Lindsay McDonell: Chemosensitivity Testing
April 13, 2021
BCCT: Lindsay, would you give us a tutorial of chemosensitivity testing from the patient’s perspective?
Lindsay: I have had several rounds of chemosensitivity testing on both liquid biopsies and tumor biopsies. In the US several labs scattered across the country offer the service of analyzing a specimen and testing different chemotherapy drugs and nutraceuticals as well to see which has the strongest effect on the sample. Ideally they are looking for cancer cell death when exposed to the drugs or natural compounds.
Most of the labs in the US require a fresh sample, which is difficult because most hospitals will not provide you with fresh tissue.
Several methods are in use at this time. Some labs are able to use a blood sample (liquid biopsy) as the base for testing. Other labs require either a fresh sample of tumor, which is ideal, or a paraffined sample that the pathology lab has preserved for long-term storage. Most of the labs in the US require a fresh sample, which is difficult because most hospitals will not provide you with fresh tissue that you would be able to ship overnight to whichever lab you have chosen. They do not have a problem sending a paraffined sample. If the lab requires fresh, you may have to go with a lab-recommended surgery space that has the capability to forward a fresh sample.
You will be provided with a chart showing the efficacy of what they tested.
Once you have submitted the sample, be it blood or tumor, the lab will test it against numerous chemotherapy drugs and natural substances. You will be provided with a chart showing the efficacy of what they tested. The larger the sample the more they can test on it. You would then discuss the results with your doctor. If the chart shows the most efficacy with a drug you are not currently using, you may have some difficulty getting your insurance or hospital protocol to be receptive to using it on you. For example, I have breast cancer but the most effective chemo drug tested was for ovarian cancer. We had to lobby with the insurance company to use the ovarian cancer drug as my treatment. Once they agreed, we had a lot of success in reducing the cancer level in my body.
|Chemosensitivity Test Results 11/2016||Blood Biopsy||Tissue Biopsy|
|Cyclophosphamide, topotecan & vincristine||25%||+||84%||++|
|Cyclophosphamide & topotecan||-||-||83%||++|
|Gemcitabine & taxotere||55%||++||27%||+|
|Nutraceuticals Test Results 11/2016|
|Vitamin C & liponat||69%||++||79%||++|
|+++ pronounced sensitivity
++ partial sensitivity
+ weak sensitivity
- too low to quantify
We had a lot of success in reducing the cancer level in my body.
BCCT: Would you explain how to work with your conventional oncologist with your chemosensitivity testing results?
Lindsay: I would not have been able to use a chemosensitivity test to influence my treatment when I was first diagnosed. When your doctor is prescribing within the protocols of the institution where he/she works, there is almost no room to go outside of those protocols. This is one of the reasons that people travel to other countries to be treated. If you have advanced, end-stage cancer, this is a different story. In theory, if you ask to go outside of the protocol based on a chemosensitivity test or for any other reason, the doctor should be able to petition for the use of drugs that showed up as effective based on the test.
When I was able to show that this drug was working, I asked my US doctor to switch to using this drug.
Initially, I was not able to use the results of my chemosensitivity test in the US. However, at a clinic in Vienna, Austria, I was given a chemotherapy drug “outside of protocol” that was based on chemosensitivity testing. When I was able to show that this drug was working, I asked my US doctor to switch to using this drug. She was only allowed to give it to me because the institution approved it in this situation and it was not an expensive drug. Insurance paid for it because of that. Had it been expensive, I may have been paying for it out of my own pocket.
It is not easy to find the people who do the testing in the US nor to arrange transporting your tissue to them.
It is not easy to find the people who do the testing in the US nor to arrange transporting your tissue to them. It was only easier for me because I had it done in Vienna. I think Dr. Nagourney in Long Beach, California, has been able to treat people from the results of his chemosensitivity testing at his clinic.
Now, I still believe it is worth being tested. There may be an FDA-approved drug that is in the protocol for your cancer type that would not have been your oncologist’s first choice, but the test indicates that it would work better for you. In that case, your oncologist may be willing to use a drug lower down on the list of options. If the recommended drug is totally outside of the protocol, you may need a journey to get it into your treatment, but doing so saved my life, and I always have that chemo drug (topotecan) in my pocket if I ever get sick again.
If the recommended drug is totally outside of the protocol, you may need a journey to get it into your treatment.
BCCT: One last question, Lindsay. Even if your doctor is not likely to use results of chemosensitivity testing to determine treatment when you are first diagnosed, is it still a good idea to have the testing done then and have those results on hand if you have a recurrence?
Lindsay: I believe it would be better to have the testing done at the time you are asking for the change in treatment. Cancer mutates. A result could change from diagnosis to recurrence.