What do you think about the drug resistant testing

[freshair]

Hi Dr. Goodman,

I had some tumor removed and it is going to be tested using Oncotech, the drug resistant test. It will tell you what doesn't work but not necessarily what will work.
Having recurrent ovarian cancer, do you think the test works better with newly diagnosed patients?
When doing chemo, some things shrink a little and some things grow. Why is that? It would seem to me that the cancer is all a little different now in all areas. Is each cancer area mutated in different ways? I just don't understand.

Also I was wondering when women are so upest  whether they have ovarian cancer or  cysts why is a pet /ct not used? Is is our health insurance?  If it is I would pay out of pocket and women should know this if this is the case.

Thank you for all your help. You are so wonderful. My father had an abdominal laparscopic aneurism done at UMASS this summer and it is a beautiful hospital. I love the cafeteria and serene outdoor setting.

[Annekathryn Goodman, M.D.]

Hi There Helen and Kimchi,

So sorry for my delay.  .

Drug resistance assays: There are several different companies who have marketed techniques to look at cancer cells in a test tube and comment on the sensitivity or resistance of the cancer sell to various chemo-therapies. this is conceptually in the same model as testing a certain bacteria in an infection to seeing if it is sensitive to a certain antibiotic.

Some oncologists do use these tests to help guide therapy. There are several problems with the tests that lead to their limited use:

- the assay requires the use of live cancer cells. This requires a biopsy or a surgery. In a piece of tissue that contains the cancer cells, there are also alot of non cancer cells such as fibrous tissue. there are also alot of dead cancer cells.

- cancer contains clones of cells. These cells mutate frequently. So in a particular tumor, the cancer cells have different properties along with varying degrees of sensitivities to chemotherapy. That is called "tumor cell heterogeneity".  One of the reasons we not successful in curing certain cancers is becasue of this. Chemo works killing some cells but not others. The chemo resistant cells grow back

-when cancers recur, they are different in some molecular way from the original tumor. So a chemo sensitivity or resistance assay from the original tumor may not be relevant for decision making about therpay years later for a recurrence.

-The PET Ct scan was not developed as a screening test. I do not think there is any information that it would identify ovarian cancer earlier
best wishes

[freshair]

But what was the best is the family waiting room while your relative is having surgery. The room was large, comfortable and quiet with the women at the front desk being so helpful. And my father's wonderful nurse Megan
Take care,
Helen

[Kimchi]

It is true the only way to do this drug resistant test ( MickAssay) is that it would require about 2-3 cm of fresh tissue? and that is not possible for patients with ovarian cancer post surgery and chemo who have minimal disease left to be tested?.
What conditions and what would be required to conduct such a test especially for post surgery patients?
Tks
Kimchi

[Kimchi]

Bumping up !! look forward to your reply..Tks

[Kimchi]

Sorry but my posting is a question? My doctor told me I needed tissue samples to have this test done...Is there no other way?

[Kimchi]

If one cannot donate tissue samples, what other types of drug resistant tests are there? Can it be done with blood? Tks