Hi there, The benefit versus toxicity of chemotherapy is always a debatable and difficult situation and naturally brings anxiety to care givers and physicians alike. If we were to not give chemo then disease will progress relentlessly and he would be suffering from disease progression. Chemotherapy may cause low red cells and low platelets but thankfully we have medical measures for them and can support the body Also according to side effects, oncologists would adjust the dose. No one can tell how much chemo human body can take as many times patients are given third line or fourth line chemo, it really depends on the bone marrow reserve and the general condition of the patient. Have a clear discussion witn your oncologist and be realistic. Regards