Hello. Third visit to the doc post May operation of removal of small cancer on hottom of mouth in May. Also select nodes were removed due to the inability to find the sentiniel node. All indications were good. Had requested scans since inception and finally got one prior to this visit. The radiologist classifed the c-scan as negative, however the doc has a concern on one remaining node (50% larger than node on other side of neck and some coloration issues) and we are running a P-scan this Friday. The doc says however that P scans can return a false negative so I am looking a full neck dissection proabably and then radition if it returns a positive. What has the group's experience been on p scan reliability?

Thanks for the help.

Hello, John.
My husband had a PETscan as a follow up to the needle biopsy which indicated metastatic cancer. The scan lit up the lymph node area as well as a spot that turned out to be the primary site - right tonsil.
The surgeon was not all that 'impressed' with the Pscan and said the same thing your doc did..that they are not all that reliable when it comes to head & neck cancers.
Tom and I are certain we will ask for another PETscan when this is over - and we'll want any other test that comes available, too!
Good luck, John. I sincerely hope there is nothing there. Did you have any radiation or chemo with the first surgery?
Nicki

John, I am not a professional here but from my observations, PET scans have a potential for false POSITVE NOT false NEGITIVE. In other words it is very sensitive and other things besides cancer might show up as abnormal. If a PET scan shows clean then you are probably clean.

At a microscopic level, nothing beats a look at nodes removed during a neck dissection. PET scans do not have sufficient resolution to compare to the microscope and live tissue. Radiation is applied to take care of anything the above tools miss.

Take care

John,
My husband had a PET scan before rad/chemo, one two months after and he will continue to have them about every three months. It helps the docs keep an eye on certain areas as Dan's cancer was quite aggressive. I think they take it all into consideration about the false positives. When I read the PET reports...I freak out because it sounds like it's cancer in other places, but I trust the docs that they know what to watch for. They seem to think they are quite helpful in Dan's case.
God bless,
Debbie

Hi,

I had a chat with Heather's surgeon a few weeks ago. During the discussion, he mentioned that he believes that a PET/CT scan is more reliable than a plain PET. He said that he now uses PET/CT's on a routine basis.

Rosie

No scan until this first one, although I asked for scans repeatedly. Interesting the doc asked for a previous scan when this problem presented it self and I of course advised him that there were none.

Hello John,

I had a combo pet/cat scan three times. I was dx July/03, followed by surgery 7/31/03 with 33 treatments of IMRT radiation which ended in early Nov/03. Had a follow up pet/cat scan on Dec 24th. It was inconclusive do to being so close to end of treatment.
I had another scan in May of 04 that lit up in the original bed as well as in my lungs. They followed the May scans up with three scans in early June. One was an MRI and two were pet/cat scans. These scans confirmed the reoccurance and metastatic cancer in my lungs. I started pallative chemo after the scans in June and after one 6-week treatment I had a mri that showed a reduction in the tumor in nthe surgical bed. I continue to receive chemo. Have a mri scheduled for Thursday to see if the tumor has gotten any smaller. I will be asking my medical on'gist the same question you asked here. What scan is right for everyone or is it just your opinion.
I had no problems getting the scans when I asked for them. The one this Thursday was requested by me. The doctor would have waited until the end of the year to do one. That was to long for me.

I believe the combo pet/cat scan is much more reliable than just the pet. As Mark says the pet tends to give a false positive rather than a false negative.

The neck disection was the easiest of all the treatments I received. Not a walk in the park but tolorable.

Hoping for the best for you, Keep us posted.

Danny Boy

The PET/CT is considerably more accurate than just a plain PET as it yields geographic information within the anatomy, which is necessary for correlation. It is thought to be as accurate as 98%. Bear in mind that the readings are subject to interpretation and scar tissue can give false positives as Mark mentioned.

My early MRI's all showed "regions of interest" (ROI) but they turned out to be nothing but scar tissue - and this just from radiation as I didn't have surgery. I have to admit that the early and erroneous scans caused me a lot of anxiety and were not the feel good "oh I'm cured from cancer" that I thought they would be. At almost 2 years I am feeling a little better about getting another scan now. And remember that the scan is but a small piece of the total diagnostic package and by no means definitive.

The reason the PET scan, in general, has a higher false positive rate is that tissue in the healing phase will uptake glucose in a higher rate thus concentrating the radioactive isotope, much the same as cancer cells do.