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P Scalliet

Publications and source records attributed to P Scalliet.

At least 19 recordsLinked to original sources
PubMed2007

Phase I/II study of preoperative cetuximab, capecitabine, and external beam radiotherapy in patients with rectal cancer.

BACKGROUND: To assess the safety and preliminary efficacy of concurrent radiotherapy, capecitabine, and cetuximab in the preoperative treatment of patients with rectal cancer. PATIENTS AND METHODS: Forty patients with rectal cancer (T3-T4, and/or N+, endorectal ultrasound) received preoperative radiotherapy (1.8 Gy, 5 days/week for 5 weeks, total dose 45 Gy, three-dimensional conformal technique) in combination with cetuximab [initial dose 400 mg/m(2) intravenous given 1 week before the beginning of radiation followed by 250 mg/m(2)/week for 5 weeks] and capecitabine for the duration of radiotherapy (650 mg/m(2) orally twice daily, first dose level; 825 mg/m(2) twice daily, second dose level). RESULTS: Four and six patients were treated at the first and second dose level of capecitabine, respectively. No dose-limiting toxicity occurred. Thirty additional patients were treated with capecitabine at 825 mg/m(2) twice daily. The most frequent grade 1/2 side-effects were acneiform rash (87%), diarrhea (65%), and fatigue (57%). Grade 3 diarrhea was found in 15%. Three grade 4 toxic effects were recorded: one myocardial infarction, one pulmonary embolism, and one pulmonary infection with sepsis. Two patients (5%) had a pathological complete response. CONCLUSIONS: Preoperative radiotherapy in combination with capecitabine and cetuximab is feasible with some patients achieving pathological downstaging.

Adult↗
PubMed2006

Factors that influence cancer patients' anxiety following a medical consultation: impact of a communication skills training programme for physicians.

BACKGROUND: No study has yet assessed the impact of physicians' skills acquisition after a communication skills training programme on the evolution of patients' anxiety following a medical consultation. This study aimed to compare the impact, on patients' anxiety, of a basic communication skills training programme (BT) and the same programme consolidated by consolidation workshops (CW), and to investigate physicians' communication variables associated with patients' anxiety. PATIENTS AND METHODS: Physicians, after attending the BT, were randomly assigned to CW or to a waiting list. The control group was not a non-intervention group. Consultations with a cancer patient were recorded. Patients' anxiety was assessed with the State Trait Anxiety Inventory before and after a consultation. Communication skills were analysed according to the Cancer Research Campaign Workshop Evaluation Manual. RESULTS: No statistically significant change over time and between groups was observed. Mixed-effects modelling showed that a decrease in patients' anxiety was linked with screening questions (P = 0.045), physicians' satisfaction about support given (P = 0.004) and with patients' distress (P < 0.001). An increase in anxiety was linked with breaking bad news (P = 0.050) and with supportive skills (P = 0.013). No impact of the training programme was observed. CONCLUSIONS: This study shows the influence of some communication skills on the evolution of patients' anxiety. Physicians should be aware of these influences.

Adult↗
PubMed2005

Phase II study of preoperative oxaliplatin, capecitabine and external beam radiotherapy in patients with rectal cancer: the RadiOxCape study.

BACKGROUND: Preoperative radiotherapy has been shown to decrease the local recurrence rate of patients with locally advanced rectal cancer. Capecitabine and oxaliplatin are both active anticancer agents in the treatment of patients with advanced colorectal cancer and have radiosensitizing properties. Therefore, these drugs would be expected to improve effectiveness of preoperative radiotherapy in terms of local control and prevention of distant metastases. PATIENTS AND METHODS: Forty patients with rectal cancer (T3-T4 and/or N+) received radiotherapy (1.8 Gy, 5 days a week over 5 weeks, total dose 45 Gy, 3D conformational technique) in combination with intravenous oxaliplatin 50 mg/m2 once weekly for 5 weeks and oral capecitabine 825 mg/m2 twice daily on each day of radiation. Surgery was performed 6-8 weeks after completion of radiotherapy. The main end points were safety and efficacy as assessed by the pathological complete response (pCR). RESULTS: The most frequent grade 3/4 adverse event was diarrhea, occurring in 30% of patients. pCR was found in five (14%) patients. According to Dworak's classification, good regression was found in six (18%) additional patients. CONCLUSIONS: Combination of preoperative radiotherapy with capecitabine and oxaliplatin is feasible for downstaging rectal cancer.

Adenocarcinoma↗
PubMed2005

Optimization of a breast implant in Brachytherapy PDR: validation with Monte Carlo simulation and measurements with TLDs and GafChromic films.

BACKGROUND AND PURPOSE: The calculation of the dose distribution of Brachytherapy breast implant has been carried out in accordance with the Paris System (PS) in the majority of the radiotherapy departments in Europe. PDR (Pulsed Dose Rate) has lead to an improvement of the treatment procedure, optimization tools, however, allow an improvement of the treatment technique. The goal of this study was to perform a dosimetric verification of an optimized seven needles implant and to try to decrease the active length while preserving the same treatment volume. This corresponds to a ratio "treated length/active length" (L(t)/L(a)) that tends towards 1. MATERIAL AND METHODS: A dosimetry phantom was made of polystyrene, capable of receiving the implant, TLDs (LiF100 1mm(3) micro cubes) and films (GafChromic MD 55-2). Dose distributions for one source position and for the implant in conformity with the PS were calculated, utilizing version 14.2 of the Plato TPS (Nucletron); the remote afterloading system was a microSelectron-PDR (Nucletron). MCNP (Monte Carlo N-Particles transport) modeling was used for various configurations to evaluate the influence of the composition of the medium, of the presence of the needles and the lack of scatter. RESULTS: The benefit of the optimization was shown by the determination of a L(t)/L(a) factor of 1.05 instead of 0.7 for the standard PS. The dose distributions calculated by Plato are in agreement with TLD and film measurements for the optimization and the PS (<5%). The TPS results were confirmed by MC calculation as well as by measurements. MC calculations also showed that only the lack of scatter had a significant influence on the dose received by the skin (20%) CONCLUSIONS: The optimization brings a significant benefit in protecting the skin and in homogeneity of the dose distribution in the treated volume. Through MC simulation, this work made it possible to update a parameter significantly influencing dose distribution calculations: the lack of scattering.

Brachytherapy↗
PubMed2004

The opinion of general practitioners on the treatment of prostate and breast cancer in elderly people: results of a survey based on clinical models.

AIMS: Several publications have reported age-related differences in the management of people with cancer. Most data have been derived retrospectively from hospital or cancer-centre databases. The aim of the present study was to identify major decisional factors observed in general practitioner (GP) practices, outside the hospital setting, regarding the clinical management of patients with prostate and breast cancer. MATERIALS AND METHODS: During three national GP meetings in Belgium, questionnaires presenting two simulated patient cases were presented to GPs who were asked two questions: one regarding further staging and referral of the case and the second regarding the treatment of the case. A total of 678 questionnaires were distributed. GPs received two randomly selected cases each: a breast cancer history and a prostate cancer history. Three variables were assessed simultaneously: age, performance status and medical history (comorbidity). RESULTS: The analysis indicated that elderly patients were more likely to be referred for non-curative treatment (OR 13.71; 95% CI 5.67-33.12; P < 0.0001 for prostate cancer and OR 17.67; 95% CI 4.04-77.31; P < 0.0001 for breast cancer). The other variables (performance status and medical history) did not affect treatment orientation. However, GPs were prepared to seek assistance from oncologists in both cases, irrespective of the patient's age. CONCLUSION: Age seems to be more important among GPs in deciding how to manage cancer patients than performance status and comorbidity. This is a very common prejudice. They are, nevertheless, inclined to refer people with cancer to oncologists independently of the patient's age.

Age Factors↗
PubMed2003

Impact of medical specialists' locus of control on communication skills in oncological interviews.

Although is it widely recognised that physicians' characteristics could influence their communication styles, no empirical evidence is currently available. No studies are available on the impact of physicians' locus of control (LOC) on their communication skills. LOC is a generalised belief regarding the extent to which life outcomes are controlled by an individual's actions (internal LOC) or by external forces such as luck, fate or other individuals (external LOC). It was hypothesised that physicians with external LOC would take more into account others' concerns than physicians with internal LOC and would consequently use more appropriate assessment, informative and supportive functions. A total of 81 medical specialists were assessed in a simulated interview and a clinical interview. Communication skills were rated according to the Cancer Research Campaign Workshop Evaluation Manual. LOC was assessed using the Rotter I-E scale. Communication skills of the upper and lower quartiles of physicians in respect of their scores on this scale were compared using Student's t-test. Results show that physicians with external LOC give more appropriate information than physicians with internal LOC in simulated interviews (P=0.011) and less premature information than physicians with internal LOC in clinical interviews (P=0.015). This result provides evidence that physicians' LOC can influence their communication styles in oncological interviews and in particular the way they provide information to the patient.

Attitude of Health Personnel↗
PubMed2002

Dosimetric study of a new palladium seed.

In this paper, the dosimetric parameters for a new palladium seed design: the InterSource(103,)(1) are presented as recommended by the AAPM in the TG-43 formalism. Measurements are made with LiF thermoluminescent dosimeters (size of 1mm(3)) in solid water phantoms WT1 to obtain the dose constant, the radial dose function and the anisotropy function. The TLD were calibrated at 6 MV and an energy correction factor of 1.40 has been applied. The same dose parameters are also obtained by Monte Carlo calculations (MCNP4B) in solid water and in liquid water. The calculated and the measured TG-43 functions for solid water are in excellent agreement. In WT1, the calculated dose rate constant is 0.657+/-1% and the measured value is 0.672+/-7%. The calculated value for water is 0.692+/-1%. The comparison with the previous study (Med. Phys. 27(5) (2000)) shows a very good agreement for the dose rate constant. The agreement for the radial function is poorer. For the measurements, it can be due to the difference of TLD settings. For the calculations the discrepancy could come from the different cross-section data utilized in the different Monte Carlo codes. In conclusion, the dosimetric functions for the new iodine seed InterSource(103) have been determined using the MCNP4B Monte Carlo code and TLD measurement in solid water WT1.

Journal Article↗
PubMed2001

Comparison of setup accuracy of three different thermoplastic masks for the treatment of brain and head and neck tumors.

PURPOSE: Setup accuracy is an important factor influencing the definition of the planning target volume (PTV). The purpose of this study was to compare the setup accuracy of three different thermoplastic masks used for immobilization of patients with brain or head and neck tumors. MATERIALS AND METHODS: Thirty patients with brain or head and neck tumors were consecutively assigned to one of three different thermoplastic masks (Posifix): head mask with three fixation points (3 FP, ten patients), head and shoulder mask with four fixation points (4 FP, ten patients), head and shoulder mask with five fixation points (5 FP, four fixations plus an additional one on the top of head, ten patients). Once a week, during the session with a 6 MV linac (Elekta), orthogonal (antero-posterior and lateral) portal images were acquired for three fictitious isocenters placed during the simulation at the level of the head, the neck and the shoulders. Portal images and digitized simulator films were compared using the PIPS pro software, and displacements in antero-posterior (A-P), cranio-caudal (C-C) and medio-lateral (M-L) directions were calculated. From these displacements, 2D or 3D errors were also calculated. RESULTS: A total of 915 portal images were obtained, of which 98% could be analyzed. For the whole population, total displacements reached a standard deviation (SD) of 2.2 mm at the level of the head and the neck. Systematic and random displacements were in the same order of magnitude and reached a SD of 1.8 mm. Patient setup was slightly worse at the shoulder level with a total displacement of 2.8 mm (1 SD) for both the C-C and the M-L directions. There again, the systematic and the random components were in the same order of magnitude below 2.4 mm (+/-SD). For isocenters in the head and in the neck, there was no substantial difference in the setup deviation between the three masks. The setup reproducibility was found to be significantly worse (P=0.01) at the level of the shoulders with the 3 FP mask. For the 2D random error, 1 SD of 2.3 mm was observed compared to 0.8 and 1.2 mm for the 4 and 5 FP masks, respectively. Lastly, 90% of the 3D total deviations were below 4.5 mm for the head and the neck. In the shoulder region, 90% of the 2D total deviations were below 5.5 mm. CONCLUSION: Thermoplastic masks provide an accurate patient immobilization. At the shoulder level, setup variations are reduced when 4 or 5 FP masks are used. These data could be used for the assessment of margins for the PTV.

Algorithms↗
PubMed2001

Prescribing, recording, and reporting in endovascular brachytherapy. Quality assurance, equipment, personnel and education.

Endovascular brachytherapy is a new, rapidly growing field of interest in radiotherapy for the prevention of neointimal hyperplasia after angioplasty in both coronary and peripheral arteries. Many physics aspects of these treatments have already been addressed in the report of the American Association of Physicists in Medicine task group on 'Intravascular brachytherapy', but up to now there are no generally accepted recommendations for recording and reporting radiation doses and volumes. The terminology to be used by all individuals involved in such treatments (radiation oncologists, physicists, and interventionalists) is not clearly defined. The Endovascular Groupe Européen de Curiethérapie/European Society for Therapeutic Radiology and Oncology Working Group in this document presents recommendations for a common language for general use in endovascular brachytherapy. This proposal addresses general terms and concepts for target and dose specification as well as detailed recommendations for dose prescription, recording and reporting in endovascular brachytherapy for both peripheral and coronary arteries. Additionally, quality assurance and radiation safety aspects are briefly addressed, as are aspects related to equipment, personnel, and training and education related to endovascular brachytherapy.

Brachytherapy↗
PubMed2001

Proton RBE for early intestinal tolerance in mice after fractionated irradiation.

BACKGROUND AND PURPOSE: To determine the influence of the number of fractions (or the dose per fraction) on the proton relative biological effectiveness (RBE). MATERIALS AND METHODS: Intestinal crypt regeneration in mice was used as the biological endpoint. RBE was determined relative to cobalt-60 gamma rays for irradiations in one, three and ten fractions separated by a time interval of 3.5h. Proton irradiations were performed at the middle of a 7-cm Spread Out Bragg Peak (SOBP). RESULTS: Proton RBEs (and corresponding gamma dose per fraction) at the level of 20 regenerated crypts per circumference were found equal to 1.15+/-0.04 (10.0 Gy), 1.15+/-0.05 (4.8 Gy) and 1.14+/-0.07 (1.7 Gy) for irradiations in one, three and ten fractions, respectively. Alpha/beta ratios as derived from direct analysis of the 'quantal radiation response data' were found to be 7.6 Gy for gamma rays and 8.2 Gy for protons. Additional proton irradiations in ten fractions at the end of the SOBP were found to be more effective than at the middle of the SOBP by a factor of 1.14 (1.05-1.23). CONCLUSION: Proton RBE for crypt regeneration was found to be independent of fractionation up to ten fractions. One can expect that it remains unchanged for higher number of fractions as the lethalities for doses smaller than 3 Gy are exclusively due to direct lethal events. As a tendency for increased effectiveness at the end of the SOBP is reported in the majority of the studies, for clinical applications it would be advisable to allow for by arranging a sloping depth dose curve in the deeper part of the target volume. Finally, it must be noticed that most of in vitro and in vivo RBE values for protons are larger than the current clinical RBE (RBE=1.10).

Animals↗
PubMed2001

Radiotherapy.

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Aged↗
PubMed2001

[Benign diseases in radiotherapy: a practice survey in Belgium. Peer review of radiotherapy in Belgium].

In 1996 and 2000, a survey of radiation practice in Belgium was performed by sending a questionnaire to the different centers asking their opinion and number of patients treated. There was a great similarity between the two surveys both for indications and total number of patients irradiated. For the most common indications (prevention of cheloids, heterotopic bone formation, hyperthyroidy ophthalmopathy), there was a trend to use similar radiation technique following recent publications. In contrast, if the number of cases of macular degeneration is declining, the prevention of vessels restenosis is becoming more and more an indication.

Belgium↗
PubMed2001

Dosimetric study of the new Intersource125 iodine seed.

The use of low energy photon emitters for brachytherapy applications, as in the treatment of the prostate or of eye tumors, has significantly increased these last few years. New seed models for 125I have been recently introduced. The aim of this study is to determine the dosimetric parameters as recommended by the AAPM in the TG43 formalism for a new iodine seed design: the InterSource125 (Furnished by IBt, Seneffe, Belgium). Measurements are made with LiF thermoluminescent dosimeters (size of 1 mm3) in solid water phantoms to obtain the dose constant, the radial dose function, and the anisotropy function. The TLDs were calibrated at 6 MV and an energy correction factor of 1.41 has been applied. The same dose parameters are also obtained by Monte Carlo calculations (MCNP4B) in solid water and in liquid water. The radial function was measured at 1, 1.5, 2, 3, 4, 5, 6, and 7 cm and calculated between 0.3 and 7 cm. The anisotropy functions were measured at 2, 3, and 5 cm and calculated between 0.3 and 7 cm. The calculated and the measured TG43 functions for solid water are in excellent agreement. We have then calculated these functions in liquid water to obtain the dosimetric information for clinical applications as per TG43 recommendations. In WTI, the calculated dose rate constant is 0.98+/-1% and the measured value is 1.03 +/- 7 %. The calculated value for water is 1.02+/- 1 %. In conclusion, the dosimetric functions for the new iodine seed InterSource125 have been determined. They are quite different from the data of the well-known model 6711 from Amersham due to the absence of silver in the new seed. The characteristics are very similar to those of model 6702.

Anisotropy↗
PubMed2000

Proton relative biological effectiveness (RBE) for survival in mice after thoracic irradiation with fractionated doses.

PURPOSE: This study aims at providing relative biological effectiveness (RBE) data under reference conditions accounting for the determination of the "clinical RBE" of protons. METHODS AND MATERIALS: RBE (ref. (60)Co gamma-rays) of the 200 MeV clinical proton beam produced at the National Accelerator Centre (South Africa) was determined for lung tolerance assessed by survival after selective irradiation of the thorax in mice. Irradiations were performed in 1, 3, or 10 fractions separated by 12 h. Proton irradiations were performed at the middle of a 7-cm spread out Bragg peak (SOBP). Control gamma irradiations were randomized with proton irradiations and performed simultaneously. A total of 1008 mice was used, of which 96 were assessed for histopathology. RESULTS: RBEs derived from LD50 ratios were found not to vary significantly with fractionation (corresponding dose range, approximately 2-20 Gy). They, however, tend to increase with time and reach (mean of the RBEs for 1, 3 and 10 fractions) 1.00, 1.08, 1.14, and 1.25 for LD50 at 180, 210, 240, and 270 days, respectively (confidence interval approximately 20%). alpha/beta ratios for protons and gamma are very similar and average 2.3 (0.6-4.8) for the different endpoints. Additional irradiations in 10 fractions at the end of the SOBP were found slightly more effective ( approximately 6%) than at the middle of the SOBP. A control experiment for intestinal crypt regeneration in mice was randomized with the lung experiment and yielded an RBE of 1.14 +/- 0.03, i.e., the same value as obtained previously, which vouches for the reliability of the experimental procedure. CONCLUSION: There is no need to raise the clinical RBE of protons in consideration of the late tolerance of healthy tissues in the extent that RBE for lung tolerance was found not to vary with fractionation nor to differ significantly from those of the majority of early- and late-responding tissues.

Animals↗
PubMed2000

[Cancer and the elderly. Management. Decision aspects].

INTRODUCTION: Age is the major risk factor for the majority of patients with cancer. More than 50% of cancers occurs after the age of 60. Cancer in the elderly is therefore a public health issue at stake. However, in daily clinical practice the elderly presenting cancer are not listened to with great interest and treatment is often not proper or suboptimal. CURRENT KNOWLEDGE AND KEY POINTS: Diagnosis in the elderly is established at a more advanced stage of cancer than in younger people; diagnostic workup is reduced and suboptimal treatments are implemented. Therefore, barriers exist that prevent the elderly from accessing the healthcare system as easily as their younger counterpart. Misconceptions about cancer also lead them to delay their first visit. As well, although treatment with curative intent and without major side-effect is feasible, physicians have misconceptions regarding therapeutic possibilities. Due to the heterogeneity of the so-called "ageing population", difficulties are related to patients' selection. FUTURE PROSPECTS AND PROJECTS: Decision in oncology for the elderly must walk a fine line in attempting to deliver the best treatment under the best conditions. Age per se must not be the only criterion for medical decision. Providing accurate information adapted to the elderly, with large circulation among healthcare professionals, should lead to the same quality of care as that in young people. Comprehensive multimodal geriatric assessments should help to further differentiate patients who may benefit from curative treatment from those for whom only palliative treatment is necessary.

Age Distribution↗
PubMed1999

Cost-minimization analysis of treatment options for T1N0 glottic squamous cell carcinoma: comparison between external radiotherapy, laser microsurgery and partial laryngectomy.

BACKGROUND AND PURPOSE: A cost minimization analysis of radiotherapy (RT), laser microsurgery (L) or partial laryngectomy (PL), which are equally effective options for T1N0 glottic SCC was carried out from the perspective of the National Health Care System. METHODS: For each modality, the various events associated with the diagnostic procedure, the primary treatment, the complications, and the salvage treatment were individualized. The charges of each of these events weighted for the frequency of occurrence were then determined using the 'fee for service' policy established by the National Health Insurance of Belgium. RESULTS: A total cost of 5172, 5847 and 11563 EURO were calculated for RT, L and PL, respectively. For L, cost included post-operative RT applied in case of positive margins (30%). For PL, the cost of the primary treatment accounted for 68% of the total cost whereas it only accounted for 50 and 43% for L and RT, respectively. For RT, L or PL, complications accounted for less than 10% of the total cost. The cost of salvage treatment reached 19, 14 and 8% of the total cost for RT, L and PL, respectively. A sensitivity analysis indicated that reduction of the duration of hospitalization decreases the costs without affecting the ranking between the three options. Also, the cost of L could be reduced even slightly below the cost of RT by decreasing the need for post-operative RT. CONCLUSIONS: RT and L have almost the same expected average cost for the treatment of T1N0 glottic SCC, whereas PL is twice as expensive.

Belgium↗