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P Scalliet

Publications and source records attributed to P Scalliet.

At least 55 records · Page 3Linked to original sources
PubMed1996

Palliative effectiveness of radiation therapy in the treatment of superior vena cava syndrome.

A study was made of 34 patients concerning the palliation effect of radiation therapy in the treatment of superior vena cava syndrome (SVCS). They were seen between 1986-1993, at the Department of Radiotherapy in Middelheim General Hospital, Belgium, Antwerp. All patients had a syndrome of superior vena cava obstruction secondary to malignancy. The histologic diagnosis delivered an equal distribution of small cell lung carcinoma (SCLC) and non-small cell lung carcinoma (NSCLC). All patients with a SCLC received chemotherapy as initial treatment, but showed no response, relapse or evolution during treatment. Each treatment began with rapid-high dose irradiation, to continue after re-evaluation with rapid high-dose in cases of poor response or with the conventional fractionation of 2 Gy daily in patients showing good relief of symptoms. The initial rapid-high dose schedules depended on the performance status of the patients. Seventy-six percent of the patients with NSCLC showed good relief of their symptoms. It was very unexpected but the majority of NSCLC patients responded more quickly than SCLC patients, within three days after initiating treatment. In SCLC, 94% of the patients responded up until death. The palliation index defined as the ratio of the symptom-free period on the total survival which is 1 in ideal circumstances, was 0.55 in NSCLC and 0.90 in SCLC. In this last group, death was mainly due to disease progression in distant sites.

Adult↗
PubMed1996

Entrance and exit dose measurements with semiconductors and thermoluminescent dosemeters: a comparison of methods and in vivo results.

BACKGROUND AND PURPOSE: In order to compare diodes and TLD for in vivo dosimetry, systematic measurements of entrance and exit doses were performed with semiconductor detectors and thermoluminescent dosemeters for brain and head and neck patients treated isocentrically with external photon beam therapy. MATERIAL AND METHODS: Scanditronix EDP-20 diodes and 7LiF thermoluminescent chips, irradiated in a 8 MV linac, were studied with similar build-up cap geometries and materials in order to assure an equivalent electronic equilibrium. Identical calibration methodology was applied to both detectors for the dose determination in clinical conditions. RESULTS: For the entrance dose evaluation over 249 field measurements, the ratio of the measured dose to the expected dose, calculated from tabulated tissue maximum ratios, was equal to 1.010 +/- 0.028 (1 s.d.) from diodes and 1.013 +/- 0.041 from thermoluminescent crystals. For the exit dose measurements, these ratios were equal to 0.998 +/- 0.049 and 1.016 +/- 0.070 for diodes and TLDs, respectively, after application of a simple inhomogeneity correction to the calculation of the expected exit dose. CONCLUSIONS: Thermoluminescence and semiconductors led to identical results for entrance and exit dose evaluation but TLDs were characterised by a lower reproducibility inherent to the TL process itself and to the acquisition and annihilation procedures.

Brain Neoplasms↗
PubMed1996

No age limit for radical radiotherapy in head and neck tumours.

The elderly are often treated less aggressively in an attempt to preserve their quality of life with regards to toxicity. However, there are few data regarding the acute and late toxicity of radiotherapy (RT) in elderly patients. From February 1980 to March 1995, 1589 patients with head and neck cancers who enrolled in EORTC trials received RT and were available for analysis on RT toxicity. Patients over 65 years of age were in excess of 20%. Data regarding age and acute objective mucosal reactions were available for 1307 patients and 1288 had toxicity > or = grade 1. Age and acute functional mucosal reactions were registered for 838 patients and 824 patients had toxicity > or = grade 1. Bodyweight alteration during treatment was available in 1252 patients; it increased in 153 patients and decreased in 1099 patients. Late toxicities were examined only if they occurred before an eventual tumour failure in order to avoid confusion between effects of first- and second-line treatments. 749 patients were available for analysis of which 646 had late toxicity grade > or = 1. Survival and toxicity were examined in different age ranges from 50 to 75 years and over. There was no significant difference in survival between each age group. A trend test was performed to assess any correlation between age and the acute occurring toxicity. There was no significant difference in acute objective mucosal reactions (P = 0.1) and in weight loss > 10% (P = 0.441). In contrast, older patients had more severe (grade 3 and 4) functional acute toxicity (P < 0.001) than younger patients. We evaluated the probability of late toxicity occurrence in relation to time with the Kaplan-Meier method and the logrank test in each age group. Eighteen per cent of patients were free of late effects at 5 years, the logrank test showing no significant difference between ages (P = 0.84). In conclusion, chronological age is irrelevant for therapeutic decisions.

Acute Disease↗
PubMed1996

Response analysis of TLD-300 dosimeters in heavy-particle beams.

In vivo dosimetry is recommended as part of the quality control procedure for treatment verification in radiation therapy. Using thermoluminescence, such controls are planned in the p(65) + Be neutron and 85 MeV proton beams produced at the cyclotron at Louvain-La-Neuve and dedicated to therapy applications. A preliminary study of the peak 3 (150 degrees C) and peak 5 (250 degrees C) response of CaF2:Tm (TLD-300) to neutron and proton beams aimed to analyse the effect of different radiation qualities on the dosimetric behaviour of the detector irradiated in phantom. To broaden the range of investigation, the study was extended to an experimental 12C heavy ion beam (95 MeV/nucleon). The peak 3 and 5 sensitivities in the neutron beam, compared to 60Co, varied little with depth. A major change of peak 5 sensitivity was observed for samples positioned under five leaves of the multi-leaf collimator. While peak 3 sensitivity was constant with depth in the unmodulated proton beam, peak 5 sensitivity increased by 15%. Near the Bragg peak, peak 3 showed the highest decrease of sensitivity. In the modulated proton beam, the sensitivity values were not significantly smaller than those measured in the unmodulated beam far from the Bragg peak region. The ratio of the heights of peak 3 and peak 5 decreased by 70% from the 60Co reference radiation to the 12C heavy-ion beam. This parameter was strongly correlated with the change of radiation quality.

Carbon↗
PubMed1996

The influence of hypoxia on the cytotoxicity of concomitant KW-2149 and ionizing irradiation in Chinese hamster fibroblasts.

7-N-((2-((2-(gamma-L-glutamylamino)ethyl)dithio)ethyl))-mitomycin C (KW-2149) is a newly synthesized water-soluble mitomycin C (MMC) analog. Preclinical testing showed an interesting activity profile and a superior hematological tolerance in murine models. The aim of this study was to investigate the interaction of this compound with ionizing radiation, both under normoxic and hypoxic conditions, in Chinese hamster fibroblasts (V79). V79 cells were irradiated both under normoxic conditions and after a 1 h period of hypoxia. Paired irradiation dose-response curves confirmed the significance of radioresistance under hypoxia with an oxygen enhancement ratio of approximately 3. In contrast to MMC, KW-2149 showed no increased cytotoxic effect on hypoxic V79 cells. The cytotoxic effect of KW-2149 increased with increasing concentration, irrespective of the ambient oxygen pressure. When KW-2149 was combined with irradiation under hypoxic conditions, cytotoxicity was significantly enhanced under these conditions. The difference in survival between normoxic and hypoxic conditions was statistically significant (p < 0.004). These data suggest a radiosensitizing effect of KW-2149, more pronounced under hypoxic conditions. This effect increases with radiation dose. It also corroborates earlier suggestions of a different mode of action of KW-2149 as compared to MMC.

Animals↗
PubMed1996

Generalized bone marrow metastases. High liver uptake on bone marrow immunoscintigraphy associated with extramedullary hematopoiesis.

Increased hepatic uptake and absent bone marrow uptake on bone marrow immunoscintigraphy has been reported after the formation of human antimurine antibodies. A case of generalized bone marrow metastases is presented, in whom an elevated liver uptake on bone marrow immunoscintigraphy proved to be associated with extramedullary hematopoiesis. Extramedullary hematopoiesis should be included as a possible cause of a disproportionately elevated liver uptake on bone marrow immunoscintigraphy, especially on initial studies, or on repeat studies with low human antimurine antibody titers. Tc-99m labeled BW 250/183 immunoscintigraphy may aid in the localization of suspected sites of extramedullary hematopoiesis.

Adult↗
PubMed1995

Quality assurance in radiotherapy. European Society for Therapeutic Radiology and Oncology Advisory Report to the Commission of the European Union for the 'Europe Against Cancer Programme'.

This document is now in the process of being endorsed by all National Scientific Societies of Radiotherapy and Medical Physics of the European countries. It can therefore not be formally considered as the definitive version and is still susceptible to benefit from further alterations or improvements.

Clinical Competence↗
PubMed1995

Metastases seen on SPECT imaging despite a normal planar bone scan.

Although bone scintigraphy is an extremely sensitive method for the detection of focal bone disease, small lesions below the resolution of planar imaging may be missed. This is a report of a patient with carcinoma of the breast who showed tumor progression 1 year after initial treatment. Complete evaluation was performed in order to detect the origin of increased level of a tumor marker. Although planar bone scintigraphy could not demonstrate any lesion in the spine, multiple metastases were detected in the lumbar and the thoracic spines on SPECT imaging. Only some of these lesions were seen with MRI. Repeat planar bone imaging 6 weeks later showed multiple bone lesions in the lumbar and thoracic areas.

Adenocarcinoma↗
PubMed1994

Analysis of complications in a prospective randomized trial comparing two brachytherapy low dose rates in cervical carcinoma.

PURPOSE: The analysis of complications in a prospective randomized trial comparing two preoperative brachytherapy low-dose rates in early stage cervical cancer is presented. METHODS AND MATERIALS: Between 1985 and 1988, 204 patients with Stage I and limited Stage II cervical cancer were randomized to receive one of two preoperative brachytherapy low-dose rates (0.4 and 0.8 Gy/hr). The objective of this trial was to determine the benefits, if any, of the higher-dose rate within the therapeutic arsenal for this patient population, in terms of survival, local control, and complications. The type and severity of all complications were evaluated according to a common glossary and a strict follow-up schedule was established given that the treatment of cervical cancer is multidisciplinary, involving gynecologists, surgeons, and radiotherapists. RESULTS: Overall survival: 85% at 2 years and local control: 93% at 2 years, were similarly distributed between the two groups. Regardless of their nature and severity, 139 and 175 complications were observed among 63% and 75% of patients, in the 0.4 and 0.8 Gy/h dose rate groups respectively. Gynecologic and urinary complications were the most frequent (38% and 28% of all complications), followed by vascular (15%), digestive (10%), nervous (5%) and cutaneous (5%). A total of 14 and 17 severe complications (Grade 3) were observed in 7% and 13% of patients, respectively in the 0.4 and 0.8 Gy/h dose rate groups (p = 0.12). Nonparametric survival methods used to compare the time to the first complication did not show a significant difference between the two groups: 62% and 72% at 2 years (p = 0.27). When the first complication and its evolution were considered (early complications), the prevalence of complications was not significantly different between the two groups: 28% vs. 34% at 2 years (p = 0.31). In this prospective trial, patients were regularly followed-up and complications of varying nature and severity were observed in succession during follow-up. When successive complications and their evolution were taken into account, the prevalence of complications was significantly greater in the higher-dose rate group: 30% vs. 45% at 2 years (p = 0.03). CONCLUSION: The results of this trial showed that long-term effects of treatment, when represented by prevalence of complications over time, were more frequent in the higher dose rate group. This underlines the importance of the regular follow-up of patients and of coding, not only the occurrence of all complications, but also their evolution over time.

Brachytherapy↗
PubMed1994

A comparison of early effects with two dose rates in brachytherapy of cervix carcinoma in a prospective randomised trial.

This phase III randomised trial examined the early effects of two low dose rates (0.38 and 0.73 Gy/h) in brachytherapy of stage I and IIp cervical cancer patients. A total of 204 patients were included between January 1985 and September 1988. Since the main analysis of this paper concerned surgical difficulties, only the 155 patients (76%) on whom surgery was performed at the Institut Gustave-Roussy were retained in this analysis. Treatment consisted of uterovaginal 137Cs irradiation followed by immediate or deferred surgery. The two groups were similar for pretreatment characteristics except for endocervix involvement. Their brachytherapy parameters were also similar (60 Gy pear dimensions, doses to critical organs, total kerma, etc.). The factors with a poor prognosis were, for surgical difficulties, older age, stage II and a small irradiated pear volume; for difficulties with haemostasis, immediate surgery, stage II and previous surgery; and for difficulties in dissection, lymph node involvement. The dose rate significantly influenced surgical difficulties for the stage IIp patients operated on by deferred surgery. Those treated with the higher dose rate showed a 2-fold increase in surgical difficulties compared to those irradiated at the lower dose rate (P = 0.03). The independent prognostic factors for sterilisation of the surgical specimen were small tumour size and absence of lymph node involvement. An inverse dose rate effect was observed for medium size tumours, with significantly more sterilisations observed in stage IIp patients in the lower dose rate group (P < 0.01).

Adult↗
PubMed1994

Is there potential for granulocyte or granulocyte-macrophage colony stimulating factors in radiotherapy?

The purpose of this communication was to explore which situations in radiotherapy might benefit from concomitant administration of haematopoietic growth factors (HGF). Only large-field radiotherapy is likely to induce bone marrow depression, such as irradiation of Hodgkin's disease. Therefore, we studied 122 patients irradiated for Hodgkin's disease, looking at peripheral blood cell count before, during and after the treatment. One hundred and four treatments were preceded by chemotherapy (MOPP and/or ABVD) and the radiation dose was between 36 and 44 Gy in 2 Gy per fraction sessions. Severe leucopenia (grade III WHO) was very uncommon and justified treatment interruption only twice. In both cases, it was paired with thrombocytopenia. No infection developed. It is concluded that when radiotherapy is used alone, prophylactic use of HGFs does not seem justified. This, of course, does not apply to radiochemotherapy combinations, although thorough investigations in this field are still awaited.

Adolescent↗
PubMed1994

[Method for evaluating long term complications. A study from a phase III trial comparing two low dose rates in gynecologic brachytherapy].

When treatment complications are the main criteria of a study, the simplest way for estimating the complication rate over time is to use the Kaplan-Meier method. The failure is the onset of the first complication. A new way is proposed here which takes into account the time to an eventual second, and third complication, and their duration as well. Results from a phase III randomized trial comparing two preoperative brachytherapy low dose rates in localized stage cervix carcinoma patients are used to illustrate both methods. The new method showed a greater long term complication rate in the higher dose rate group.

Brachytherapy↗
PubMed1993

Phase III trial comparing two low dose rates in brachytherapy of cervix carcinoma: report at two years.

This Phase III randomized trial examined the effect of two low dose rates (0.73 or 0.38 Gy.h-1) on the local control, survival, relapse-free survival, complications, and secondary effects in the treatment of cervical cancers. A total of 204 Stage Ib or II cervical carcinoma patients were included between January 1985 and September 1988. Treatment consisted of uterovaginal 137Cs irradiation followed by surgery. The two groups were similar for age, tumor stage and medical or surgical history. Their brachytherapy parameters were also similar (60 Gy pear dimensions, dose to critical organs, total kerma, etc....) There were no differences in the short-term effects or therapeutic outcome. However, overall complications and side effects observed after 6 months were significantly more frequent (p < 0.01) in the higher dose rate group.

Adenocarcinoma↗
PubMed1993

HDR versus LDR gynecological brachytherapy revisited.

Despite the obvious breakthrough of high dose-rate (HDR) afterloading systems on the gynecological brachytherapy market, questions still remain regarding the transfer of available expertise gained throughout the last 80 years with low dose-rate (LDR) radium and cesium, especially regarding the conversion of LDR total dose into equivalent HDR dose per fraction and total dose. Calculation of biologically equivalent schedules requires a knowledge of repair capacity and repair kinetics of tumors and normal tissues, both of which influence the biological effect of any radiation dose. The clinical experience with HDR is, however, accumulating and it is acknowledged that the new technique entails an acceptable therapeutic index as compared to the classical LDR. There is thus a state of apparent 'equivalence' between the two treatment modalities. This state is influenced by many factors in which, in contrast to what is frequently claimed, radiobiological factors do not play the most important role. It is probably its high-tech environment which makes HDR an acceptable alternative. Treatment at LDR, indeed, has proven to be quite tolerant to a lack of absolute precision, something that would be disastrous with HDR techniques. Because HDR intracavitary brachytherapy has not been compared in controlled trials with the best existing LDR brachytherapy, but only retrospectively with heterogeneous LDR clinical data, it cannot be claimed to be equivalent, but simply feasible.

Brachytherapy↗