Recurrence patterns of locally advanced head and neck squamous cell carcinoma after 3D conformal (chemo)-radiotherapy

<p>Abstract</p> <p>Background</p> <p>To establish recurrence patterns among locally advanced head and neck non-nasopharyngeal squamous cell carcinoma (HNSCC) patients treated with radical (chemo-) radiotherapy and to correlate the sites of loco-regional recurrence with radiotherapy doses and target volumes</p> <p>Method</p> <p>151 locally advanced HNSCC patients were treated between 2004-2005 using radical three-dimensional conformal radiotherapy. Patients with prior surgery to the primary tumour site were excluded. The sites of locoregional relapses were correlated with radiotherapy plans by the radiologist and a planning dosimetrist.</p> <p>Results</p> <p>Median age was 59 years (range:34-89). 35 patients had stage III disease, 116 patients had stage IV A/B. 36 patients were treated with radiotherapy alone, 42 with induction chemotherapy, 63 with induction and concomitant chemoradiotherapy and 10 concomitant chemoradiotherapy. Median follow-up was 38 months (range 3-62). 3-year cause specific survival was 66.8%. 125 of 151 (82.8%) achieved a complete response to treatment. Amongst these 125 there were 20 local-regional recurrence, comprising 8 local, 5 regional and 7 simultaneous local and regional; synchronous distant metastases occurred in 7 of the 20. 9 patients developed distant metastases in the absence of locoregional failure. For the 14 local recurrences with planning data available, 12 were in-field, 1 was marginal, and 1 was out-of-field. Of the 11 regional failures with planning data available, 7 were in-field, 1 was marginal and 3 were out-of-field recurrences.</p> <p>Conclusion</p> <p>The majority of failures following non-surgical treatment for locally advanced HNSCC were loco-regional, within the radiotherapy target volume. Improving locoregional control remains a high priority.</p

Evaluating "superiority", "equivalence" and "non-inferiority" in clinical trials

Clinical studies are usually performed with the aim of justifying that a new treatment approach is "superr rior" to the common standard approach (active control) with respect to benefits. In a general sense, this justification is carried out on the basis of the "null hypothesis significance test" with the P value based on this test used for justification. Today, new drugs differ so little from existing ones that factors such as cost and side effects affect the choice of therapy, when the bioavailability of treatment methods are found equivalent. Therefore, the aim of comparative clinical trials has extended beyond showing that a treatment is "superior" and now attempts to show that new treatments are "equal" and "nonrinferior" to existing treatments. New approaches have become necessary since the classical null hypothesis approach is insufrr ficient to justify the use of new agents, especially in cases of "equivalence" and "nonrinferiority". This new approach to justification makes use of the "clinical equivalence interval", , which determines the limits of the differences between specific endpoints that can be regarded as clinically "equal" to the value that was prerspecified based on studies of established therapies. It also makes use of the quantitativerbased "conrr fidence intervals" as the criteria for statistical justification. Many analyses can be done confidently when these tools are applied and the data are interpreted correctly

The adaptation and preliminary psychometric properties of the Derived Chemistry Anxiety Rating Scale

The current study adapted the Derived Chemistry Anxiety Rating Scale (DCARS) into Turkish and investigated the preliminary psychometric properties of the Turkish version. The Turkish DCARS is composed of three components, which are derived from 32 Likert-type items that purport to measure anxiety experienced in chemistry-related situations. In the adaptation procedure, English-Turkish conformity, Turkish language conformity and understandability, and back translation were used. In the preliminary psychometric investigation, structural validity, content validity, concurrent validity, internal consistency, and test-retest reliability were examined. Results show that item translations have high conformity with the original items and experts found the Turkish items understandable. Validity analyses confirmed the adapted scale's three-factor structure. In addition, concurrent validity was evidenced by significant positive correlation coefficients between the scale scores and the test anxiety and state-trait anxiety scores. Reliability analyses indicate high consistency among the scale items both at the total and sub-scale levels and that scale and subscale scores were stable over time. We conclude that the Turkish DCARS is a promising assessment instrument in measuring chemistry anxiety levels among Turkish college students

Assessment of the performances of multilayer perceptron neural networks in comparison with recurrent neural networks and two statistical methods for diagnosing coronary artery disease

We aimed to examine the diagnostic performances of multilayer perceptron neural networks (MLPNNs) for predicting coronary artery disease and to compare them with different types of artificial neural network methods, namely recurrent neural networks (RNNs) and two statistical methods (quadratic discriminant analysis (QDA) and logistic regression (LR)). MLPNNs were trained with backpropagation, quick propagation, delta-bar-delta and extended delta-bar-delta algorithms as classifiers; the RNN was trained with the Levenberg-Marquardt algorithm; LR and QDA were used for predicting coronary artery disease. Coronary artery disease was classified with accuracy rates varying from 79.9% to 83.9% by MLPNNs. Even though MLPNNs achieved higher accuracy rates than the statistical methods, LR (73.2%) and QDA (58.4%), their performances were lower compared to the RNN (84.7%). Among the four different types of training algorithms that trained MLPNNs, quick propagation achieved the highest accuracy rate; however, it was lower than the RNN trained with the Levenberg-Marquardt algorithm. RNNs, which demonstrated 84.7% accuracy and 86.5% positive predictive rates, may be a helpful tool in medical decision making for diagnosis of coronary artery disease

Evaluating "superiority", "'equivalence" and "non-inferiority" in clinical trials

Clinical studies are usually performed with the aim of justifying that a new treatment approach is "superior" to the common standard approach (active control) with respect to benefits. In a general sense, this justification is carried out on the basis of the "null hypothesis significance test" with the P value based on this test used for justification. Today, new drugs differ so little from existing ones that factors such as cost and side effects affect the choice of therapy, when the bioavailability of treatment methods are found equivalent. Therefore, the aim of comparative clinical trials has extended beyond showing that a treatment is "superior" and now attempts to show that new treatments are "equal" and "non-inferior" to existing treatments. New approaches have become necessary since the classical null hypothesis approach is insufficient to justify the use of new agents, especially in cases of "equivalence" and "non-inferiority". This new approach to justification makes use of the "clinical equivalence interval", which determines the limits of the differences between specific endpoints that can be regarded as clinically "equal" to the value that was pre-specified based on studies of established therapies. It also makes use of the quantitative-based "confidence intervals" as the criteria for statistical justification. Many analyses can be done confidently when these tools are applied and the data are interpreted correctly

The use of cyclic processes in medical decision making: an application of the Markov model

Objectives: We aimed to explain the conceptual basis of the Markov model and to show the use of this model by an example application in medical decision making and medical predicting

Prevalence of Peripheral Neuropathy and Painful Peripheral Neuropathy in Turkish Diabetic Patients

The aim of this study was to determine the prevalence of diabetic peripheral neuropathy (DPN) and neuropathic pain in diabetic patients attending university outpatient clinics in Turkey. In this multicenter cross-sectional study, neurologic examinations and nerve conduction studies along with clinical diabetic neuropathy score, and Leeds Assessment of Neuropathic Symptoms and Signs pain scale were performed on 1,113 patients (46.2% male) from 14 centers. Prevalence of DPN determined only by clinical examination was 40.4% and increased to 62.2%, by combining nerve conduction studies with clinical examination. According to Leeds Assessment of Neuropathic Symptoms and Signs scores, neuropathic pain prevalence was 16.0% in those who reported pain. Poor glycemic control, retinopathy, microalbuminuria, hyperlipidemia, diabetic foot, and foot amputation were more commonly observed in patients with DPN. Clinical DPN affected 40.4% of diabetic patients, and neuropathic pain prevalence in diabetic patient population was 14.0%. Clinical examinations and nerve conduction studies are important components for early detection and accurate diagnosis of DPN and painful DPN

Dendritic cell sarcoma: A pooled analysis including 462 cases with presentation of our case series

Dendritic cell tumors are extremely rare and current knowledge on these tumors is limited. The characteristics of three dendritic cell sarcoma subtypes and their optimal treatment approaches are not fully clarified. We aimed to make a systematic review of the literature and enrich the current data with five new cases. Pooled analysis of 462 reported cases revealed that the tumor had no age, gender or racial predilection. Our analysis suggests that the young age, advanced stage, intraabdominal involvement and unfavorable histological features (i.e. large tumor size, absence of lymphoplasmacytic infiltration, coagulative necrosis, high mitotic count) may predict poor prognosis. Subtypes of this tumor have different clinical behaviors with interdigitating dendritic cell sarcoma being the most aggressive form. In general, surgery is the most effective treatment modality and adjuvant radiotherapy has no significant effect on overall survival of patients. The role of chemotherapy for the management of advanced disease is controversial. (C) 2013 Elsevier Ireland Ltd. All rights reserved

Fate of abstracts presented at the annual scientific meeting of the Undersea and Hyperbaric Medical Society

Introduction: The full-text publication of abstracts presented at any given scientific meeting in peer-reviewed journals is accepted as a measure of scientific quality of that particular meeting. The aim of this study is to determine the full-text publication rate of abstracts presented at the 2005 Scientific Meeting of the Undersea and Hyperbaric Medical Society (UHMS)