| 1. |
- Erfurth, Eva Marie, et al.
(författare)
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Is there an increase in second brain tumours after surgery and irradiation for a pituitary tumour?
- 2001
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Ingår i: Clinical Endocrinology. - : Wiley. - 1365-2265 .- 0300-0664. ; 55:5, s. 613-616
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Tidskriftsartikel (refereegranskat)abstract
- Objective To assess the incidence of second brain tumours in patients operated and irradiated for pituitary tumours. Design and patients The study base consisted of a consecutive series of 325 patients operated and irradiated for pituitary tumours, excluding patients with acromegaly and Cushing's disease. Comparison was made with the general population from the same catchment area as the patients. The follow-up period started in 1958 and on an individual basis patients were followed from the onset of postoperative irradiation until December 1995, or until date of death, emigration or a second brain tumour diagnosis, whichever occurred first. Results Three brain tumours (two astrocytomas and one meningioma) were observed, compared with 1.13 expected (standardized incidence ratios (SIR) 2.7; 95% confidence interval (CI) 0.6-7.8). Conclusion The present study gives no firm support for an increased incidence of a second brain tumour in patients operated and irradiated for pituitary tumours. A crude meta-analysis of the present and previously published cohort studies of patients with irradiated pituitary tumours gives an SIR of 6.1 (95% Cl 3.16-10.69). Thus, the results of the meta-analysis are in favour of an increased risk for second brain tumours. A genetic trait that predisposes to both pituitary tumours and brain tumours is an alternative causal factor. There is no definite proof that cranial irradiation per se is the causal factor. This question cannot be fully answered until sufficient cohort studies of nonirradiated pituitary tumour patients have been carried out.
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| 2. |
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| 3. |
- Guerin, S, et al.
(författare)
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Radiation dose as a risk factor for malignant melanoma following childhood cancer
- 2003
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Ingår i: European Journal of Cancer. - 1879-0852. ; 39:16, s. 2379-2386
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to determine therapy-related risk factors for the development of melanoma after childhood cancer. Among 4401 3-year survivors of a childhood cancer in eight French and British centres and 25 120 patients younger than 20 years old at first malignant neoplasm (FMN) extracted from the Nordic Cancer Registries, 16 patients developed a melanoma as a second malignant neoplasm (SMN). A cohort study of the French and British cohorts was performed. In a nested case-control study, the 16 patients who developed a melanoma as a SMN (cases) were matched with 3-5 controls in their respective cohort according to gender, age at the first cancer, the calendar year of occurrence of the first cancer and follow-up. Radiotherapy appeared to increase the risk of melanoma for local doses > 15 Gy, Odds Ratio (OR)= 13 (95% Confidence Interval (CI): 0.94-174). Regarding chemotherapy, we observed an increased OR for both alkylating agents and spindle inhibitors, OR 2.7 (95% CI: 0.5-14). Children treated for a gonadal tumour as a FMN were found to be at a higher risk of melanoma, OR 8.7 (95% CI: 0.9-86). The adjusted OR for the local radiation dose was 1.07 (95% CI: 1.00-1.15). In conclusion, radiotherapy may contribute to an increased risk of melanoma as a SMN, but only at very high doses of low linear energy transfer radiation. Common genetic origins between gonadal tumours and malignant melanomas are likely. (C) 2003 Elsevier Ltd. All rights reserved.
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| 4. |
- Hurkmans, Coen, et al.
(författare)
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Limitations of a pencil beam approach to photon dose calculations in the head and neck region
- 1996
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Ingår i: Medical Dosimetry. - : Elsevier BV. - 1873-4022 .- 0958-3947. ; 21:1, s. 38-38
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Tidskriftsartikel (refereegranskat)abstract
- The inherent limitations of a specific pencil beam model have been studied when applied to a cylindrical geometry simulating the neck region. A comparison is made between measured and calculated absorbed dose in a cylindrical phantom. The goal is to quantify the deviations in the absorbed dose level, i.e., the dose per monitor unit, when photons are used for the treatment of head and neck tumours. Square fields ranging from 5 x 5 up to 30 x 30 cm[super:2] are studied for photon beam energies of [super:60]Co, 4, 6 and 18 MV. Ionisation chamber measurements have been performed in the cylinder as well as in two other configurations in order to trace the origin of possible deviations. For 18 MV no significant deviations are found between measurement and calculation in the cylindrical configuration. For the lower energies, an over-estimation of the calculated dose in the cylindrical configuration up to about 6% for a 20 x 20-cm[super:2] [super:60]Co field has been found. These deviations have been traced to the basic approximation for the integration volume for phantom scatter calculations inherent in this pencil beam implementation.
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| 5. |
- Hurkmans, Coen, et al.
(författare)
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Limitations of a pencil beam approach to photon dose calculations in the head and neck region
- 1995
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Ingår i: Radiotherapy and Oncology. - 1879-0887. ; 37:1, s. 74-80
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Tidskriftsartikel (refereegranskat)abstract
- The inherent limitations of a specific pencil beam model have been studied when applied to a cylindrical geometry simulating the neck region. A comparison is made between measured and calculated absorbed dose in a cylindrical phantom. The goal is to quantify the deviations in the absorbed dose level, i.e., the dose per monitor unit, when photons are used for the treatment of head and neck tumours. Square fields ranging from 5 x 5 up to 30 x 30 cm2 are studied for photon beam energies of 60Co, 4, 6 and 18 MV. Ionisation chamber measurements have been performed in the cylinder as well as in two other configurations in order to trace the origin of possible deviations. For 18 MV no significant deviations are found between measurement and calculation in the cylindrical configuration. For the lower energies, an overestimation of the calculated dose in the cylindrical configuration up to about 6% for a 20 x 20-cm2 60Co field has been found. These deviations have been traced to the basic approximation for the integration volume for phantom scatter calculations inherent in this pencil beam implementation.
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| 6. |
- Svahn-Tapper, Gudrun, et al.
(författare)
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Calculation and measurements of absorbed dose in total body irradiation
- 1990
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Ingår i: Acta Oncologica. - : Informa UK Limited. - 1651-226X .- 0284-186X. ; 29:5, s. 627-633
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Tidskriftsartikel (refereegranskat)abstract
- A method which is simple, reliable, and rapid to use in clinical routine for basic dose calculation in total body irradiation (TBI) has been tested with 8 MV x-rays. The dosimetry follows, as far as possible, national and international recommendations for conventional radiotherapy. The dose rate at different locations and depths is calculated from the absorbed dose rate at dose maximum for a phantom size of 30 x 30 x 30 cm in the TBI field (Dc), an inverse square law factor (SAD2/SPD2), the tissue-maximum ratio (TMR), an equivalent phantom and patient size correction factor (A), a factor for lack of back-scattering material (B), an off-axis output correction factor (O), and a factor that corrects for off-axis variations in effective photon beam energy and for oblique beam penetration of the patient (R). The collimator opening is constant for all patient sizes. It is shown that TMR, A, B and R can be measured in conventional geometry in ordinary phantoms but at an extended distance, while Dc, O and SAD2/SPD2 must be measured in TBI geometry. Tests in Humanoid phantoms showed an agreement in measured and planned AP/2 doses of 2% or better. If the calculation method is used for lower photon energies or in other TBI geometries it may be necessary to correct for the elliptical shape of the patient and for back-scattered radiation from the walls or floor.
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| 7. |
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| 8. |
- Tukenova, Markhaba, et al.
(författare)
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Second malignant neoplasms in digestive organs after childhood cancer: a cohort-nested case-control study
- 2012
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Ingår i: International Journal of Radiation Oncology, Biology, Physics. - : Elsevier BV. - 0360-3016. ; 82:3, s. 383-390
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: Cancers of the digestive system constitute a major risk for childhood cancer survivors treated with radiotherapy once they reach adulthood. The aim of this study was to determine therapy-related risk factors for the development of a second malignancy in the digestive organs (SMDO) after a childhood cancer. Methods and Materials: Among 4,568 2-year survivors of a childhood solid cancer diagnosed before 17 years of age at eight French and British centers, and among 25,120 patients diagnosed as having a malignant neoplasm before the age of 20 years, whose data were extracted from the Nordic Cancer Registries, we matched 58 case patients (41 men and 17 women) of SMDO and 167 controls, in their respective cohort, for sex, age at first cancer, calendar year of occurrence of the first cancer, and duration of follow-up. The radiation dose received at the site of each second malignancy and at the corresponding site of its matched control was estimated. Results: The risk of developing a SMDO was 9.7-fold higher in relation to the general populations in France and the United Kingdom. In the case-control study, a strong dose-response relationship was estimated, compared with that in survivors who had not received radiotherapy; the odds ratio was 5.2 (95% CI, 1.7-16.0) for local radiation doses between 10 and 29 Gy and 9.6 (95% CI, 2.6-35.2) for doses equal to or greater than 30 Gy. Chemotherapy was also found to increase the risk of developing SMDO. Conclusions: This study confirms that childhood cancer treatments strongly increase the risk of SMDO, which occur only after a very long latency period. (C) 2012 Elsevier Inc.
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