Serum Her2 test

[Mary Jo]

Hello,

Could someone please explain the serum test for her2 to me? After reading Emelie's post it got me wondering about it. I do not know anything about the test. From what I've researched I am under the impression that I need to be on herceptin or just finishing up with it to do this test? I also read something about mets. I have been off of herceptin for a little more than a year and did not have mets - other than 1 micromet to 1st sent. node.

So, if someone could offer me an explanation, I'd appreciate it. I go in for my 6 month check up the end of December and if this is something I should be asking about I would like to do it at that time.

Thanks in advance,

Mary Jo

[tousled1]

Marejo,

The Serum HER2 test is a simple blood test that is similar to tumor marker tests. I've had it done every 12 weeks since I started Herceptin. A reading of 15 or below is considred "normal." When I was getting the test while on Herceptin my level kept dropping gradually. When it went up from 6.3 to 9.5 even though it was still within normal limit my oncologist ordered a scan and that's when we found the mets. It's been extremely reliable for me where as tumor marker tests have not. I know that it is approved for metastic breast cancer but not sure about early breast cancer.

The serum Her2/neu test is sometimes used to monitor cancer therapy. If the level is initially elevated then falls, it is likely that treatment is working; if it stays elevated, treatment is not working; and if the level falls then rises, the cancer may be recurring. It measures the amount of HER-2/neu protein released into the blood stream from the surface of HER-2/neu positive breast cancer cells

There is a lot of information on this site about the HER2 serum test. I think the initial one was an interview with Dr. Carney so if you search for Dr. Carney you should be able to get a lot of your questions answered. Also there's information about the test on the information page.

Since you are two years out since your diagnosis and having no problems I doubt that you would need the test. You can always print the information from this site and take it to your oncologist and see what he/she thinks.

[eric]

If tumor markers seem to reliable does anyone know if the serum test makes sense anyway?

[tousled1]

Eric,

Ther serum test is extremely reliable for me. Iknow there are other women on the board who use the HER2 serum test as well. But as I said it is usually used for advanced or metastic breast cancer.

[Cathya]

Mary Jo;

I take this test regularly and I think for someone like yourself who is ER/PR- it would be a very valuable tool as you are not taking a hormone inhibitor. By taking it initially to get a level following treatment....hopefully it would be low, you could take it only every quarter year or half year unless you saw it raising. You could then increase the frequency to monitor it. If it continued to raise you would then expect to take herceptin again at least until it is lowered to normal levels. In this way you would have a way to try to keep from having an actual tumor develop. That is one theory in any case. My onc follows my results with interest and this is how we are intending to use the test....as an indicator of when herceptin is necessary without a tumor being identified.

Cathy

[Becky]

The Her2 Serum test measures the amount of "external domain" of the Her2 receptor in your blood. The external domain is the part that sticks out of the cancer cell on the outside - the part that Herceptin would latch onto. Theory is that the external domain is routinely shed. It ends up in the blood and can therefore be measured. So, if you have mets growing, the count would go up. However, what it is especially good for is if you have mets and are in treatment, you can get the test run and if the counts aren't going down, it is an indication the treatment is not working so it can cut down on scans just to see if the treatment is working.

Theoretically, it would be a waste in early bc because there is nothing much to measure.

[Julie2]

It might be useful to catch the recurrence early. It looks like Her2 serum will be more sensitive than other tumor markers for some people and will rise atleast few weeks before other markers rise in case of recurrence. But many oncologists are still very skeptical about it.

Julie