CA 19 9 marker, with CAPOX plus Avastin questions


1)How many CAPOX (Capecitabine plus Oxaliplatin) plus Avastin cycles we can expect it to begin lowering? what's your experience, or what did you read or the oncologist you trust more said?


2)Does that test requires, (or is better made) stopping taking some kind of pills for some hours or days, to avoid false marker values? (for example Ranitidine, that avoids Capecitabine nauseas) or some foods?


3)We are planning to do it just before a CAPOX plus Avastin session, that is, three weeks after the most recent session, do you think it's a good moment? I think so, because the drugs already acted in three weeks and the blood is more stabilized


Any other related advice appreciated, thanks in advance