Protective effects of female reproductive factors on gastric signet-ring cell carcinoma

Table 3 Associations of sex and risk of mortality among gastric cancer patients with signet-ring cells by subgroups

Variable	Male		Menstrual female		Menopausal female		P-interaction3
	n1 (%)	HR (95%CI)2	n1(%)	HR (95%CI)2	n1 (%)	HR (95%CI)2
BMI (kg/m2)							0.014
> 24	501 (53.6)	Ref	41 (22.7)	0.56 (0.27–1.16)	117 (37.1)	1.04 (0.72–1.50)
≤ 24	434 (46.4)	Ref	140 (77.4)	0.58 (0.39–0.85)	198 (62.9)	0.84 (0.62–1.12)
Signet-ring cell proportion (%)							0.038
≤ 50	733 (78.4)	Ref	129 (71.3)	0.56 (0.38–0.82)	247 (78.4)	0.94 (0.74–1.21)
> 50	202 (21.6)	Ref	52 (28.7)	0.73 (0.33–1.61)	68 (21.6)	0.74 (0.40–1.35)
Adjuvant chemotherapy							< 0.001
No	598 (64.0)	Ref	119 (65.8)	0.38 (0.22–0.65)	207 (65.7)	1.01 (0.75–1.36)
Yes	337 (36.0)	Ref	62 (34.3)	0.83 (0.53–1.29)	108 (34.3)	0.80 (0.56–1.16)
Neoadjuvant chemotherapy							< 0.001
No	861 (92.1)	Ref	165 (91.2)	0.53 (0.36–0.77)	289 (91.8)	0.80 (0.35–1.82)
Yes	74 (7.9)	Ref	16 (8.8)	0.97 (0.76–1.25)	26 (8.3)	0.65 (0.33–1.26)
Nerve invasion							0.0294
No	184 (19.7)	Ref	54 (29.8)	0.36 (0.07–1.86)	75 (23.8)	0.78 (0.27–2.27)
Yes	477 (51.0)	Ref	87 (48.1)	0.60 (0.40–0.89)	150 (47.6)	0.91 (0.69–1.21)
Unknown	274 (29.3)	Ref	40 (22.1)	0.65 (0.31–1.39)	90 (28.6)	0.95 (0.60–1.49)
Lymphovascular invasion							< 0.004
No	249 (26.6)	Ref	70 (38.7)	0.89 (0.40–1.95)	97 (30.8)	1.13 (0.61–2.11)
Yes	373 (39.9)	Ref	56 (30.9)	0.49 (0.30–0.80)	125 (39.7.2)	0.81 (0.59–1.10)
Unknown	313 (33.5)	Ref	55 (30.4)	0.68 (0.37–1.23)	93 (29.5)	1.23 (0.80–1.91)

¹Column percentage was reported for the overall sample; percentage can differ slightly from 100% because of rounding.

²The Cox proportional hazards model included gender, BMI, signet-ring cell proportion, T stage, N stage, adjuvant chemotherapy, neoadjuvant chemotherapy, nerve invasion, and lymphovascular invasion.

³Wald test was used to examine the interaction term between sex (male, menstrual female, and menopausal female) and BMI, signet-ring cell proportion, adjuvant chemotherapy, neoadjuvant chemotherapy, nerve invasion, and lymphovascular invasion.

⁴The P value shows the outcome of interaction test between sex difference and nerve invasion (no vs yes) and lymphovascular invasion (no vs yes).

BMI: Body mass index. P < 0.05 indicates statistical significance.