The TNM classification for intrahepatic cholangiocarcinoma assigns a stage to a tumor based on three factors: tumor size and extent (T), regional lymph node involvement (N), and presence of distant metastasis (M). 

Inputs: 
- Tumor classification (T) can be one of the following: 
  Tx: Primary tumor cannot be assessed 
  T0: No evidence of primary tumor 
  Tis: Carcinoma in situ (intraductal tumor) 
  T1a: Solitary tumor <= 5 cm without vascular invasion 
  T1b: Solitary tumor > 5 cm without vascular invasion 
  T2: Solitary tumor with intrahepatic vascular invasion or multiple tumors with or without vascular invasion 
  T3: Tumor perforating the visceral peritoneum 
  T4: Tumor involving local extrahepatic structures by direct invasion 

- Lymph Node classification (N): 
  Nx: Regional lymph nodes cannot be assessed 
  N0: No regional lymph node metastasis 
  N1: Regional lymph node metastasis present 

- Metastasis classification (M): 
  M0: No distant metastasis 
  M1: Distant metastasis present 

The computation determines the stage of intrahepatic cholangiocarcinoma based on a combination of the tumor, lymph node, and metastasis classifications:

- Stage 0 is assigned if the tumor is in situ (Tis), with no regional lymph node metastasis (N0), and no distant metastasis (M0).

- Stage IA is assigned when there is a solitary tumor ≤ 5 cm without vascular invasion (T1a), no regional lymph node metastasis (N0), and no distant metastasis (M0).

- Stage IB applies to a solitary tumor > 5 cm without vascular invasion (T1b), no regional lymph node metastasis (N0), and no distant metastasis (M0).

- Stage II is for a solitary tumor with intrahepatic vascular invasion or multiple tumors (T2), no lymph node involvement (N0), and no distant metastasis (M0).

- Stage IIIA involves a tumor perforating the visceral peritoneum (T3) with no lymph node involvement (N0) and no distant metastasis (M0).

- Stage IIIB applies in two scenarios: if the tumor involves local extrahepatic structures (T4), no lymph node metastasis (N0), and no distant metastasis (M0), or if there is any degree of tumor involvement (Tis, T1a, T1b, T2, T3, or T4), with lymph node involvement (N1), and no distant metastasis (M0).

- Stage IV is designated if there is any degree of tumor involvement (Tis, T1a, T1b, T2, T3, or T4), any lymph node status (Nx, N0, or N1), and presence of distant metastasis (M1).

- If the information is incomplete or does not fit the criteria, the output is "Stage cannot be fully assessed".

If none of the conditions for staging is met, the output encourages the user to ensure all inputs are provided.

This framework helps clinicians evaluate the progression of the disease, guiding treatment strategies and prognosis estimation for patients with intrahepatic cholangiocarcinoma.

The TNM classification for intrahepatic cholangiocarcinoma is a clinical staging system developed by the American Joint Committee on Cancer (AJCC). It is designed for the stratification of patients with intrahepatic cholangiocarcinoma, a type of liver cancer, based on the extent of the disease. This classification system aids in determining prognosis and guiding treatment decisions.

The primary components of the TNM classification for intrahepatic cholangiocarcinoma include the size and extent of the primary tumor (T), the absence or presence and number of regional lymph node metastases (N), and the absence or presence of distant metastases (M). Each of these components is assigned a numerical value, with higher numbers indicating a more advanced stage of the disease. 

The T category is further subdivided based on the size of the tumor and whether it involves major branches of the hepatic or portal vein. The N category is determined by the number and location of regional lymph nodes involved, while the M category is based on the presence or absence of distant metastases.

The final stage of the disease, from stage I to stage IV, is determined by combining the T, N, and M categories. This comprehensive staging system provides a standardized language for clinicians to communicate about the extent of disease and plan appropriate treatment strategies.