Others may be able to explain this better than me, but I will take a shot.
The main reason they recommended chemo for me is that in addition to my main tumor they found a "noncontiguous tumor deposit" nearby during surgery. This means that the cancer had spread locally and started a 2nd tumor that was not directly connected to the first, although it was not far from the main tumor. (Although it may be possible that this was an additional unrelated tumor; I'm not 100% clear on that, but I think it adds up to the same thing.) This 2nd tumor deposit essentially gets treated as if I had lymph node involvement, because it is evidence that local spreading is going on, even if it hasn't gotten to the lymph nodes. The language of the staging is pretty confusing to me but that's why I have that "pN1c" classification to my tumor; it's not technically lymph node involvement, but they treat it like it is.
My tumor was also stage 3 where yours was stage 2, so that's another difference. I am not sure if I would have been recommended chemo if I were stage 3 without that additional tumor deposit.
This page is pretty informative about the different kinds of tumor staging, with diagrams that I haven't seen elsewhere:
https://www.cancer.net/cancer-types/col ... cer/stagesHope that helps! I hope you start feeling better soon. That is a long time to feel so bad. I had lost a lot of weight from not eating before my surgery, but at this point most of my discomfort seems to be from chemo.
DX: sigmoid colon cancer 5/2018. 48 F
laparoscopic sigmoid resection (24 cm removed); no stoma.
7.5cm adenocarcinoma -- mod. diff.
1 noncontiguous tumor deposit removed; 0/31 lymph nodes
T3 pN1c M0
5/18 before surgery, CEA 11.2
6/18 began FOLFOX
7/18: CEA 1.9; added neulasta post infusion
9/18: CEA 2.8
10/18: 25% chemo reduction
11/18: CEA 1.8
7/19 CT scan clear