My mom did not have a scan - our doctor recommended that it's not necessary for now since the CEA has not shown an increase (It is currently 4.2). My mom's CEA has always been a little high, varying from 3.6 to 5.1.
Her last scan was in November 2018. The plan is to do the scan three months from now. I have always been worried about CEAs, but it seems that it does jump around quite a bit due to inflammation. So as long as they're within range, it seems alright. Your reading of 2.3 is certainly within range. (My dad's CEA is 3.3 for instance - he doesn't have cancer.) In this forum, dianetavegia had previously mentioned that she often had borderline high CEAs - but her only recurrence happened only when it jumped to 6.x.
My mom's been doing well otherwise (I just took her out on vacation, and made her walk around quite a bit). Recently she had once instance of hypertension. It's probably from the avastin she takes; so we might cut that out at some point.
Try not to worry - I've enquired with multiple doctors about CEA numbers. 2.3 is well within range.
Dear Mom 58yrs, Stage 3 RC (T3CN2M0), CEA 9
6.5cm from verge, 30mm in Mesorectal Fascia
Surgery 08/17, CAPOX 5 rounds (planned 6, but blood counts low)
CEA 6, para-aortic node in CT 01/18
CEA 5.6, PET 1 malign para-aortic node 02/18
Pre-op CEA 4.8; Surgery (open) - 1.6 cm Inferior Mesenteric Node - 26/02/18
FOLFIRI+Avastin start 03/18 (12 cyc)
Chemo over - 09/18
Clean PETs - 23/05/18, 06/11/18 (CEA 3.6)
Cap+Avastin Maint (18/11/18)
CEA 3.6 26/01/19, 4.2 02/19, 5.1 11/04/19