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Integrating tumor size and number of positive nodes into estimates of death
(the Size+Nodes method)

Using the statistical-mechanical model of cancer metastasis, we have been able to derive equations that capture the relationships between tumor size, nodal status, and cancer lethality. These methods revealed that for breast carcinoma, each positive node has been found to contribute ~6% risk of death while each millimeter of primary tumor diameter contributes ~1% risk of death. For melanoma, each positive node has been found to contribute ~23% risk of death while each millimeter of primary melanoma thickness contributes ~8% risk of death. This information is captured by a pair of linked equations, the Size+Nodes method, which has been found to accurately predict the chance of melanoma and breast cancer death, and to stratify these patients on the basis of their risk of death.

When both tumor size and nodal status are known, the Size+Nodes equation estimates the risk of cancer death from information on tumor size and nodal status:
Source of Lethality	Method of Estimation	Independent Variable	Parameters	Interpretation
The lethal contribution from cancer at the primary site directly to the periphery		= tumor size: For breast carcinoma: diameter (mm) For melanoma: thickness (mm)	For breast carcinoma: =0.0062 =1.34 =0.661 if nodal status is known; =1 if nodal status is unknown For melanoma: =0.1428 =0.89 =0.801 if nodal status is known; =1 if nodal status is unknown	The lethal contribution of the primary mass increases gradually with tumor size.
The lethal contribution from cancer in the lymph nodes		= the number of positive nodes	For breast carcinoma: =0.0608 For melanoma: =0.22527	The presence of each positive lymph node contributes approximately "" extra chance of death.

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