@montyd , Nobody ever put it (the stage) writing, and the first surgeon to assess said "it depends" (citing a lot of variables).

It was initially measured during EUS as 2 cm, which is the size boundary between 1a and 1b (with no detected spread to lymph nodes).

Stage 2a did not apply (per https://www.cancer.org/cancer/types/pancreatic-cancer/detection-diagnosis-staging/staging.html ) because it was smaller than 4 cm.

Within AJCC Stage 2b (T1N1M0 and T2N1M0) it was also at the 2cm boundary between those two TNM size values. There was uncertainty on all MRIs about one possible lymph node (3 or fewer on TNM scale is N1), so 2b was a possibility as well,

During Whipple surgery after 12 Folfirinox, the tumor had shrunk to under 2cm and the lymph node was confirmed negative, which actually qualifies as 1a (T1N0M0).

So, as the surgeon mentioned originally, "It depends." 😉

As far as recurrence, the first detection was on MRI at the anastomosis between the remnant pancreas and the section of jejunum it was reconnected to. So basically, yeah, right where the surgeon quit slicing. His first slice showed cancer and "funny cells" at the margin during the intraoperative pathology, so he cut about another 1/2" of pancreas off and saw clean margins in that one. He said unfortunately they miss stuff in the pathology. 🙁 Another surgeon told me the same thing. Of course there's also the possibility that other remaining pancreas tissue simply turned malignant after the surgery, but I doubt we'll ever know exactly which happened.