Histopathological validation of magnifying endoscopy for diagnosis of mixed-histological-type early gastric cancer

Table 1 Clinicopathological characteristics and treatment outcomes of all the patients and lesions treated with endoscopic submucosal dissection at our facilities between January 2005 and June 2016, n (%)

	Pure DT (n = 1863)	Pure UDT (n = 56)	MT (n = 92)	P value (Pure DT vs MT)
Age (yr), mean ± SD	71.7 ± 8.5	66.0 ± 10.3	71.0 ± 9.1	< 0.0001
Male	1409 (75.6)	30 (53.6)	62 (67.4)	0.0739
Location				0.5385
Upper third	340 (18.3)	6 (10.7)	14 (15.2)
Middle third	536 (28.8)	28 (50.0)	31 (33.7)
Lower third	987 (53.0)	22 (39.3)	47 (51.1)
Macroscopic type				0.0002
Elevated	759 (40.7)	3 (5.4)	18 (19.6)
Flat	34 (1.83)	0	1 (1.1)
Depressed	1070 (57.4)	53 (94.6)	73 (79.4)
Tumor diameter (mm), mean ± SD	16.1 ± 11.4	14.6 ± 9.6	24.4 ± 13.9	< 0.0001
Depth				< 0.0001
Mucosal	1635 (87.8)	45 (80.4)	50 (54.4)
Submucosal	228 (12.2)	11 (19.6)	42 (45.7)
Ulcerative findings	150 (8.1)	9 (16.1)	18 (19.6)	0.0001
Lympovascular invasion	57 (3.1)	4 (7.1)	21 (22.8)	< 0.0001
En bloc resection	1853 (99.5)	55 (98.2)	92 (100)	0.4811
R0 resection	1835 (98.5)	53 (94.6)	81 (88.0)	< 0.0001
Curative resection	1686 (90.5)	27 (48.2)	35 (38.0)	< 0.0001
Additional surgery	97 (5.2)	13 (23.2)	36 (39.1)	< 0.0001

ESD: Endoscopic submucosal dissection; DT: Differentiated-type; UDT: Undifferentiated-type; MT: Mixed-histological-type.

Table 2 Clinicopathological characteristics and treatment outcome of the 49 mixed histological-type early gastric cancers investigated in this study (n = 49), n (%)

Patient characteristics
Age (yr), mean ± SD	71.7 ± 9.5
Male	34 (69.4)
Endoscopic examination
Location
Upper third	4 (8.2)
Middle third	12 (24.5)
Lower third	33 (67.3)
Macroscopic types
Elevated	5 (10.2)
Flat	0
Depressed	44 (89.8)
Preoperative biopsy results
Only DT component (tub1, tub2 or pap)	36 (73.5)
UDT component (por1, por2, sig or muc) with or without DT component	13 (26.5)
ME-NBI findings of UDT gastric cancer	12 (24.5)
Histopathological examination
Tumor diameter (mm), mean ± SD	23.3 ± 14.4
Depth
Mucosal	34 (69.4)
Submucosal, < 500 um	7 (14.3)
Submucosal, ≥ 500 um	8 (16.3)
Lymphovascular invasion
Lymphoid invasion	10 (20.4)
Vascular invasion	2 (4.1)
Vertical margin positive	2 (4.1)
Horizontal margin positive	1 (2.0)
Ulcerative finding	10 (20.4)
Predominant histological type
Differentiated	36 (73.5)
Undifferentiated	13 (26.5)
The whole mucosal layer extension of UDT component	33 (67.3)
Exposure of UDT cancer to the surface of the mucosa	39 (79.6)
Clear border between DT and UDT components	17 (34.7)
Treatment outcome
Curative resection	24 (49.0)
Additional surgery	19 (38.8)
Lymph node metastasis	1 (2.0)
Recurrence	0

ME-NBI: Magnifying endoscopy with narrow-band imaging; DT: Differentiated-type; UDT: Undifferentiated-type.

Table 3 Comparison between magnifying endoscopy with narrow-band imaging and histopathological findings

	ME-NBI findings of UDT component		P value
	Present (n = 12)	Absent (n = 37)
Tumor diameter (mm), mean ± SD	20.6 ± 10.2	24.2 ± 15.5	0.450
Preoperative biopsy results			0.259
Only DT component	7 (19.4)	29 (80.6)
UDT component with or without DT component	5 (38.5)	8 (61.5)
Ulcerative findings			1
Present	2 (20)	8 (80)
Absent	10 (26)	29 (74)
Depth			0.0754
Mucosal	11 (32)	23 (68)
Submucosal	1 (7)	14 (93)
Predominant histological type			0.0009
Differentiated	4 (11)	32 (89)
Undifferentiated	8 (62)	5 (38)
The whole mucosal layer extension of UDT component			0.290
Present	10 (30)	23 (70)
Absent	2 (12)	14 (88)
Exposure of UDT cancer to the surface of the mucosa			0.0926
Present	12 (31)	27 (69)
Absent	0 (0)	10 (100)
Clear border between DT and UDT components			0.175
Present	2 (12)	15 (88)
Absent	10 (31)	22 (69)

ME-NBI: Magnifying endoscopy with narrow-band imaging; DT: Differentiated-type; UDT: Undifferentiated-type.