Hi Everyone,

I hope this finds you all comfortable.

I have a question though that I hope isn't redundant. I've searched the net, but I'm still confused.

Dennis' oncologist ordered another PET scan before he sees her again next month. The last PET he had in January showed sugar uptake in the radiation field and was discounted as inflammation. We were told that it can take anywhere from 9 to 12 months before the inflamation subsides and gives them a clear indication of whether there is cancer activity. Well, the problem is, Dennis did not finish RAD until Thanksgiving. This is only June.

We understand the problems with false positives with these scans, so I'm at a loss as to why she wants to repeat it now. Wouldn't it be more prudent to wait a few more months? I wasn't able to go to this particular visit because our son was sick, so I'm trying to decipher this on my own.

Any experience you have had with this test would be appreciated.

God Bless,
Mandi

Hi Mandi,
Six months doesn't sound too unreasonable for a PET. I have had a CT and an MRI since I've completed treatment and it's only been 81 days. All scanning modalities can give false positives or show anomalies that may not be cancer. At my last MRI, my mastoid area was inflamed where the tumor was so they're watching it. They think it's probably due to the radiation. The future "gold standard" will be PET/CT. They have had exceptional accuracy which the fusion of the 2 modalities.

PS - the major cause for mastoid inflammation in adults is cancer.

I'm not sure how this thread got on the topic of mastoid inflammation, as it normally relates to those who have had inner ear tumors, both benign and malignant. The malignant ones are relatively rare when compared to all other types of tumors. Mastoid inflammation is relatively common and its primary causes are mostly benign. Inner ear tumors are extremely dangerous as they are close to structures such as the base of the skull, which when penetrated allows the tumor access through the dura to the brain itself. As to the PET showing increased metabolism in an area which has been radiated in recent history, I do not think that this is unusual as the healing process continues for some extended time after the end of treatments, and it would certainly show up as increased sugar consumption by those cells. A secondary scan compared to the original, even if only 3-6 months apart, will offer the diagnostician a comparison trend, determining if things are toning down or stepping up. Getting scans immediately after treatment is common, and not only establishes the impact of the treatment itself, but provides baseline information for all future scans of that area. Both MRI's and CT's are useful especially when done with contrast as each one has it's own strengths in revealing issues in either soft or hard tissues. The use of a combined PET/CT is realtively new, but shows information which either scan alone fails to paint in full. See the news article awhile ago in the OCF news section on the combined scanning technique. http://www.oralcancerfoundation.org/news/story.asp?newsId=32

Hi Brian,
It didn't really switch to mastoid inflammation, I was merely commenting on one of the anomalies that was on my recent MRI scan, paralleling, false positives on scans in general.

While at the doctors, they brought it to my attention and they thought it may be caused by the radiation after effects.

I was unable to relocate the subsequent internet source for the quote that I gave about the "...major cause for mastoid inflammation in adults is cancer", and in fact, discovered many other potential reasons for inflammation. I apologize for anyones anxiety reading that post.

Gary, your posts are consistently accurate and helpful, please don't take my comment in the wrong way.

Thanks guys.

I know these tests are very expensive, and the potential outcome had me confused as to why we would repeat it so soon. But, Brian, your explanation makes perfect sense.

Thanks again,
Mandi

Mandi, to share my personal experience on this PET/CT and the 6 month follow up..

Finished the radiation treatment on Thanksgiving last year, then did the PET/CT follow up end of February. Yep, it showed the inflamation on the side I had the radiation, but also showed tumors on the opposite side. These were new tumors that popped up after the surgery and radiation. Because of the false positive problem, repeated the scans in March, the uptake showing the inflamation had reduced, but the tumors remained.

Bad thing, there were new tumors and mestasasis, good thing, the follow up scan caught them before they got too extensive. The rest as they say is history, more surgery, radiation, etc.

Next PET/CT is in August, would be year since the first one, or 6 months from the Feb scan. Should be interesting since I've now had surgery and radiation on both sides, what this one shows.

So, as Brian said, can be good to spot trends, but also a good idea every 6 months or so for the first couple of years just for safety's sake.