The impact of 3-D radiotherapy planning after a pneumonectomy compared to a conventional treatment set-up.

Three-dimensional radiotherapy planning (3-D RTP) is becoming more available in clinical practice, although so far there is little data showing its clinical advantage. The goal of this study was to compare 3-D RTP and dose delivery with conventional treatment planning in pneumonected lung cancer patients, receiving postoperative irradiation. Adjuvant radiotherapy in 20 pneumonected patients was planned with a 3-D system and patients were irradiated according to this plan. The resulting dose distribution was compared with the combination of a simulator and 2-D planned treatment to the same target volume. Dose volume histograms of the target, the lung and the heart of both treatment plans were analysed. A biophysical model was added to estimate the differences in the biological effect. 3-D RTP significantly reduced the mean dose to the lung in 14/20 patients and to the heart in 20/20 patients. The mean dose delivered to the target was equal in both planning methods. The early clinical results do not differ from published results in postoperatively treated lung cancer patients.