Investigation of the potential gains obtainable in tumour control probability (TCP) and normal tissue complication probability (NTCP) for lung radiotherapy patients

Overview

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Lung cancer is the fifth most common form of cancer in Australia. However, the prognosis for lung cancer patients is generally poor; it has the highest rate of mortality of cancers in Australia (1). Radical radiotherapy forms an important component in the management of many lung cancer patients whose disease is either localised and medically inoperable or locally advanced and inoperable. One reason for the failure of radical radiotherapy to control the disease is that it has not been possible to safely escalate the dose due to the need to spare the surrounding healthy lung tissue. The problem is complicated by the motion of the tumour due to breathing at the time of treatment which results in large margins being applied to ensure adequate dose coverage of the tumour volume. There have been a number of developments recently that allow the reduction of these margins, for example, use of PET/CT to improve the definition of the tumour in the treatment planning process (2), imaging at the time of treatment to determine the location of the tumour (3), breath hold techniques to limit the motion of the tumour (4). The result of these developments offers the possibility of hypo-fractionated treatment regimes. Conventional radical radiotherapy treatments typically deliver the prescription dose in a large number of small 2 Gy fractions to minimise the damage to the surrounding healthy tissue. Stereotactic body techniques have recently been introduced that enable a small number of high dose fractions to be used instead (e.g. 3 x 15 Gy) with the aim of increasing the likelihood of local control of the tumour (5). Obviously, the volume of healthy lung tissue is required to be kept to a minimum to safely deliver these treatments. The potential advantages of hypo-fractionation include shorter overall treatment time with a reduction on demand for already stretched resources, potential dose escalation and patient convenience.

The is project aims to determine the theoretical gains in local control of the disease and reduction in side effects that can be achieved through the use of new technology that enables hypo-fractionated lung radiotherapy treatments.

Radiobiological modelling will be used to determine the gains in Tumour Control Probability (TCP) and Normal Tissue Complication Probability (NTCP) that can be achieved through these new techniques. The project will involve collaborating with radiation oncologists, radiation therapists and physicists at hospitals in Brisbane.

References:

  • AIHW Report 2005
  • M. MacManus, Ursula Nestle and K.E. Rosenzweig et al (2009) Use of PET and PET/CT for Radiation Therapy Planning: IAEA expert report 2006-2007 Radiotherapy and Oncology 91 85-9
  • D. Verellen, M. De Ridder, G. Storme (2008) A (short) history of image-guided radiotherapy Radiotherapy and Oncology 86 4-13
  • Panakis N, McNair HA, Christian JA et al (2008) Defining the margins in the radical radiotherapy of non-small cell lung cancer (NSCLC) with active breathing control (ABC) and the effect on physical lung parameters. Radiotherapy and Oncology 87 65-73
  • Brock J, Ashley S, Bedford J et al (2008) Review of Hypo-fractionated Small Volume Radiotherapy for Early-Stage Non-Small Cell Lung Cancer Clinical Oncology 20 666-676.
Study level
Honours
Supervisors
QUT
Organisational unit

Science and Engineering Faculty

Research area

Physics

Contact
Please contact the supervisor.