GSTM1 and colorectal carcinoma: Methods: Cohort study of CRC patients between 2012 and 2018, divided into groups: non-anemic patients (Hemoglobin Hb > 13 g/dL, Group 1), mildly anemic patients (Hb 12–13 mg/dL, Group 2), and patients treated with IVI (Hb < 12 mg/dL or Hb 12–13 mg/dL with risk factors, Group 3).