You are thinking of allogeneic bone marrow transplants (bone marrow is transplanted from a donor) where there is a 20% chance of death. Typically, myeloma patients get autologous transplants (the patient self donates bone marrow stem cells) which are much less dangerous (less than 5% death rate). I know someone who has had five ASCTs (autologous stem cell transplants) and he is still kicking. It's not a cake walk but at least you don't die.