Table 1. Demographic data (sex, age, number of tumors) of the patients.

	Group	Number (n=600)	Ratio (%)
Sex	Male	322	53.7
	Female	278	46.3
Age	20−40	16	2.7
	41−50	34	5.7
	51−60	121	20.2
	61−70	219	36.5
	71−80	147	24.5
	Over 80	63	10.5
Number of tumors	1−5	267	44.5
	6−10	105	17.5
	11−15	55	9.2
	16−20	41	6.8
	21−25	23	3.8
	Over 26	109	18.2