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Chem sensitivity testing?????


northstar

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I read something here about this a while back. I was wondering if anyone here knows anything about it or has had the procedure done. And if so, if it was helpful

I dont know what it is called exactly, but you have your cancer cells sent to a lab and they test it against all the different types of chemo to see which one is most effective in killing the cancer cells

My mom has some fluid in her lung again and is going to ask if it can be drained. This is the time to get the testing done if we are going to do it

thinking of you all~

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I'm in a trial that began with a biopsy to determine which chemo would be most effective on my tumor. The study had 4 options for treatment based on the biopsy results. I'm on Gemcitibine and Carboplatin.

I would be interested if there is treatment that is more targeted, since I assume my treatment will soon reach optimum results.

Mary

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Mary, thank you for replying! I'm glad to hear that there is a studying involving sensitivity testing. I hope you get great benefit out of it!

Ry, I did a search before posting but only came up with a few results. I should play around with the words some to see if I can find anymore threads. I did see that someone here did try it and was having some sucess

Since this might be a new idea to my moms onc. I wanted to get as much info as possible. I am all for the idea, she is very interested in it, I just dont want to dr to discourage her though if he doesnt know much about it

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Nevermind I guess

I just got back from the onc and he didnt want to have any part of it. He seemed irritated by my asking actually. Even though I tried to explain that all we would need would be the sample and that everything else would be taken care of, he wouldnt participate in it. He said it was experimental and expensive and he wouldnt take the results into consideration

I tried to inform him that there are actually clinical trials now being conducted and that medicare and health insurance covers part of the cost, but he shut me up essentially

Thanks for the replies though

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Your mother may be better off whith the onc she has rather than look for another one, but...my response would be to look for another oncologist. I would insist on a a partner relationship in my medical care between the onc and me and I would not want to be treated so cavalierly. For me, the attitude of the oncologist is just as important as his techincal expertise.

Don M

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An doctor faces many challenges, the greatest of which is helping patients fight daily battles against this disease that are not always won. A number of studies have shown that a more educated patient is a more compliant patient. What is essential is effective communication between provider and patient that can prevent miseducation and misunderstanding.

As patients launch increased explorations into medical cyberspace (from research to other peoples' personal experiences), they are finding out more about diseases, researching therapies and therapeutic alternatives. Increasingly, they are questioning and challenging physician authority. Properly managed, it can enhance the doctor-patient relationship, rather than undermine it.

I've heard the term a number of times from people on web discussion boards, "I do not want to upset my doctor by challenging him/her." It's your body. They are working for you. If and when you find what you feel is pertinent information in managing your health, one should not be afraid to question what is being done, and in fact, contibute information in helping to have a better understanding. It just may be the life that you save, maybe your own.

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  • 4 months later...

It must be realized that cell culture assays are complex procedures, fraught with the potential for error and misinterpretation. The results are only meaningful to the extent that the laboratory in question is experienced and diligent in its quality assurance practices. A patient interested in this testing should not hesitate to ask specific questions and to require specific answers of the laboratories under consideration.

The "extreme drug resistance" (EDR) method of cell culture assay testing uses "cell proliferation" (cell growth) as the endpoint of testing. This method cultures tumor cells in the presence of single chemotherapy drugs and observes in the presence of a very high (extreme) dosage which drugs prevent the tumor cells from growing. In numerous cases, a report generated by this method can show drugs that best prevented the "growth" of tumor can be the same drugs that failed in previous chemotherapy. This type of assay method would not provide clinically useful information (other than to know why previous drugs failed - they were resistant to the tumor). The EDR assay is not useful for the purpose of identifying "effective" treatment regimens.

The other method of cell culture assay testing uses "cell death" (apoptosis) as the endpoint of testing. The test exposes tumor cells to chemotherapy drugs and observes which drugs actually "killed" tumor cells. It can identify which combination of drugs that are able to "kill" tumor cells in the laboratory. Cell death assays are better at getting more useful information -- namely: (1) higher evaluability rates, (2) more drugs tested per specimens, (3) multiple drug concentrations tested using multiple complementary endpoints, and (4) more extensive clinical validation of assay results. Assays based on "cell-death" occur in the entire population of tumor cells, as opposed to only in a small fraction of the tumor cells occurring in "cell-growth." Cell-death assays correlate very well with each other on direct comparisions of different methods.

Different Types of Cell-Death Assays

The TCR Assay

ChemoFX Assay

The MiCK Assay

HDRA Assay

EVA Assay

DiSC Assay

MTT Assay

ATP Assay

Fluorescein Diacetate Assay

Cell death assays focus more on the discrimination between a relatively lower probability of response on one hand and a relatively higher response on the other hand. Basically, identify each and every drug as being either "good prognosis," "poor prognosis," or "average prognosis," with the advantage of a good prognosis over a poor prognosis drug as being (on average) 7:1, meaning a good prognosis drug is 7 times as likely to work as a poor prognosis drug. Results used in a "positive" way to "select" the drugs most likely to work.

A "fresh" sample tumor can be obtain from surgery or biopsy (Tru-cut needle biopsies). Tissue, blood, bone marrow, and ascites and pleural effusinos are possibilities, providing tumor cells are present, and only live cells can be used. At least one gram of fresh biopsy tissue is needed to perfom the tests, and a special kit must be gotten in advance from the lab. Arrangements have to be made with the surgeon and/or pathologist for preparation and sending of the specimen.

Upgrading clinical therapy by using drug sensitivity assays measuring "cell death" of three dimensional microclusters of live "fresh" tumor cells, can improve the conventional situation by allowing more drugs to be considered. Drug sensitivity tests support the idea that a marginal benefit in terms of overall survival is observed in cancer patients with normal prognoses, but there are marked survival benefits for cancer patients with poor prognoses.

The key to improving drug sensitivity tests is related to the number and types of drugs tested. The more anti-cancer drug types there are in the selective arsenal, the more likely the system is to prove beneficial. In order to acquire sufficient data, tumors should be tested with at least two assay endpoints, and most often three, for sensitivity tests in any one patient. On average, up to twenty drugs and combinations at two concentrations in three different assay systems, is an effective way to avoid false-positive or false-negative data. Careful choice of drug doses and administration intervals also improves outcomes.

Drug sensitivity assays do not harm patients in any way except in terms of cost. Every cancer patient should have his/her own unique chemotherapy trial based on consultation of pathogenic profiles and drug sensitivity testing data. Research and application of drug sensitivity assays are being encouraged by growing patient demands, scientific advances and medical ethics. Drug sensitivity tests are not a luxury but an absolute necessity, and a powerful strategy that cannot be overlooked. Having some foreknowledge of a given agent's expected result before its administration would benefit the individual patient.

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That is if they can get a good biopsy. Dad had over twenty nodules bilateraly...out of the 6 samples they collected not a single one was malignant....but the did have cancer we just never knew which definitive type. The consensus was squamous cell from cells in the plueural effusions.

HOw I hate this disease. But I agree with others here....fight for your rights to live better.

eppie

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Yes eppie, if they can get a good biopsy. In medical centers where oncologists use such tests frequently, the policy is made known in advance to both surgeons and pathologists. Then, when a biopsy is performed (Tru-cut needle), the tissue is sent for testing in the same fashion as it is sent for estrogen receptors or chromosomes or whatever is the custom at the particular medical center and with the particular physician. It is a "team" approach.

It is important to culture solid tumor specimens in conical polypropylene microwell plates. Polypropylene is a slippery material which, in most cases, prevents the attachment of fibroblasts and epithelial cells and encourages the tumor cells to remain in the form of three dimensional, floating clusters. Culturing cells in conical polypropylene microwells and culturing them for 96 hours increases the proportion of tumor cells, relative to normal cells.

It is critical that the specimen be "fresh" and properly cared for. It must be made clear, in advance of biopsy, that the tissue is to be sent for these studies. If not, the surgeon may not be fully prepared ahead of the procedure, or the pathologist may not prepare the specimen properly for transport. Special specimen collection materials are needed which must be provided by the laboratory. The laboratory should be given a couple of days notice in order to ensure that specimen collection and transportation materials can be FedExed or UPS'd to the medical center in advance of the procedure. Some labs are willing to teach individual hospital personnel about proper procedures.

In order to have an assay done properly, tumor cells must be accessible. Tissue, blood, bone marrow, and ascites and pleural effusions are possibilities, providing tumor cells are present, and only "live" cells can be used. At least one gram of fresh biopsy tissue is needed to perform the tests, and a special FDA-approved kit must be gotten in advance from the lab.

Arrangements have to be made with the surgeon for preparation and sending of the specimen. Biopsies and inital or follow up surgery is an excellent time to obtain a specimen for testing, even when chemotherapy is not planned, as the tumor tissue may not be accessible later on when the information may possibly be needed. Data suggest that patients' patterns of sensitivity and resistance do not change in the absence of intervening chemotherapy. And even after a patient fails a previous chemotherapy treatment, the test still can be done once a patient waits at least four weeks. If proper protocol is followed, evaluability rates are very high. Greater than 95% of all specimens submitted produce clinically useful results.

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