Oncology (General Cancer)/Cardiac sarcoma - PET/CT
QUESTION: Dear Dr. Higby
I am going to have the surgery/autotransplant in a few days. I have now the preliminary results of the new PET/study.
According to the study, there is an increased uptake with a SUV of 5.6 in the area of he heart.
(right atrium/pericardium which seems to correspond to the sites involved by the tumor as revealed by cardiac MRI).
Additionally, there is a questionable slightly hypermetabolic spot (SUV of 3.2) in the thoracic spine which has no correlate in the MRI study.
The radiologists told me that he couldnt tell for sure if this was a positive finding. he said that a single metasasis would be unusual though it cannot be excluded. However, metasases usually displayed a higher suv. Anyway, the results wouldnt alter the plan of treatment/surgery.
What do you think?
Does the finding fit a low grade sarcoma?
Could a sarcoma double its metabolic activity within 2years (if it was already there back then)?
Thanks so much.
ANSWER: Sarcomas can "evolve" from low grade to high grade over time, thus becoming more PET avid. As for the finding of some uptake in the thoracic spine, my inclination would be to go ahead with the surgery and worry about that later. In the worst case scenario, assuming the thoracic spine is involved, you would still live significantly longer if the heart is fixed. And I would agree with your radiologist that at this point it seems unlikely that this thoracic spine issue is sarcoma; it may be due to some disc disease in that area.
Hope this helps.
---------- FOLLOW-UP ----------
QUESTION: Thanks so much. Anyway, i dont worry much about the spinal uptake for now, i will deal with it later. Maybe it is just nothing, and the neurological back symptoms are just due to the SVC syndrome and/or mild compression of the thoracic spine by the cardiac mass as suggested by MRI.
But is an uptake of 5.6 rather at the lower or higher spectrum of findings for sarcoma? So do you think that a low grade sarcoma which could have already been there 2 years ago but did not show up neither on regular MRI/CT nor on PET/CT due to small size and minimal metabolic activity, respectively, could have been transformed into a high grade sarcoma within the last 6 months (When symptoms became pretty severe and the SVC syndrome developed)?
I mean does am uptake of 5.6 point towards a high grade sarcoma rather than towards a low grade sarcoma or is this uptake a grey zone where both scenarios are equally possible?
Thanks so much.
I'd say that is a grey zone; and until you have the necessary surgery and recover, things will be confusing. It is possible, although unlikely, that two years ago something was there that did not show up on MRI or PET/CT. MRI is related to water content; PET is related to sugar uptake; and CT is related to tissue density. So a lesion would have to be very small and metabolically inactive to escape all three. Could happen, but no way of knowing. Good luck.