Rikiya Onimaru1, Hiroki Shirato2, Taro Shibata3, Masahiro Hiraoka4, Satoshi Ishikura5, Katsuyuki Karasawa6, Yukinori Matsuo4, Masaki Kokubo7, Yoshiyuki Shioyama8, Haruo Matsushita9, Yoshinori Ito10, Hiroshi Onishi11. 1. Department of Radiation Medicine, Hokkaido University Graduate School of Medicine, Sapporo, Japan. Electronic address: ronimaru@pop.med.hokudai.ac.jp. 2. Department of Radiation Medicine, Hokkaido University Graduate School of Medicine, Sapporo, Japan. 3. JCOG Data Center, Center for Research Administration and Support, National Cancer Center, Tokyo, Japan. 4. Department of Radiation Oncology and Image-Applied Therapy, Graduate School of Medicine, Kyoto University, Japan. 5. Department of Radiology, Koshigaya Municipal Hospital, Japan. 6. Metropolitan Cancer and Infectious Diseases Center, Komagome Hospital, Tokyo, Japan. 7. Department of Image-based Medicine, Institute of Biomedical Research and Innovation, Kobe, Japan. 8. Department of Clinical Radiology, Kyushu University Graduate School of Medicine, Fukuoka, Japan. 9. Department of Radiation Oncology, Tohoku University Graduate School of Medicine, Sendai, Japan. 10. Department of Radiation Oncology, National Cancer Center Hospital, Tokyo, Japan. 11. Department of Radiology, University of Yamanashi Graduate School of Medical Science, Chuo, Japan.
Abstract
PURPOSE: To estimate the maximum tolerated dose (MTD) and to determine the recommended dose (RD) of stereotactic body radiation therapy (SBRT) for peripheral T2N0M0 non-small cell carcinoma (NSCLC) with target volume (PTV) < 100 cc. MATERIALS AND METHODS: The continual reassessment method (CRM) was used to determine the dose level that patients should be assigned to and to estimate the MTD. Dose limiting toxicity (DLT) was grade 3 radiation pneumonitis (RP) within 180 days after the start of SBRT, grade 2 RP was used as a surrogate DLT. The RD was equal to the MTD. The dose was prescribed at D95 of the PTV. RESULTS: Fifteen patients were accrued. Only 1 experienced grade 2 RP at 60 Gy in 4 fractions. It was difficult to fulfill the dose constraints at 60 Gy in 4 fractions, and the maximum dose level assigned by CRM was changed to 55 Gy in 4 fractions. The lower limit of 95% of the credible interval exceeded the adjacent level, and the RD was determined as 55 Gy in 4 fractions. CONCLUSIONS: The RD of SBRT for peripheral T2N0M0 NSCLC with PTV<100 cc was determined to be 55 Gy in 4 fractions.
PURPOSE: To estimate the maximum tolerated dose (MTD) and to determine the recommended dose (RD) of stereotactic body radiation therapy (SBRT) for peripheral T2N0M0 non-small cell carcinoma (NSCLC) with target volume (PTV) < 100 cc. MATERIALS AND METHODS: The continual reassessment method (CRM) was used to determine the dose level that patients should be assigned to and to estimate the MTD. Dose limiting toxicity (DLT) was grade 3 radiation pneumonitis (RP) within 180 days after the start of SBRT, grade 2 RP was used as a surrogate DLT. The RD was equal to the MTD. The dose was prescribed at D95 of the PTV. RESULTS: Fifteen patients were accrued. Only 1 experienced grade 2 RP at 60 Gy in 4 fractions. It was difficult to fulfill the dose constraints at 60 Gy in 4 fractions, and the maximum dose level assigned by CRM was changed to 55 Gy in 4 fractions. The lower limit of 95% of the credible interval exceeded the adjacent level, and the RD was determined as 55 Gy in 4 fractions. CONCLUSIONS: The RD of SBRT for peripheral T2N0M0 NSCLC with PTV<100 cc was determined to be 55 Gy in 4 fractions.