Chuong (7) used 5 fractions to potentially decrease the risk of late normal tissue injury compared with 1 to 3 fractions commonly used in other institutions. Assuming α/β=3, the BED3 delivered to normal tissue in this study (using a mean 36.4 Gy in 5 fractions to the high dose PTV) was 125 Gy, which is lower than the mean BED3 from other series, the corresponding values from Boston and Stanford were 153.7 Gy (mean, 32.96 Gy in 3 fractions) and 233.3 Gy (mean, 25Gy in 1 fraction), respectively (8, 9). And a relatively lower incidence of grade ≥3 late adverse effects (5.3% VS 9%) was observed.