GSTM1 and cancer: Other prognostic variables that had a significant impact on OS from the log-rank test were age (p < 0.0001), BMI (p = 0.0014), gender (p < 0.0001), ASA score (p = 0.04), cancer stage (p < 0.0001), number of transfused units (p < 0.0001), preoperative and postoperative chemoradiation (< 0.0001) and preoperative Hb (p = 0.001) (Table 4).