Stomach
Miscellaneous
TNM staging of gastrointestinal stromal tumors (AJCC 8th edition)

Author: Raul S. Gonzalez, M.D. (see Authors page)

Revised: 7 August 2018, last major update August 2018

Copyright: (c) 2003-2018, PathologyOutlines.com, Inc.

PubMed Search: Staging gastrointestinal stromal tumor [title]
Cite this page: Gonzalez, R.S. TNM staging of gastrointestinal stromal tumors (AJCC 8th edition). PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/stomachgiststaging.html. Accessed September 24th, 2018.

Pathologic TNM staging of gastrointestinal stromal tumors, AJCC 8th edition
Definition / general
  • Sporadic nonpediatric gastrointestinal stromal tumors (GISTs) of any gastrointestinal organ are covered by this staging system
  • Pediatric, familial and syndromic GISTs are not staged using AJCC criteria
Essential features
ICD-10 coding
  • C49.A0: Gastrointestinal stromal tumor, unspecified site
Primary tumor (pT)
  • TX: Primary tumor cannot be assessed
  • T0: No evidence of primary tumor
  • T1: Tumor 2 cm or less
  • T2: Tumor more than 2 cm but not more than 5 cm
  • T3: Tumor more than 5 cm but not more than 10 cm
  • T4: Tumor more than 10 cm in greatest dimension
Regional lymph nodes (pN)
  • N0: No regional lymph node metastasis or unknown lymph node status
  • N1: Regional lymph node metastasis

Notes:
  • Nodal metastasis is very rare in sporadic nonpediatric GISTs; regional lymph nodes vary depending on site of origin
Distant metastasis (pM)
  • M0: No distant metastasis
  • M1: Distant metastasis
Mitotic rate
  • Low: 5 or fewer mitoses per 5 mm2
  • High: More than 5 mitoses per 5 mm2
Prefixes
  • y: Preoperative radiotherapy or chemotherapy
  • r: Recurrent tumor stage
Stage grouping
Gastric and omental GIST
Stage IA: T1 - 2 N0 M0 Low mitotic rate
Stage IB: T3 N0 M0 Low mitotic rate
Stage II: T1 - 2 N0 M0 High mitotic rate
T4 N0 M0 Low mitotic rate
Stage IIIA: T3 N0 M0 High mitotic rate
Stage IIIB: T4 N0 M0 High mitotic rate
Stage IVA: Any T N1 M0 Any mitotic rate
Any T Any N M1 Any mitotic rate

Esophageal, small intestinal, colorectal, mesenteric and peritoneal GIST
Stage I: T1 - 2 N0 M0 Low mitotic rate
Stage II: T3 N0 M0 Low mitotic rate
Stage IIIA: T4 N0 M0 Low mitotic rate
T1 N0 M0 High mitotic rate
Stage IIIB: T2 - 4 N0 M0 High mitotic rate
Stage IVA: Any T N1 M0 Any mitotic rate
Any T Any N M1 Any mitotic rate
Registry data collection variables
  • Tumor size
  • Tumor site (esophagus, stomach, duodenum, jejunum / ileum, rectum, extraintestinal)
  • Tumor mitotic rate
  • Tumor rupture
  • Tumor metastasis (liver, peritoneum, other)
  • Tumor KIT immunohistochemistry
  • Tumor mutational status of KIT and PDGFRA (if known)
Histologic grade
  • Same as mitotic rate (see above)
Histopathologic type
  • Spindle cell, epithelioid and mixed cell types
Survival data
Gastric GISTs
Stage Tumor size (cm) Mitotic rateObserved rate of
progressive disease
Stage IA: ≤ 5 Low 0 - 2%
Stage IB: > 5 - 10 Low 3 - 4%
Stage II: ≤ 2 High Insufficient data
> 2 - 5 High 16%
> 10 Low 12%
Stage IIIA: > 5 - 10 High 55%
Stage IIIB: > 10 High 86%

Small intestinal GISTs
Stage Tumor size (cm) Mitotic rateObserved rate of
progressive disease
Stage IA: ≤ 5 Low 0 - 4%
Stage II: > 5 - 10 Low 24%
Stage IIIA: ≥ 10 Low 52%
≤ 2 High 50%
Stage IIIB: > 2 - 5 High 73%
> 5 - 10 High 85%
> 10 High 90%
Board review question #1
Using AJCC 8th edition criteria, which of the following neoplasms may be staged as pN0 even if no lymph nodes are received for pathologic examination?

  1. Appendiceal goblet cell carcinoid
  2. Gastric neuroendocrine carcinoma
  3. Gastrointestinal stromal tumor
  4. Rectal adenocarcinoma with neoadjuvant treatment
Board review answer #1
C. Gastrointestinal stromal tumor