GSTM1 and polycythemia: Documentation of potential polycythemia: Any sustained Hb above the target, especially ≥13 g/dL or persistent upward velocity despite dose reductions/interruptions, should prompt evaluation for post-transplant erythrocytosis and other secondary causes (e.g., dehydration and androgen exposure), temporary ROX cessation, and risk mitigation for thrombosis [25,26,63,64,65].