In univariate and multivariate analyses, choice of CRT (OR 2.62; 95%CI 1.34–5.14, scRT reference) or scRT/CRT + CTX (4.70; 2.23–9.93), cT1–2 (3.37; 1.30–8.78; cT4 reference), tumour length ≤ 3.5 cm (2.27; 1.24–4.18), and CEA ≤ 5 μg/L (1.73; 1.04–2.90) demonstrated significant associations with achievement of pCR. The gene discussed is CEACAM5; the disease is neoplasm.