TNM Staging.md

Converting TNM to a Staging Value

The current algorithm for determining the numeric staging algorithm is based on the TNM classification and works as follows:

1. If M is 1, staging is 4. Skip remaining steps.
2. If N is greater than 0, staging is 3. Skip remaining steps.
3. If T is greater than 2, staging is 2. Skip remaining steps.
4. If T is 1, staging is 1. Skip remaining steps.
5. If T is "is" (in situ), staging is 0. Skip remaining steps.
6. Otherwise, the value is T0 N0 M0 which is effectively "no cancer." This has no corresponding staging, so staging is null.

This breaks down as follows:

T	N	M	Staging
T0	N0	M0	null
Tis	N0	M0	0
T1, T2	N0	M0	1
T3, T4	N0	M0	2
(any)	N1, N2, N3	M0	3
(any)	(any)	M1	4