Pathologic M
This input is used for staging
Notes
**Note 1:** When a patient has more than one area of gastrointestinal stromal tumor (GIST), it is important to try to distinguish between intra-abdominal metastasis and tumor multiplicity. Distant metastases are relatively rare in GISTs, but they are increasingly detected with sophisticated radiological studies. Intra-abdominal metastasis will present as tumor involvement in the abdominal cavity outside the main tumor mass, in the peritoneum, omentum, serosae of organs, and the cul-de-sac, among other areas. * Assign this form of metastasis as cM1 **Note 2:** Tumor multiplicity, in contrast, will present with anatomically separate, multiple tumors of different sizes arising independently in the GI tract. This form of tumor multiplicity usually will be seen in patients with neurofibromatosis type 1 or familial GIST syndrome, but in rare instances may be seen in patients without these conditions. This form of multiplicity should not be coded as metastasis, but the presence of multiple tumors should be coded in **Site-Specific Factor 9, Tumor Multiplicity**. * When a solitary omental or mesenteric tumor mass is found with a primary GIST elsewhere, do not code this as a metastasis. Code it as multiple tumors in **Site-Specific Factor 9, Tumor Multiplicity** * When multiple tumor areas are present and it is not stated whether these are metastases or independent tumors, consult with a physician if possible to determine how to code them. If a decision cannot be made, assign cM0NAACCR Item
NAACCR #900| Pathologic M | Pathologic M Display | Description | Registrar Notes |
|---|---|---|---|
| c0 | cM0 | No distant metastasis | Unknown; distant metastasis not stated Distant metastasis cannot be assessed Not documented in patient record |
| c1 | cM1 | Distant metastasis | CLINICAL assessment only: Distant lymph node(s) Carcinomatosis Distant metastasis WITH or WITHOUT distant lymph node(s) Carcinomatosis Distant metastasis, NOS Stated as M1 |
| p1 | pM1 | Distant metastasis | HISTOLOGICALLY confirmed: Distant lymph node(s) Carcinomatosis Distant metastasis WITH or WITHOUT distant lymph node(s) Carcinomatosis Distant metastasis, NOS |
| 88 | 88 | Not applicable | In situ case but no pTis is defined by TNM Death certificate only (DCO) case |
| <BLANK> | BLANK | See Registrar Notes | Pathologic classification criteria not met No pathologic workup for T and N categories and no pathologic evidence of metastasis Only Pathologic Stage Group documented (no T, N, or M information available) |