Tumour control probability of a UK cohort of lung SABR patients

Abstract Aims: The aim of this work is to report on the tumour control probability (TCP) of a UK cohort of lung stereotactic ablative radiotherapy patients ( n = 198) for a range of dose and fractionations common in the UK. Materials and methods: TCP values for 3 (54 Gy), 5 (55 and 60 Gy) and 8 (50 Gy) fraction (#) schemes were calculated with the linear-quadratic Marsden TCP model using the Biosuite software. Results: TCP values of 100% were computed for the 3 # and for 5 # ( α / β = 10 Gy) cohorts; reduced to 99% (range 97–100) for the 5 # cohort only when an α / β of 20 Gy was used. The average TCP value for the 50 Gy in 8 # regime was 97% (range 92–99, α / β = 10 Gy) and 64% (range 48–79, α / β = 20 Gy). Statistical significant differences were observed between the α / β of 10 Gy versus 20 Gy groups and between all data grouped by fraction. Conclusion: TCPs achievable with current planning techniques in the UK have been presented. The ultra-conservative 50 Gy in 8 # scheme returns a significantly lower TCP than the other regimes.