Coding M Equivalent
Important
These modules are archived and should only be referenced for historical purposes.
Figure 1 below shows how the registrar codes in CS to obtain the "M" in "TNM".
Figure 1: Diagram showing how the registrar codes in CS to obtain the "M" in "TNM".
CS Metastasis at Diagnosis
This data field identifies the distant site(s) of metastatic involvement at diagnosis.
| Code | Description |
|---|---|
| 00 | No; none |
| 10 | Distant lymph node(s) |
| 40 | Distant metastases except code 10 Distant metastasis, NOS Carcinomatosis Site-specific codes where needed |
| 50 | (40) + (10) |
| 99 | Unknown; distant metastasis cannot be assessed; not stated in patient record |
Click here to see the General Rules for Coding M Equivalent.
Suggested Citation
SEER Training Modules: Coding M Equivalent. U.S. National Institutes of Health, National Cancer Institute. Cited 19 December 2025. Available from: https://training.seer.cancer.gov.