Additional PET/CT in week 5–6 of radiotherapy for patients with stage III non-small cell lung cancer as a means of dose escalation planning?

Gillham, Charles; Zips, Daniel; Pönisch, Falk; Evers, Carsten; Enghardt, Wolfgang; Abolmaali, Nasreddin; Zöphel, Klaus; Appold, Steffen; Hölscher, Tobias; Steinbach, Jörg; Kotzerke, Jörg; Herrmann, Thomas; Baumann, Michael

doi:10.1016/j.radonc.2008.05.004

« Previous Next »Radiotherapy & Oncology
Volume 88, Issue 3 , Pages 335-341, September 2008

Additional PET/CT in week 5–6 of radiotherapy for patients with stage III non-small cell lung cancer as a means of dose escalation planning?

Charles Gillham
- OncoRay, Centre for Radiation Research in Oncology, Technische Universität Dresden, Germany
- Medical Faculty and University Hospital Carl Gustav Carus, Technische Universität Dresden, Germany
Daniel Zips
- OncoRay, Centre for Radiation Research in Oncology, Technische Universität Dresden, Germany
- Department of Radiation Oncology, Technische Universität Dresden, Germany
- Medical Faculty and University Hospital Carl Gustav Carus, Technische Universität Dresden, Germany
- Corresponding author. Daniel Zips, Department of Radiation Oncology, Medical Faculty and University Hospital Carl Gustav Carus, Technische Universität Dresden, 01307 Dresden, Germany.
Falk Pönisch
- OncoRay, Centre for Radiation Research in Oncology, Technische Universität Dresden, Germany
- Medical Faculty and University Hospital Carl Gustav Carus, Technische Universität Dresden, Germany
Carsten Evers
- OncoRay, Centre for Radiation Research in Oncology, Technische Universität Dresden, Germany
- Department of Radiation Oncology, Technische Universität Dresden, Germany
- Medical Faculty and University Hospital Carl Gustav Carus, Technische Universität Dresden, Germany
Wolfgang Enghardt
- OncoRay, Centre for Radiation Research in Oncology, Technische Universität Dresden, Germany
- Medical Faculty and University Hospital Carl Gustav Carus, Technische Universität Dresden, Germany
Nasreddin Abolmaali
- OncoRay, Centre for Radiation Research in Oncology, Technische Universität Dresden, Germany
- Medical Faculty and University Hospital Carl Gustav Carus, Technische Universität Dresden, Germany
Klaus Zöphel
- OncoRay, Centre for Radiation Research in Oncology, Technische Universität Dresden, Germany
- Department of Nuclear Medicine, Technische Universität Dresden, Germany
- Medical Faculty and University Hospital Carl Gustav Carus, Technische Universität Dresden, Germany
Steffen Appold
- OncoRay, Centre for Radiation Research in Oncology, Technische Universität Dresden, Germany
- Department of Radiation Oncology, Technische Universität Dresden, Germany
- Medical Faculty and University Hospital Carl Gustav Carus, Technische Universität Dresden, Germany
Tobias Hölscher
- OncoRay, Centre for Radiation Research in Oncology, Technische Universität Dresden, Germany
- Department of Radiation Oncology, Technische Universität Dresden, Germany
- Medical Faculty and University Hospital Carl Gustav Carus, Technische Universität Dresden, Germany
Jörg Steinbach
- OncoRay, Centre for Radiation Research in Oncology, Technische Universität Dresden, Germany
- PET Centre, Research Centre Dresden-Rossendorf, Germany
- Institute of Radiopharmacy, Research Centre Dresden-Rossendorf, Germany
Jörg Kotzerke
- OncoRay, Centre for Radiation Research in Oncology, Technische Universität Dresden, Germany
- Department of Nuclear Medicine, Technische Universität Dresden, Germany
- Medical Faculty and University Hospital Carl Gustav Carus, Technische Universität Dresden, Germany
- PET Centre, Research Centre Dresden-Rossendorf, Germany
Thomas Herrmann
- OncoRay, Centre for Radiation Research in Oncology, Technische Universität Dresden, Germany
- Department of Radiation Oncology, Technische Universität Dresden, Germany
- Medical Faculty and University Hospital Carl Gustav Carus, Technische Universität Dresden, Germany
Michael Baumann
- OncoRay, Centre for Radiation Research in Oncology, Technische Universität Dresden, Germany
- Department of Radiation Oncology, Technische Universität Dresden, Germany
- Medical Faculty and University Hospital Carl Gustav Carus, Technische Universität Dresden, Germany

Received 15 December 2007; received in revised form 4 April 2008; accepted 1 May 2008. published online 03 June 2008.

Abstract

Background and purpose

Loco-regional failure after radiotherapy with total doses of 60–70 Gy for non-small cell lung cancer (NSCLC) remains a major clinical problem. Escalation of radiation dose is often limited because of exceeding normal tissue constraints. The present study was designed to test the hypothesis that a reduction in disease volume during radiotherapy detected by FDG PET/CT would facilitate radiation dose escalation, whilst remaining within normal tissue constraints.

Materials and methods

Ten patients with localised inoperable NSCLC were prospectively enrolled. Each received standard 3D-conformally planned radiotherapy to a dose of 66 Gy in 33 fractions over 6.5 weeks. FDG PET/CT imaging in the treatment position was performed prior to treatment and repeated following 50 or 60 Gy. CT and PET-delineated gross tumour volumes were generated and a composite created. A margin of 15mm was added in all planes to form the planning target volume (PTV). Treatment planning was performed to compare two dose escalation strategies: 78 Gy delivered to the initial PTV with treatment in two phases (shrinking field), i.e., 66 Gy to the initial PTV with a 12 Gy-boost to the PTV after 50/60 Gy. As an alternative planning approach the maximal dose without exceeding normal tissue constraints was evaluated for each patient (individualized dose prescription).

Results

There was a median PTV reduction after 50/60 Gy of 20%. Delivering 78 Gy to the initial PTV could have been achieved in 4/10 patients. Of the remaining 6, delivering 78 Gy to the initial PTV would have exceeded normal tissue constraints and no benefit was seen when delivered in two phases. The results from the individualized dose prescription indicated a higher median maximal dose when treatment would be given in two phases compared to one phase resulting in a modest increase of calculated tumour control probability.

Conclusions

Our data suggest that despite tumour shrinkage determined by subsequent FDG PET/CT during treatment the tested adaptive targeting strategy would result only in a modest improvement in the context of dose escalation. Further studies on the optimal use of FDG PET/CT and other approaches for dose escalation in loco-regionally advanced NSCLC are warranted.

Keywords: Lung cancer, PET/CT, Dose escalation, Adaptive targeting, Radiotherapy