Table 2.

AJCC 2017 TNM for rectal NET.

T Category

TX Primary tumor cannot be assessed

T0 No evidence of primary tumor

T1 Tumor invades the lamina propria or submucosa and is <= 2 cm

T1a Tumor < 1 cm in greatest dimension

T1b Tumor 1–2 cm in greatest dimension

T2 Tumor invades the muscularis propria or is > 2 cm with invasion of the lamina propria or submucosa

T3 Tumor invades through the muscularis propria into subserosal tissue without penetration of overlying serosa

T4 Tumor invades the visceral peritoneum (serosa) or other organs or adjacent structures

N Category

NX Regional lymph nodes cannot be assessed

N0 No regional lymph node metastasis has occurred

N1 Regional lymph node metastasis

M Category

M0 No distant metastasis

M1 Distant metastasis

M1a Metastasis confined to liver

M1b Metastasis in at least one extrahepatic site (e.g., lung, ovary, nonregional lymph node, peritoneum, bone)

M1c Both hepatic and extrahepatic metastases