pet vs cat.

[n37ch]

my wife had an ovarian ca  dx in may this year,at that time her ca125 was 650, she underwent a tah bso extensive debulking and started on 6 rxs of cisplatin and taxane. Her Ca125 fell to 20 .A pet scan at the end of nov showed one small area of activity in the left paracolic border. A cat scan performed at MD Anderson two weeks later showed multiple small nodules in the omentem and chest .her ca 125 continues to be 20 and she is asymptommatic. She just started on a rx of Gemzar and cisplatin. I am a physician and can not reconsile the results of the pet scan and the ca125 with the results of the cat.Is there a minum  size for the leisons to show up on pet.please ask your experts for some imput thank you  Ricard Bromberg MD

[alanpvegas]

The PET only shows glucose uptake by forming or existing tumors...that's it's primary usage in ovarian cancer monitoring (normally after remission).  It's not given that often, though, due to the cost so CT is the mainstay in monitoring along with CA125.  It's obviously hard to answer part of your question without a full medical HX, but yes...in two weeks that is very possible that new nodules would appear that the PET didn't 'see'.

If your wifes medical plan and physicians are allowing PETs (wow), you may want to consider a PET/CT in the future...it does both and gives the radiologist a better view of what's going on at that particular point in time by giving them both types of scans in one combined image.  In the overall scheme of things, however, PET is not highly necessary in OvCa monitoring due to how current treatment of OvCa is performed.

CA-125, as you may have heard, will be mixed in it's usefullness...for some it's a good marker, for others it has less usage ( my mom's ca-125 was so high at one point her oncologist was amazed she was still functioning well).  I think it's excellent your wife is still in the 20's...I know we are all hoping it stays there!

I am curious, however, why your wife was given Cisplatin (it's not too common in the U.S. since Carboplatin came out years ago that has less side effects) and also why she would be going on Cisplatin again if this is a recurrance.  Typically if she has a recurrance within a certain timeframe she would be platinum resistant and should not be put on a monthly platinum based chemo...usually it's only recommended to be placed back on a platinum based chemo if remission was greater than 6mo.

[gah_70]

I was told by my physician at MD Anderson that anything less than about one inch could very likely be missed in a PET scan.  You might also ask this question on the Expert Forum and get Dr. Goodman's opinion.

Best wishes to you both.  Hope the Gemzar/Cisplatin combo works for her.

Gail