Low hemoglobin is a bad prognostic factor in many malignancies. Low count bad means high count good, right? Don't hold your breath (especially if you're anemic). In 2015, RTOG 9903 demonstrated a possible detrimental effect when erythropoietin was given during head and neck (H&N) radiation. The most recent damning data now comes from DAHANCA 10, which randomized patients receiving H&N radiation with a hemoglobin <14 to standard therapy +/- darbepoietin. Interestingly, patients who received darbepoietin had worse tumor control and even worse overall survival. TBL: There is consistent data that erythropoietin stimulating agents during H&N radiation has a detrimental effect on cancer control.