Hypofractionated focal lesion ablative microboost for prostate cancer.

The project, focusing on prostate cancer (PCa), will investigate the feasibility and safety of a simultaneous integrated focal boost to the macroscopic tumor in addition to whole gland prostate SBRT (Stereotactic Body Radiation Therapy), within the phase II hypo-FLAME trial. In extreme hypofractionation, using high ablative fraction doses, the spatial aspects of the dose delivery will overrule the biology of healthy tissue sparing achieved by conventional treatment delivery in small fractions. The high dose needs to be confined strictly to the target volume alone, demanding high precision and a sharp spatial distinction between target and normal tissue. To allow safe delivery of prostate SBRT, intra-fraction prostate motion monitoring and treatment adaptation technology will be developed for application in the trial. A focal boost treatment planning strategy, which offers the possibility to further escalate the dose to intraprostatic tumor nodule(s) while keeping the exposure and related toxicity of surrounding tissues similar to treatment with a conventional, homogeneous dose to the prostate target volume, could offer an additional advantage in local tumor control. Extreme hypofractionation in PCa may biologically escalate the dose since a higher dose per fraction and lower total prescribed dose is being used. Moreover, reducing the number of treatment fractions to 5 weekly high dose fractions, instead of f.e. 38 daily 2.0 Gy treatment fractions, will improve resources/cost efficiency and patient convenience.

Keywords:tumor tracking, intra-fraction prostate motion, FLAME, Prostate SBRT, focal boost

Disciplines:Morphological sciences, Oncology