What accuracy is required and can be achieved in radiation therapy (review of radiobiological and clinical data)

2001 ◽  
Vol 89 (4-5) ◽  
Author(s):  
A. Wambersie
Keyword(s):  
Radiation Therapy ◽  
Standard Deviation ◽  
Clinical Data ◽  
Normal Tissue ◽  
Absorbed Dose ◽  
Dose Effect ◽  
Tumour Control ◽  
Local Tumour Control ◽  
Treatment Conditions ◽  
Local Tumour

An attempt is made to formulate the requirements for the accuracy in the delivery of absorbed dose to a patient during radiation therapy. These requirements are mainly based on the relative steepness and separation of the dose-effect curves for local tumour control and normal tissue damage. The curves for normal tissue complications in general may be steeper than those for local tumour control. From these data, a standard requirement of 3.5% is proposed for the combined uncertainty of type A (random) and type B (systematic), given as one relative standard deviation in the absorbed dose delivery. However, it is recognized that, in many cases, larger uncertainties are acceptable palliative treatments). This value of 3.5% applies to the absorbed dose at the specification point for curative treatments. As far as the dose accuracy requirements at other points in the planning target volume are concerned, a value of 5% (one standard deviation) seems more appropriate. This required accuracy in the delivery of the absorbed dose cannot always be completely achieved in photon therapy even for simple treatment conditions. All the clinical data which were reviewed, including some results from the ldquo;Patterns of Care Study”, indicate a close correlation between the outcomes of therapy (control rates, complications) and dose level, inaccuracy or errors in dosimetry and patient-machine positioning. This has been reported for external beam therapy as well as for brachytherapy. Only the clinical results will allow us to select the optimal treatment conditions (e.g. selection and definition of the planning target volumes, dose levels and beam arrangement), but they could be interpreted correctly only to the extent that the treatment execution would be correct. This result strongly endorses the Quality Assurance Programmes, in which the clinicians and physicists should be fully involved. Lastly, the outcome of a treatment can only be interpreted meaningfully if the parameters of the irradiation, in particular, the distribution of dose in space and time can be accurately correlated with the type and extent of the disease. It is essential that clear, well defined and unambiguous concepts and parameters be used for reporting purposes to ensure a common language between collaborating centres. This is one of the major tasks that the ICRU undertook several years ago.

Comparing plaque brachytherapy and proton therapy for choroidal melanoma: a review of the literature

2010 ◽  
Vol 9 (1) ◽  
pp. 53-61
Author(s):  
Jeremy P. Appleton ◽  
Peter Bridge
Keyword(s):  
Conservative Treatment ◽  
Proton Therapy ◽  
Normal Tissue ◽  
Treatment Options ◽  
Choroidal Melanoma ◽  
Review Of The Literature ◽  
Tumour Control ◽  
Local Tumour Control ◽  
Local Tumour ◽  
Plaque Brachytherapy

AbstractThe aims of conservative treatment in patients with ocular melanoma are globe retention, good visual acuity (VA) and local control. Two well-established radiation conservative treatment options are proton beam radiotherapy and episcleral plaque brachytherapy (EPB). Patients who receive treatment with either of these options will experience some degree of radiation-related ocular complications and poor VA. The purpose of this review of the literature is to establish whether there is a significant clinical difference in normal tissue morbidity and local tumour control between proton therapy and EPB, and whether this difference can justify the purchase and implementation of additional proton therapy facilities. Based on this review, evidence suggested that both treatment options are comparable, and that neither proton therapy nor EPB is clinically superior than the other regarding normal tissue morbidity and local tumour control. This review highlighted the need for further research on a larger scale in order to bridge the gap that is apparent within the literature.

High dose level radiation therapy for local tumour control in esthesioneuroblastoma

1994 ◽  
Vol 30 (12) ◽  
pp. 1757-1760 ◽  
Author(s):  
F. Guedea ◽  
E. Van Limbergen ◽  
W. Van Den Bogaert
Keyword(s):  
Radiation Therapy ◽  
Dose Level ◽  
High Dose ◽  
High Dose Level ◽  
Tumour Control ◽  
Local Tumour Control ◽  
Local Tumour

scholarly journals Interactions between radiotherapy and endocrine therapy in breast cancer.

2002 ◽  
pp. 197-205 ◽  
Author(s):  
R del Moral ◽  
M E L√≥pez ◽  
M I N√∫√±ez ◽  
F J Oliver ◽  
M T Valenzuela ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Hormonal Therapy ◽  
Normal Tissue ◽  
Treatment Options ◽  
Tumour Response ◽  
Tissue Response ◽  
Curative Intent ◽  
Tumour Control ◽  
Local Tumour Control ◽  
Local Tumour

Whenever radiation therapy is given with curative intent there is the risk of serious damage to normal tissue. This risk increases with the dose of radiation, as does the probability of local tumour control. In the attempt to cure, the doses reach a level that inevitably causes some undesirable adverse effects, ranging from undetectable, or minimal, to unacceptably severe. Over the last few years, a number of reports have suggested that the prediction of normal tissue response after radiotherapy may be achieved by assays on samples withdrawn from the patients prior to treatment, although recent reports have described mixed results. The ability to predict tumour response to anti-hormones in patients with breast cancer has important implications with regard to treatment. Recent discoveries promise to provide individualized treatment options. However, there are no data to support that, used jointly, the combination of radiotherapy and hormone therapy may achieve an enhancement of breast cancer tumour response. Nowadays, development in cancer therapy is increasingly arising out of studies in basic science; its implementation in the hands of clinicians is improving the management of patients with cancer. In addition, as the biological aspects of irradiation and hormonal therapy offer an explanation, at least in part, for the outcome observed in patients with breast cancer after therapy, we have focused this review on trying to analyse the most relevant experimental research about the relative roles of radiotherapy and hormonal therapy, the corresponding side-effects and, taking into account recent advances, future areas of research that we consider of major importance in the field.

A review of radiation induced abscopal effect: combining radiotherapy and immunotherapy to treat the untreated distant metastatic tumours

2020 ◽  
pp. 1-8
Author(s):  
Ernest Osei ◽  
Ruth Francis ◽  
Lyba Sheraz
Keyword(s):  
Radiation Therapy ◽  
Immune Responses ◽  
Cancer Patients ◽  
Metastatic Tumour ◽  
Abscopal Effect ◽  
Tumour Control ◽  
Local Tumour Control ◽  
Local Tumour ◽  
Abscopal Effects

Abstract Background: Radiotherapy is an effective and significant mode of definitive cancer treatment with well-established local tumour control success, especially in the treatment of localised tumours. Although, for metastatic disease, the role of radiotherapy has generally been limited to palliation of symptoms. In the treatment of metastatic diseases settings, the radiation therapy technique has always been confronted with the challenge of the simultaneous treatment of all of the various distant metastatic tumour sites, however, some recent evidence suggests that radiotherapy can potentially induce anticancer immune responses whose effectors potentially migrate to distant metastatic tumours to provoke their regression in cancer patients. Thus, unirradiated distant metastatic tumour sites can exhibit a delayed therapeutic response termed the abscopal effect. Materials and methods: This paper reports on a review of the abscopal effect, including its biological mechanism, the effect of radiation dose and fractionation regime and the timing of immunotherapy administration on radiotherapy-induced abscopal effect, the enhancement of radiotherapy-induced abscopal effects with immunotherapy, the effect of the location of the irradiated tumour and the radiotherapy of multiple tumour sites on the likelihood and effectiveness of inducing abscopal responses in the preclinical and clinical settings and also reports on some evidence of clinical observations in patients. Conclusions: Although abscopal effects of radiotherapy are still relatively rare in patients, it has gained a lot of interest due to recent development and use of immunotherapy strategies incorporating combinations of targeted immunomodulators and immune checkpoint blockade with radiation therapy. The enhancement of cancer immunotherapy could potentially enable the translation of the concept of abscopal effect into the clinics as a new strategy to induce therapeutically effective anti-tumour immune responses in cancer patients. The combination of radiotherapy and immunotherapy has the potential to expand the role of radiotherapy from a purely local tumour control treatment to play a significant role in advanced and metastatic tumour control and this could likely lead to a paradigm shift in the treatment of patients with metastatic cancer.

scholarly journals Radiation therapy for intracranial tumours in cats with neurological signs

2018 ◽  
Vol 21 (8) ◽  
pp. 765-771
Author(s):  
Maximilian Körner ◽  
Malgorzata Roos ◽  
Valeria S Meier ◽  
Alena Soukup ◽  
Simona Cancedda ◽  
...  
Keyword(s):  
Radiation Therapy ◽  
Epileptic Seizures ◽  
Neurological Status ◽  
External Beam Radiation ◽  
Beam Radiation ◽  
Intracranial Tumours ◽  
Tumour Control ◽  
Neurological Signs ◽  
Local Tumour Control ◽  
Local Tumour

Objectives The aim of this study was to evaluate the outcome of cats with intracranial tumours presenting with neurological signs treated with radiation therapy. Methods This study comprised a retrospective multicentre case series. Medical records of a total of 22 cats with intracranial space-occupying lesions, presenting with neurological signs and/or epileptic seizures and treated with external beam radiation therapy, were reviewed. In the treated cats, patient-, tumour- and treatment-related variables were investigated, including age, sex, tumour location, tumour volume, total radiation dose, equivalent dose in 2 Gy fractions (EQD2), corticosteroid dose, overall treatment time and institution for influence on local tumour control and survival. Results Based on advanced imaging characteristics, the 22 treated cats presented with meningioma (n = 11), pituitary tumour (n = 8), choroid plexus tumour (n = 2) or glioma (n = 1). Allocated to the neuraxis, 11 lesions were extra-axial, three were intra-axial and eight were located in the pituitary region. At diagnosis, 21 cats exhibited altered neurological status. One cat presented with epileptic seizures and another cat had both seizures and altered neurological status. The mean total physical dose of radiation was 41.63 Gy (± 4.33), range 24–45 Gy. In all but one cat (95.5%), neurological signs improved after radiation therapy. The median progression-free survival was 510 days (95% confidence interval [CI]: 51–969). The proportion free of progression at 1 year was 55.7% (95% CI: 33–78). Fourteen cats died (only in five cases was death related to the intracranial tumour) and eight cats were still alive or lost to follow-up. The median overall survival time was 515 days (95% CI: 66–964). None of the tested variables influenced outcome. Conclusions and relevance Radiation therapy seems to represent a viable treatment option in cats with intracranial tumours, relieving neurological signs and improving local tumour control. Radiation therapy may be considered for cats with tumours in complicated/inoperable localisations or for cases with a high peri- and postoperative risk.

Nuklearmedizin trifft Strahlentherapie

2010 ◽  
Vol 49 (S 01) ◽  
pp. S11-S15
Author(s):  
C. Schütze ◽  
M. Krause ◽  
A. Yaromina ◽  
D. Zips ◽  
M. Baumann
Keyword(s):  
Nuclear Medicine ◽  
Radiation Oncology ◽  
External Beam Radiotherapy ◽  
Biological Knowledge ◽  
Important Research ◽  
Tumour Control ◽  
Research Areas ◽  
Normal Tissue Damage ◽  
Local Tumour Control ◽  
Local Tumour

SummaryRadiobiological and cell biological knowledge is increasingly used to further improve local tumour control or to reduce normal tissue damage after radiotherapy. Important research areas are evolving which need to be addressed jointly by nuclear medicine and radiation oncology. For this differences of the biological distribution of diagnostic and therapeutic nuclides compared with the more homogenous dose-distribution of external beam radiotherapy have to be taken into consideration. Examples for interdisciplinary biology-based cancer research in radiation oncology and nuclear medicine include bioimaging of radiobiological parameters characterizing radioresistance, bioimage-guided adaptive radiotherapy, and the combination of radiotherapy with molecular targeted drugs.

PO-1926 Enhanced local tumour control by combining proton radiation and immunotherapy

2021 ◽  
Vol 161 ◽  
pp. S1642
Author(s):  
M. Horsman ◽  
S. Nielsen ◽  
M. Sitarz ◽  
M. Høyer ◽  
B. Sørensen
Keyword(s):  
Proton Radiation ◽  
Tumour Control ◽  
Local Tumour Control ◽  
Local Tumour

scholarly journals Extensive systemic metastases from primary central nervous system haemangiopericytoma

2020 ◽  
Vol 6 (2) ◽  
pp. 20190081
Author(s):  
Chi Long Ho ◽  
Jeremy JH Lam ◽  
Robert Chun Chen
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Fatal Outcome ◽  
Imaging Features ◽  
Tumour Control ◽  
Local Tumour Control ◽  
Meningeal Tumour ◽  
Local Tumour ◽  
The Central Nervous System ◽  
Extracranial Metastases

Primary intracranial tumours rarely metastasise outside of the central nervous system (CNS). This report describes a rare case of recurrent meningeal haemangiopericytoma with extensive systemic metastases, which eventually resulted in a fatal outcome. We discuss some prevailing theories as to the rarity of extracranial metastases from primary CNS haemangiopericytoma, and elucidate the epidemiology, imaging features, differential diagnosis, treatment, and prognosis of this unusual but surprisingly aggressive meningeal tumour. Besides aggressive treatment for local tumour control, patients with primary CNS haemangiopericytoma require long-term post-treatment surveillance to detect systemic metastases.

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