GSTM1 and cancer: However, our results are in-line with those of a large observational study in FCM-treated anemic cancer patients (n = 420; 233 patients received FCM alone), which showed improvement in median Hb from 10.0 g/dL to above 11 g/dL within 5 weeks and a median Hb increase of 1.4 g/dL.