Lance Armstrong returning to the Tour next year

the drugs he used just happened to be illegal. It's called EPO which promotes red blood cell production.
It's necessary to take during and following chemotherapy to increase/sustain the blood count since chemotherapy dramatically reduces the amount of red blood cells produced and kills them off too.
Since Armstrong received a barbaric amount of chemotherapy, his blood count i suspect was deadly low, hence why he had to take it.

i think it was admitted to the cycling authorities by his doctors and manager as he had no choice but to take it for health reasons, not sporting advantage.

Balls.. there goes my cover for the HH track day ..oh no pun intended!