Anyone get false positive PET scan results?

9lives70

I am scheduled for a pet scan this Thursday due to rising CA 125 levels over the past three months. While I'm looking forward to finding out exactly what's going on in my body I'm also nervous about the reported level of false positives that can occur with the scans.

Wondering how many of you had false positive results and how much additional testing and biopsies needed to be done unnecessarily as a result?

Just hoping to not go further down the rabbit hole of poking prodding and testing due to Inaccurate results. As a sidenote I've already had a CAT scan, with contrast, for the same issue a rising CA 125 ( now 52) and that was considered all clear so I am hoping the pet scan will confirm the same.

Thanks,

9lives

Anonymous

I haven't, but I know plenty here who have had false positives and wonky test results that freak us out but turn out to be nothing. I'm hoping for the same for you. About 3 years ago I had elevated liver enzymes during a routine check up (can mean baddie is trying to come back) and I freaked out for about 10 days, then redid my labs and my CBC came back completely normal. Turns out it was all the aspirin and advil I had been taking--which can cause screwy #s.

Because I can relate to what you're feeling exactly, here's a quote from a sci. article and the link: "...In cancer cells, there is an overproduction of glucose transporters and, as a result, increased FDG uptake. However, not all PET-positive lesions are cancer, and in many instances, PET findings can be false positive...."

http://link.springer.com/article/10.1007/s10151-01...

My friend who is a twice survivor of Stage IV ovarian cancer has had two false positive scans. I think you can google preparing for a PET and see what you are supposed to do to get more accurate results. Something about not eating any carbs/sugar the day before till the scan is over is part of it.

ElaineTherese

Hi!

I had a false positive re: my left femoral neck (hip). It lit up on three PET scans, but never showed up on a CT scan or an MRI. If it had shown up on the MRI, MO would have biopsied it.

claireinaz is right that there's a special diet the day before a PET scan. All you can eat is protein, protein, protein (no carbs).

9lives70

thank you Claire. I had the PET last week and it's all clear :-) but being that like you I am prone to anxiety, I'm now wondering if it's a false negative because I know lobular breast cancer cells are resistant to the uptake of the contrast material used in a pet scans! Always something to worry about right :-)

Kicks

As I was told - the PET does not give a positive for cancer - it shows where there is something (inflamation possibly) that requires checking with a biopsy - not that there is cancer there. I had an area along my jaw that 'lit up' on my PET so it was immediately that day biopsied with path. report the next day - nothing there.

Christina313

They thought that my mom's cancer spread to her bones. It was lit up during the scan. The radiologist looked and determined she just had osteoporosis. These are many fale positives.

I wonder too if the cancer she had in her liver was maybe just fatty liver? She's been on Prednisone for years which can buildup in the liver. After her chemo the liver seems to be clear. I guess we don't know because they never did a liver biopsy.

So many unanswered questions. Cancer is such a complicated disease. I pray one day that we will be able to defeat this.

ShetlandPony

As I did on another thread by 9lives, I want to clarify something, because with such serious issues at stake we should be as accurate as possible in what we say. Above 9lives said, "I know lobular breast cancer cells are resistant to the uptake of the contrast material used in a pet scans!" But in reality most ILC mets are indeed FDG-avid. In other words, they do take up the radioactive glucose (it is not a contrast material) at a faster rate than normal cells, and the cancer does show up on the PET scan. (This has been the case for me. My PET scans for ILC have been very accurate.) It is only sometimes that a particular ILC does not take up the radioactive glucose very avidly. So just in case, the interpreting radiologist, aware that the patient had ILC, will scrutinize the CT portion of the scan to check for non-avid mets. I offer this correction not to be critical, but to hopefully allay fears.

(My statements about PET for ILC are based on notes I took at the ILC Symposium 2016, from a talk by an expert radiologist, and reflect my own understanding. Please consult the literature and your own experts to verify and apply.)