As a continuous variable, the pretreatment Hb level did not show any association with tumour response; however, with dichotomisation with a cut-off value of 12.0 g/dl, patients with Hb < 12 g/dl showed less response to neoadjuvant chemoradiation, if regression of T stage was considered as a response (P = 0.03). This evidence concerns the gene GSTM1 and neoplasm.