I'm sorry to hear about your sister. I'm not sure if my experience can help you but here is goes. I was diagnosed with bone cancer 16 years ago when I was only 12 years old. I cannot remember the names of the chemo therapy I received. I know it was several. Each one was stronger and stronger. I received them from January to April. In april I had to get my leg amputated because the chemo was not shrinking the tumor quick enough. I received chemo for exactly one year. I am now 28 and healthy. I would say always get a second opinion. Good luck!