I know there are a wide range of strong opinions on this and I'm not trying to rekindle an old debate. Let me preface by saying I'm not a doctor...just a patient of this disease, so I present this purely as my opinion based on my recent experiences. I hope it is of value to somebody out there.

I know PET scans seem to have a bad rap for 'false positives'. Perhaps the criticism is not entirely without merit, as I have experienced a 'false positive' PET scan myself, as many of you have. I finished chemo and IMRT X 35 in May of 2006. In October 2006 I had a PET scan which indicated "possible recurrence in the right lateral tongue" - same place my original tumor was. Based on the PET scan, my doctor performed a biopsy, which came back negative for cancer. My doctor believes the PET gave a 'false positve' due to tissues in my mouth still healing from radiation. As far as I was concerned - GREAT! I was just sooo glad it's not cancer.

Since then, everything has looked great for me. There's been no signs of anything but progress. But last month (July 12) I had a checkup PET/CT scan. It indicated 'moderate FDG accumulation' in a lower jugular lymph node on my right side, and surrounding tissue. The corresponding CT indicated a slight enlargement of the same node. This was an area which was radiated to a lesser degree than my mouth in treatment, and had NOT previously been abnormal in previous PET/CT scans.

I just had a neck dissection last week. Due to the location of the suspicious area, my doctor felt a needle biopsy was too prone to be inaccurate, and felt we should take out all the nodes on that side.

The pathology came back from the dissection - the suspicious node was in fact cancerous, and as the PET scan suggested, the cancer had begun to spread to other tissues around the affected node (including my carotid artery).

The node was only 1.5 cm and was barely palpable to the doctor in his office prior to surgery. Had he not been specifically looking for it based on the PET/CT, I don't know if he would have even noticed it yet.

Now, I'm heading into more radiation and chemo because the cancer got onto the carotid artery on that side and they couldn't get clear margins in the dissection. But THANK GOODNESS for the PET scan that said, "hey, there's a potential problem here". How far would it have gotten if I hadn't done a PET/CT, and the doc only found it when it was swollen enough for him to notice it via palpation on one of my monthly visits? How much damage would it have done to my carotid artery by then? I suppose I'll never know, and I'm so very thankful.

As many have said and as I've personally experienced, an area of healing/damaged tissues can cause a PET 'false positive ' - so can infection and probably other things. But in my opinion, that doesn't make a PET scan completely worthless. In my case, it may have been a life-saver. Like any other tool, they have strengths and weaknesses, but they are another tool and in some cases, a very effective one.

PET scans are hardly worthless. The PET/CT accuracy is at least 95% I understand. The Older PET scans were less accurate because there was no anatomical point of reference or spacial registration accuracy. Yes there are some false positives with PET and PET/CT and there are many false positives with many lab tests. The PET amd PET/CT have tremendous value in both pre Tx triage and post Tx analysis of Tx efficacy.

There have been many here who have had recurrences caught early as a result of a PET or PET/CT. Scans in general are only a component of a diagnostic workup. I have had MRI's with ROI that turned out to be nothing and the MRI is considered the gold standard of imaging.

I would like to add to what Gary said in that "false negatives" for fused PET/CT scans are very uncommon -- that is, a situation where there IS cancer but the scan fails to find it. Comparative studies have quoted figures from essentially "none" to 2-3%. So if you get a "clear" scan read by someone who knows what he or she is doing, you can breathe a bit easier.

Rate of false positives may also reflect experience and hence, confidence, of the radiologist in distinguishing cancer from hightened uptake by inflammation, infection or healing tissues.

Of course the PET/CT is only part of a proper diagnostic workup, as Gary notes.

Gail

PET/CT definitely worked in our case. My husband had pain in his neck for about a year and kept visiting the ENT with no results. Nothing showed up on a CT, MRI, ultrasound or physical exam. Thankfully, the ENT listened to my DH about something not being right and sent him for a PET/CT. And guess what? It showed a suspicious area on BOT which was then biopsied and came back as SCC stage 1. In his case, the pain was the main factor in catching it early but the PET/CT picked something up that none of the other diagnostic tools did.

He finished radiation at the end of Dec and is doing great. He goes every 4 months for a PET/CT for the first year.

Steve,

I totally agree. My husband Mike was given a false positive on a PET, but I am extremely glad that he still gets one every 6 months.

Jess