Stereotactic Fractionated Radiotherapy (SRT) for Intra-Thoracic Tumours

Abstract

Purpose/Objective: To evaluate tumour response, acute and late toxicity, following stereotactic radiotherapy (SRT) of primary lung cancer and lung metastases. Materials/Methods: Records of 42 patients who received SRT for intrathoracic tumours between July 2001 and May 2004 and who had their follow up at the same institute (AZ-VUB) were reviewed. The patient characteristics were: 30 male, 12 female; mean age 65 (range: 32–92) years; 25 primary lung cancer (22 NSCLC, 1 SCLC, 1 melanoma, 1 sarcoma; 11 stage I-II, 12 stage III-IV) and 17 lung metastasis from other primary cancers. Treatment planning was performed with image fusion of CT and FDG-PET scan. Treatment was delivered with X-ray image guidance (IGRT). IGRT was based on fiducial metallic markers (Fibered Platinum Coil, Boston Scientific/Target Therapeutics, Fremont, CA) implanted intra-tumouraly in 16 cases. IGRT was based on bone structures in the other 26 patients. The mean total doses delivered were 74.2 2 Gy-EQD for primary lung cancer and 63.7 Gy for lung metastasis. PTV was enclosed by the 95%-isodose. The PTV-margins were 4–8 mm in case of markers, 10–12 mm without marker. Pre- and post- SRT lung function evaluation was performed in 22 patients. Results: With a median follow-up of 14 months, there were 21 (50.0%) complete responses, 15 (35.7%) partial responses and 3 (7.1%) patients with stable disease. The observed local recurrence free survival was 54% at 21 months. In the lung primary group the cause specific survival after 12 and 24 months was 94.1 and 84.7% (for T1-T2 tumours 100% each). Local tumour control was 68.0%. In the metastasis group, local tumour control was 76.5%. Acute side effects were mild. There was no grade 3–4 toxicity. 18 patients had a mild cough, 5 had grade 1 and another 5 had grade 2 pneumonitis, most patients experienced no acute toxicity. As late complications we observed grade 3 dyspnoe (1 case), grade 1 pain (2 cases) and grade 1 dysphagia (1 case). Lung function parameters decreased at 3 months after SRT but recovered at 12 months (see figure). Conclusions: In this single institution study, SRT was associated with high local control rate and with good cause specific survival. There was little major toxicity and lung function was preserved.