metastatic left mesorectal lymph common outcome in PETCT scan post biopsy ?

[OB23]

If Biopsy and PET CT scan is done with in a week, will this result in pet ct scan incorrectly showing metastasis mesorectal lymph node? As per doctor this is a very common outcome as my dad’s biopsy was done on 7/12/2024 and PETCT scan was done on 12/12/2024. I am very scared of metastases mentioned and being dismissed by doctors

[Xavier10]

So your doctor says that a PSMA avid finding in a lymph node found in the rectal area is often a false positive? and not to worry about it? Is that what you mean? On occasion, PSMA scans can give false positives related to other issues. Often the uptake can relate to other cancers and other issues. Sometimes infection and inflammation. But I agree you have reason to be concerned. Normally other tests are done with more traditional imaging that can corroborate the finding. Maybe those tests did not corroborate the finding of metastasis. I would pin your doctor down on why he says that.

urotoday.com/video-lectures...

[OB23 in reply to Xavier10]

Yes he mentioned that it is a false positive and we often see false positives when biopsy and scans are done so close. He also mentioned in case of prostrate cancer there are other lymph node occurrences which is more common and rarely mesorectal lymph node

[Tall_Allen]

Does the newer Posluma PET/CT obviate the problem?

[OB23 in reply to Tall_Allen]

Yeah the doctor advised to continue Firmagon and do an MRI 3 months later to check what is going on. I was just stressed that I have to wait for 3 months and wanted to understand if biopsies usually cause incorrect PET CT results

[Xavier10 in reply to OB23]

first thing that pops up on google's A/I when you type in can a biopsy cause a false positive on a PSMA scan:

"While a biopsy itself doesn't directly cause a false positive PSMA scan, the inflammation or tissue disruption caused by the biopsy procedure can sometimes lead to increased PSMA uptake in the area, potentially appearing as a positive finding on the scan, which could be interpreted as a false positive if not carefully evaluated in the context of other clinical information; meaning the increased uptake might not be due to cancer but rather a reaction to the biopsy itself"

Makes sense.

[OB23 in reply to Xavier10]

Yeah. Thank you.