Impact and relationship of anterior commissure and time-dose factor on the local control of T1N0 glottic cancer treated by 6 MV photons

Table 6 Calculated tumor BED (Gy₁₅), acute mucosal BED (Gy₁₀) and late normal tissue BED (Gy₃) for common radiation schedules

Dose size (Gy)	Fraction number	Total dose (Gy)	Overall treatment time (OTT) in days	Tumor BED (Gy₁₅)	Acute Mucosal BED (Gy₁₀) (aim 59-63 Gy₁₀)[46]	Late normal BED (Gy₃) (aim <117 Gy₃)[46]	references
2.0	33	66	45	64.60	49.1	110	[22, 25, 27] & current study
2.25	28	63	38	66.45	52.62	110.2	[3, 5, 20, 24, 37]
2.5	23	57.5	31	65.28	52.87	105.4	current study

BED = biologically effective dose
= total dose (1 + fraction size/[α/β]) - log_e 2 (OTT -T k)/αT p [14]
Assume: 1. α/β = 15 for laryngeal cancer [12]
2. T k: kick off time (T k) for tumor repopulation = 28 days [13]
3. T p = average cell number doubling time during continuing radiation, 3 days for tumor [14]
4. Alpha (α) = [coefficient of non-repairable injury, log cell kill (exponentially-based logs) per gray of dose]
= 0.35 Gy^-1 (14)]