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


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

Even, A. J.; van der Stoep, J.; Zegers, C. M.; Reymen, B.; Troost, E. G.; Lambin, P.; van Elmpt, W.

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±466cm3 for PTVprim, 173±127cm3 for PTVFDG and 114±73cm3 for PTVHX4. The smaller PTVHX4 overlapped on average 87±16% with PTVFDG. Prescribed dose was escalated to 87±10Gy for PTVprim, 107±20Gy for PTVFDG, and 117±15Gy 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.

Keywords: Dose painting; FDG; HX4; NSCLC; Positron emission tomography; Radiotherapy

Permalink: https://www.hzdr.de/publications/Publ-22445
Publ.-Id: 22445