Abstract
Background. Patients with non-small cell lung cancer (NSCLC) have poor prognosis partly because of high local failure rates. Escalating the dose to the tumour may decrease the local failure rates and thereby, improve overall survival, but the risk of complications will limit the possibility to dose-escalate a broad range of patients. Escalating only PET-active areas of the tumour may increase the potential for reaching high doses for a variety of tumour sizes and locations. Material and methods. Ten patients were randomly chosen for a dose escalation planning study. A planning target volume (PTV) was defined on the mid-ventilation scan of a four-dimensional computed tomography (4D-CT) scan and a boost planning target volume (PTV-boost) was defined based on a positron emission tomography computed tomography (PET-CT) scan. Treatment plans were created aiming to reach the highest achievable of 74 Gy, 78 Gy or 82 Gy in 2 Gy per fraction prescribed to the PTV-boost without compromising normal tissue constraints and with the PTV prescribed in all cases a biological equivalent dose in 2 Gy fractions of 66 Gy. Results. Nine of ten patients could be escalated to the highest dose level (82 Gy), while one patient was limited by the oesophagus dose constraint and could only reach 74 Gy. Four patients could be dose-escalated above 82 Gy without compromising normal tissue constraints. Conclusion. Dose-escalating only the PET-active areas of lung tumours to doses of 82 Gy while respecting normal tissue constraints is feasible, also in a series of unselected patients including cases with relatively large tumours.