At my last visit to Oncologist, who insisted in the past that CT scans did not increase long term survival rates, he admitted that he learned that there is benefit to scanning stage 3 for 5 years. I didn't have to argue with him this time, and like you, I'm still unconvinced that I'm NED, since I have some lung nodes.
Resection of splenic flexure 7/24/13
T3N2BM0, Stage 3c,12/29 nodes
Folfox x12 9/13-3/14
CT scan 4/14, enlarged spleen, otherwise clear
CT scan 10/14, spleen shrank a bit, otherwise NED?
CT 4/15, spleen WNL.