Question about CT / PET

P64
My first question would be why so soon after the surgery...it's only been 7-days since your surgery...with all of the inflammation and the like, it would not be uncommon to have your PET light up all over the place - probably resulting in a false/negative report.

PETs are notorious for false/positives anyway...I've been misled a time or two. My current practice does not believe in them. I've had ONE in the 3-years I've been there.

At my first practice, my first onc ordered 'em like they were going out of style...you'd do a CT and then a week or so later, do the PET...it was easy money for the facility...almost an automatic although they still have to get insurance approval.

Of course, like the CT, the PET is a toxic test....that's a radioactive tracer they are injecting into you....there's a reason that they pass it through a lead-lined safe from one room to the other and why they wear protective gear and the like. It's not the healthies thing for us.

I can understand doing them when the situation looks right...but from my experience, I side with a CT, because it sees mass.....and mass is mass....if it grows it has to come out whether it be malignant or benign. PETs have been really hit and miss for me.

It's your call, Phil...you might feel the onc out to get a take from him and then register your concern...I know we tend to follow the onc's protocol and I'm not advocating otherwise...just to talk to him and find out his reasoning. It puts them on notice that you are taking an active role in your healthcare and are not merely one of those that follows blindly.

He may be right, but it does not hurt to question as to the why.

As far as the chemo goes...it's pretty standard for the onc to prescribe 6-months "right off the top." They will say it is preventive or insurance against recurrence.

There is no definitive answer here...this is the crossroad where all of us come to a grinding halt - each time, without fail.

There are two schools of thought here:

One is, if you get clear margins, you could elect not to do the chemo and watch and wait for the next scan cycle.

Second is, you did not get clear margins and thus chemo is almost mandated here.

So, the big choice is #1...clear margins, what do I do?

When I first started, I always thought that we fire every bullet we can - early and often. I still think for the newly diagnosed, that this is a good approach....leave it all on the table...there is a good chance you will walk away and not recur.

Only time will tell you that.

As we get older in the battle, we have fired several mortars and find we don't have as many weapons left in our arsenals...so any big guns we've got left, it's sometimes prudent to leave those in the holster until it's time to draw. My onc shares this opinion.

I'm sure this is just enough to confuse you more...but to me, the issue is why a PET now, a week after major surgery? Why can't we wait until the inflammation quiets down so we can get a more accurate reading?

-Craig

CT and PET
The two scans have different strengths. CTs show the shape and structure of the soft tissues including looking for growths. They are less good at telling you exactly what the tissues you are seeing are especially discriminating between scar tissue and tumours. PET scans look at metabolic activity of tissue so looks for bits of tissue that are using abnormal amounts of sugar as cancer cells do- hence they can discriminate between viable tissue and scar tissue better. Hence when you do a PET you often do a CT and overlay the two images. Both require abnormalities to be a decent size before they are detected- about 1cm in size.
They do use radiation and tehy have false positives (leading to unnecessary anxiety and further tests) and false negatives (falsely reassuring). However, in this game they are the best tools we have in detecting cancers in the body. The above info is right though , that soon after surgery the false positive rate will be higher.
Ultimately it is up to you and your oncologist. It may not add much at this stage if you are going to have chemo anyway and may be better to have chemo, wait a month or two after that and have one then.
Your decision but knowledge is power.
steve

experience counts
After encountering droubling differences of opinion between two radiologist evaluating the same PET/CT scans I would add that it is very important for you to have a radiologist who is very experienced in and focuses on cancers. It is not your oncologists who reads the scans but the radiologist and you can avoid a lot of worry by making sure your ONC uses a well qualified radiologists and the same one each time. Get your own copies of the radiologist reports and ask questions..

Just my experience...
I had my first PET done about 6 weeks after surgery. My doctor said that we needed to wait 4-6 weeks post-surgery for inflammation to go down, allowing for a more accurate read. On another occasion, I had a CT scan done prior to starting chemo, to set a "baseline" for future scans as my doc put it...that one was also done about six weeks after surgery. I do think the PET can be very useful (in my case, it basically saved my life, when the CT alone gave incredibly inaccurate results), but i think it needs to be done at the right time to avoid false positives. Good luck! Ann