Gastrointestinal Stromal Tumors Staging 

Updated: Dec 31, 2015
  • Author: Terence D Rhodes, MD, PhD; Chief Editor: N Joseph Espat, MD, MS, FACS  more...
  • Print

TNM Classification for Gastrointestinal Stromal Tumors

The TNM classification for staging of gastrointestinal stromal tumors (GISTs) is provided below. [1, 2, 3]

Table. TNM Classification for Gastrointestinal Stromal Tumors (Open Table in a new window)

Primary tumor (T)
TX Primary tumor cannot be assessed
T0 No evidence of primary tumor
T1 Tumor ≤ 2 cm
T2 Tumor > 2 cm but ≤ 5 cm
T3 Tumor > 5 cm but ≤ 10 cm
T4 Tumor > 10 cm in greatest dimension
Regional lymph nodes (N)
N0 No regional lymph node metastasis
N1 Regional lymph node metastasis
Distant metastasis (M)
M0 No distant metastasis
M1 Distant metastasis

Table. Histologic grade (Open Table in a new window)

Histologic grade (G)
GX Grade cannot be assessed
G1 Low grade; mitotic rate 5/50 per high-power field (HPF) or less
G2 High grade; mitotic rate > 5/50 HPF

Anatomic stage/prognostic groups

Table. Gastric GIST (Open Table in a new window)

Stage T N M Mitotic rate
IA T1 or T2 N0 M0 Low mitotic rate
IB T3 N0 M0 Low mitotic rate
II T1 N0 M0 High mitotic rate
T2 N0 M0 High mitotic rate
T4 N0 M0 Low mitotic rate
IIIA T3 N0 M0 High mitotic rate
IIIB T4 N0 M0 High mitotic rate
IV Any T N1 M0 Any rate
Any T Any N M1 Any rate

Table. Small intestinal GIST (Open Table in a new window)

Stage T N M Mitotic rate
I T1 or T2 N0 M0 Low mitotic rate
II T3 N0 M0 Low mitotic rate
IIIA T1 N0 M0 High mitotic rate
T4 N0 M0 Low mitotic rate
IIIB T2 N0 M0 High mitotic rate
T3 N0 M0 High mitotic rate
T4 N0 M0 High mitotic rate
IV Any T N1 M0 Any rate
Any T Any N M1 Any rate