You are on Folfiri, and are Stage 4.
Why is Avastin not part of the regimen? it's pretty standard for Stage 4 to reduce further mets.
Was your prior regimen 5-FU alone, or Folfox (5-FU + Oxilaplatin)?
If you haven't had Oxi yet, that would be the next big gun to pull out of the arsenal.
If you are KRAS-wild, then Erbitux and Vectibix are also available.
Finally, the dosage rate for 5-FU is well-established.
The rates for Oxaliplatin and Irinotecan are also established by the testing protocols, but they have a 'subjectivity' factor for the oncologist to make adjustments based on how the onc thinks the patient will respond, and based on testing of the patients progress/side-effects.
For Iri, the 'base dosage rate' for single-agent treatment is 125mg/m2, and can be set by the onc at as little as 50 and as high as 150mg/m2; don't worry about the numbers, just understand that there's an allowable range.
Your onc *might* have started your Iri rate 'low', and thus is not worried that the CEA climbed a point or 2 (he might have been expecting it); if you tolerate this rate well in terms of side-effects, the onc could increase the rate to maximum strength.
For more about dosing, see:
http://www.drugs.com/dosage/irinotecan. ... tal_CancerHTH, Rick