Stereotactic radiotherapy for lung and liver tumors using a body cast system: Setup accuracy and preliminary clinical outcome

Purpose: To evaluate the feasibility and treatment outcomes of stereotactic radiotherapy (SRT) using a newly developed simple body cast system for lung and liver tumors. Materials and Methods: From April 2003 to July 2004, 20 patients were treated with SRT at the Kyushu University Hospital. Thirteen patients had primary lung cancer, 5 had metastatic lung cancer, and 2 had hepatocellular carcinoma. All patients were fixed with a thermoplastic body cast combined with a vacuum pillow, arm and leg support, and a carbon plate. SRT was given in 5-8 fields with an isocenter dose of 48-60 Gy in 4-10 fractions. Target verification was performed by computed tomography (CT) during the first session, and by anterior-posterior (A-P) and lateral portal images during the second and subsequent sessions. Results: The average setup errors and deviation in the first treatment session were 1.4 ± 1.2, 1.1 ± 1.0, and 3.3 ± 2.8 mm in the lateral, A-P, and cranio-caudal (C-C) directions, respectively. The setup errors in the second and subsequent sessions were 2.4 ± 0.5, 1.4 ± 1.8, and 3.7 ± 2.6 mm in the lateral, A-P, and C-C directions, respectively. The patient's movement during a treatment session was within 5 mm in any direction. Despite the short follow-up periods (1-15 months), complete response was shown in 4 lesions, and partial response was shown in 15 lesions. Neither local progression nor serious complication was observed in any patient. Conclusion: SRT using our body cast system was a safe and reliable treatment method for extracranial tumors.