Primary tumor (T)* | ||||
T category | T criteria | |||
TX | Primary tumor cannot be assessed | |||
T0 | No evidence of primary tumor | |||
Tis | Carcinoma in situ (intramucosal carcinoma; invasion of the lamina propria or extension into but not through the muscularis mucosae) | |||
Tis(LAMN) | Low-grade appendiceal mucinous neoplasm confined to the muscularis propria; Acellular mucin or mucinous epithelium may invade into the muscularis propria. T1 and T2 are not applicable to LAMN; Acellular mucin or mucinous epithelium that extends into the subserosa or serosa should be classified as T3 or T4a, respectively. | |||
T1 | Tumor invades the submucosa (through the muscularis mucosa but not into the muscularis propria) | |||
T2 | Tumor invades the muscularis propria | |||
T3 | Tumor invades through the muscularis propria into the subserosa or the mesoappendix | |||
T4 | Tumor invades the visceral peritoneum, including acellular mucin or mucinous epithelium involving the serosa of the appendix or mesoappendix, and/or directly invades adjacent organs or structures | |||
T4a | Tumor invades the visceral peritoneum, including acellular mucin or mucinous epithelium involving the serosa of the appendix or serosa of the mesoappendix | |||
T4b | Tumor directly invades or adheres to adjacent organs or structures | |||
Primary tumor suffix
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Regional lymph nodes (N)* | ||||
N category | N criteria | |||
NX | Regional lymph nodes cannot be assessed | |||
N0 | No tumor involvement of regional lymph node(s) | |||
N1 | Tumor involvement of one to three regional lymph nodes (tumor in lymph node measuring greater than or equal to 0.2 mm) or any number of tumor deposits is present with no tumor involvement in all identifiable lymph nodes | |||
N1a | Tumor involvement of one regional lymph node | |||
N1b | Tumor involvement of two or three regional lymph nodes | |||
N1c | No tumor involvement of regional lymph nodes, but there are tumor deposits in the subserosa or mesentery | |||
N2 | Tumor involvement of four or more regional lymph nodes | |||
Regional lymph nodes suffix
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Distant metastasis (M)* | ||||
M category | M criteria | |||
cM0 | No distant metastasis | |||
cM1 | Distant metastasis | |||
cM1c | Metastasis to sites other than peritoneum | |||
pM1 | Microscopic confirmation of distant metastasis | |||
pM1a | Intraperitoneal acellular mucin, without identifiable tumor cells in the disseminated peritoneal mucinous deposits | |||
pM1b | Intraperitoneal metastasis only, including peritoneal mucinous deposits containing tumor cells | |||
pM1c | Microscopic confirmation of metastasis to sites other than peritoneum | |||
NOTE: For specimens containing acellular mucin without identifiable tumor cells, efforts should be made to obtain additional tissue for thorough histologic examination to evaluate for cellularity. | ||||
Histologic grade (G)* | ||||
G | G definition | |||
GX | Grade cannot be assessed | |||
G1 | Well differentiated | |||
G2 | Moderately differentiated | |||
G3 | Poorly differentiated | |||
NOTE: In rare cases of discordance in primary and metastatic histological grade, the grade of metastatic disease is utilized for stage group assignment. | ||||
AJCC prognostic stage group is assigned based on the stage classification and categories chosen.* | ||||
Prognostic stage groups | ||||
When T is... | And N is... | And M is... | And grade is... | Then the stage group is... |
Tis | N0 | M0 | Any | 0 |
Tis(LAMN) | N0 | M0 | Any | 0 |
T1 | N0 | M0 | Any | I |
T2 | N0 | M0 | Any | I |
T3 | N0 | M0 | Any | IIA |
T4a | N0 | M0 | Any | IIB |
T4b | N0 | M0 | Any | IIC |
T1 | N1 | M0 | Any | IIIA |
T2 | N1 | M0 | Any | IIIA |
T3 | N1 | M0 | Any | IIIB |
T4 | N1 | M0 | Any | IIIB |
Any T | N2 | M0 | Any | IIIC |
Any T | Any N | M1a | Any | IVA |
Any T | Any N | M1b | G1 | IVA |
Any T | Any N | M1b | G2, G3, or GX | IVB |
Any T | Any N | M1c | Any G | IVC |
AJCC: American Joint Committee on Cancer; TNM: tumor, node, metastasis; UICC: Union for International Cancer Control.
* AJCC data elements required for staging are identified with an asterisk.Do you want to add Medilib to your home screen?