Hi Sandy-
The name of the test is a "Chemo-sensitivity Assay", and they do need a good bit of tumor sample to conduct the test - parafin preseverd biopsied tissue won't suffice.It's my understanding that the test is a better gauge of what does NOT work, rather that what will work, because, as Judy mentioned, chemo may work differently in the body vs. in a petri dish.At least you can rule out certain drug combos, rather than investing in 8 weeks of tx in the wrong combo and learn that you're not responding.
Hope this is helpful,
Jessica