Table 1. Characteristics of the patients enrolled in the study.

	Differentiated type n = 42	Undifferentiated type n = 10	P value
Age, mean ± SD, years	73.3 ± 9.0	60.3 ± 10.4	< 0.001
Sex, male/female, n (%)	35 (83.3) : 7 (16.7)	5 (50.0):5 (50.0)	0.039
Size of tumor mean ± SD, mm	18.5 ± 9.8	12.1 ± 5.5	0.053
Macroscopic type, 0-IIa/0-IIb/0-IIc, n (%)	12 (28.6) : 4 (9.5) : 26 (61.9)	0 (0) : 1 (10.0) : 9 (90.0)	0.149
Location, upper/middle/lower, n (%)	5 (11.9) : 17 (40.5) : 20 (47.6)	1 (10.0) : 8 (80.0) : 1 (10.0)	0.065
Depth of invasion, pT1 m/pT1sm, n (%)	34 (81.0) : 8 (19.0)	9 (90.0) : 1 (10.0)	0.830
WOS, positive/negative, n (%)	8 (19.0) : 34 (81.0)	0 (0) : 10 (10.0)	0.311
Color of tumor, reddish/discolored, n (%)	31 (73.8) : 11 (26.2)	1 (10.0) : 9 (90.0)	< 0.001

SD, standard deviation; 0-IIa, superficial elevated; 0-IIb, superficial flat; 0-IIc, superficial depressed; pT1 m, tumor confined to the mucosa; pT1sm, tumor invading the layer of the submucosa; WOS, white opaque substance.