Pathological response measured using virtual microscopic slides for gastric cancer patients who underwent neoadjuvant chemotherapy

Table 1 Clinicopathological characteristics of the patients

Background	n (%)	Background	n (%)
Age	Median 64	M-classification
	Range 39–77
< 65 yr	28 (51.9)	0	51 (94.4)
≥ 65 yr	26 (48.1)	1	3 (5.6)
Gender		Tumor histology
Male	40 (74.1)	Differentiated	26 (48.1)
Female	14 (25.9)	Undifferentiated	28 (51.9)
ECOG PS		Reason for NAC
0	46 (85.2)	Clinical SE or T4b	14 (25.9)
1	8 (14.8)	Extended LN	24 (44.4)
Tumor type		Large type 3	5 (9.3)
Non-type 4	44 (81.5)	Type 4	4 (7.4)
Type 4	10 (18.5)	Others	7 (13.0)
Primary site		HER2 overexpression
Stomach	51 (94.4)	Negative or unknown	48 (88.9)
Esophagogastric junction	3 (5.6)	Positive	6 (11.1)
T-classification		NAC regimen
1	1 (1.9)	SP or SOX (+ trastuzumab)	49 (90.7)
2	2 (3.7)	DCS	5 (9.3)
3	13 (24.1)	Adjuvant treatment
4	38 (70.4)	S-1	52 (96.3)
N-classification		Others or no treatment	2 (3.7)
0	6 (11.1)	Participant of clinical trials
1	10 (18.5)	Yes	17 (31.5)
2	22 (40.7)	No	37 (68.5)
3	15 (27.8)
Not evaluable	1 (1.9)

NAC: Neoadjuvant chemotherapy; LN: Lymph node; SP: S-1 + cisplatin; SOX: S-1 + oxaliplatin; DCS: Docetaxel + cisplatin + S-1; ECOG PS: Eastern cooperative oncology group performance status.

Table 2 Prognostic analysis according to patients’ characteristics

Background		HR (95%CI)	P value
Age	≥ 65 yr	0.57 (0.21–1.51)	0.26
Gender	Male	1.09 (0.38–3.07)	0.87
ECOG PS	0	0.37 (0.04–2.84)	0.34
Macroscopic type	Type 4	1.51 (0.53–4.25)	0.43
Primary site	Stomach	0.27 (0.05–1.24)	0.09
Tumor histology	Undifferentiated	1.14 (0.44–2.90)	0.78
T-classification	≥ 4a	4.73 (0.62–35.7)	0.13
N-classification	≥ 3a	1.63 (0.57–4.61)	0.35
M-classification	1	0.96 (0.22–4.19)	0.95
HER2	Positive	< 0.001 (0–infinity)	0.14
Main reason for NAC	Extended LN	1 (reference)
	Large type 3	1.22 (0.32–4.70)	0.76
	Type 4	1.49 (0.48–4.60)	0.48
	Others	0.62 (0.13–3.02)	0.58
NAC regimen	SP or SOX	1.85 (0.24–14.2)	0.55
Adjuvant treatment	Yes	0.43 (0.05–3.39)	0.42
Participant of clinical trials	Yes	0.79 (0.29–2.14)	0.65

NAC: Neoadjuvant chemotherapy; LN: Lymph node; SP: S-1 + cisplatin; SOX: S-1 + oxaliplatin; DCS: Docetaxel + cisplatin + S-1; HR: Hazard ratio; CI: Confidence interval; ECOG PS: Eastern cooperative oncology group performance status.

Table 3 Comparison of prognostic utility of 10% cut-off evaluated using virtual microscopic slides with JCGC criteria

Histological criteria of JCGC	RFS		OS
	HR (95%CI)	P value	HR (95%CI)	P value
Grade 0 vs 1a–3	0.52 (0.15–1.80)	0.304	2.27 (0.27–19.0)	0.449
Grade 0–1a vs 1b–3	0.63 (0.26–1.55)	0.321	0.72 (0.26–1.95)	0.52
Grade 0–1b vs 2–3	0.33 (0.12–0.87)	0.026	0.39 (0.13–1.15)	0.089
Grade 0–2 vs 3	0.69 (0.08–5.34)	0.722	0.62 (0.07–5.34)	0.665
Our method
Responder vs non-responder	0.29 (0.10–0.82)	0.019	0.23 (0.07–0.78)	0.018

NAC: Neoadjuvant chemotherapy; HR: Hazard ratio; JCGC: Japanese Classification of Gastric Carcinoma; CI: Confidence interval; RFS: Relapse-free survival; OS: Overall survival.