Fowler Jack F
Department of Human Oncology and Medical Physics, University of Wisconsin, Madison, WI, USA.
Int J Radiat Oncol Biol Phys. 2008 Jun 1;71(2):326-9. doi: 10.1016/j.ijrobp.2008.01.052.
To correct several elementary radiobiologic errors in the otherwise admirable article by Kasibhatla, Kirkpatrick, and Brizel (2007) on estimating the equivalent radiation effect of the concomitant chemotherapy in head-and-neck chemoradiotherapy.
(1) Their equation was wrong because it omitted the lag or onset time of repopulation in tumors, Tk. Instead of zero days this should be 18-35 days. (2) Instead of a doubling time of 5 days, at most 3 days should be used for head-and-neck tumors. (3) Their slope "S" (the gamma-50 slope) for head-and-neck tumors should be 1.7, not 1.1. The same percentages of increased locoregional control as quoted by Kasibhatla et al. are used.
The average time-corrected biologically effective dose for the 16 schedules listed should be 72.4 instead of 63.1 Gy(10). The average gains in locoregional tumor control are the equivalent of 8.8 Gy(10), not 10.6 Gy(10) (p = 0.05).
The equivalent number of 2-Gy fractions of concomitant chemotherapy as used in the 16 listed schedules is 3.6 (95% confidence interval, 2.7-4.1), not 5 as claimed by Kasibhatla et al. The difference is statistically significant (p < 0.001).
纠正卡西巴特拉、柯克帕特里克和布里泽尔（2007年）在关于估计头颈部放化疗中同步化疗等效辐射效应的那篇原本令人钦佩的文章中的几个基本放射生物学错误。
（1）他们的公式有误，因为它忽略了肿瘤再增殖的延迟或起始时间Tk。这个时间不应为零天，而应为18 - 35天。（2）对于头颈部肿瘤，不应使用5天的倍增时间，最多应使用3天。（3）他们对头颈部肿瘤的斜率“S”（γ - 50斜率）应为1.7，而非1.1。使用与卡西巴特拉等人所引用的相同的局部区域控制增加百分比。
列出的16个治疗方案的平均时间校正生物等效剂量应为72.4，而非63.1 Gy(10)。局部区域肿瘤控制的平均增益相当于8.8 Gy(10)，而非10.6 Gy(10)（p = 0.05）。
列出的16个治疗方案中所使用的同步化疗2 - Gy分次等效数量为3.6（95%置信区间，2.7 - 4.1），而非卡西巴特拉等人所声称的5。差异具有统计学意义（p < 0.001）。
