Angiography-proven liver metastases explain low efficacy of lymph node dissections in medullary thyroid cancer patients

AIM

To report the role of liver angiography in the staging of medullary thyroid cancer (MTC) patients.

MATERIAL AND METHODS

Sixty MTC patients with persistent or recurrent hypercalcitonemia (n=49), a characteristic general symptom (diarrhea, n=4) or a normal basal calcitonin level without general symptoms (n=7) were investigated by dynamic liver CT, MRI and angiography between 06/1998 and 06/2002.

RESULTS

Dual-phase CT and MRI investigations identified hepatic metastases with relatively low frequency (8/58 on MRI, and 7/60 on CT). Angiography indicated liver involvement in 54/60 cases. The hepatic metastases were typically multiple, hypervascular, small foci (only 13 foci measured >/=10 mm). With one exception significant disease progression was not observed over 5 years of follow-up.

CONCLUSIONS

Liver angiography is a powerful tool to reveal hepatic metastases in MTC patients. Frequent, inoperable liver metastases in hypercalcitoninemic MTC patients demonstrate that secondary lymph node dissection is an inefficient technique for restoration of a normal calcitonin level.

Characteristics of radiogenic lower motor neurone disease, a possible link with a preceding viral infection

OBJECTIVE

To investigate the pathogenesis of the rare radiogenic lower motor neurone disease (LMND) on the basis of a meta-analysis of the published case histories.

MATERIALS AND METHODS

The authors reviewed 47 well-documented radiogenic LMND cases from the English literature.

RESULTS

The disease typically occurs following the irradiation of radiosensitive cancers situated near the spinal cord. It arises predominantly (46 cases) in the lower extremities; only one case involved the upper extremities. There is a male predominance (male:female ratio 7.8:1), and the patients are characteristically young (13-40 years, with four exceptions). An overdose does not seem to be a particular risk factor for the development of the disease, as total dose, fraction size and biologically effective dose are typically below 50 Gy, 2 Gy and 128 Gy2, respectively, which are regarded as safe doses. Other risk factors (chemotherapy, operations, etc) have been identified only rarely. Radiogenic LMND is manifested in an apparently random manner, 4-312 (mean 48.7) months after the completion of radiotherapy.

DISCUSSION

The complete lack of a dose-effect relationship argues strongly against a pure radiogenic nature of the pathological process. The latency period is typically several years and it varies extremely, which excludes a direct and complete causal relationship between radiotherapy and LMND. As the interaction of ionizing radiation with living tissues is highly unspecific, thus a selective motor injury due to irradiation alone, without comparable effects on the sensory and vegetative fibers, seems improbable.

CONCLUSIONS

On analogy with the viral motor neurone diseases, we suppose that radiogenic LMND may be preceded by viral (enterovirus/poliovirus) infection. Based on the meta-analysis, it is suggested that irradiation may be only a single component of the set of factors jointly resulting in the clinical state regarded as radiogenic LMND.

FDG PET imaging in hereditary thyroid cancer

AIM

To report the role of different imaging methods in staging individuals with multiple endocrine neoplasia 2A (MEN2A) or familial medullary thyroid carcinoma (FMTC).

MATERIAL AND METHODS

Fourteen newly diagnosed gene carriers underwent cervical ultrasound scanning (US), cervical and mediastinal CT, MRI and whole-body meta-[131I]iodobenzylguanidine (MIBG) scintigraphy and [18F]fluorodeoxyglucose (FDG) PET scanning.

RESULTS

US identified seven true primary cancer. CT and MRI located only tumors > or =5 mm in diameter. MIBG scintigraphy and FDG PET could not identify MTC foci within the thyroid. Whole-body FDG PET identified two true-positive and one false-positive lymph node metastases. MIBG scintigraphy did not identify lymph node metastases. Total thyroidectomy was performed in 12 cases, and subtotal thyroidectomy in two subjects.

CONCLUSIONS

Whole-body FDG PET and cervical US help stage individuals carrying mutant genes verifying MEN2A or FMTC.

A novel technique with a flexible applicator for MRI-based brachytherapy of cervical cancer

PURPOSE

To introduce a novel technique for magnetic resonance (MR)-based 3-dimensional planned high-dose rate intracervical brachytherapy (BT).

MATERIALS AND METHODS

During 2002, 16 patients received external beam radiotherapy and BT as part of radiochemotherapy for cervical cancer. A special adjustable applicator device was designed and used for BT. The isodose distribution was calculated from MR images with the applicator in place.

RESULTS

The planning target volume coverage was adequate and the radiation burden on the organs at risk was within acceptable limits. Complete regression was achieved in two patients (12.5%), and partial regression in ten (62.5%) patients. The overall response rate for the complex treatment was 93.75%. In three cases the disease was considered to be stable.

CONCLUSION

The MR-compatible, flexible applicator allows safe and reproducible cervical radiotherapy with no added discomfort or hazard for the patient.

Autopsy verifies demyelination and lack of vascular damage in partially reversible radiation myelopathy

STUDY DESIGN

Case report of recovering radiation myelopathy.

OBJECTIVE

To present autopsy and functional imaging findings on a unique case of slowly recovering radiation myelopathy with the aim of the clarification of the underlying mechanism.

PATIENT

The cervical spinal cord and the distal part of the medulla oblongata of a 36-year-old thyroid cancer patient had been incorrectly irradiated with a total dose of 61 Gy and a fraction size of 3.4 Gy (J Neurol Sci 1999; 163:39-43), resulting in incomplete cervical transection with a 5-month latency period following the termination of radiotherapy. This was followed by a 9.5-year spontaneous improvement until her demise, during which the check-ups were supplemented by positron emission tomography (PET) investigations; these indicated increased [18F]deoxyglucose and [15O]butanol uptakes, but a diminished [11C]methionine accumulation by the irradiated spinal cord segment.

RESULTS

Autopsy revealed demyelination (with axonal loss) and neuronal damage in the cervical spinal cord and the distal part of the medulla oblongata. In the same region, only minimal vascular injury (thickening of some of the capillary walls) was detected, but not cell proliferation or chronic inflammation. Bilateral, secondary pyramidal tract degeneration caudal to the irradiated segment was observed. The PET and autopsy findings, although separated by 2 years, are consistent.

CONCLUSIONS

The pathological state of the spinal cord revealed by the autopsy is concordant with the incomplete cervical transection, implying that the functional recovery is supported by a process that probably differs from the restoration of the mechanism destroyed by the radiotherapy. For the restoration of the function, we suggest an altered conduction mechanism of the action potential, involving an increased number of sodium channels along the demyelinated segments of the injured axons, which is fully congruent with the PET findings.

A PET study on the characterization of partially reversible radiogenic lower motor neurone disease

OBJECTIVE

To investigate the pathomechanism of the rare radiogenic lower motor neurone disease (LMND) on the basis of a case history involving a partial functional recovery.

PATIENT

A 31-year-old seminoma patient received postoperative para-aortic and para-iliac telecobalt irradiation with a biologically effective dose of 88 Gy(2) (44 Gy in 2 Gy fractions/day, with an estimated alpha/beta of 2 Gy) delivered to the spinal cord following a single cycle of chemotherapy. LMND developed 4 months after the completion of radiotherapy. The patient exhibited flaccid paraparesis of the lower extremities (without sensory or vegetative signs), followed by a worsening after further chemotherapy, due to pulmonary metastatization. A gradual spontaneous functional improvement commenced and led several years later to a stabilized state involving moderately severe symptoms.

METHODS

In the 15th year of the clinical course, magnetic resonance imaging (MRI) and positron emission tomography (PET) with [(18)F]fluorodeoxyglucose (FDG) and [(11)C] methionine were conducted. Four lines of experiments (clonogenic assay using fibroblasts isolated from a skin biopsy sample of the patient, comet assay, micronucleus assay, and the testing of chromosome aberrations after in vitro irradiation of peripheral blood samples) were performed in a search for an increased individual radiosensitivity.

RESULTS

MRI investigations failed to reveal any pathological change. PET demonstrated an increased FDG accumulation, but a negligible [(11)C] methionine uptake in the irradiated spinal cord segments. The radiobiological investigations did not indicate any sign of an increased individual radiosensitivity.

CONCLUSIONS

We suggest that the observed partial functional recovery and stabilization of the symptoms of radiogenic LMND may be explained by the higher than normal density of sodium channels expressed along the demyelinated axons of the restored conduction. The increased energy demands of this type of conduction are proved by a higher metabolic rate (increased FDG uptake) of the irradiated spinal cord segments without a substantial regenerative process (lack of detectable protein synthesis).

Ovarian steroid cell tumor and a contralateral ovarian thecoma in a postmenopausal woman with severe hyperandrogenism

A 49-year-old woman presented with rapidly progressing hirsutism, receding hairline, male-pattern baldness and deepening of voice, which had developed over the past 2 years. Hormonal evaluation showed a markedly elevated serum testosterone level (418 ng/dl) and no evidence of increased production of cortisol, dehydroepiandrosterone, dehydroepiadrosterone-sulfate, androstenedione, or 17-hydroxyprogesterone. Transvaginal ultrasound examination suggested the presence of a small mass within the left ovary, but all other radiological studies, including adrenal and ovarian computed tomography, magnetic resonance imaging, radio-labelled cholesterol scintigraphy and positron emission tomography, were negative. Subsequently, bilateral selective venous sampling showed a marked testosterone gradient in the right ovarian vein. Bilateral salpingo-oophorectomy was performed (the patient had had a previous vaginal hysterectomy), and histopathological examination revealed a 10-mm steroid cell tumor within the right ovary and a 15-mm thecal cell tumor within the left ovary. The postoperative serum testosterone level returned to normal and the patient showed a slow regression of clinical symptoms. The simultaneous occurrence of a virilizing ovarian steroid cell tumor and an apparently non-functioning thecoma within the contralateral ovary emphasizes the potential pitfalls that may exist in the preoperative evaluation of patients with markedly increased testosterone production.

Second malignancies after treatment for Hodgkin's disease

The occurrence of treatment-related second malignancy following Hodgkin's disease (HD) has now been recognized as a major problem. The purpose of this study was to review our experience with second malignancies in patients treated for Hodgkin's disease, comparing the results with the international literature data. Six hundred and sixty five patients with HD were treated in our department, between 1978 and 1996. Second neoplasm developed in 32 cases (4.8%). Seven secondary hematological malignancies were observed: four acute nonlymphocytic leukemias, two non-Hodgkin's lymphomas and one chronic myeloid leukemia. Among patients with second hematological malignancies, the mean age at diagnosis of HD was 44 years and the mean interval until the development of second malignancy was 6.1 years. Five patients received chemo- and radiotherapy and in two cases chemotherapy was used. Three of the seven patients are alive. Twenty-five patients have had solid tumors, affecting lung (5), breast (3), colon (3), stomach (2), urinary bladder (2), head-and-neck (1), thyroid gland (1), esophagus (1), liver (1), pancreas (1), furthermore, three sarcomas and two malignant melanomas were observed. Their mean age at the diagnosis of HD was 46 years and the mean period of latency was 8.3 years. Chemotherapy was applied to nine patients, 16 patients received both chemo- and radiotherapy. Eleven patients had solid tumors in the region irradiated earlier. Ten out of the 25 patients are alive, three patients' present state is unknown. Since alkylating agents increase the risk of leukemia and irradiation contributes mainly to other malignancies, future treatment protocols should attempt to reduce the most serious consequence of therapy without compromising the survival. It is necessary to investigate the impact of additional risk factors. Careful, lifelong observation is indicated for patients with HD, with special attention given to new clinical signs and symptoms.

Hypoglycemia activates compensatory mechanism of glucose metabolism of brain

The effect of plasma glucose concentration on the cerebral uptake of [18F]-fluorodeoxy-D-glucose (FDG) was studied in a broad concentration range in a rabbit brain model using dynamic FDG PET measurements. Hypoglycemic and hyperglycemic conditions were maintained by manipulating plasma glucose applying i.v. glucose or insulin load. FDG utilization (K) and cerebral glucose metabolic rate (CGMR) were evaluated in a plasma glucose concentration range between 0.5 mM and 26 mM from the kinetic constant k1, k2, k3 obtained by the Sokoloff model of FDG accumulation. A decreasing set of standard FDG uptake values found with increasing blood glucose concentration was explained by competition between the plasma glucose and the radiopharmacon FDG. A similar trend was observed for the forward kinetic constants k1, and k3 in the entire concentration range studied. The same decreasing tendency of k2 was of a smaller magnitude and was reverted at the lowest glucose concentrations where a pronounced decrease of this backward transport rate constant was detected. Our kinetic data indicate a modulation of the kinetics of carbohydrate metabolism by the blood glucose concentration and report on a special mechanism compensating for the low glucose supply under conditions of extremely low blood glucose level.

Molecular genetic diagnostic program of multiple endocrine neoplasia type 2A and familial medullary thyroid carcinoma syndromes in Hungary

Medullary thyroid carcinoma (MTC) occurs usually in sporadic form, but about a quarter of the cases are hereditary and appear as part of one of the multiple endocrine neoplasia type 2 (MEN2) syndromes. Mutations in the RET protooncogene are known to be the cause of the MEN2A and familial medullary thyroid carcinoma (FMTC) syndromes in the majority of the families. Direct DNA testing allows prophylactic thyroidectomy to be offered to individuals carrying a mutation in the above codons, and in mutation-negative cases it reduces the yearly screening-related burden on family members at risk of the disease. By DNA sequencing and PCR-restriction fragment length polymorphisms, 65 MTC probands were examined for mutations in residues 609, 611, 618, 620 of exon 10, and in residues 634, 768, 804 of exons 11, 13, and 14 respectively of the RET protooncogene. In our study, mutations in the above codons were detected in all of the 14 clinically MEN2A and FMTC families. One of these mutations, TGC609 TCC has not been reported previously. Of the 14 probands with the mutation, 25 relatives also had the identified mutation and 18 relatives proved to be non-carriers. Among the 51 probands with clinically sporadic MTC, none was found to carry a mutation in the above positions even if indirect signs of MTC, pheochromocytoma or hyperparathyroidism could be detected in some families. The frequency of the TGC634AGC mutation is unexpectedly high in our samples, which can probably be attributed to a founder effect. We conclude that screening for mutations in these codons is effective in families fulfilling the strict clinical criteria of MEN2A or FMTC.

Angiography effectively supports the diagnosis of hepatic metastases in medullary thyroid carcinoma

BACKGROUND

Medullary thyroid carcinoma (MTC) belongs in the group of neuroendocrine tumors with early lymphatic and hepatic dissemination. A high rate of undetectable metastases is hypothesized to be responsible for the frequent mismatch between the apparent relatively small tumor burden and the elevated plasma tumor marker level.

METHODS

Thirty-six MTC patients with residual/recurrent biochemical signs (elevated basal calcitonin level) and/or characteristic general symptoms (diarrhea and/or flushing) were systematically examined by conventional radiology, whole-body 18F-deoxyglucose positron emission tomography (PET), dynamic liver computed tomography and magnetic resonance imaging, and hepatic angiography.

RESULTS

Conventional diagnostic imaging revealed lymph node (LN) involvement in the cervical, mediastinal, supraclavicular, and axillary regions (16 cases), and multiple pulmonary (3 cases), bony (1 solitary and 1 multiple case), and breast (1 case) metastases. (18)F-deoxyglucose PET identified all these extralymphatic metastatic lesions (except 2 cases with multiple pulmonary metastases), and also supradiaphragmatic LN involvement in 34 (94%) patients. In 32 (89%) cases, multiple small (generally < or = 1 cm) hypervascular, hepatic metastases undetectable by other imaging methods were localized angiographically. Of the 23 original pathologic specimens investigated, 18 (78%) exhibited LN involvement. The smallest primary tumor in patients with hepatic metastases was 1 cm.

CONCLUSIONS

Hepatic angiography is recommended for primary staging in MTC patients with a primary tumor measuring 1 cm or larger, and/or pathologically proven LN involvement, and also during restaging for suspected recurrences to avoid unnecessary extensive surgical LN dissection in the neck and mediastinum.

[PET scanning in head and neck cancer]

INTRODUCTION: FDG (fluorine-labeled deoxy-glucose) and 11C-methionine positron emission tomography was evaluated in the diagnostics of head and neck cancer. PET scans were applied for identifying/staging relapse after oncotherapy or searching unknown primary tumor with metastatic lymph nodes of the neck. METHODS: Retrospective analysis of 22 patients examined by 17 (18)FDG and 15 (11)C-methionine PET scan. In 9 cases indication was unknown primary tumor with positive neck, in 13 cases previously treated head and neck cancer patients were examined for recurrence/restaging. RESULTS: In searching for unknown primary tumor not detectable with conventional methods, PET was effective in 22%, however, false positivity and uncertain results were found as well. In restaging PET proved to be very effective (85%) to discover recurrences and to differentiate them from post-treatment (mainly irradiation) effects. In two cases silent distant metastase were detected. CONCLUSION: PET can provide valuable information about unknown primary tumors, recurrences after oncotherapy and distant metastases as well. Simultaneous use of FDG/methionine scans does not improve the results.

[Current diagnostic method, prognosis estimation and therapy of papillary thyroid cancer: recommendations of the medical universities and the National Oncologic Institute of Budapest]

Physical examination, cervical ultrasonography (US) and aspiration cytology are the mainstays of the preoperative diagnostics of papillary thyroid carcinoma. For the staging of suspected malignant cases, cervical and mediastinal CT (MRI for inconclusive results) is indicated before any surgery. The end-result of primary treatment is assessed by total-body iodine scintigraphy and the serum human thyroglobulin (hTG) level. For long-term follow-up, physical examination and the serum hTG level are the most reliable tools (6-monthly), supplemented by cervical US and chest X-ray (yearly), and total-body iodine scintigraphy (2-yearly). If these furnish positive results, further examinations may be indicated. In suspected relapses of hTG non-producing and iodine non-accumulating papillary carcinomas, 201thallium chloride or 99mTc-sesta-MIBI (methoxy-isobutyl-isonitrile) scintigraphy, and positron emission tomography with 18fluoro-deoxyglucose or 11C-methionine may be of help. For estimation of the prognosis (cause-specific survival) of the patients, the MACIS score system of the Mayo Clinic is widely accepted, the patients being divided into low-risk and intermediate/high-risk categories. The recommended standard surgical intervention is near-total thyroidectomy (2-4 g residual glandular tissue left at the upper pole of the less-involved lobe), with a central cervical lymph node dissection for diagnostic purposes. In cases of lymph node dissemination, dissection (radical, modified radical, selective or microdissection) of any of the involved compartments (central, right or left cervical, or upper mediastinal) is indicated for therapeutic reasons, the method of which is depending on the extent of the metastatic involvement. Following adequate surgical intervention, no adjuvant radioiodine therapy is indicated for low-risk cases with a tumour of less than 1 cm diameter. For other low-risk or intermediate/high-risk patients, radioiodine ablation (R0N0M0) or a therapeutic radioiodine dosage (R2N1M1) is indicated. In cases at high-risk of local/regional relapse and in radioiodine non-accumulating tumorous cases, external radiotherapy may be applied. Thyroid hormone medication in a TSH suppressive dose is indicated during the first 5 postsurgical years: the goal is to achieve a TSH level below 0.1 (determined by a 3rd generation assay). If no relapse occurs or the case is a low-risk one, following the 5 years, it is enough to maintain the TSH level in a subnormal range (0.1-0.3).

[Molecular genetic study of medullary thyroid cancer]

Around 25% of medullary thyroid carcinoma (MTC) cases are familial and follow an autosomal dominant mode of inheritance. In these cases, MTC is part of an inherited cancer syndrome that has three distinct forms: MEN2A, MEN2B and familial MTC (FMTC). MEN2A is the most frequent syndrome, followed by FMTC and MEN2B. In 95% of MEN2A families and 85% of FMTC families, the germ-line missense mutations underlying the disease affect one of the five cysteine codons of the extracellular domain of the RET proto-oncogene. The mutated codons are 609, 611, 618 and 620 in exon 10, and 634 in exon 11. The most frequent mutations (80% in MEN2A, and 50% in FMTC) occur in codon 634. In our laboratory, the mutations of the codon 634 was detected by two independent methods: DNA sequencing and restriction fragment length polymorphism with polymerase chain reaction (PCR-RFLP). We have so far examined 105 persons at risk and found 19 positive cases. A positive genetic diagnosis allows preventive thyroidectomy, with a resultant cause-specific survival similar to that for the general population. In the event of a negative result, the family members of the affected proband are relieved of the physical and emotional consequences of the disease and the follow-up procedures. We plan to screen all 240 known Hungarian MTC patients and their relatives.

Total body irradiation before bone marrow transplantation. Technique and acute toxicity

PURPOSE

To evaluate the total body irradiation methods in the National Institute of Oncology between January 1984 and February 1998.

PATIENTS AND METHODS

One hundred and twenty-four patients underwent total body irradiation prior to bone marrow transplantation in the last 15 years. A special cobalt unit has been used, the dose rate was 6 to 8 cGy/min in the midline of the abdomen. The source-midline distance (SMD) was 340 cm and the field size was 80 x 200 cm. The dose calculation was done on the basis of a tissue-phantom ratio curve measured in total body irradiation conditions and effective tissue thickness (ETT). Between 1984 and 1992 the beam direction was horizontal, the patients laid in lateral position. In 11 cases the total dose to the abdominal midline was 10 Gy in 1 fraction. From 1986 the fractionation changed to 4 x 3 Gy in 4 days. Within individual lung shielding the average lung dose was 8.5 Gy. In 44/124 cases the order of conditioning treatment was chemo-radiotherapy. Since 1992 vertical beams were used, and the patients (80/124) laid in prone/supine position. The fractionation remained the same but radio-chemotherapy regime has been used.

RESULTS

The irradiation in prone position proved to be safer than lateral because of smaller patient motion and it resulted in a more accurate positioning of lung shielding too. In all cases, the acute side effects (headache, nausea, vomiting) were moderate. Using radio-chemotherapy the acute side effects during the total body irradiation were uncommon and well tolerable.

CONCLUSION

Our technique with the large source-midline distance, vertical beam direction and the supine/prone position is stable, convenient and safe to produce homogeneous dose distribution and ensures accurate and reproducible lung shielding.

[Positron emission tomography ia an effective tool in modern oncology]

A total of 399 positron emission tomography (PET) examinations were carried out with a GE 4096 Plus PET scanner during the past 5 years on patients referred to the National Institute of Oncology in Budapest. The majority (n = 316) of these investigations were performed with the use of [18F]-fluorodezoxyglucose (FDG) to map the glucose metabolism; [11C]-methionine PET was indicated in 79 cases to detect protein transport and metabolism. The perfusion tracer [15O]-butanol was applied in only 4 cases to answer certain oncology-related, differential diagnostic questions. The oncological examinations were related to primary diagnostics, staging/restaging and therapy monitoring. In the staging/restaging and therapy monitoring of known tumours, conclusive results were achieved in 81-82% of the cases by using either FDG or [11C]-methionine as tracer. The concordant numerical data indicated that the PET investigation provides a definite answer to the question of the presence or absence of viable tumour tissue, with similar effectivity in any of the above indications, no matter whether FDG or [11C]-methionine is used. The search for occult primary tumours was the most frequent indication within the primary diagnostics: 10 (37%) primaries were localized by using FDG PET in the 27 investigated cases. This is a remarkably high value, especially in view of the failure of all the conventional diagnostic procedures carried out prior to the PET investigations. Application of PET may be indicated in all cases when the ultimate question is a non-invasive estimation of viable tumorous tissue.

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.

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.

[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.

[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.

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.

[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.

[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.

[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).

[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.

[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.

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.

[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.

[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).

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.

[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.

[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.

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.

[Survival potentials of patients with papillary carcinoma of the thyroid gland in Hungary]

The typically benign, but occasionally rapid fatal clinical course of papillary thyroid cancer has raised the need for individual survival probability estimation, to tailor the treatment strategy exclusively to the given patient. A retrospective study was performed on 400 papillary thyroid cancer patients, with a mean follow-up time of 10.3 years, to establish a clinical database for uni- and multivariate analysis of the survival probability-related prognostic factors (Kaplan-Meier product limit method and Cox regression). For a more precise prognosis estimation, in the next step the most important clinical events were investigated and survival functions for each patient were calculated on the basis of a Markov renewal model. The basic concept of this approach is as follows: 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), that a patient experiences throughout the course of the disease. On the supposition that these events and the cause-specific death are influenced by the same biological process, the parameters of transient survival probability characterizing the speed of the course of the disease for each sequence of clinical events were determined. The individual survival curves for each patients were calculated by using the former parameters and the independent, significant clinical variables, summation of which resulted in an overall cause-specific survival function valid for the entire group. The patient's age, a distant metastasis at presentation, the extent of the surgical intervention, the primary tumour size, the dosage of the external irradiation and the degree of the TSH suppression proved to be statistically significant (in that sequence) and independent prognostic factors as concerns cause-specific survival in multivariate studies. During follow-up 14%, 14%, 9% and 12% of the patients underwent local/regional/distant relapses and thyroid cancer-related death. Through use of the above six independent clinical variables and the parameters relating to the interrelations of the four clinical events, mean cause-specific survival probabilities of 88%, 83% and 78% were determined at 10, 20 and 30 years, respectively. The 30-year individual survival probability prediction for these study cases showed that no cancer-related death occurred > or = 92% (low-risk group), while the tumour-related deaths were considerable (31%) < or = 78% (high-risk group), and there were only 6% deaths in the intermediate-risk group. The constructed survival function permits a prediction of the individual survival probability of extra-study cases under the given treatment conditions and within the given population, and thus affords a rationale for individualization of the treatment of papillary thyroid cancer patients.

[Malignant thyroid tumors in Hungary: morbidity and mortality]

In 1993, 181 new cases (36 men and 145 women) of thyroid cancer were diagnosed pathologically in Hungary, i.e. a morbidity of 1.8/100,000 for the total population, and of 0.7/100,000 and 2.7/100,000 for men and women, respectively. The distribution of the histological diagnoses: 61% papillary, 25% follicular, 5% medullary and 3% anaplastic carcinomas, and 6% others. In the same year, 125 patients (31 men and 94 women) died from thyroid cancer, i.e. a mortality rate of 1.2/100,000 for the total population, and of 0.6/100,000 and 1.8/100,000 for men and women, respectively. The relatively low morbidity reflects the fact that no new strong aetiological factor is operative in Hungary. The substantial mortality rate, however, is influenced by the geographically determined aggressivity of the disease, the inadequacy of the diagnostic procedures and therapeutic measures, and lack of the active follow-up. The latter facts are especially prominent in centres with a low patient turnover. In the field of health care, various measures must be introduced to prevent an increase in the morbidity and to diminish the mortality. Reduction of the iodine deficiency, rationalization of the medical use of ionizing irradiation, and implementation of the necessary hormonal medication for all patients operated by resection for thyroid diseases are needed for tumour prophylaxis. Before any medical decision-making, the achievement of complete diagnostic information, including the pathological revision of clinically questionable cases, is of paramount importance. The fundamental goals as concerns the treatment modalities are as follows: increased surgical skill and level of performance of external irradiation, the availability of radionuclide therapy, and guidance of all types of thyroxine medication by endocrine experts.

[Positron emission tomography: foundations and applications]

Positron emission tomography (PET) is a non-invasive biomedical imaging technique whereby the distribution of biological tracer molecules, labelled by positron emitting isotopes, in the living body can be studied quantitatively. As theoretically an metabolically active molecule can be labelled, the technique is applicable to the measurement of any biochemical or physiological process in proper anatomical context. The introduction of PET has revolutionised the exploration of normal physiological functions. With the help of technique, among others, anatomical structures underlying mental functions can be localised in the human brain, the receptor architecture of the nervous system can be mapped, or the kinetics of pharmacons can be properly measured and modelled. In the clinical practice, PET has proven to be a uniquely useful diagnostic technique in neurology, psychiatry, cardiology, and oncology in establishing primary diagnosis and differential diagnosis, designing therapeutic interventions as well as assessing their efficacy. Hungary's and Central European region's first PET center has been established at the University Medical School in Debrecen.

A retrospective analysis of different modalities for treatment of primary orbital non-Hodgkin's lymphomas

We have reviewed 37 patients with primary orbital lymphoma, using the Ann Arbor criteria and the Working Formulation and its modification. Thirty-one patients had stage I disease, four stage II, one stage III and one stage IV. The male to female ratio was 2.7:1. There were 34 low-grade tumours (including 24 mantle zone) and three intermediate-grade. Patients were divided into three groups according to their primary treatment. Group 1: radiotherapy (17 cases); Group 2: surgery alone (13 cases); Group 3: chemotherapy (seven cases). Patients were followed up from 5 months to 24.3 years, with a mean and median of 7.6 and 6.2 years, respectively. The BMDP software package was used for survival estimation (Kaplan-Meier) and determination of prognostic variable (univariate Cox regression). Local relapse-free survival at 10 years was 100% in Group 1, 0% in Group 2 and 42% in Group 3 with a statistically significant difference (p < 0.01) in favour of radiotherapy. Statistically significant good prognostic features were: complete remission (CR) in response to initial treatment, primary radiotherapy and older age. For stage I cases, there was no difference in distant relapse-free survival in the three groups. The overall cause-specific survival for stage I patients at 10 years was 100% for each group and at 20 years was 100, 67 and 0% for Groups 1, 2 and 3. The difference between the primary radiotherapy and chemotherapy-treated groups was significant at the p = 0.08 level. Statistically significant prognostic factors were early stage, low-grade histology and primary radiotherapy. In one patient, ptosis and diplopia appeared after surgery. One case of glaucoma required enucleation, one patient suffered severe dry eye syndrome. All patients (11/11) in whom the lens received direct radiation developed cataracts of different degrees if follow-up was long enough. Cataract formation was prevented by adequate lens shielding. One patient in CR from a stage I low-grade tumour died from chemotherapy-induced marrow aplasia. Primary orbital lymphoma is an indolent, usually stage I disease, showing low to intermediate-grade histology. After biopsy the best treatment is 30 (low-grade) to 40 Gy (intermediate-grade) carefully planned, lens-sparing megavoltage radiation without adjuvant chemotherapy.

[Quality assurance, audit and quality control of radiotherapy at radiology departments in Hungary]

The first quality assurance, audit and control system in the Hungarian "'health" care industry" is described for the medical specialty of radiotherapy. The prerequisites of the elaboration of the programme were an exact knowledge of the current Hungarian infrastructural and staffing conditions, and the radiotherapeutic activities. The recommendations cover the 5 medical universities including the national institute (the Debrecen, Pécs, Semmelweis, Szent-Györgyk Albert Medical Universities, and Haynal Imre University of Health Sciences) and the 5 regional oncological centres in hospitals (Jósa András, Markusovszky, Petz Aladár, Szentpéteri kapu and Uzsoki Hospitals). The departmental functions (patient care, teaching-education, research work and scientific organizing activity) and the structure (organization, infrastructure, staffing conditions, etc.) are described first, followed by the therapeutic principles and clinical process (patient referral and selection, decision-making, priorities in therapy initiation, treatment preparation and execution, etc.). The informal daily/weekly quality assurance programme long applied in the routine patient care has been formalized and supplemented with a weekly audit conference. In the course of the medical audit, all relevant clinical data are reviewed and scored by an internal or an external expert (not participating directly in the treatment process), e.g. for the adequacy of the medical decision preparative process, conformation to the institutional treatment protocol, equipment selection, treatment planning, simulation and portal film, etc. If a major deviation is detected, an immediate correction is initiated; minor deviations need analysis and then preventive and correcting action. As concern the audit of the other activities of the departments, the important indicators and their minimally desirable level are defined. The final goal of the implementation of this programme is high-precision radiotherapy with the best achievable treatment result.

[Tridimensional radiation treatment planning]

The effectiveness of radiotherapy and the possibility that the patient will be cured are basically determined by the accuracy of the therapy planning and the treatment. The tumour with its environment is a three-dimensional (3D) phenomenon, and therefore 3D radiation treatment planning and performance are needed for adequate coverage of the target volume (tumour+safety zone). The prerequisities of the elaboration of the 3D radiotherapy planning were as follows: the availability of high-performance hardware, the establishment of interactive computer graphics, and the development and direct integration into the therapy planning process of the digitalized information derived from diagnostic imaging, and especially computer tomography. The introduction of 3D treatment planning will mean the modernization of the radiotherapy, the accuracy of which may permit more cures, i. e. more patients will recover their ability to work.

Prophylactic external irradiation in differentiated thyroid cancer: a retrospective study over a 30-year observation period

Following surgery which left no microscopic residue, 114 patients with differentiated thyroid cancer (58 papillary, 56 follicular) were subgrouped on the basis of the dose of externally applied prophylactic postoperative radiation: group 1 received an adequate dose of radiation (> or = 4,500 cGy of telecobalt, > or = 4,000 R of orthovoltage therapy), while group 2 received an inadequate dose of radiation (this group included non-irradiated patients). Local/regional-relapse-free survival (LRRFS), distant-metastatic-relapse-free survival (DMRFS) and total-cause-specific survival (TCSS) were calculated by means of life-table analysis for each histologic type. TCSS and LRRFS were significantly (p < 0.001) better for group 1 in papillary cancer. No difference was found in DMRFS. LRRFS was significantly (p < 0.001) better for group 1 in follicular cancer. No differences were found in TCSS and DMRFS. We conclude that (1) prophylactic postoperative external irradiation is an effective method for survival prolongation in papillary cancer, reducing local/regional recurrences, and (2) external irradiation should be considered in the postoperative management of follicular cancer, to diminish local/regional relapse.

Bone marrow (reticuloendothelial system) scintigraphy for haematological follow-up of radiochemotherapy-treated patients

To assess the bone marrow capacity before a new treatment decision, 99mTc-human serum albumin bone marrow scintigraphy (with qualitative and quantitative evaluation) was performed in 32 patients with solid tumours or malignant lymphomas previously treated with radiochemotherapy. In the group with a normal bone marrow capacity, the blood counts were normal (14/16 cases) or became normal (2/16 cases) in the follow-up period, and the examined marrow samples exhibited normal haemopoiesis. In the group with a reduced bone marrow capacity, one or more blood counts were low in 14/16 cases. Decreased haemopoiesis was observed in only 4 of 8 examined marrow samples. The following conclusions were drawn. (1) A scintigraphically normal bone marrow capacity relates to normal haematological parameters, and therefore treatment plans could be decided on. (2) Although a reduced bone marrow capacity indicates pathological haematological conditions in the majority of cases, further studies are needed to evaluate its precise significance. (3) Application of this non-invasive, inexpensive, repeatable, non-immunizing method is recommended before a therapeutic plan is decided on for patients at considerable haematological risk.

[External irradiation of differentiated thyroid cancer: 30 follow up]

Following surgery which left no macroscopic residue 114 patients with differentiated thyroid cancer (58 papillary, 56 follicular) were subgrouped on the basis of the dose of prophylactic postoperative external radiation applied: group I--an adequate dose of radiation (greater than or equal to 4500 cGy of telecobalt, greater than or equal to 4000 R of orthovolt therapy); group II--an inadequate dose of radiation (including non-irradiated patients). Local/regional relapse-free survival (LRRFS), distant metastatic relapse-free survival (DMRFS) and total cause-specific survival (TCSS) were calculated by means of life-table analysis for both histologic types separately. Results. 1. TCSS and LRRFS were significantly (p less than 0.001) better for group I in papillary cancer. No difference was found in DMRFS. 2. LRRFS was significantly (p less than 0.001) better for group I in follicular cancer. No differences were found in TCSS and DMRFS.

CONCLUSIONS

1. The prophylactic postoperative external irradiation is an effective method for survival prolongation in papillary cancer, the local/regional recurrences thereby being reduced. 2. External irradiation, in conjunction with radioiodine treatment, should be considered in the postoperative management of follicular cancer to diminish local/regional relapse.

Three-dimensional photon radiotherapy planning for laryngeal and hypopharyngeal cancers. 2. Conformation treatment planning using a multileaf collimator

Three-dimension dose distributions have been computed for 15 MV X-ray radiation therapy (MEVATRON 77, Siemens) of laryngeal and hypopharyngeal cancers using isocentric rotational technique with multileaf collimator. Using a new concave contour tracing algorithm, satisfactory dose delivery to the target volume and efficient protection of the normal tissues can be achieved.

Three-dimensional photon radiotherapy planning for laryngeal and hypopharyngeal cancers. 1. Conventional rotational technique

Three-dimensional dose distributions have been computed for the photon radiation therapy of laryngeal and hypopharyngeal cancers, using biaxial and eccentric rotatory techniques. Treatment plans obtained under various conditions of irradiation with a 15 MV linear accelarator (MEVATRON 77, Siemens) are analysed and compared. Dose delivery to the tumour and the degree of spinal cord protection are evaluated for both treatment techniques. The eccentric plan is somewhat superior to the biaxial one, suggesting a justifiable preference to use this method in the radiation treatment of these tumours. Simulations show that extreme care is needed in positioning the axis: an accuracy of +/- 3 mm is required in the sagittal plane.

[Clinical observations on breast cancer in males]

The analysis of clinical parameters of seventeen male breast cancer patients clearly demonstrate the correlation between prognosis and size of primary tumour as well as regional spread. The localization of the tumour in the breast is not correlated to survival. Intelligent hormonal therapy contributes to improving of survival. Detections of plasma FSH, LH, testosterone, 17 beta estradiol levels are useful in examining of pathomechanism, revealing relapse, and monitoring hormonal therapy.