PET-based dose painting in non-small cell lung cancer: Comparing uniform dose escalation with boosting hypoxic and metabolically active sub-volumes

Abstract Background and purpose We compared two imaging biomarkers for dose-escalation in patients with advanced non-small cell lung cancer (NSCLC). Treatment plans boosting metabolically active sub-volumes defined by FDG-PET or hypoxic sub-volumes defined by HX4-PET were compared with boosting the entire tumour. Materials and methods Ten NSCLC patients underwent FDG- and HX4-PET/CT scans prior to radiotherapy. Three isotoxic dose-escalation plans were compared per patient: plan A, boosting the primary tumour (PTVprim ); plan B, boosting sub-volume with FDG >50% SUVmax (PTVFDG ); plan C, boosting hypoxic volume with HX4 tumour-to-background >1.4 (PTVHX4 ). Results Average boost volumes were 507 ± 466 cm3 for PTVprim , 173 ± 127 cm3 for PTVFDG and 114 ± 73 cm3 for PTVHX4 . The smaller PTVHX4 overlapped on average 87 ± 16% with PTVFDG . Prescribed dose was escalated to 87 ± 10 Gy for PTVprim , 107 ± 20 Gy for PTVFDG , and 117 ± 15 Gy for PTVHX4 , with comparable doses to the relevant organs-at-risk (OAR). Treatment plans are available online ( https://www.cancerdata.org/10.1016/j.radonc.2015.07.013 ). Conclusions Dose escalation based on metabolic sub-volumes, hypoxic sub-volumes and the entire tumour is feasible. Highest dose was achieved for hypoxia plans, without increasing dose to OAR. For most patients, boosting the metabolic sub-volume also resulted in boosting the hypoxic volume, although to a lower dose, but not vice versa.