Toxicity of dose-escalated, hypofractionated helical tomotherapy for inoperable thoracic esophageal squamous cell carcinoma

Table 2 Summary of dose, fraction and IV grade esophageal toxicity

Dose level (Gy per fraction)	Number of fractions	BED (α/β), 10	EQD2 (α/β), 10	EQD2 (α/β), 15	EQD2 (α/β), 3	Number of patients	Toxicity IV grade	Time, months
3.6	15	73.44	61.20	59.08	71.28	1.00
3.5	20	94.50	78.75	76.18	91.00	1.00
3.3	20	87.78	73.15	71.05	83.16	1.00
3.2	20	84.48	70.40	68.52	79.36	3.00	B	5
3	25	97.50	81.25	79.41	90.00	1.00	B	6
3	23	89.70	74.75	73.06	82.80	1.00
3	22	85.80	71.50	69.88	79.20	1.00
3	20	78.00	65.00	63.53	72.00	2.00	A	6
2.8	27	96.77	80.64	79.16	87.70	1.00	A	5
2.8	20	71.68	59.73	58.64	64.96	1.00
2.7	27	92.58	77.15	75.90	83.11	1.00	B	3
2.7	25	85.73	71.44	70.28	76.95	1.00
2.5	27	84.38	70.31	69.49	74.25	2.00	a: A; b: A	a: at 4th RT; b: 10
2.5	25	78.13	65.10	64.34	68.75	2.00
2.5	20	62.50	52.08	51.47	55.00	1.00
2.5	18	56.25	46.88	46.32	49.50	1.00
2.4	28	83.33	69.44	68.78	72.58	1.00
2.4	26	77.38	64.48	63.87	67.39	1.00
2.4	25	74.40	62.00	61.41	64.80	3.00
2.4	20	59.52	49.60	49.13	51.84	1.00	B	2
2.3	28	79.21	66.01	65.54	68.26	1.00
2.3	27	76.38	63.65	63.20	65.83	1.00
2.3	26	73.55	61.30	60.86	63.39	2.00
2.3	25	70.73	58.94	58.51	60.95	2.00	B	7
2.3	23	65.07	54.22	53.83	56.07	1.00
2.2	28	75.15	62.63	62.32	64.06	2.00
2.2	25	67.10	55.92	55.65	57.20	2.00
2	30	72.00	60.00	60.00	60.00	2.00
2	27	64.80	54.00	54.00	54.00	2.00	B	7
2	25	60.00	50.00	50.00	50.00	5.00

Biologic effective dose at 2Gy per fraction = nd [1 + d/(α/β)]; Equivalent dose at 2Gy per fraction = nd (α/β + d)/(α/β + 2). “A” refers to tracheo-esophageal fistulas; “B” refers to bleeding related to aorto-esophageal fistulalization. BED: Biologic effective dose; EQD: Equivalent dose; RT: Radiation