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Chemosensitivity Assays: Still Eyeing the Clinic
Imagine taking a snapshot of a tumor in
action as it overwhelms healthy cells to survive—and then using that
information in
the clinic to monitor which drugs best kill cancer
cells. In vitro chemosensitivity assays promise to do that—using
proprietary
screening tests for clues about each individual’s
cancer.
But more than two decades after these
assays debuted, oncologists remain divided: those who support such
laboratory analyses
and those who maintain that they unduly raise
patients’ hopes, often at considerable expense, while not improving
survival.
“Predicting what doesn’t work [as opposed to what
will] is not seen by most as an advance,” said Jeffrey Abrams, M.D.,
associate
director of the National Cancer Institute’s Cancer
Therapy and Evaluation Program.
Last year, the American Society of
Clinical Oncology (ASCO) performed a literature review of data published
between December
1, 2003, and May 31, 2010, on chemosensitivity
testing. ASCO concluded, as it had in 2004, that this “in vitro analytic
strategy
has potential importance” but should be confined to
patients participating in clinical trials. The National Cancer
Comprehensive
Network holds a similar view.
“In vitro testing is an old oncologist’s
dream,” said Alain Hendlisz, M.D., chief of gastroenterology in the
medical oncology
clinic at the Jules Bordet Institute in Brussels,
where researchers are using metabolic imaging to evaluate colorectal
cancer
treatments after an initial round of therapy.
“In an ideal world, we should know what
will be the effect of a treatment before its very beginning. That’s the
purpose of
in vitro testing, and that’s the philosophical
reason why people are attracted by tests with a high positive predictive
value,”
Hendlisz wrote in an e-mail. “However, that’s a
philosophical point of view, not a scientific one.”
Still, in certain circumstances, where no standard of care exists, chemosensitivity testing may be useful to determine …
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What is it that ASCO is saying? Chemosensitivity testing should not be used outside the confines of a clinical trial setting. The same people who maintain that assay-directed therapy should not be used until proven in prospective, randomized clinical trials, are the same people whose entire careers are utterly dependent upon mega-trials 100% funded by pharmaceutical companies (that, plus fees from speeches they give for these companies), are the same people who control the clinical trials system, the grant review study sections, and the journal editorial boards. Why else would they want this technology tested under the clinical trial setting?
ReplyDeleteNo wonder ASCO doesn't recommend the use of chemosensitivity tests (no matter how good they are) to select chemotherapeutic agents for individual patients outside of the clinical trial setting. Besides the authors, in their "closed" tech assessments, trying to invent a brand new criterion for validating a laboratory test, they'd like to have these tests in clinical trial$. Would it be wrong to make a clinical decision based on chemosensitivity assays? Should they be denied to patients who walk in the door asking for it? Patients who want this testing, after a thorough discussion about the peer-reviewed studies and experience that supports them, should not be hindered by restrictive ASCO policy. I never heard that ASCO had been knighted a regulatory agency.
http://cancerfocus.org/forum/showthread.php?t=3442