The TNM classification calculator for vulvar cancer evaluates the stage of the cancer based on three user-provided inputs: tumor classification, lymph node classification, and metastasis classification. Each of these inputs is selected from a predefined list of options, and the combination of responses determines the cancer stage according to a specific set of rules.

The tumor classification input includes options from "Tx: Primary tumor cannot be assessed" to "T4: Tumor invading bladder or rectum". The lymph node classification has options ranging from "Nx: Regional lymph nodes cannot be assessed" to "N1: Regional lymph node metastasis present". The metastasis classification consists of "M0: No distant metastasis" and "M1: Distant metastasis present".

The computation involves evaluating logical expressions for each combination of inputs to categorize the cancer stage. A set of conditions checks specific patterns of inputs to match them with predefined stages:

- Stage IA is assigned if the tumor is limited to the uterus (<= 5 cm or T1a), has regional lymph node metastasis at 2 or more sites (T3b), and no distant metastasis (M0).
- Stage IB is given if the tumor is limited to the uterus (> 5 cm or T1b), with regional lymph node metastasis at 2 or more sites (T3b), and no distant metastasis (M0).
- Stage II results when the tumor involves the adnexa (T2a), has regional lymph node metastasis at 2 or more sites (T3b), and no distant metastasis (M0).
- Stage IIIA is determined when the tumor is limited to the uterus, the adnexa, or involves other pelvic tissues, invades bladder or rectum (T4), and no distant metastasis (M0).
- If any of these tumors, with unassessed or no lymph node metastasis, have no distant metastasis, then it's Stage IIIB.
- Stage IIIC occurs when there are isolated tumor cells in regional lymph nodes (< 0.2 mm) and no distant metastasis.
- Stage IVA is assigned if any of these primary tumors have regional lymph node metastasis and no distant metastasis, or when tumors involve other pelvic tissues with specific conditions.
- Stage IVB is given if there's distant metastasis present with tumors at any stated location or condition.

The calculator in question is the TNM Classification for Vulvar Cancer. TNM stands for Tumor, Node, Metastasis, a system used to classify the extent of cancer spread in the body. This specific classification is applied to patients diagnosed with vulvar cancer.

The TNM Classification for Vulvar Cancer is used to determine the stage of the cancer, which is crucial for deciding the most appropriate treatment strategy and for predicting patient prognosis. The 'T' refers to the size and extent of the main tumor, 'N' refers to the number of nearby lymph nodes that have cancer, and 'M' refers to whether the cancer has metastasized, or spread to other parts of the body.

This classification system is not applicable to patients with benign (non-cancerous) vulvar conditions or those with other types of cancer. It is also less useful in early-stage cancers where the extent of disease is not yet clear.

TNM classification for vulvar cancer