Clean PET, but MRI still shows mass??

julierene · 08-22-2006, 02:45 PM

So I just got back my official results....

December 2005 Results
Liver MRI - 3 Lesions, largest being 3.2 cm
Brain MRI - clear
Chest X-Ray - clear
Spine MRI - tumors on T7, T8, S1, L1
Bone Scan - tumors on right femural neck, left clavical, 3 areas on spine

March 2006 Results
PET/CT Scan - clear

May 2006 Results
PET/CT Scan - clear

August 2006 Results
Liver MRI - 1.3 cm lesion is a dimished liver met. It was 3.2 cm.
PET/CT Scan - clear

What is the deal with having a very small lesion that doesn't show up on PET? Is it scar tissue or just a small MET that doesn't show up on PET because it's too small? Am I clear enough to have to remain on Herceptin alone or start chemo again? I am baffled! Any advice would be SO helpful!

Thanks Ladies!

Sherryg683 · 08-22-2006, 03:54 PM

I think PET is very sensitive (with a lot of false positives), it lit up my 2 lung mets (at least we think they were) that were smaller than a centimeter. If it is not lighting up for your liver lesion, it could be that your liver lesion is not cancerous. I have two liver lesions 12mm and one that is 4mm that have never lit up for cancer on either PET scans that I have taken, I was told they were hemangiomas (sp?), they have not grown or decreased with chemo either. My doctor is not concerned with them, although they do worry me. I have heard they are pretty common. Could yours be that, or scar tissue. Since yours are not lighting up with the PET, I wouldn't rush back on chemo..I would have more scans done or even a biopsy if possible...sherryg683

StephN · 08-22-2006, 06:11 PM

Hi Julierene -
If that spot is not showing bright on the PET/CT it could be the dead tumor area that shows on the MRI. Without the radiologists notes, what you wrote seems to indicate that the spot is an old tumor area.

Wait for another scan and I bet it will be even smaller. If not, then I would want to do something about it.

You seem to respond well to Herceptin for those mets to have cleared as fast and well as they did earlier this year.

Enjoy the end of the summer with your llittle ones and try not to worry.

chrisy · 08-22-2006, 07:08 PM

Hi Julierene,

I've been wondering if you had gotten any further news.

Now it seems that this may not be progression at all. Is this something that you may have seen "shrinking" all along on an MRI - you just didn't have those as follow up? This has never been, and still is not, visible on the PET/CT. I would think a lesion of this size would be visible if it were cancerous.

It can take some months for necrosis and scar tissue to resolve, even after you've stopped chemo. For me, I still had quite a bit of "stuff" showing on the CT just after I finished chemo - 4 months later it was all gone* (*except for my stubborn stable <5mm "area of interest" that no doctor will even entertain!).

So, you have something that sounds like bad news (MRI) up against something that sounds like continued good news (PET/CT) With the likelihood that this is NOT active tumor since it didn't light up on the PET, I'd be surprised if your oncologist would recommend firing up the chemo without further confirmation!

What DOES your oncologist say?

I know it's hard not to worry and think the worst - but checking it out again in a couple months might, as Steph said, show further shrinkage or maybe even a disappearing act!

Take care
Chris

doh2pa · 08-23-2006, 10:01 AM

Hi Julierene,

I was wondering how you had made out. This sounds like good news to me! I am in the same boat, 4 liver mets discovered last sept, did 6 months of carbo, herceptin and a taxane study drug. Clean CAT in May. Most recent CAT still shows original 4 tumors gone but a new 2 cm bugger in another spot. I have my PET tomorrow and see my onc in the afternoon. I also have 3 other opinions lined up - one next week at U of Penn, one in early September at Sloan in NYC. I'll post tomorrow night to let you know what he recommends.

Donna