The calculator in question is the TNM Classification for Colorectal Cancer. TNM stands for Tumor, Node, Metastasis, and it is a globally recognized system used for staging different types of cancers, including colorectal cancer. 

This classification system is applicable to patients diagnosed with colorectal cancer. It helps clinicians to determine the extent of cancer spread in the body, which is crucial for planning the most effective treatment strategy and predicting patient prognosis. 

The TNM system classifies cancer based on three key factors: the size and extent of the primary tumor (T), whether the cancer has spread to nearby lymph nodes (N), and the presence of distant metastasis (M). Each factor is assigned a numerical value, with higher numbers indicating more advanced disease.

There are no specific exclusion criteria for the use of the TNM classification for colorectal cancer. However, it is less useful in early-stage cancers where the disease is localized and has not spread to lymph nodes or distant organs. It is also less applicable in patients with rare forms of colorectal cancer, such as neuroendocrine tumors, as these may behave differently from common adenocarcinomas.

TNM classification for colorectal cancer

# Criteria
 ## Tumor classification
A. Tx: Primary tumor cannot be assessed
B. T0: No evidence of primary tumor
C. Tis: Carcinoma in situ, intramucosal carcinoma (involvement of lamina propria with no extension through muscularis mucosae)
D. T1: Tumor invading submucosa (through muscularis mucosa but not into muscularis propria)
E. T2: Tumor invading muscularis propria
F. T3: Tumor invading through muscularis propria into pericolorectal tissues
G. T4a: Tumor invading through visceral peritoneum (including gross perforation of bowel through the tumor and continuous invasion of the tumor through areas of inflammation to the surface of visceral peritoneum)
H. T4b: Tumor directly invades or adheres to adjacent organs or structures
## Lymph node classification
I. Nx: Regional lymph nodes cannot be assessed
J. N0: No regional lymph node metastasis
K. N1a: 1 positive regional lymph node
L. N1b: 2-3 positive regional lymph nodes
M. N1c: No positive regional lymph nodes, but tumor deposits in subserosa, mesentery, or nonperitonealized pericolic or perirectal/mesorectal tissues
N. N2a: 4-6 positive regional lymph nodes
O. N2b: >= 7 positive regional lymph nodes
## Metastasis classification
P. M0: No distant metastasis
Q. M1a: Metastasis to 1 site or organ with no peritoneal metastasis
R. M1b: Metastasis to >= 2 sites or organs with no peritoneal metastasis
S. M1c: Metastasis to the peritoneal surface, with or without other site or organ metastases

# Conditions
- C and J and P
- (D or E) and J and P
- F and J and P
- G and J and P
- H and J and P
- ((D or E) and (K or L or M) and P) or (D and N and P)
- ((F or G) and (K or L or M) and P) or ((E or F) and N and P) or ((D or E) and O and P)
- (G and N and P) or ((F or G) and O and P) or (H and (K or L or M or N or O) and P)
- (D or E or F or G or H) and (I or J or K or L or M or N or O) and Q
- (D or E or F or G or H) and (I or J or K or L or M or N or O) and R
- (D or E or F or G or H) and (I or J or K or L or M or N or O) and S
- true