Table 2.

Correlations of factors with parotid (actual) volume and dose.

Factor	Volume (p value)	D mean   (p value)	V 1  (p value)	D 50  (p value)
Age	0.683	0.858	0.846	0.743
T stage	0.690	0.862	0.883	0.716
N stage	0.044	0.439	0.607	0.413
Volume of primary tumor	0.712	0.422	0.689	0.093
Volume of metastatic nodes	0.086	0.463	0.521	0.308
Treatment method	0.061	0.059	0.031	0.039
Initial parotid volume	0.000	0.205	0.241	0.254
Initial parotid D mean	0.549	0.226	0.286	0.002
Weight loss rate	0.036	0.000	0.004	0.014
Reduction of skin separation at C1 level	0.000	0.000	0.000	0.000
Reduction of skin separation at C2 level	0.010	0.000	0.000	0.013
Reduction of skin separation at C4 level	0.042	0.090	0.110	0.271