Predicting the 5-Year Risk of Biochemical Relapse After Postprostatectomy Radiation Therapy in ≥PT2, pN0 Patients With a Comprehensive Tumor Control Probability Model

2016 ◽  
Vol 96 (2) ◽  
pp. 333-340 ◽  
Author(s):  
Claudio Fiorino ◽  
Sara Broggi ◽  
Nicola Fossati ◽  
Cesare Cozzarini ◽  
Gregor Goldner ◽  
...  
Keyword(s):  
Radiation Therapy ◽  
Probability Model ◽  
Tumor Control ◽  
Tumor Control Probability ◽  
Biochemical Relapse

scholarly journals Radiobiological Evaluation of Dosimetric Plans for Stereotactic Radiotherapy for Prostate Cancer According to Fractionation Regimen

2019 ◽  
Vol 100 (5) ◽  
pp. 263-269
Author(s):  
E. S. Sukhikh ◽  
I. N. Sheyno ◽  
L. G. Sukhikh ◽  
A. V. Taletskiy ◽  
A. V. Vertinskiy ◽  
...  
Keyword(s):  
Radiation Therapy ◽  
Total Dose ◽  
Rectal Wall ◽  
Tumor Control ◽  
Anterior Rectal Wall ◽  
Tumor Control Probability ◽  
Equivalent Uniform Dose ◽  
Dose Volume Histograms ◽  
Dose Volume ◽  
Fractionation Regimen

Objective. To determine the most effective irradiation regimen (total dose and dose per fraction) for hypofractionated treatment for prostate carcinomas according the TCP/NTCP radiobiological criteria.Material and methods. Using the tomographic information of five patients with low-risk prostate adenocarcinoma as an example, the authors devised dosimetric radiation therapy plans using the volumetric modulated arc therapy (VMAT) procedure. They considered the range of total doses of 33.5 to 38 Gy administered in 4 and 5 fractions. Based on the equivalent uniform dose concept proposed by A. Niemierko and on the computed differential dose volume histograms, the investigators modeled local tumor control probability (TCP) values, by taking into account the uncertainties of main radiobiological parameters, and estimated normal tissue complication probabilities (NTCP) for the anterior rectal wall as the organ most at risk of irradiation. An effective dosimetric plan was selected according to the UTCP criterion and the probability of complication-free tumor control, i.e. TCP (1 – NTCP).Results. The results of modeling the UTCP criterion show that with a higher total dose, the TCP value increases and so does the NTCP value, therefore the optimal radiation therapy plans are to irradiate with a total dose of 34 Gy over 4 fractions or with a dose of 36–37 Gy over 5 fractions. The difference between the fractionation regimens is that the UTCP value is achieved with a higher TCP value over 4 fractions and with a lower load on the rectal wall over 5 fractions.Conclusion. The choice of a specific fractionation regimen should be determined from the calculated values of differential dose volume histograms for each patient, as well as from radiobiological criteria, such as TCP, NTCP and UTCP.

Radiobiological Models of Tissue Response to Radiation in Treatment Planning Systems

1998 ◽  
Vol 84 (2) ◽  
pp. 140-143 ◽  
Author(s):  
Andrzej Niemierko
Keyword(s):  
Radiation Therapy ◽  
Treatment Planning ◽  
Three Dimensional ◽  
Tissue Response ◽  
Tumor Control ◽  
Practical Implementation ◽  
Target Cells ◽  
Tumor Control Probability ◽  
Planning Systems ◽  
Treatment Planning Systems

Aims To present several biological concepts and models of tissue response to fractionated radiotherapy. To describe practical implementation of these models in three-dimensional treatment planning systems. Methods Models of cell survival, Equivalent Uniform Dose (EUD) and Tumor Control Probability (TCP) are discussed. These models are based on the target-cell hypothesis which assumes that response of organs and tissues to radiation therapy can be explained and mathematically described in terms of survival of the specific target-cells. Results Several formulae for deriving and calculating EUD and TCP for a given three-dimensional dose distribution are presented and discussed. Conclusions Biological models of tissue response to radiation, when used wisely, have a potential to be useful in radiation therapy treatment planning. The models can advance our understanding of the underlying biological mechanisms, and may help in designing new and better treatment strategies. They should be particularly useful in modern conformai radiotherapy where treatment strategy for each patient can be individualized and optimized according to patient characteristics and available technology of delivering sophisticated treatment plans.

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