### Abstract

It is shown that in order to derive a general model for tumor control probability (TCP) the two assumptions that on the microscopic level (1) clonogens are non-interacting and (2) clonogen killings are uncorrelated events are not necessary. In fact, these two assumptions can be replaced with two weaker ones that only ask that (a) therapy fractions are independent and non-overlapping and (b) the probability of an event only depends on the number of incidents happening during a time interval and the length of this time interval but not on time itself. This change in assumptions implies that TCP models based on clinical data are flexible enough to include interaction of clonogens on the microscopic level and therefore also a possible bystander effect in cell killing. Based on this new set of assumptions the equation for TCP is derived, first for the homogenous case and then for the general case of a heterogeneous ensemble of tumors irradiated inhomogeneously.

Original language | English (US) |
---|---|

Pages (from-to) | 406-411 |

Number of pages | 6 |

Journal | Acta Oncologica |

Volume | 45 |

Issue number | 4 |

DOIs | |

State | Published - Jun 1 2006 |

Externally published | Yes |

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### ASJC Scopus subject areas

- Oncology

### Cite this

*Acta Oncologica*,

*45*(4), 406-411. https://doi.org/10.1080/02841860500468935

**Does a local bystander effect necessitate a revision of TCP models that are based on observed clinical data?** / Tome, Wolfgang A.; Fenwick, John; Bentzen, Søren.

Research output: Contribution to journal › Article

*Acta Oncologica*, vol. 45, no. 4, pp. 406-411. https://doi.org/10.1080/02841860500468935

}

TY - JOUR

T1 - Does a local bystander effect necessitate a revision of TCP models that are based on observed clinical data?

AU - Tome, Wolfgang A.

AU - Fenwick, John

AU - Bentzen, Søren

PY - 2006/6/1

Y1 - 2006/6/1

N2 - It is shown that in order to derive a general model for tumor control probability (TCP) the two assumptions that on the microscopic level (1) clonogens are non-interacting and (2) clonogen killings are uncorrelated events are not necessary. In fact, these two assumptions can be replaced with two weaker ones that only ask that (a) therapy fractions are independent and non-overlapping and (b) the probability of an event only depends on the number of incidents happening during a time interval and the length of this time interval but not on time itself. This change in assumptions implies that TCP models based on clinical data are flexible enough to include interaction of clonogens on the microscopic level and therefore also a possible bystander effect in cell killing. Based on this new set of assumptions the equation for TCP is derived, first for the homogenous case and then for the general case of a heterogeneous ensemble of tumors irradiated inhomogeneously.

AB - It is shown that in order to derive a general model for tumor control probability (TCP) the two assumptions that on the microscopic level (1) clonogens are non-interacting and (2) clonogen killings are uncorrelated events are not necessary. In fact, these two assumptions can be replaced with two weaker ones that only ask that (a) therapy fractions are independent and non-overlapping and (b) the probability of an event only depends on the number of incidents happening during a time interval and the length of this time interval but not on time itself. This change in assumptions implies that TCP models based on clinical data are flexible enough to include interaction of clonogens on the microscopic level and therefore also a possible bystander effect in cell killing. Based on this new set of assumptions the equation for TCP is derived, first for the homogenous case and then for the general case of a heterogeneous ensemble of tumors irradiated inhomogeneously.

UR - http://www.scopus.com/inward/record.url?scp=33745104414&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=33745104414&partnerID=8YFLogxK

U2 - 10.1080/02841860500468935

DO - 10.1080/02841860500468935

M3 - Article

VL - 45

SP - 406

EP - 411

JO - Acta Oncologica

JF - Acta Oncologica

SN - 0284-186X

IS - 4

ER -