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O Esik

Publications and source records attributed to O Esik.

At least 19 recordsLinked to original sources
PubMed1999

[Evaluation of the effectiveness of radiotherapy in an Austrian-Hungarian collaboration].

To present an example of how to study and analyse the clinical practice and the quality of medical decision-making under daily routine working conditions in a radiotherapy department, with the aims of detecting deficiencies and improving the quality of patient care. Bimonthly audits (6 with a duration of 4-6 hours in each institution) were carried out by 3 auditors from the evaluating departments; they reviewed a total of 452 cases in Department A, and 265 cases in Department B. During the ongoing external audits, the qualifying parameters were (1) the sound foundation of the indication of radiotherapy, (2) the conformity to the institution protocol (3), the adequacy of the choice of radiation equipment, (4) the appropriateness of the treatment plan, and the correspondence of the latter with (5) the simulation and (6) verification films. Various degrees of deviation from the treatment principles were defined and scored on the basis of the concept of Horiot et al. (10), with some modifications. The action was regarded as adequate (score 1) in the event of no deviation or only a small deviation with presumably no alteration of the desired end-result of the treatment. A deviation adversely influencing the result of the therapy was considered a major deviation (score 3). Cases involving a minor deviation (score 2) were those only slightly affecting the therapeutic end-results, with effects between those of cases with scores 1 and 3. Non-performance of the necessary radiotherapeutic procedures was penalized by the highest score of 4. Statistical evaluation was performed with the BMDP software package, using variance analysis. Despite the comparable staffing and instrumental conditions, a markedly higher number (1.5 times) of new cases were treated in Department A, but with a lower quality of radiotherapy, as adequate values of qualifying parameters (1)-(6) were more frequent for the cases treated in Department B (85, 94%, 83%, 28%, 42% and 81%) than for those in Department A (67%, 83%, 88%, 26%, 33% and 18%). The responsible division (including staff and instrumentation), the responsible physician and the type of the disease each exerted a highly significant effect on the quality level of the treatment. Statistical analysis revealed a positive influence of the curative (relative to the palliative/symptomatic) intention of the treatment on the level of quality, but the effect of the first radiotherapy (relative to the second or further one) was statistically significant in only one department. The external audit related to the provision of radiotherapeutic care proved feasible with real valuation of the staff's activity.

Analysis of Variance↗
PubMed1999

[Ret-protooncogene mutation, verified by molecular genetic methods, in a Hungarian MEN Type 2a family].

Multiple endocrine neoplasia Type 2 (MEN2) is a hereditary tumour syndrome characterized by the association of medullary thyroid cancer, phaeochromocytoma and hyperparathyroidism. It is inherited as an autosomal dominant trait. During the past few years the cloning of the gene responsible for the syndrome, the ret protooncogene, made the molecular genetic diagnosis of the disease possible. In this study we demonstrate the results of the MEN2 mutation analysis performed in three members of a Hungarian MEN2A family. The mutation analysis was carried out according to the method of Dr. W. Hoppner's Laboratory (Hamburg) that is the main centre for MEN2 genetic diagnosis in Germany. Two Members of the family are affected, one suffered from both medullary thyroid cancer and phaeochromocytoma, the other (the first patient's daughter) had only medullary thyroid cancer. We found a ret exon 11 codon 634 mutation, that resulted in the change of TGC to TAC, a cysteine-tyrosine amino acid exchange. We found no mutation in the youngest member of the family. This result is of great clinical significance, because the carrier status of this individual can thus be excluded and, therefore, there is no need for prophylactic thyroidectomy and further clinical screening tests. As molecular genetic diagnosis of MEN2 becomes possible, the uncertain clinical examinations used for MEN2 diagnosis seems to be less important.

Adult↗
PubMed1999

Radiation myelopathy with partial functional recovery: PET evidence of long-term increased metabolic activity of the spinal cord.

Postoperative telecobalt irradiation was performed with a biologically effective extrapolated response dose of 165 Gy2 delivered to the spinal cord of a papillary thyroid cancer patient. Incomplete cervical transection developed, followed by a gradual functional improvement, which is still continuing 8 years after radiotherapy. Between the 6th and 8th years of the clinical course, positron emission tomography investigations demonstrated an increased 18F-deoxyglucose accumulation and (15)O-butanol perfusion, but negligible 11C-methionine uptake in the irradiated spinal cord segment. We suggest that the increased metabolism and perfusion, and the lack of detectable protein synthesis may be related to the increased energy demands of action potential conduction, due to the higher than normal density of sodium channels along demyelinated axons displaying restored conduction.

Adult↗
PubMed1999

External audit on the clinical practice and medical decision-making at the departments of radiotherapy in Budapest and Vienna.

PURPOSE: To present an example of how to study and analyze the clinical practice and the quality of medical decision-making under daily routine working conditions in a radiotherapy department, with the aims of detecting deficiencies and improving the quality of patient care. METHODS: Two departments, each with a divisional organization structure and an established internal audit system, the University Clinic of Radiotherapy and Radiobiology in Vienna (Austria), and the Department of Radiotherapy at the National Institute of Oncology in Budapest (Hungary), conducted common external audits. The descriptive parameters of the external audit provided information on the auditing (auditor and serial number of the audit), the cohorts (diagnosis, referring institution, serial number and intention of radiotherapy) and the staff responsible for the treatment (division and physician). During the ongoing external audits, the qualifying parameters were (1) the sound foundation of the indication of radiotherapy, (2) conformity to the institution protocol (3), the adequacy of the choice of radiation equipment, (4) the appropriateness of the treatment plan, and the correspondence of the latter with (5) the simulation and (6) verification films. Various degrees of deviation from the treatment principles were defined and scored on the basis of the concept of Horiot et al. (Horiot JC, Schueren van der E. Johansson KA, Bernier J, Bartelink H. The program of quality assurance of the EORTC radiotherapy group. A historical overview. Radiother. Oncol. 1993,29:81-84), with some modifications. The action was regarded as adequate (score 1) in the event of no deviation or only a small deviation with presumably no alteration of the desired end-result of the treatment. A deviation adversely influencing the result of the therapy was considered a major deviation (score 3). Cases involving a minor deviation (score 2) were those only slightly affecting the therapeutic end-results, with effects between those of cases with scores 1 and 3. Non-performance of the necessary radiotherapeutic procedures was penalized by the highest score of 4. Statistical evaluation was performed with the BMDP software package, using variance analysis. RESULTS: Bimonthly audits (six with a duration of 4-6 h in each institution) were carried out by three auditors from the evaluating departments; they reviewed a total of 452 cases in Department A, and 265 cases in Department B. Despite the comparable staffing and instrumental conditions, a markedly higher number (1.5 times) of new cases were treated in Department A, but with a lower quality of radiotherapy, as adequate values of qualifying parameters (1-6) were more frequent for the cases treated in Department B (85.3%, 94%, 83.4%, 28.3%, 41.9% and 81.1%) than for those in Department A (67%, 83.4%, 87.8%, 26.1%, 33.2% and 17.7%). The responsible division (including staff and instrumentation), the responsible physician and the type of the disease each exerted a highly significant effect on the quality level of the treatment. Statistical analysis revealed a positive influence of the curative (relative to the palliative/symptomatic) intention of the treatment on the level of quality, but the effect of the first radiotherapy (relative to the second or further one) was statistically significant in only one department. At the same time, the quality parameters did not vary with the referring institution, the auditing person or the serial number of the audit. CONCLUSION: The external audit relating to the provision of radiotherapeutic care proved feasible with the basic conformity and compliance of the staff and resulted in valuable information to take correction measures.

Austria↗
PubMed1999

A case of bilateral testicular lymphoma.

Authors report on a 75-year-old man with bilateral testicular lymphoma. He complained of painless right testicular enlargement. Orchidectomy was indicated by ultrasound examination and the diagnosis (large cell, non-Hodgkin lymphoma B-cell origin) was established by histology and immunohistochemistry. Two months later, the left testis enlarged, orchidectomy was performed, and a lymphoma with identical histology was found. PET revealed retroperitoneal spread of the tumor. Irradiation (18 Gy) was applied. Three months later, because of gastric metastases of the lymphoma the patient underwent CVP and CAVP (Cyclophosphamide, Adriablastin, Vincristin, Prednisolone) chemotherapy. Despite of the repeated courses, eleven months after the primary diagnosis the patient died due to of multiple metastases.

Aged↗
PubMed1998

[Multiple endocrine neoplasia-type medullary thyroid carcinoma in three generations of a family].

The familial accumulation of a multiple endocrine neoplasia (MEN) type 2a medullary thyroid carcinoma, is described based on the retrospective analysis of a family history. The proband was characterized by medullary carcinoma (MC) combined with phaeochromocytoma, her child had been shown to suffer from MC. In the third generation of the family C-cell hyperplasia and bilateral adrenal hyperplasia occurred. It is shown that in order to arrive at a correct decision as regards the therapy to be used, modern laboratory tests (serum calcitonin, CEA-analysis) and diagnostic imaging methods (ultrasound, computer tomography, magnetic resonance imaging, positron emission tomography, metaiodobenzylguanidine scintigraphy) should be used. It is emphasized that the available therapeutic means (surgery, radiotherapy, nuclear medicine) have to be carefully selected and, if necessary, combined. In medullary thyroid carcinoma associated tumours in other endocrine organs should be expected to occur. Family screening using blood chemical and genetic tests are recommended in asymptomatic cases, since their surgical treatment can in this way lead to complete recovery.

Adult↗
PubMed1998

[Cytogenetic study of thyroid patients treated with external irradiation or radioiodine].

Where clinically permitted, either external irradiation or radioiodine therapy is usually recommended for the treatment of differentiated thyroid cancer patients. This paper describes an attempt to clarify the radiation burden and the distribution of radiation doses on the lymphocytes in consequence of these two therapeutic modalities, and the circumstances of the applicability of biological dosimetry. Thyrotoxic patients with intact thyroid glands underwent 131I therapy were also analysed for this purpose. An analysis was made of the extent to which exposure to local neck irradiation (50 Gy) or radioiodine therapy (1734-2600 MBq) causes chromosomal aberrations in the lymphocytes of thyroid disease patients after total or subtotal thyroidectomy, or thyrotoxic patients with intact thyroid glands (185-595 MBq). The irradiated volume of lymphatic tissues played the most important role in the formation of chromosomal aberrations. External irradiation caused 10-times more aberrant cells than 131I therapy did in cancer patients. In thyrotoxic patients the lower therapy doses of radioiodine caused a significantly higher frequency of aberrations than that observed in thyroid cancer patients. Selective radiosensitivity of lymphocytes was supported by the analysis of the Poisson distribution of aberrations, which suggested a homogeneous dose distribution only in 131I-treated and thyroidectomized cancer patients. In conclusion, we suggest that the results of studies of the genetic alterations in the lymphocytes exposed to radioiodine, under well-defined circumstances should not be ignored before the mode of radiation treatment is chosen. On the other hand, in the modelling of accidental environmental radioiodine exposure, only thyrotoxic patients with an intact thyroid gland and heterogeneous dose-distribution are a suitable group.

Adult↗
PubMed1998

[Juvenile aneuploid papillary cancer of the thyroid with pulmonary metastasis].

The long-term cause-specific survival results of papillary thyroid cancer patients in Hungary are (78%) worse than the best international data (90%). The authors have recited its causes through the case of a young papillary thyroid cancer patient during the diagnostics (aspiration cytology, diagnostic imaging technics, DNA-analysis) the treatment (surgery-external radiotherapy-radioiodine treatment) and the follow-up (HTG, diagnostic imaging).

Adult↗
PubMed1998

[Results of radiotherapy in the year of the Röntgen centenary].

In 1996, the three leading radiation oncology periodicals (Int. J. Radiat. Oncol. Biol. Phys.--USA, Radiother. Oncol.--Europe, and Strahlenther. Onkol.--Germany) published 681 papers. Among the different topics, the clinical subjects accounted for almost half (46%) of the total number of publications, followed by radiation physics/techniques (18%) and radiation biology (17%). The 13% of editorials/review articles reflects a considerable endeavor towards integration; the contribution of papers relating to professional organization amounted to 2%. The fact that 1996 was the centennial year of the discovery of the Röntgen rays explains the reasonable proportion (4%) of historical reviews. Within the special topics, prostatic cancer and breast cancer were the two most frequent issues. Dose escalation was the most important tool applied to improve the results of the radiation therapy of tumors with unfavorable prognostic signs or radioresistance. The increase in the applied dose was made possible by a decrease in the planning target volume (PTV), 3D forward and inverse radiation treatment planning, a combination of tomographic (CT/MRI/US) diagnostic methods (image registration/fusion), optimizing algorithms, computer-controlled delivery of radiation dose and electronic portal imaging with in vivo dosimetry. In contrast, the trends in the radiotherapy of tumors with favorable long-term survival (e.g. Hodgkin's disease and seminoma) include a decreased dose and PTV reduction to diminish the late, radiation-related morbidity. Fractionation has remained the only tool of radiobiology routinely used in the everyday clinical practice. A comparison of the results and achievements in the special fields reveals that radiation physics/techniques clearly outstrip clinical subjects and especially radiation biology, as they allow direct and instant exploitation of the advantages offered by computers. It is highly probable, however, that, subsequent to a wider use of computers in clinical subjects and radiation biology, this situation will change.

Germany↗
PubMed1997

[Image fusion of different tomographic methods (PET/CT/MRI) effectively contribute to therapy planning].

Image fusion (and image registration) is a fundamental topic of three-dimensional (3D) medical image processing. The need to register different imaging modalities arises for several reasons: some anatomical details, especially soft tissues, are more easily seen in MRI than CT images, but the bony structures are better visualised by CT. The visualisation of any morphological volume with a functional data set which may come from SPECT or PET is a very important method both for research purposes and for routine diagnostics. Our developed programs allowing us to solve image fusion tasks also contained some free available softwares. These packages helped us to start additional software development for more advanced applications having elaborated this way the informatical background of multimodality image processing. This paper presents three oncological applications of the image fusion: PET-CT-MRI registration for 3D radiotherapy planning, PET-MRI registration in planning surgery and metastasis localization. All these registration processes were solved by the landmark-matching registration method.

Decision Making↗
PubMed1997

[11C-methionine: an effective radio-tracer for PET scan in the detection of tumors of low proliferating capacity].

11C-methyl-methionine is available at the PET Center of University Medical School Debrecen since June, 1996. The first 5 oncological examinations were indicated for clinically suspected recurrent/residual tumorous tissue of low-grade/low proliferative capacity, following the negative or inconclusive results of previous 18F-deoxyglucose (FDG) examinations. In these situations, the methionine examinations provided conclusive results in 4 cases (out of the total of 5 examinations). On the basis of published data and own experience, the authors recommend methionine PET investigations for diagnosis, differential diagnosis and therapy monitoring of tumours of low-grade/low proliferative capacity following inconclusive results of previous FDG examination.

Adult↗
PubMed1997

[PATHYPRE: Pascal program for the estimation of the individual course of patients with papillary thyroid cancer].

Individual survival probability estimation provided by mathematical models based on cases with a known clinical course is of great help as concerns the treatment strategy decision relating to malignant tumours. Data on four hundred Hungarian papillary thyroid cancer patients were used together with the Markov method to construct a survival model (Orv. Hetil. 1996 137: 1067-1078,) for prediction of the individual clinical course of newly diagnosed cases for 30 years following surgical intervention. Input data included the age, the primary tumour size and extent (pT), distant metastasis at presentation, the extent of the surgical intervention, the external irradiation dosage and the degree of TSH suppression. From the input data, the PATHYPRE program can estimate the individual local/regional/distant relapse-free survival probabilities and overall cause-specific survival probability. The survival probabilities may be predicted for variations in the treatment parameters, and thus the model helps in the selection of the most appropriate therapy for the patient. The PATHYPRE software is available through the Internet connections on the home page of the National Institute of Oncology, Budapest (www.oncol.hu).

Adult↗
PubMed1997

[First Hungarian experiences with positron emission tomography (PET) studies. Members of the PET working group].

Diagnostic investigations commenced on the 28th of June 1994 in Hungary's and Central Europe's first PET Centre at the University Medical School of Debrecen. The Centre is equipped with a GE 4096 Plus whole body PET scanner. A metabolic tracer, 18F-deoxy-D-glucose (FDG), was used in the investigations. During the first 15 months 249 PET investigations were made in the Centre of which 242 were diagnostic and 7 normal subjects served as control for the patient studies with brain scans. The number of oncological indications (intra- and extracranial tumours, Hodgkin's lymphomas) was n = 105 (43.4% of the 242 diagnostic examinations), neurological investigations (without intracranial tumours) formed the dominant group (n = 117; 48.3%), whereas the number of cardiological indications was 20 (8.3%). The oncological studies included those of intracranial tumours (n = 76; 31.4%); thyroid tumours (n = 9; 3.7%); Hodgkin's lymphomas (n = 7; 2.9%) and other extracranial tumours (n = 13; 5.4%). The distribution of different neurological and psychiatric investigations was as follows: localization of focal epileptogen zone (n = 60; 24.8%); differential diagnosis of dementias (n = 30; 12.4%); exploration of cerebrovascular diseases (n = 10; 4.1%); and other neurological diseases (n = 17; 7.0%). The main objective of the cardiological PET investigations was the exploration of viable myocardium. The present paper overviews both the procedures (including administrative issues, as well) and the results of the first 249 FDG-PET investigations.

Aged↗
PubMed1997

Inverse radiotherapy planning for a concave-convex PTV in cervical and upper mediastinal regions. Simulation of radiotherapy using an Alderson-RANDO phantom. Planning target volume.

AIM: Three-dimensional inverse treatment planning with modulated beams was applied for dosimetric optimization of a lengthy (22 cm) and complex (concave-convex) shaped planning target volume (PTV) in the cervical and upper mediastinal regions. MATERIAL AND METHOD: The planning was done for 9 coplanar beams spaced evenly at 40 intervals. Properties of 15 MV photons from a linear accelerator were simulated. The optimization of the fluence modulation profiles for each beam was based on a definition of the desired/permitted relative dose levels in the PTV and organs at risk, and a definition of the strengths of the constraints to achieve these objectives. RESULTS: An adequate dose delivery to the PTV and protection of the spinal cord are completely achievable. The dose delivered to the lungs is clinically acceptable with respect to the risk of radiation-induced pneumonitis. For reasons of physics, no further decrease in the radiation burden on the lungs can be attained with X-rays without compromising the PTV coverage. The radiation burden on some critical part of normal tissues was effectively reduced by application of a dummy organ at risk. CONCLUSION: The inverse planning is an effective method for conformal radiotherapy of large tumors as well. However, the power of the technique is insufficient when the tolerance dose of the neighbouring normal tissue is too low and its volume effect is high. Although requiring further operator interactions, introduction of dummy organs at risk may be of help in reducing the radiation burden on normal tissues.

Body Burden↗
PubMed1997

Survival chance in papillary thyroid cancer in Hungary: individual survival probability estimation using the Markov method.

PURPOSE: The typically benign, but occasionally rapidly fatal clinical course of papillary thyroid cancer has raised the need for individual survival probability estimation, to tailor the treatment strategy exclusively to a given patient. MATERIALS AND METHODS: A retrospective study was performed on 400 papillary thyroid cancer patients with a median follow-up time of 7.1 years to establish a clinical database for uni- and multivariate analysis of the prognostic factors related to survival (Kaplan-Meier product limit method and Cox regression). For a more precise prognosis estimation, the effect of the most important clinical events were then investigated on the basis of a Markov renewal model. The basic concept of this approach is that each patient has an individual disease course which (besides the initial clinical categories) is affected by special events, e.g. internal covariates (local/regional/distant relapses). On the supposition that these events and the cause-specific death are influenced by the same biological processes, the parameters of transient survival probability characterizing the speed of the course of the disease for each clinical event and their sequence were determined. The individual survival curves for each patient were calculated by using these parameters and the independent significant clinical variables selected from multivariate studies, summation of which resulted in a mean cause-specific survival function valid for the entire group. On the basis of this Markov model, prediction of the cause-specific survival probability is possible for extrastudy cases, if it is supposed that the clinical events occur within new patients in the same manner and with the similar probability as within the study population. RESULTS: The patient's age, a distant metastasis at presentation, the extent of the surgical intervention, the primary tumor size and extent (pT), the external irradiation dosage and the degree of TSH suppression proved to be statistically significant and independent prognostic factors with regard to cause-specific survival in multivariate studies. During follow-up, 14, 14, 9 and 12% of the patients underwent local/regional/distant relapses or thyroid cancer-related death, respectively. Through use of the above six independent clinical variables and the parameters relating to the four clinical events and their interrelations, mean cause-specific survival probabilities of 88, 83 and 78% were determined at 10, 20 and 30 years, respectively. The survival-predicting software (PATHYPRE) written on the basis of the biostatistical model is available through Internet connections on the home page of the National Institute of Oncology, Budapest (www.oncol.hu). CONCLUSION: Prediction of the individual survival probability for extrastudy cases affords a rationale for individualization of the treatment of papillary thyroid cancer patients.

Adolescent↗
PubMed1996

[The state of radiotherapy in 1996 Hungary and principles of its development].

Although the number of radiation treatments (external) fields and brachytherapeutic insertions) increased substantially, by 9% of a year, in Hungary in 1994 and 1995, about half of the patients who needed radiotherapy did not receive this form of treatment. The regionalization of radiotherapeutic care resulted in the establishment of 12 centres, with considerable discrepancies in infrastructural and staff conditions, characterized by presence of Western European conditions in 1 institution or by close to them in 3 institutions, but by lack of the required infrastructure or personnel in two-thirds (8) of the centres. To reach the minimum recommended infrastructural level, Hungarian radiotherapeutic care requires the following items for the 12 centres: 4 radioprotected treatment rooms, 8 linear accelerators of dual energy, 4 low-monoenergetic linacs/telecobalt units, 5 after-loading set-ups, 6 simulators, 6 CT-based treatment planning systems and 6 automatic water phantoms. With respect to the present workload, the number of personnel in the different groups is low; the situation is especially problematic in newly organized or reconstructed centres. Furthermore, provision of radiation treatment to all cancer patients who need it, requires development at every level of the staff. Increases in the infrastructural and staff conditions of the currently existing radiotherapeutical centres should be the actual goal, and not the foundation of new centres. The most important aspects of the priority in the development of the infrastructure are the following: higher number of adequately trained staff, academic obligations (universities), change of the amortized facilities and supplementation of the currently empty radioprotected rooms with equipment.

Forecasting↗
PubMed1996

Cytogenetic study of radiation burden in thyroid disease patients treated with external irradiation or radioiodine.

Where clinically permitted, either external irradiation or radioiodine therapy is usually recommended for the treatment of differentiated thyroid cancer patients. The choice depends on the treatment philosophy of the responsible physician. This paper describes an attempt to clarify the radiation burden on the lymphocytes in consequence of these two therapeutic modalities. An analysis was made of the extent to which exposure to local neck irradiation (25 x 2 Gy) or radioiodine therapy (1734-2600 MBq) causes chromosomal aberrations in the lymphocytes of thyroid disease patients after total or subtotal thyroidectomy. External irradiation caused many more chromosomal aberrations than 131I therapy did, but analysis of the distribution of the aberrations suggested a homogeneous dose distribution only in 131I-treated and thyroidectomized cancer patients. In thyrotoxic patients with intact thyroid glands, the lower therapy doses (185-595 MBq) caused a significantly higher frequency of aberrations than that observed in thyroid cancer patients, and the dose distribution in the lymphocytes was inhomogeneous. Thus, in the modelling of accidental environmental radioiodine exposure, thyroid patients with small if any residual thyroids are not a suitable group.

Adult↗