Key Words: phase I study, continual reassessment method, non-small cell lung cancer (NSCLC), stereotactic body radiotherapy, SBRT.
Short running title:
Previous presentationThis work was presented at the 55th Annual Meeting of the American Society for Radiation Oncology, September 22 -25, 2013 in Atlanta, GA.
/ 28Abstract 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 D 95 of the PTV.Results: Fifteen patients were accrued. Only 1 experienced grade 2 RP at 60 Gy in 4fractions. 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.
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