Basically, genotyping is tumor analysis coupled with clinical
trial literature search, which tries to match therapies to
patient-specific biomarker information to generate a treatment
approach. In other words, information that may help when
considering "potential" treatment options (theoretical
analysis).  Genotyping will only be of value for drugs for which
a gene mutation is informative -- basically KRAS and EGFR
mutations -- and we already have tests for those and they are of
very limited value. Otherwise, it's a ton of information for
which the drug selection value is pretty darn useless.
Phenotyping is tumor analysis that "actually" measures the
response of the tumor cells to drug exposure. Following this
exposure, it measures both cell metabolism and cell morphology.
The integrated effect of the drug on the whole cell, resulting
in a cellular response to it, measuring the interaction of the
entire genome (actual analysis).  What's more important than
what genes are in the DNA is what genes are actively