I put it to you that I don't give a shit.
Again with the evidence based commentary…
I'm no fan of Armstrong, and have read just about all the circumstantial evidence regarding his cancer and alleged drug use/abuse. That fact that he was winning while everyone around him was using performance enhancing drugs is strong enough evidence to convince me.
But his testicular cancer and subsequent metastases do not mean he was unable to produce his own endogenous epo.
Whoever was telling you about this doesn't know the specifics of Armstrongs case; how did the metastatic deposits affect his kidneys? Were they superficial or did they grow within the kidney tissue itself? How much of his kidney tissue was affected?
Pinches of salt are often required when 'experts' tell stories, particularly when they are trying to liven up lectures…