My Mother In Law Is 80 Years Old, Although In

My mother in law is 80 years old, although in good shape, and is having her 3rd recurrence of Ovarian Cancer (caught at stage 3, had gone into her colon).
Her first line of treatment was Carboplatin and it recurred within 5 months, her second line treatment was Gemsar and it recurred within 4 months.
Now they want to give her Doxil and Avastin if she passes the heart stress tests - is this the best course of treatment given her age and what she has already had?

Thank you