PET SCAN RESULTS ACCURATE?

A second opinion at Dana Farber indicated that some of the "spots" on the PET Scan that were supposed to be mets were actually inflammation. His opinion was slightly different than the report the radiologist sent to the treating oncologist. He indicated that he felt there was limited involvement in the chest (lymph nodes and sternum) and the spread was only on the bone –
not in the bone.

Does anyone know the percentage of "false" positive results or readings that are inaccurate? It's my understanding that this test is utilized to stage the disease and create the treatment plan. Is there anyway to increase the accuracy of the scan (i.e. warming blankets, avoiding strenuous exercise)? Has anyone else had this experience? It does really concern me since the mets only appear in areas where my husband has had previous injuries.

I am not questions that my husband has Stage IV lc only the accuracy with where the cancer has spread. Any help would be greatly appreciated.

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Did they do a ct also? Every Pet I have had done is read with a CT that is done at the same time.
I had a false positive pet that showed inflammation as there was nothung to back up mets from the CT.
They may want to wait a couple of weeks and run another to make sure.

Bettie Ann

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then get a second or even third opinion. My first doctor was associated with Dana Farber.

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MRI's of the spine will be very helpful and an MRA of the Aorta also..CT should be done in conjunction...also should be mindful of suv's..

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He had three CT scans about two weeks before the PET Scan. We were told that CT scans would not show the lymph nodes in his chest or any bone involvement. Also when they did
the lung biopsy, the oncologist requested a biopsy of his hip. The radiologist ran back and
forth from the PET Scan imaging in one room to the CT scan room. He could not find any
thing to biopsy. He told us that the CT scan would not show anything until 75% of the bone
was destroyed. The next time he has a scan I will ask more questions.

Thanks for the information!

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The staging is NOT done by the Pet Scan. The Pet scan suggests what might be there, but sometimes lymph nodes are swollen or inflamed because they are doing their job: fighting disease.

After the Pet Scan gives them an idea what's going on they usually do a bronchoscopy and a mediastinoscopy. They take some lung samples and some lymph node samples. They test them all for cancer. Then they know what the cancer is and where the cancer is and then they stage it.

If you are going to a cancer center, they know all about staging.

I don't agree with the people who suggest running around getting opinion after opinion. If you get two opinions from top cancer centers, these people should know what they are doing. Then, get going on your treatment.

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The hardest thing for any of us is to realize that science is not perfect and neither are the results of PET scans. I have heard pros and cons on false positives and negatives. Not sure what the answer is. I think he is being treated and evaluated at excellent facilities. Maybe you need to visit one on one with his team and have them help you understand the PET results and ask them these same questions. They have the expert opinions and the experience to support what they say. Their goal is to keep him healthy and safe, so don't be afraid to talk with them. They are there for both of you and part of the battle is confidence in all aspects of treatment. Best of luck and prayers. Jolene

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I scanned a few research articles. Looks like many of the studies are retrospective (after the fact) and done on people whose cancer has been clinically determined - they took it out and checked. Then they went back to see if the PET or CT scans found it. Some find the PET superior to the CT and others find the opposite - and in some they tie!

Here's what one indicated as causal: All but one patient had a concurrent inflammatory process or an anatomic factor associated with the false positive.

I had read about warm blankets helping some time last year and they were used on me at Memorial Sloan-Kettering Cancer Center last year (February, 2006). Here's part of an article about that. It tells about another causal factor:

In up to 9 percent of patients, doctors have difficulty interpreting scans because of the presence of brown adipose tissue, also known as brown fat, which may lead to a cancer misdiagnosis.

"This is a significant finding," says Medhat Osman, M.D., Ph.D., assistant professor of nuclear medicine and PET director at Saint Louis University School of Medicine. "It is a solution that not only is effective but low-cost and extremely easy for any PET facility to implement."

Osman says brown fat serves an important physiological role – it keeps the body warm in cold temperatures. But accumulations of the tracer that is used to identify malignancies during PET/CT scans that appear in brown fat can mimic cancer – or even mask the appearance of cancer in areas such as the lymph nodes.

New research presented by Osman, co-author Scott Huston and other Saint Louis University Hospital scientists at the 2006 Society of Nuclear Medicine in San Diego this month suggests that covering patients with a heated blanket before the scan can reduce the brown fat uptake by 62 percent.

Hope this helps - but it is suspicious that the uptake only appears in areas where he has had previous injuries. To be sure, I'll bet they need to access the suspected tumor and biopsy it. This was the conclusion in several studies.

Courage

Chum

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Hi Ladybug, I,m going on my 8 year of survivorship. Now it was 7 years ago or so when I had my only pet but it was a dousy.
I had been through chemo, radiation and surgery where they removed 2 lower lobes of my right lung.
After all this they decided to give me the pet scan. According to my first appointment with a radiologist / oncologist. she said my left lung lit up like a christmas tree. she wanted to start rad. the nxt week. I went in a week later new radiologist and he said I'm not treating you , I think you have trauma from surgery and thats what is showing up in my opinion. Then he says and if it is cancer you'll be gone in 6 months and treatment wouldn't help.
So I waited and low and behold I'm still here talking to you 7 years later. Miricale I don't think so. In my case it was a false positive. at the time my general practitioner said that he did'nt see the sense in even doing a pet scan.
Now in 7 years I would hope they made some advances in pet scans but I woukd definatly be very cautious.
you and your family are in my thoughts and prayers, good luck to your husband- john

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