temperature photoluminescence and excitation spectroscopy techniques show that on the average these samples are similar in quality to similar structures from this laboratory grown by molecular beam epitaxy (MBE) and in certain specific characteristics superior to the MBE ones. Furthermore, in some important respects, they are also superior to those grown by organometallic chemical vapor deposition (OMCVD). The very small red shifts observed between emission and n=1 exciton transition E1h with continuous growth show that the emission is dominated by E1h excitons. An interface roughness of δL<=±a/2, where a is the lattice constant, and very square wells (undistorted) even with continuous growth, in contrast to OMCVD are inferred from the excitation spectra. Unusually sharp exciton transition peaks up to E3h including forbidden transitions were obtained in single quantum wells. Such high quality line shape has not been obtained in MBE or OMCVD grown wafers so far. The excitation spectra also show no evidence of band filling due to holes or electrons from the AlxGa1-xAs layers which is a common problem with the OMCVD technique. From this study, it is also shown that the GaAs and AlxGa1-xAs materials are of very high purity. [ABSTRACT FROM AUTHOR]

GaAs-AlxGa1-xAs single and multiquantum well structures grown by metalorganic chemical vapor deposition have been examined for the first time in detail using low-temperature photoluminescence, cathodoluminescence, and transmission electron microscopy. The better heterointerfaces are very uniform with a large scale roughness of approximately plus or minus a monolayer along the interface on a scale of the exciton diameter or larger and a composition gradient width of less than three monolayers across the interface. The GaAs well interface roughness and associated impurity luminescence are not very sensitive to the thickness of the AlxGa1-xAs prelayer. With nonoptimum growth conditions, the quantum well photoluminescence characteristics suggest a substantial amount of band filling due to holes presumably from the AlxGa1-xAs layers. [ABSTRACT FROM AUTHOR]

A correlation has been demonstrated between impurity trapping and the interface structure in GaAs quantum well (QW) superlattices and single quantum well structures grown by molecular beam epitaxy (MBE) on (100) GaAs. Using low-temperature cathodoluminescence, photoluminescence, and transmission electron miscroscopy, we have shown that interface roughness in QW superlattices is related to trapped impurities at interfaces. We have observed that impurities originate from either the substrate or from the GaAlAs MBE layers. A new getter smoothing effect associated with QW structures is shown to produce efficient impurity trapping and yield higher quality GaAs QW with atomically smooth interfaces. [ABSTRACT FROM AUTHOR]

We report growth of ultrapure GaAs by molecular beam epitaxy (MBE) and show that the arsenic source has a dramatic effect on the purity. With every thing else the same, by changing the arsenic source from 6N grade double refined chunks to a 7N grade slug which closely fits the 35 cm3 crucible, the deep electron trap and the residual acceptor densities were reduced by nearly two orders of magnitude. When intentionally doped with Si to an electron density of 3×1013 cm-3, the measured mobility at 77 K was 205 600 cm2 V-1 s-1, which increased to 294 700 cm2 V-1 s-1 at 42 K. These mobilities are the highest ever observed in intentionally n-doped MBE GaAs. Low-temperature photoluminescence studies of both undoped and Si-doped GaAs layers grown with the As slug show a marked decrease in acceptor- and defect-related luminescence over that observed when the As chunks are used. Our study conclusively proves that the major source of residual acceptor impurities and typical MBE GaAs traps observed by deep level transient spectroscopy is the chemical impurities present in the arsenic source, although the exact nature of these impurities is yet to be identified. These impurities or their complexes with the native crystal defects, and not the native defects alone, are responsible for the deep traps. [ABSTRACT FROM AUTHOR]

Background: Self-expandable esophageal stents are increasingly used for palliation or as an adjunct to chemoradiation for esophageal neoplasia. The optimal esophageal stent design and material to minimize dose perturbation with external beam radiation are unknown.We sought to quantify the deviation from intended radiation dose as a function of stent material and mesh density design. Methods: A laboratory dosimetric film model was used to quantify perturbation of intended radiation dose among 16 different esophageal stents with varying material and stent mesh density design. Results: Radiation dose enhancement due to stent backscatter ranged from 0% to 7.3 %, collectively representing a standard difference from the intended mean radiation dose of 1.9 (95% confidence interval [CI] 1.5-2.2). This enhancement was negligible for polymer-based stents and approached 0% for the biodegradable stents. In contrast, all metal alloy stents had significant radiation backscatter; this was largely determined by the density of mesh design and not by the type of alloy used. Conclusions: Stent characteristics should be considered when selecting the optimal stent for treatment and palliation of malignant esophageal strictures, especially when adjuvant or neo-adjuvant radiotherapy is planned. [ABSTRACT FROM AUTHOR]

Small cell carcinoma of the esophagus (SCCE) is a rare and aggressive malignant tumor with a poor prognosis. The aims of this retrospective study were to analyze the epidemiology, clinical characteristics, and treatment outcomes of these patients. Between 1994 and 2004, 24 patients with SCCE from several centers were reviewed for data on demographics, presenting symptoms, diagnosis, disease stage, type of treatment, and outcome. SCCE occurs in the sixth decade: median age (interquartile range [IQR]): 65 (59-69) years with a male predominance (63%). The most common complaining symptoms were rapidly progressive dysphagia (79%), weight loss (54%), and retrosternal/epigastric pain (46%). The tumor arises primarily in the middle (52%) or in the lower (35%) third of the esophagus. History of tobacco and alcohol exposure was present in 90% and 70% of case, respectively. Extensive disease was present in 13 cases (54%) at initial diagnosis. The overall median survival (IQR) was 11 (8-20) months for all 24 patients, and the 2-year overall survival was 25.1%. Four patients were alive more than 2 years after treatment. Chemotherapy increased the survival compared with symptomatic management in extensive disease (median survival [IQR]: 9.5 [6-14] vs. 6 [4-7] months, P= 0.05). In limited disease, concurrent chemo-radiotherapy was more effective than non-concurrent treatment (median survival [IQR]: 36 [14-93] vs. 11 [9-15] months, P= 0.04). Two patients were treated by surgery and chemoradiation therapy with a survival of 35 and 66 months. Chemotherapy is the cornerstone of treatment of SCCE in all stage. For limited disease SCCE, concurrent chemo-radiotherapy is the primary choice compared with sequential approach. The role of surgery was not assessable in our study. [ABSTRACT FROM AUTHOR]

Background: This study analyzed prognostic factors and treatment outcomes of primary thyroid lymphoma.Patients and Methods: Data were retrospectively collected for 87 patients (53 stage I and 34 stage II) with median age 65 years. Fifty-two patients were treated with single modality (31 with chemotherapy alone and 21 with radiotherapy alone) and 35 with combined modality treatment. Median follow-up was 51 months.Results: Sixty patients had aggressive lymphoma and 27 had indolent lymphoma. The 5- and 10-year overall survival (OS) rates were 74% and 71%, respectively, and the disease-free survival (DFS) rates were 68% and 64%. Univariate analysis revealed that age, tumor size, stage, lymph node involvement, B symptoms, and treatment modality were prognostic factors for OS, DFS, and local control (LC). Patients with thyroiditis had significantly better LC rates. In multivariate analysis, OS was influenced by age, B symptoms, lymph node involvement, and tumor size, whereas DFS and LC were influenced by B symptoms and tumor size. Compared with single modality treatment, patients treated with combined modality had better 5-year OS, DFS, and LC.Conclusions: Combined modality leads to an excellent prognosis for patients with aggressive lymphoma but does not improve OS and LC in patients with indolent lymphoma. [ABSTRACT FROM AUTHOR]

Background Mandibular osteosarcomas (MOS) mostly affect young adults. Their treatment is extrapolated from that of extragnathic osteosarcomas. Material and methods A retrospective multicooperative group study was conducted to determine the impact of chemotherapy, adjuvant radiation therapy and surgery on outcomes and to identify prognostic factors. This ethical committee-approved study included a centralized review of histology slides and operative reports. Results Of 111 patients, 58.6% were male, median age 35 years (13%, ≤18 years). Histology was osteoblastic, chondroblastic, fibroblastic, conventional not otherwise specified and others in 39.6%, 30.6%, 8.1%, 12.6% and 8.0%, respectively. Pathological World Health Organisation grades were low, intermediate and high grade in 6.4%, 11.8% and 81.8%, respectively. Surgery was carried out for 94.5% of patients. Neoadjuvant chemotherapy (mixed protocols) was carried out in 93.1% of patients. Postoperative chemotherapy and radiotherapy were carried out in 54.7% and 23.8%, respectively. Median follow-up was 59.6 months (range). Five-year local control, metastasis-free, disease-free and overall survival rates were 64.6%, 68.9%, 53.2% and 69.2%, respectively. Survival was significantly associated with age, tumor size and surgery. Wide surgery with clear margins and free flap reconstruction was the strongest prognostic factor. Neoadjuvant chemotherapy improved disease-free and metastatic-free survival and increased clear margins rates from 50% to 68%. Intermediate grades behaved like high grades in terms of metastatic-free and disease-free survival. Conclusion This homogeneous series is the largest to date and emphasizes the major impact of clear margins and multidisciplinary management. Neoadjuvant chemotherapy improves disease-free survival and should be recommended for both high and intermediate grade MOS. [ABSTRACT FROM AUTHOR]

Background: Self-expandable esophageal stents are increasingly used for palliation or as an adjunct to chemoradiation for esophageal neoplasia. The optimal esophageal stent design and material to minimize dose perturbation with external beam radiation are unknown. We sought to quantify the deviation from intended radiation dose as a function of stent material and mesh density design.Methods: A laboratory dosimetric film model was used to quantify perturbation of intended radiation dose among 16 different esophageal stents with varying material and stent mesh density design.Results: Radiation dose enhancement due to stent backscatter ranged from 0 % to 7.3 %, collectively representing a standard difference from the intended mean radiation dose of 1.9 (95 % confidence interval [CI] 1.5 - 2.2). This enhancement was negligible for polymer-based stents and approached 0 % for the biodegradable stents. In contrast, all metal alloy stents had significant radiation backscatter; this was largely determined by the density of mesh design and not by the type of alloy used.Conclusions: Stent characteristics should be considered when selecting the optimal stent for treatment and palliation of malignant esophageal strictures, especially when adjuvant or neo-adjuvant radiotherapy is planned. [ABSTRACT FROM AUTHOR]

While endoscopic ultrasonography (EUS) and EUS-guided fine-needle aspiration (EUS-FNA) are the most accurate techniques for locoregional staging of esophageal cancer, little evidence exists that these innovations impact on clinical care. The objective on this study was to determine the frequency with which EUS and EUS-FNA alter the management of patients with localized esophageal cancer, and assess practice variation among specialists at a tertiary care center. Three gastroenterologists, three medical oncologists, three radiation oncologists and four thoracic surgeons were asked to independently report their management recommendations as the anonymized staging information of 50 prospectively enrolled patients from another study were sequentially disclosed on-line. Compared to initial management recommendations, that were based upon history, physical examination, upper endoscopy and CT scan results, EUS prompted a change in management 24% (95% CI: 12–36%) of the time; usually to a more resource-intensive approach (71%), for example from recommending palliation to recommending neoadjuvant chemoradiation therapy. EUS-FNA plus cytology results altered management an additional 8% (95% CI: 6–15%) of the time. Agreement between specialists ranged from fair (intraclass correlation [ICC=0.32) to substantial (ICC=0.65); improving with additional information. Among specialists, agreement was greatest for patients with stage I disease. EUS and EUS-FNA changed patient management the most for patients with stages IIA, IIB or III disease. EUS, with or without FNA, significantly impacts the management of patients with localized esophageal cancer. With respect to the optimal treatment for each patient, agreement among physicians incrementally increases with endoscopic ultrasound results. Specialty training appears to influence therapeutic decision-making behavior. [ABSTRACT FROM AUTHOR]

The National Quality Management Program of the Military Health Services System of the United States has undertaken a series of projects whose objective is the active, on-going monitoring and improvement of the effectiveness and efficiency of the care provided to a broad population that encompasses troops on active duty, retirees and dependents. The analytic activities consist of (1) identification by clinical panels of conditions and procedures of interest; (2) collection of data from electronic repositories and from charts to characterize the patients, how they are managed, the clinical outcomes they experience, the resource costs their care entails, and, from questionnaires, their functional status and level of satisfaction, and (3) generation of 'report cards' that inform organizational units down to the level of the hospital of the characteristics of their patients, their practices, and the risk-adjusted outcomes they achieve. The patterns of care employed by the hospitals that obtain the best risk-adjusted outcomes and resource utilization ('best clinical practice') are identified and made known. In addition, (4) a systematic process of developing outcomes-based practice guidelines has been devised. It intent is to serve as a decision-support tool for clinicians. Initial estimates have been obtained of the probable consequences of the application of this tool to operative interventions in childbirth. Use of the tool would result in a higher occurrence of elective Caesarean sections, a reduced rate of emergency Caesarean sections and much lower use of forceps, with an overall improvement in outcomes and lower resource costs. This program is currently in the early phases of implementation. The two principal requirements for the immediate future are (1) education of the clinical and administrative communities in the use of the data and the decision-support tools and (2) evaluation of the consequences of the use of the data by the clinical and administrative communities. [ABSTRACT FROM AUTHOR]

The potential radiation hazards associated with routine screening mammography, in terms of breast cancer induction, are discussed in the context of the potential benefits. The very low energy X-rays used in screening mammography (26-30 kVp) are expected to be more hazardous, per unit dose, than high-energy X- or γ-rays, such as those to which A-bomb survivors (from which radiation risk estimates are derived) were exposed. Based on in vitro studies using oncogenic transformation and chromosome aberration end-points, as well as theoretical estimates, it seems likely that low doses of low-energy X-rays produce an increased risk per unit dose (compared with high energy photons) of about a factor of 2. Because of the low doses involved in screening mammography, the benefit-risk ratio for older women would still be expected to be large, though for younger women the increase in the estimated radiation risk suggests a somewhat later age than currently recommended—by about 5-10 years—at which to commence routine breast screening. [ABSTRACT FROM AUTHOR]

Photoluminescence spectra from Al0.37Ga0.63As/AlAs multiple quantum well structures with staggered band alignments are presented which provide the first direct optical measure of the valence-band offset at a semiconductor heterojunction. The experiment takes advantage of the crossover occurring at a critical aluminum concentration above which the indirect X minima in the AlAs become the lowest energy conduction bands in the system, and recombination occurs across the interface. The resulting emission fixes the valence-band offset at ΔEv =342±4 meV for this structure. [ABSTRACT FROM AUTHOR]