Clinical and histopathological research on radiation therapy in the multidisciplinary treatment of non-small cell lung cancer

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1) To reduce the normal tissue damage, we have developed an apparatus using spiro analyzer to control respiratory organ motion. Using this respiratory monitoring system the reproducibility of target location in the lung at the end-expiratory phase was excellent, because the mean deviations were almost less than 1.5mm, and this apparatus can be used to reduce margin for 3D conformal irradiation.2) We performed to evaluate the clinical outcomes of three dimensional (3D) conformal single high-dose boost radiosurgery (SRS) for peripheral T1 NSCLC using this system. Nineteen patients with peripheral stage 1 NSCLC were treated in our hospital and were followed for >3 months. Fourteen patients had T1 tumors and 5 had T2 tumors. The size of T1 tumors ranged from 15 mm to 30 mm in diameter and T2 tumors were less than 45 mm in diameter. All patients were treated with a standard fractionation of 30Gy/10fractions or 40Gy/20 fractions and a single high-does boost of 20Gy using 3D non-coplanar SRS. … More C-arm linear accelerator (Mitsubishi Co. Ltd.) was used for SRS and a spiro-analyzer was adopted for gating respiratory tumor motion. Of the 19 tumors 10 tumors (53%) almost disappeared after treatment. Six tumors (32%) decreased in size by 50% or more after treatment. Therefore 16 tumors (84%) showed a local response. During the follow-up of 4-24 months (median 15), no radiation pneumonitis greater than National Cancer. Institute-Common Toxicity Criteria Grade 1 was noted except one patient had grade 2 pneumonitis.3) The effectiveness of high dose rate (HDR) endobronchial brachytherapy for roentgenographically negative carcinoma of the bronchus was prospectively evaluated. In our department, 13 lesions in 11 patients (5 patients, endobronchial early cancer) were treated with a combination of external radiotherapy and HDR endobronchial brachytherapy. Radiation dose was 40 Gy in 20 fractions for external radiotherapy. Endobronchial brachytherapy consisted of 10-25 Gy with 5 Gy/fr and the dose reference point varied 5-10 mm radius from the center of the applicator each according to a diameter of the bronchus. All patients had macroscopic complete response. The follow-up period ranged from 10 to 46 months. Although there ware two patients with local progression, no patient with early cancer had local recurrence. Radiation pneumonitis or other severe treatment-related complications have not been observed. These results suggested that the combination treatment of external radiotherapy and HDR brachytherapy can be used as curative intent for selected patients who have roentgenographically negative tumors limited to the bronchial wall without adjacent parenchymal extension or metastatic disease. Less