Tumor size & spread.
Stage i: the cancer
is not touching the major blood vessels near the pancreas
Stage ii: the cancer extends beyond the pancreas, or the cancer has spread to a nearby lymph node.
Stage iii: the cancer has wrapped around the major blood vessels near the pancreas.
Stage iv: the cancer has spread to other organs.
Surgery is usually not recommended for stage iii or IV tumors, but there are exceptions.