Just to be clear
"Secondary polycythemia" would be a condition involving both white and red blood cells. Not just effecting HCT
Secondary erythrocytosis is what we are referring to when talking about increased HCT due to AAS, smoking, living in altitude etc.
I dont know of many conditions effecting white and red blood cells that isn't a result of polycythemia vera/primary polycythemia (cancer/mutation) so I wonder if that makes Secondary polycythemia a redundant term to use
my understanding is
You either have polycythemia vera (cancer) or Secondary erythrocytosis (increased HCT not caused by cancer)
Of course I could be wrong and happy to be corrected