# Tnm Stage Calculator

> Fast TNM stage group calculation from pT, pN, pM categories using AJCC 8th edition criteria, with automatic consistency validation. Use when the user asks "what stage is pT2 N1 M0", "calculate TNM stage", "stage group for pT3 N1b breast", "is pT2 N0 M0 stage I or II", "stage this pancreatic cancer", or any pT/pN/pM to stage-group conversion. Supports breast, colorectal, pancreas, and gastric carcinoma. Flags inconsistencies like tumor-size-vs-pT mismatches and node-count-vs-pN mismatches.

- Skill: `patolojiai/tnm-stage-calculator` (Agent Skill)
- Install (CLI): `npx skillmds@latest add patolojiai/tnm-stage-calculator`
- Raw SKILL.md: https://api.skillmd.com/api/skills/patolojiai/tnm-stage-calculator/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- License: MIT
- Author: patolojiAI (https://skillmd.com/u/patolojiai)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/patolojiai/tnm-stage-calculator

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# TNM Stage Calculator

Quick and accurate TNM stage group calculation based on AJCC 8th edition staging manual.

## When to Use This Skill

Use this skill for:
- Quick stage group lookup from pT/pN/pM
- Teaching TNM staging to residents
- Verifying report staging accuracy
- Calculating stage from pathologic findings
- Tumor board preparation

## Supported Tumor Types

- Breast invasive carcinoma (AJCC 8th pathologic stage groups)
- Colorectal carcinoma (AJCC 8th pathologic stage groups)
- Exocrine pancreas carcinoma (AJCC 8th pathologic stage groups)
- Gastric carcinoma (AJCC 8th pathologic stage groups)

## Key Features

1. **Stage Group Calculation**: Input pT/pN/pM → Output stage group (0, I, IIA, IIB, IIIA, etc.)
2. **Validation**: Checks if pT/pN/pM combination is valid
3. **Prognostic Info**: Provides stage group meaning
4. **Fast Lookup**: Lightweight skill optimized for speed

## Reference Files

Reference on-demand (DO NOT load at startup):
- Staging tables: `../../shared-references/staging/tnm_stage_calculator.md`

## Usage Examples

```bash
# Calculate stage
claude "What stage is pT2 N1 M0 for breast using tnm-stage-calculator"

# Quick lookup
claude "Stage pT3 N1b M0 colorectal using tnm-stage-calculator"

# Verify staging
claude "Is pT1c N0 M0 stage IA for breast using tnm-stage-calculator"
```

## Processing Instructions

1. **Parse input**: Extract pT, pN, pM categories and tumor type
2. **Load staging table** for specific tumor type
3. **Look up stage group** from pT/pN/pM combination
4. **Validate**: Check if combination exists in AJCC 8th
5. **Output**: Stage group with brief prognostic interpretation

## Important Notes

- Uses **pathologic stage groups** (pTNM), not clinical stage groups (cTNM)
- Based on **AJCC 8th edition** (2017)
- For breast, does not include anatomic stage groups (uses prognostic stage groups where applicable)
- For colorectal, includes post-neoadjuvant treatment modifications (ypTNM)

## Input Format Examples

- "pT2 N1a M0 for breast"
- "What is the stage for pT3 N1b M0 colorectal?"
- "Calculate stage: pT2 N1 M0 pancreas"
- "Stage group for gastric pT3 N2 M0"

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**Note**: Lightweight skill. Staging table loaded on-demand during processing only.