PET scan results question - 1254919

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PET scan results question - 1254919

My mom is stage IV lung cancer for almost 6 years now. Lately she hasn't done as well and has had to switch drugs a few times. Lastest PET scan shows "hypo metabolic activity in left scaroiliac consistent with metatasis'. She has had on and off back pain for a few months now she kept attributing to over activity. Her oncologist says that this result is likely just inflamation and not cancer b/c she has back pain and pet scan shows all kinds of inflamtion. He is sending for an xray. I was wondering if it common for a pet scan to pick up simple inflamation ? Per the radiologist reading it they say its mets. I guess my question is whether it is correct that it is likely not the cancer.

Reply To: PET scan results question

Yes, a PET scan can pick up simple inflammation, and so it's not definitive to determine that a particular spot is cancer. As far as the radiologist's report, they tend to overcall at times, since often they are given only a previous scan and the information that there is a history of cancer. So if it looks like a bone met and it's a cancer patient, that's what they call it.

You can get some background on bone metastases in Dr. West's thorough introduction:

And you can read all about PET scans here:

I hope your oncologist is right and that it is just inflammation. As you can see from the above posts, further scans such as X-ray or MRI may provide a better picture of what's going on.

Forum moderator

<p>I began visiting GRACE in July, 2008 when my wife Liz was diagnosed with lung cancer, and became a forum moderator in January, 2010. My beloved wife of 30 years passed away Nov. 4, 2011 after battling stage IV lung cancer for 3 years and 4 months</p>

Dr West
Reply To: PET scan results question

I don't have anything to add to Jim's very good explanation. PET scan activity is notoriously non-specific, and it's not uncommon for there to be ambiguous findings in the bone or elsehwere that may need additional imaging, a biopsy, or some other intervention to help clarify what it represents. In fact, just today I had a patient undergo a hip MRI because the PET scan picked up some non-specific uptake that could be from benign musculoskeletal changes or possibly cancer. I suspect it's not cancer but haven't seen the result of the MRI yet. So yes, you can definitely get ambiguous results from a PET scan.

-Dr. West

Dr. Howard (Jack) West
Medical Oncologist
City of Hope Cancer Center
Duarte, CA

Founder & President
Global Resource for Advancing
Cancer Education