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You ask why chemosensitivity (profiling) testing is not done more?
There is so much misinformation about the cell culture assay technology being perpetuated. All the important progress in the technology has come outside of NCI-sponsored university-based research and it strikes at the heart of the standard NCI/university clinical research paradigms. That's why some doctors have not yet made the effort to learn about this.
Because of the efforts of a dedicated private sector and the availability of media such as the Internet, the NCI and NCI-oriented institutions will soon find themselves in the position of having to make the effort to learn and to be forced to provide sound reasons if they choose not to use these tests in the management of individual patients.
Conventionally, what clinical oncologists have been attempting to do is to define the best treatment to give to the average patient with a given disease, otherwise known as the lowest common denominator theory of cancer chemotherapy (roll-the-dice). Why would they want to hold cancer patients hostage to hypothetical series of clinical trials?
For 30 years they have been attempting to define the best drugs to give to the average patient, with no real progress with regard to identifying better chemotherapy regimens for the average patient.
It is a scientifically bankrupt paradigm which has not fostered either efficient or humane progress in cancer chemotherapy. Balance is much needed to the flow of cancer information which is largely controlled by people with their own biases and self interests.
Whenever a surgeon friend has difficulty finding a medical oncologist to use assay-directed therapy on a delicately excised tumor specimen from one of his patients, he says it's like herding cats. He sent this to me. It is so apopro! Imagine all those cats as medical oncologists!?
And why is it that some private insurance companies are not paying for this testing?
The validaton standard that private insurance companies are accepting from molecular profiling tests is accuracy and not efficacy. The 'bar' had been instantly lowered. No longer will it be essential to prove that the use of a diagnostic test improves clinical outcomes, all they have to do for these molecular profiling tests is prove that the test has a useful degree of accuarcy. However, the validation standard wanted for functional tumor cell profiling is efficacy. What's good for the goose is good for the gander.
Remember, giving a targeted drug on the basis of a molecular test is simply clinical correlations. It shows that the test correlates with clinical outcomes. It doesn't show that doing the test will make a difference. It is never tested against an individual patient's cancer cells. What that would take would be a clinical trial in which you performed molecular tests on half the patients and didn't perform them on the other half and half would be treated with the knowledge of tests results and half would be treated without knowledge of the test results. Then you show that patients who got the test did better than those who didn't. That's never been done, with EGFR, ER, PR, Her2/neu, KRAS, OncotypeDx, diagnostic imaging studies, bacterial C&S, etc.
The preponderance of available evidence certainly does indicate that cell
culture assay tests are usefully accurate iin taking a long list of drugs
with average probabilities of providing clinical benefit and sorting them
into groups with above-average and below-average probabilities of benefit, in
disease settings where drugs could otherwise be selected by a coin toss, but
in the real world, are often selected on the basis of which drugs provide the
best reimbursement for the treating oncologist.
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