As noted above, it is most likely all or most of the surgical...

As noted above, it is most likely all or most of the surgical patients had borderline resectable disease. Borderline resectable means involvement of portal vein, the SMV, or the confluence. Although technically resectable with a vein graft, the chance of cure is low because of the high risk of metastasis, or infiltrative disease not identified on disease staging. These patients therefore tend to be recommended to have preoperative chemotherapy to assess whether the disease can be shrunk prior to considering surgery. Unresectable disease is that which involves a major artery e.g. hepatic artery or coeliac trunk. Although I am aware some centres, e.g. UCSF, will try aggressive chemo/radiotherapy protocols to try and get the tumour off the artery and then aim for resection, that is not widely practiced. What would be really interesting would be if any of the unresectable patients in the study received R0 (clear surgical margin) surgery.