JOURNAL ARTICLE

A novel analytical population TCP model includes cell density and volume variations: application to canine brain tumor

Stephan Radonic, Jürgen Besserer, Valeria Meier, Carla Rohrer Bley, Uwe Schneider
International Journal of Radiation Oncology, Biology, Physics 2021 April 7
33838213

PURPOSE: Tumor control probability (TCP) models based on Poisson statistics characterize the distribution of surviving clonogens. Thus enabling the calculation of TCP for individuals. In order to mathematically describe clinically observed survival data of patient cohorts it is necessary to extend the Poisson TCP model. This is typically done by either incorporating variations of model parameters, or by using an empirical logistic model. The purpose of this work is the development of an analytical population TCP model by mechanistic extension of the Possion model.

METHODS AND MATERIALS: The frequency distribution of gross tumor volumes (GTVs) was used to incorporate tumor volume variations into the TCP model. Additionally the tumor cell density variation was incorporated. Both versions of the population TCP model were fitted to clinical data and compared to existing literature.

RESULTS: It was shown that clinically observed brain tumor volumes of dogs undergoing radiotherapy are distributed according to an exponential distribution. The average GTV size was 3.37 cm3 . Fitting the population TCP model including the volume variation using linear-quadratic and track-event model yielded α=0.36Gy-1 ,β=0.045Gy-2 ,a=0.9yr-1 ,TD =5.0d and p=0.36Gy-1 ,q=0.48Gy-1 ,a=0.80yr-1 ,TD =3.0d, respectively. Fitting the population TCP model including both the volume and cell density variation yielded α=0.43Gy-1 ,β=0.0537Gy-2 ,a=2.0yr-1 ,TD =3.0d,σ=2.5 and p=0.43Gy-1 ,q=0.55Gy-1 ,a=2.0yr-1 ,TD =2.0d,σ=3.0 respectively.

CONCLUSION: Two sets of radiobiological parameters were obtained which can be used for quantifying the TCP for radiation therapy of brain tumors in dogs. We established a mechanistic link between the poisson statistics based individual TCP model and the logistic TCP model. This link can be used to determine the radiobiological parameters of patient specific TCP models from published fits of logistic models to cohorts of patients.

Full Text Links

We have located open access full text paper links.

Discussion

You are not logged in. Sign Up or Log In to join the discussion.

Trending Papers

Remove bar
Read by QxMD icon Read
33838213
×

Save your favorite articles in one place with a free QxMD account.

×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"