EOD Primary Tumor
Notes
**Note 1:** For GIST tumors arising in the tubular organs of the digestive system (Esophagus, Stomach, Small Intestine, Appendix, Colon and Rectum), any extension beyond the muscular wall (e.g. invasion beyond the muscularis propria/muscularis, NOS) into adjacent tissues, sites or organs is no longer considered confined to the site of origin (EOD Primary Tumor code 100).
* Extension through the wall, NOS, or through the muscularis propria/muscularis, NOS without further extension would be EOD Primary Tumor code 100 (confined to the site of origin).
* Extension through the wall, NOS or through the muscularis propria/muscularis, NOS with any further extension into underlying tissues/fat, organs or structures would be included in EOD Primary Tumor codes 400 or 700 (Adjacent (connective) tissue, NOS or Extension to organs/structures, NOS).
**Note 2:** See the chapter (schema) corresponding to the primary site for information about the site's anatomy. The corresponding schema can be used to help determine what the adjacent (connective) tissues, structures or organs are, but the site-specific schema codes are not to be used to determine whether a GIST tumor is localized, regional or distant.
**Note 3:** For GIST tumors arising in the Retroperitoneum (C480-C482, C488), refer to the EOD General Instructions for the definition of adjacent (connective) tissue. Refer to the General Instructions to determine whether the GIST tumor involves adjacent tissues, or is confined to the primary site.
| Code |
Description |
SS2018 T |
| 000 |
In situ, intraepithelial, noninvasive |
IS |
| 100 |
Any size tumor
Confined to site of origin
Localized, NOS |
L |
| 400 |
Any size tumor
Adjacent (connective) tissue, NOS |
RE |
| 700 |
Any size tumor
- Adherent to organs/structure, NOS
- Extension to organs/structures, NOS |
D |
| 800 |
No evidence of primary tumor |
U |
| 999 |
Unknown; extension not stated
Primary tumor cannot be assessed
Not documented in patient record
Death Certificate Only |
U |
(1) Fritz AG, Ries LAG (eds). **SEER Extent of Disease 1988: Codes and Coding Instructions (3rd Edition, 1998)**, National Cancer Institute, NIH Pub. No. 98-2313, Bethesda, MD, 1998
(2) Young JL Jr, Roffers SD, Ries LAG, Fritz AG, Hurlbut AA (eds.). **SEER Summary Staging Manual-2000: Codes and Coding Instructions**, National Cancer Institute, NIH Pub. No. 01-4969, Bethesda, MD, 2001.
(3) Collaborative Stage Work Group of the American Joint Committee on Cancer. **Collaborative Stage Data Collection System User Documentation and Coding Instructions, version 02.05**. American Joint Committee on Cancer (Chicago, IL)
(4) Gress, D.M., Edge, S.B., Gershenwald, J.E., et al. **Principles of Cancer Staging**. In: Amin, M.B., Edge, S.B., Greene, F.L., et al. (Eds.) AJCC Cancer Staging Manual. 8th Ed. New York: Springer; 2017: 3-30
(5) Pollock, R.E., Maki, R.G. **Introduction to Soft Tissue Sarcoma**. In: Amin, M.B., Edge, S.B., Greene, F.L., et al. (Eds.) AJCC Cancer Staging Manual. 8th Ed. New York: Springer; 2017: 489-497
(6) DeMatteo, R.P., Maki, R.G., Pollock, R.E., et al. **Gastrointestinal Stromal Tumor**. In: Amin, M.B., Edge, S.B., Greene, F.L., et al. (Eds.) AJCC Cancer Staging Manual. 8th Ed. New York: Springer; 2017: 523-529
