CEACAM5 and signet ring cell carcinoma: Patient age <60 years (OR:1.869, 95% CI: 1.505–2.321, p < 0.001), poorly differentiated or mucinous or signet ring cell adenocarcinoma (OR:2.075, 95% CI: 1.584–2.717, p < 0.001), elevated carcinoembryonic antigen (CEA) level (OR:1.343, 95% CI: 1.022–1.763, p = 0.033) and perineural invasion (PNI) (OR:6.212, 95% CI: 3.502–11.017, p < 0.001) were significantly associated with LNM in pT1 stage patients.