Logistic multivariable analysis including the results in all study patients identified tumor diameter before treatment ≥ 5.0 cm (HR 6.943, 95% CI 2.250-21.428, P = 0.001), cN2 (HR 5.054, 95% CI 1.553-16.448, P = 0.007) and CEA clearance pattern Group B after chemoradiation (HR 8.435, 95% CI 1.062-66.992, P = 0.044) as independent risk factors for poor regression response (Table 4). Here, CEACAM5 is linked to neoplasm.