My recent post about selecting the right treatment for an individual tumor is part of a long history of trying to tailor cancer therapy.  Many companies offer such services, and in fact advertise them heavily.  However, the oncology community as a whole has not enthusiastically embraced such approaches, as many patients suggesting these tests may have found when they raise the question.   This is based on decades of general disappointment, on marketing of ideas ahead of the clinical research to really prove the value of lab-based selection of optimal treatment.  Because of these issues, there are no management guidelines that include recommendations for these types of tests, certainly not in lung cancer management.
 
  In fact, there are good reasons to be suspicious that a treatment that looks promising in a test tube model of cancer is actually going to work in real live people.  This is exactly the cautionary point I raised in a prior post about the difference between pre-clinical and actual patient-based testing of cancer treatments.  Many, many more cancer treatments have looked sensational in test tube and animal models than in the clinic, which should be expected because the human experience depends on absorption of the drug, and delivery through the bloodstream, while cancer cells are constantly mutating, developing resistance to our treatments all too quickly.  The lab models can’t quite capture the dynamic and more challenging nature of actual living cancer in human patients.  Consequently, a lab report saying drug X will work for Mr. Smith’s lung cancer often falls short on that promise.  If the companies that made broad claims actually backed up their contentions with clinical data, the way investigators are trying to follow up on the MADeIT trial with a larger direct comparison of tailored vs. standard unselected chemotherapy, the oncology community would likely be much more eager to adopt such testing as a standard of care. 

   There has been one company, called Oncotech, with which I and my colleagues at Swedish Cancer Institute have worked for about a year.   My understanding is that this testing is actually covered by Medicare and many private insurers, and the company has not been billing patients for any of the difference between their charges and what their insurance coverage has provided (but I don’t think they’re guaranteeing such a policy…they’re just happy to communicate that patients aren’t getting squeezed).  The basic idea is that they take tissue from the live tumor, sent right at the time of surgery, then they grow tumor in their lab, and they test to see if it can survive growing in the presence of various commonly used chemotherapy drugs.  This technique is known as testing for extreme drug resistance (company info on this work here).  A report looks like this:

 (click to enlarge)

Importantly, the company really focuses more on what won’t work rather than trying to claim that a drug will work, and I would consider this an important distinction.  They can say that the tumor does not show obvious resistance to taxol, for instance, but that doesn’t mean that the treatment is likely to work.   Instead, the value that I see in it is that it can potentially keep someone from wasting time and toxicity on a drug that the cancer happily grows in a bath of, especially if there are other very good alternatives that the cancer might be more sensitive to.  This work hasn’t been clearly and irrefutably demonstrated to improve clinical outcomes in cancer, and it hasn’t been widely adopted or incorporated into any standard treatment recommendations. Moreover, at the case-based lung cancer conference that I conducted with my colleagues in late April, we presented a case of someone who had this testing done, and there was some quite heated debate about the value of this work, with some of the experts on our panels also adopting this approach, but several others critical of its lack of proven benefit.

   There are certainly some limitations, such as the requirement for fresh tumor tissue.  This is very important, because the company can’t provide information from a tissue biopsy or surgery from the past, and it would be potentially problematic to do an extra invasive procedure to just get tissue for a test that hasn’t been shown to improve treatment outcomes at this point.  Right now platinum-based doublet chemo is the standard adjuvant chemotherapy option, and this Oncotech work could suggest that a patient’s cancer is resistant to both cisplatin and carboplatin, leading an oncologist to now make an uncomfortable judgment about deviating from the better established standard treatment based on results of a test that hasn’t really been validated and widely accepted.  I find it to be most appealing in guiding a decision about whether to use a taxane or gemcitabine or navelbine or etoposide in combination with platinum for post-operative treatment, for instance.  In this case, all of these are reasonable options, and the Oncotech EDR battery may help you select a better choice among several equally “correct” options. 

   Finally, when you send tumor tissue to Oncotech, they also send back a battery of additional tests, looking at things like protein expression of EGFR and VEGF and several other variables that at this point don’t have an established role in modifying our treatment decisions:

  This can be problematic because the surgeon may send off a huge array of tests, thinking that all of this information will be helpful, but then the medical oncologist receives the test results and is in a position of having information that is hard to interpret and use intelligently.  More isn’t always better, if we don’t know what to do with the results.  Some tests have a growing consensus for potential utility, such as FISH testing for EGFR, and they’ve also started testing for ERCC1, which I’ve mentioned as being potentially useful in prior posts here and here. 

   Our institution has been in discussions with the company about potentially developing clinical trials that could clarify the real value and credibility of this work, but we haven’t gotten this work off the ground as of yet.  In the meantime, I consider this work interesting and promising, and while we do sometimes use information from these tests in our clinical decision-making, it would be far preferable to have strong data to corroborate the impression that this work can be helpful.  Until then, these strategies are likely to remain used only at certain institutions, based on the very reasonable desire of the skeptics to wait for further validation before using such testing to individualize treatment decisions.