Does CK/GK usually kill the AN, or does it just stop growth?

[dalemccl]

From reading here, I see some patients mention, at some point months after CK or GK, the tumor starts to show dark areas on an MRI with contrast, meaning those tumor cells are dead and can't absorb the contrast agent.  Is that the norm, that a successful treatment not only stops growth, but kills the tumor? Or is it the exception and normally the growth stops but the tumor doesn't die?

After my last CK treatment today, I asked my radiation oncologist about tumor death and he told me if the treatment is successful, the growth will stop, but the tumor will continue to be "enhancing", by which I think he meant it will absorb the contrast agent and show as white on the MRI, meaning the tumor cells are still alive and none died.  I know stopping the growth is the most important thing, but I was hoping the thing would also die.

What is normal with regard to this?

[PaulW]

To preserve your hearing, facial nerve and anything else nearby they give you a very low dose of radiation. I believe the latest theory is that the radiation dose is so low that it does not damage the DNA of the acoustic neuroma. If it did it would cause more cases of malignant transformation.
It does however give a dose high enough to disrupt intracellular processes.. which means the cells are unable to reproduce, eventually the cells do die of old age. If they gave enough radiation to kill it quickly, you would have a lump of rotting meat in your skull... that's not good. It would cause hydrocephalus and worse... Due to the blood brain barrier, dead cells are not removed as fast as the rest of the body.
As for the loss of enhancement it doesn't mean much at all.
Blood vessels within the tumour are susceptible to radiation.
Radiation damage to the blood vessels restrict the blood flow, which means less contrast, creating the dark spot.. it is very common for the dark spot to disappear in later MRI's It does not mean the radiation isn't working..

[ANSydney]

Paul, it great to have someone who is so well informed and keeps up to date with AN treatments. Much appreciated.

[rupert]

It takes a long time for the radiation to have it's full effects on the AN.  My team at UPMC told me that it would take 9-10 years for the tumor to realize the full effects of the GK treatment.  Early on the radio dose was a bit higher but, the standard now is 12-13 gy.  A fine line to give just enough radiation to do damage to the tumor but, not so much as to cause other problems.  As Paul said,  it damages the cells in a way that they no longer function properly and they will eventually die off.  That is the goal.

[dalemccl]

Thanks everyone.  I guess I won't worry about whether the tumor darkens on the scans as long as the growth is stopped.

[JLR]

Hello. I had CK 2010. Had 18 gys. Anyway it stopped the growth for 6 years then with a vengeance it compromised my trigeminal nerve painfully and I eventually had surgery. Recovery has been a long journey. I am improving every day but very very slowly. Good luck.

[PaulW]

I am so sorry to hear that CK didn't work for you.
18Gy in three sessions is the same as 12Gy in one session.
Or 45Gy in 30 sessions.....