A term that refers to the staging of gastrointestinal stromal tumor (GIST), following the rules of the TNM AJCC v8 classification system. This staging system does not apply to pediatric GIST, familial GIST (germline mutant KIT or PDGFRA), or syndromic GIST (no AJCC staging system available). (from AJCC 8th Ed.) [from NCI]