Staging laparoscopy improves treatment decision-making for advanced gastric cancer

Table 1 Modality-specific staging criteria

Stage	Criteria
T stage	CT criteria
T2/3	Neoplasm shows focal or diffuse thickening of gastric wall with transmural involvement, is almost well enhanced, and has smooth outer wall border and clear fat plane around tumor
T4a	Transmural tumor with irregular or nodular outer border and/or perigastric fat infiltration
T4b	Obliteration of fat plane between gastric tumor and adjacent organ or invasion of adjacent organ
M stage	CT criteria
M0	Distant metastasis absent
M1	Distant metastasis present
T stage	EUS criteria
T2/3	Tumor extent beyond the muscularis propria up to 4 mm
T4a	Tumor extent beyond the muscularis propria greater than 4 mm
T4b	Direct extension and invasion of tumor into adjacent organ
M stage	EUS criteria
M0	Distant metastasis absent
M1	Distant metastasis present
T stage	SL criteria
T2/3	Tumor with clear and smooth outer gastric surface
T4a	Tumor with nodular or irregular outer gastric surface
T4b	infiltration of adjacent organs
M stage	SL criteria
M0	Distant metastasis absent
M1	Distant metastasis present

CT: Computed tomography; EUS: Endoscopic ultrasound; SL: Staging laparoscopy.

Table 2 Agreement of computed tomographic and laparoscopic staging of T stage (n = 582)

		Computed tomography					Staging laparoscopy
		T2/3	T4a	T4b			T2/3	T4a	T4b
Final stage
T2/3		115	35	3			126	27	0
T4a		82	176	4			49	212	1
T4b		22	136	9			0	0	167
	Acc.	Sens.	Spec.	PPV	NPV	Acc.	Sens.	Spec.	PPV	NPV
T2/3	76%	75%	76%	53%	90%	87%	82%	89%	72%	93%
T4a	56%	67%	47%	51%	63%	87%	81%	92%	89%	85%
T4b	72%	5%	98%	56%	72%	100%	100%	100%	99%	100%

Overall accuracy: 51.5% (computed tomography), and 86.8% (staging laparoscopy). Acc.: Accuracy; Sens.: Sensitivity; Spec.: Specificity; PPV: Positive predictive value; NPV: Negative predictive value.

Table 3 Agreement of endoscopic and laparoscopic staging of T stage (n = 150)

		Endoscopic ultrasound					Staging laparoscopy
		T2/3	T4a	T4b			T2/3	T4a	T4b
Final stage
T2/3		28	42	3			64	9	0
T4a		4	29	18			8	42	1
T4b		0	11	15			0	0	26
	Acc.	Sens.	Spec.	PPV	NPV	Acc.	Sens.	Spec.	PPV	NPV
T2/3	67%	38%	95%	88%	62%	89%	88%	90%	89%	88%
T4a	50%	57%	46%	35%	68%	88%	82%	91%	82%	91%
T4b	79%	58%	83%	42%	90%	99%	100%	99%	96%	100%

Overall accuracy: 48.0% (endoscopic ultrasound), and 86.7% (staging laparoscopy). Acc.: Accuracy; Sens.: Sensitivity; Spec.: Specificity; PPV: Positive predictive value; NPV: Negative predictive value.

Table 4 Agreement of computed tomographic and laparoscopic staging of M stage (n = 582)

			Computed tomography					Staging laparoscopy
			M0		M1			M0		M1
Final stage	M0		442		2			444		0
	M1		121		17			2		136
		Acc.	Sens.	Spec.	PPV	NPV	Acc.	Sens.	Spec.	PPV	NPV
	M1	79%	89%	79%	12%	100%	100%	100%	100%	99%	100%

Overall accuracy: 78.7% (computed tomography), and 100% (staging laparoscopy). Acc.: Accuracy; Sens.: Sensitivity; Spec.: Specificity; PPV: Positive predictive value; NPV: Negative predictive value.

Table 5 Relationship between clinicopathologic features determined by clinical staging and peritoneal metastasis or positive cytology (n = 582)

Characteristic	P-negative(n = 457)	P-positive(n = 125)	P value
Gender			0.001
Male (n = 397)	328	69
Female (n = 185)	129	56
Age			0.573
< 65 (n = 441)	334	88
≥ 65 (n = 141)	123	37
ECOG score			0.751
0 (n = 224)	175	49
1 (n = 291)	227	64
2 (n = 67)	55	12
Tumor size (mm)			< 0.001
< 40 (n = 238)	215	21
≥ 40 (n = 346)	242	104
Upper third			0.903
Not involved (n = 455)	358	97
Involved (n = 127)	99	28
Middle third			< 0.001
Not involved (n = 401)	333	68
Involved (n = 181)	124	57
Lower third			0.750
Not involved (n = 200)	159	41
Involved (n = 382)	298	84
fT stage			< 0.001
T2/3 (n = 153)	145	8
T4a (n = 262)	232	30
T4b (n = 167)	80	87
Borrmann type			< 0.001
Type I or II (n = 285)	265	20
Type III (n = 253)	166	87
Type IV (n = 44)	26	18
Differentiation			0.293
Differentiated (n = 577)	454	123
Undifferentiated (n = 5)	3	2
Lymph node metastasis			0.305
Negative (n = 240)	183	57
Positive (n = 342)	274	68

fT stage: Final T stage; P-negative: No peritoneal metastasis and positive cytology; P-positive: Peritoneal metastasis or positive cytology.

Table 6 Correlation between clinicopathologic features determined by clinical staging and peritoneal metastasis or positive cytology (multivariate analysis)

Variables	P value	Odd ratio	95%CI
Tumor size (mm)
< 40		1.000
≥ 40	0.015	2.123	1.160-3.887
fT stage	< 0.001
T2/3		1.000
T4a	0.215	1.714	0.731-4.020
T4b	< 0.001	11.54	4.942-26.947
Borrmann type	< 0.001
Type I or II		1.000
Type III	< 0.001	6.291	3.524-11.231
Type IV	< 0.001	5.844	2.457-13.904

Table 7 Indications for staging laparoscopy determined based on the number of independent risk factors

No. of independentrisk factors	P0 CY0	P1 or CY1	Total
0, 1	314	19	333
2, 3	143	106	249
Total	457	125	582
Accuracy			72%
Sensitivity			85%
Specificity			69%
PPV			43%
NPV			94%

PPV: Positive predictive value; NPV: Negative predictive value.