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1.
Clin Oncol (R Coll Radiol) ; 31(1): 50-57, 2019 01.
Artículo en Inglés | MEDLINE | ID: mdl-30361128

RESUMEN

Geometric uncertainties in radiotherapy are conventionally addressed by defining a safety margin around the radiotherapy target. Misappropriation of such margins could result in disease recurrence from geometric miss or unnecessary irradiation of normal tissue. Numerous quantitative organ motion studies in adults have been published, but the first paediatric-specific studies were only published in recent years. In the very near future, intensity-modulated proton beam therapy and magnetic resonance-guided radiotherapy will be clinically implemented in the UK. Such techniques offer the ability to deliver radiotherapy to the pinnacle of precision and accuracy, if geometric uncertainty relating to internal organ motion and deformation can be optimally managed. The optimal margin to account for internal organ motion in children remains largely undefined. Continuing efforts to characterise motion in children and young people is necessary to optimally define safety margins and to realise the full potential of intensity-modulated radiotherapy, magnetic resonance-guided radiotherapy and intensity-modulated proton beam therapy. This overview offers a timely review of published reports on paediatric organ motion, in anticipation of the increasing application of advanced radiotherapy techniques in paediatric radiotherapy.


Asunto(s)
Neoplasias Encefálicas/radioterapia , Planificación de la Radioterapia Asistida por Computador/métodos , Adolescente , Niño , Humanos , Pronóstico , Dosificación Radioterapéutica
2.
Clin Oncol (R Coll Radiol) ; 30(1): 5-14, 2018 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-29033164

RESUMEN

Six UK studies investigating stereotactic ablative radiotherapy (SABR) are currently open. Many of these involve the treatment of oligometastatic disease at different locations in the body. Members of all the trial management groups collaborated to generate a consensus document on appropriate organ at risk dose constraints. Values from existing but older reviews were updated using data from current studies. It is hoped that this unified approach will facilitate standardised implementation of SABR across the UK and will allow meaningful toxicity comparisons between SABR studies and internationally.


Asunto(s)
Radiocirugia/métodos , Consenso , Guías como Asunto , Humanos , Reino Unido
3.
Br J Radiol ; 85(1016): 1128-33, 2012 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-22215885

RESUMEN

OBJECTIVES: The processes involved in the treatment of paraspinal tumours by volumetric modulated arc therapy (VMAT) are described here by means of an illustrative case. METHODS: Az single anticlockwise arc from gantry angle 179° to 181° was constructed using SmartArc (Philips Radiation Oncology Systems, Fitchburg, WI) with control points spaced at 2°. The dose prescription was 60 Gy in 30 fractions to cover the planning target volume (PTV) as uniformly as possible while sparing the 0.3-cm planning risk volume (PRV) around the spinal cord. The plan was verified before treatment using a diode array phantom and radiochromic film. Treatment delivery was on a Synergy linear accelerator with a beam modulator head (Elekta Ltd, Crawley, UK). RESULTS: Homogeneous dose coverage of the PTV was achieved with a D(2%) of 62.0 Gy and D(98%) of 55.6 Gy. Maximum spinal cord dose was 49.9 Gy to 0.1 cm(3) and maximum dose to the spinal cord PRV was 55.4 Gy to 0.1 cm(3). At pre-treatment verification, the percentage of the high-dose region receiving a dose within 3% and 3 mm of the planned dose was 98.8% with the diode array and 93.4% with film. Delivery time was 2 min 15 s and the course of treatment was successfully completed. CONCLUSIONS: VMAT was successfully planned, verified and delivered for this challenging tumour site. VMAT provides a very suitable method of treating complex paraspinal tumours, offering a high-quality conformal dose distribution with a short delivery time.


Asunto(s)
Recurrencia Local de Neoplasia/radioterapia , Radioterapia de Intensidad Modulada/métodos , Neoplasias de la Columna Vertebral/radioterapia , Humanos , Fantasmas de Imagen , Dosificación Radioterapéutica , Dolor de Hombro/etiología , Neoplasias de la Columna Vertebral/cirugía
4.
Clin Oncol (R Coll Radiol) ; 20(3): 253-60, 2008 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-18261891

RESUMEN

AIMS: To evaluate different treatment techniques in whole ventricular radiotherapy (WVRT) for localised intracranial germinomas with respect to target volume and organ at risk (OAR) dose. As a second end point, a comparison of OAR doses between WVRT and whole brain radiotherapy was made. MATERIALS AND METHODS: Co-registered computed tomography-magnetic resonance images (MRI) of five patients were studied. Planning target volumes for whole ventricles (phase 1, PTV(1)) and boost to the primary tumour (phase 2, PTV(2)) were prescribed to 24 and 16 Gy. For phase 1, lateral parallel-opposed pairs (PP), non-coplanar three- and four-field (3F and 4F) and optimised four- and seven-field intensity-modulated radiotherapy (4FIMRT and 7FIMRT) plans were compared. A conformal non-coplanar six-field technique was used for phase 2. RESULTS: For phase 1, statistically significant high-dose sparing of normal brain was achieved with increasing treatment complexity for supratentorial brain (STB) minus PTV(1) (STB-PTV(1)) and infratentorial brain (ITB) minus PTV(1) (ITB-PTV(1)). Median pituitary gland dose sparing was 1 Gy with IMRT techniques (P=not significant). CONCLUSION: WVRT using 7FIMRT is the most conformal technique, which offers significant sparing of normal brain from high-dose irradiation, a mean reduction of 1 Gy in the pituitary gland (P<0.05) with no significant reduction in other OARs. Yet even with the most complex technique the absolute reduction in mean dose to normal brain tissue achieved was modest in clinical terms. Whether this could translate into a reduction in late sequelae in a predominantly adolescent patient population remains hypothetical.


Asunto(s)
Neoplasias del Ventrículo Cerebral/radioterapia , Germinoma/radioterapia , Radioterapia Conformacional , Radioterapia de Intensidad Modulada , Adolescente , Adulto , Neoplasias del Ventrículo Cerebral/patología , Niño , Femenino , Germinoma/patología , Humanos , Masculino , Estudios Prospectivos , Radioterapia Conformacional/instrumentación , Resultado del Tratamiento
5.
Lancet Oncol ; 6(7): 509-19, 2005 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-15992700

RESUMEN

The optimum management of localised intracranial germinoma remains controversial. Cure rates for this rare CNS tumour, which arises mainly in adolescents, exceed 90% at 10 years, and limitation of treatment-related late morbidity is therefore essential. Craniospinal radiotherapy plus boost is perceived to be the gold-standard treatment, but there have been suggestions that reduced-volume radiotherapy could be adequate for cure. We reviewed publications since 1988 to compare patterns of disease relapse and cure rates after craniospinal radiotherapy, reduced-volume irradiation alone (i.e., whole-brain or whole-ventricular irradiation followed by a boost), and focal or localised irradiation alone. The recurrence rate after whole-brain or whole-ventricular radiotherapy plus boost was 7.6% compared with 3.8% after craniospinal radiotherapy, with no predilection for isolated spinal relapses (2.9% vs 1.2%). We challenge the consensus that craniospinal radiotherapy is the best treatment for localised germinomas and conclude that reduced-volume radiotherapy plus boost should replace craniospinal radiotherapy when a radiotherapy-only approach is used.


Asunto(s)
Neoplasias Encefálicas/radioterapia , Germinoma/radioterapia , Adolescente , Protocolos de Quimioterapia Combinada Antineoplásica/administración & dosificación , Protocolos de Quimioterapia Combinada Antineoplásica/efectos adversos , Niño , Terapia Combinada , Irradiación Craneana/efectos adversos , Humanos , Recurrencia Local de Neoplasia , Dosificación Radioterapéutica , Columna Vertebral/efectos de la radiación
7.
Clin Oncol (R Coll Radiol) ; 13(3): 228-34, 2001.
Artículo en Inglés | MEDLINE | ID: mdl-11527300

RESUMEN

PURPOSE: Surgery is considered to be the treatment of choice for patients with solitary brain metastases. We report a single-centre experience of stereotactic radiotherapy (SRT)/radiosurgery as an alternative to surgery and define prognostic parameters that provide for a more rational selection of patients for appropriate treatment. PATIENTS AND METHODS: Between 1990 and 1997, 96 patients with 106 brain metastases received SRT to a dose of 20 Gy in two fractions (range 20-30 Gy in 24 fractions) either alone or in combination with whole brain radiotherapy. RESULTS: After SRT, 51% of patients had improvement in neurological function. The median survival of the 96 patients was 9 months. The Radiation Therapy Oncology Group prognostic grouping for patients with multiple brain metastases (prognostic factors: age, performance status, systemic metastases, status of primary tumour) was applicable to this cohort, with median survivals of 15, 8 and 2 months for favourable, intermediate and poor prognostic groups respectively. CONCLUSION: SRT is a non-invasive method of treatment of solitary brain metastases and the outcome is comparable with the results obtained after surgical excision. Prognosis is determined by factors defined for patients with multiple brain metastases, with performance status being the most important. SRT/radiosurgery should be reserved for patients with favourable prognostic factors, with a Karnofsky performance status >70, who have a reasonable chance of good quality prolonged survival. In future trials, radiosurgery should be compared in terms of survival, quality of life and health economics to whole brain radiotherapy and surgery.


Asunto(s)
Neoplasias Encefálicas/secundario , Neoplasias Encefálicas/cirugía , Radiocirugia/métodos , Adulto , Anciano , Femenino , Estado de Salud , Humanos , Masculino , Persona de Mediana Edad , Pronóstico , Calidad de Vida , Estudios Retrospectivos , Análisis de Supervivencia , Resultado del Tratamiento
8.
Radiother Oncol ; 50(2): 145-50, 1999 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-10368037

RESUMEN

PURPOSE: Stereotactically guided conformal radiotherapy, (SCRT) is a high precision technique of conformal radiotherapy (RT) which reduces the volume of normal tissue irradiated compared to conventional RT and may lead to a reduction in long-term toxicity We describe the technique and the preliminary results in patients with inoperable, residual or recurrent meningiomas. MATERIAL AND METHODS: From July 1993 to November 1997, 24 patients (median age: 56 years, range: 28-72) with base of skull (n = 21). falx or upper skull (n = 3) meningiomas were treated with SCRT. The technique employed immobilization in a Gill-Thomas-Cosman (GTC) frame and CT localization with a Brown-Roberts-Wells (BRW) fiducial system for stereotactic space definition. The planning target volume (PTV) was defined as gross tumour volume (GTV) and a 0.5-1 cm margin. Treatment was delivered with three (12 patients) or four non-coplanar conformal fixed fields (12 patients) Conformal blocking was achieved either with lead alloy blocks (n = 11) or with a multi-leaf collimator (MLC) (n = 13). Patients were treated on a 6 MV linear accelerator to doses of 50-55 Gy, in 30-33 daily fractions. The treatments were carried out as part of a routine work of a busy radiotherapy department. RESULTS: Median GTV for 24 meningiomas was 21.7 cm3 (range: 4.4-183 cm3). SCRT was well tolerated with minimal toxicity Three months after the end of radiotherapy, seven of 15 patients with neurological deficit had an improvement and eight remained unchanged. Two patients experienced early side effects (one VII nerve palsy, one Addisonian state). At a median follow-up of 13-months (range: 3-43) the 1 year progression free survival and overall survival are 100%. which is within the range expected for conventional fractionated radiotherapy for meningiomas. CONCLUSIONS: SCRT is a feasible technique of high precision conformal RT for patients with meningiomas. Potential advantages in tumour control, survival and toxicity over conventional RT, require evaluation in long-term prospective studies.


Asunto(s)
Neoplasias Meníngeas/radioterapia , Meningioma/radioterapia , Radioterapia Conformacional/métodos , Técnicas Estereotáxicas , Adulto , Anciano , Supervivencia sin Enfermedad , Femenino , Estudios de Seguimiento , Humanos , Masculino , Neoplasias Meníngeas/diagnóstico por imagen , Neoplasias Meníngeas/mortalidad , Meningioma/diagnóstico por imagen , Meningioma/mortalidad , Persona de Mediana Edad , Recurrencia Local de Neoplasia , Radiografía , Estudios Retrospectivos , Base del Cráneo , Tasa de Supervivencia , Resultado del Tratamiento
9.
Int J Radiat Oncol Biol Phys ; 42(5): 959-67, 1998 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-9869216

RESUMEN

PURPOSE: Very young children with medulloblastoma are considered to have a worse prognosis than older children. As radiotherapy remains an important part of the treatment, the adverse prognosis could be due to inadequate radiation treatment rather than biological factors. We analyzed the published literature to examine the impact of radiotherapy on survival in this group. METHODS AND MATERIALS: A Medline search was performed and we reviewed studies of treatment of medulloblastoma where radiotherapy was delivered using megavoltage equipment and the minimum follow-up allowed the calculation of 5-year survival rates. RESULTS: Thirty-nine studies were published between 1979 and 1996 with a treatment including craniospinal irradiation and boost to the posterior fossa. Eleven studies comprising 1366 patients analyzed survival by age at diagnosis. Eight of 11 studies showed a worse 5-year survival for the younger patient group which reached statistical significance in two. There is also a suggestion of a higher proportion of children with metastatic disease at presentation in the very young age group. The usual policy in younger children was to give a lower dose of radiotherapy to the craniospinal axis (CSA) and posterior fossa (PF) with reduction of dose in the range of 15 to 25% compared to standard treatment. As dose reduction to the posterior fossa is associated with worse survival and local recurrence is the predominant site of failure, the major determinant of worse survival in very young children with medulloblastoma may be suboptimal radiotherapy. Protocols including postoperative chemotherapy with delayed, omitted, or only local tumor irradiation do not reach survival rates of protocols with standard radiotherapy, also suggesting a continued importance for irradiation. CONCLUSION: Very young children with medulloblastoma have a worse prognosis than older children. Inadequate radiation dose and technique to the primary tumor region may be a major contributing factor. Current chemotherapeutic regimes alone are not sufficient to compensate for reduced radiation doses and volumes.


Asunto(s)
Neoplasias Encefálicas/mortalidad , Neoplasias Encefálicas/radioterapia , Meduloblastoma/mortalidad , Meduloblastoma/radioterapia , Tumores Neuroectodérmicos Primitivos/mortalidad , Tumores Neuroectodérmicos Primitivos/radioterapia , Factores de Edad , Neoplasias Encefálicas/patología , Preescolar , Fosa Craneal Posterior , Humanos , Lactante , Meduloblastoma/patología , Estadificación de Neoplasias , Tumores Neuroectodérmicos Primitivos/patología , Pronóstico , Análisis de Supervivencia
10.
Acta Oncol ; 36(1): 55-8, 1997.
Artículo en Inglés | MEDLINE | ID: mdl-9090967

RESUMEN

The increasing number of HIV-infected patients makes palliative treatment of HIV-associated Kaposi's sarcoma more common. We retrospectively evaluated a reduced fractionated radiotherapy with 20 Gy in respect to response rates and acute side-effects. From January 1992 to January 1995, 52 patients with HIV-associated Kaposi's sarcoma were treated with 133 single portals. Six weeks after the end of radiotherapy 42 patients with 124 portals were evaluable with respect to response rates and side-effects. Of the treated portals 32% were judged as complete responses (CR), 55% as partial responses (PR) and 12% as no change (NC). Skin reactions RTOG, grade 1 were seen in 74% of the patients. Compared with literature data the reduced overall dose of 20 Gy in 10 fractions led to a reduction of CRs by approximately 50% while the overall response rate remained equal. The success of radiotherapy for the nodular component of Kaposi's sarcoma can be improved, if a dose exceeding 20 Gy in 10 fractions is applied but at the cost of increasing side-effects in case that non-conventional fractionation schemes are used.


Asunto(s)
Infecciones por VIH/complicaciones , Cuidados Paliativos , Sarcoma de Kaposi/radioterapia , Neoplasias Cutáneas/radioterapia , Adulto , Humanos , Masculino , Persona de Mediana Edad , Radioterapia/efectos adversos , Dosificación Radioterapéutica , Estudios Retrospectivos , Sarcoma de Kaposi/virología , Neoplasias Cutáneas/virología , Resultado del Tratamiento
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