Using neoadjuvant chemotherapy and replanning intensity-modulated radiotherapy for nasopharyngeal carcinoma with intracranial invasion to protect critical normal tissue

Table 2 Dosimetry comparisons of serial structures and parallel structures

Variable	Replanned	Not replanned	P value	Variable	Replanned	Not replanned	P value
Brain stem				Temporal lobe
D1 (Gy)	56.45 ± 3.33	57.31 ± 5.65	0.209	D-Mean (Gy)	20.20 ± 3.26	21.48 ± 3.86	0.000
D5 (Gy)	52.76 ± 3.28	54.09 ± 4.34	0.001	D50 (Gy)	14.87 ± 4.75	16.05 ± 5.23	0.000
D10 (Gy)	50.38 ± 3.36	51.40 ± 4.36	0.023	D80 (Gy)	6.53 ± 2.66	6.96 ± 2.88	0.000
Optic chiasm				Inner ear
D1 (Gy)	58.55 ± 7.79	62.76 ± 7.64	0.000	D-Mean (Gy)	52.96 ± 4.94	53.41 ± 5.23	0.018
D5 (Gy)	57.86 ± 7.63	62.00 ± 7.47	0.000	D-50 (Gy)	52.83 ± 5.34	53.98 ± 5.81	0.009
D10 (Gy)	57.41 ± 7.66	61.30 ± 7.58	0.000	D-80 (Gy)	45.82 ± 5.43	46.28 ± 5.73	0.030
Optic nerve				Middle ear
D1 (Gy)	57.77 ± 8.95	61.74 ± 8.45	0.000	D-Mean (Gy)	59.24 ± 5.53	59.51 ± 5.76	0.097
D5 (Gy)	56.31 ± 8.96	60.29 ± 8.49	0.000	D-50 (Gy)	59.52 ± 5.81	60.00 ± 6.09	0.009
D10 (Gy)	54.83 ± 9.15	58.75 ± 8.72	0.000	D-80 (Gy)	54.39 ± 6.71	54.79 ± 6.97	0.027

Abbreviations: D1 dose to 1% of the volume, D5 dose to 5% of the volume, D10 dose to 10% of the volume, D50 dose to 50% of the volume, D80 dose to 80% of the volume, Dmean mean dose per fraction.