Scar tissue in tumor 1 year post cyberknife-a good thing?

[rrsandstrom]

My husband was treated with cyberknife at Swedish Hospital in February 2014 with no problems and no side effects.  At his 6 month MRI the tumor was the same size and was blackening in the middle, indicating necrosis.  At today's appointment, 18 months post treatment, the tumor is the same size though is now filled in white again on the MRI.  The doctor said that is probably scar tissue and that we'll re-check in another 6 months.  After the initial black necrosis seeing the tumor all white and bright on the MRI looking just like it did before and the doctors use of the term "filled in again" I got a little freaked out about whether or not it was "working".   Is this common?  Can any of you share what your tumors looked like on MRI post cyberknife?  Thanks!

[PaulW]

This is very common and does freak people out.
I wish I could find the study for you... There is one somewhere on pubmed...  www.pubmed.com
The study found that visible necrosis has no bearing on the eventual outcome of radiation treatment...

First of all the "Necrosis" may not be "Necrosis" at all.... Its just how the tumour lights up with the gadolinium dye.
which relates to how the blood with the dye is flowing through the tumour.. It says little about the health of the cells within the tumour itself.

If you are treated with Cyberknife, you are usually treated to the 80% isodose line..
That means the center of the tumour gets 25% more radiation.... Radiation does damage blood vessels which can lead to the "Necrosis" look... and as the tumour gets more radiation in the middle it is more likely to go dark..

Radiation gives you just enough radiation to stop the cells from replicating... It doesn't actually kill the cells immediately.
Its actually bad to kill the cells immediately. You would end up with a rotting piece of meat in your head... no good....

The cells will eventually die from old age but that takes years

So dont panic, its very common for the 6 month MRI to show a darkened center and for it to fill again..
Just remember the study... that I can't find....... Necrosis has no bearing on the eventual outcome