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Combining tumor size, nodal status, and other prognostic factors into predictions of death
(the Size+Nodes+PrognosticFactors [SNP] method)

The SNP (Size+Nodes+PrognosticMarkers) method for estimating the risk of cancer death from information on tumor size, nodal status, and other prognostic factors:
Source of Lethality Method of Estimation Independent Variable Parameters Interpretation
The lethal contribution from cancer at the primary site = 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 complete list of parameters, see technical reports.

For melanoma:
=0.1428
=0.89
=0.801 if nodal status is known;
=1 if nodal status is unknown
=1.206 if male;
=0.771 if female
=1.229 if ulcerated;
=0.887 if not ulcerated;
=1 if ulceration 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.
The SNP (Size+Nodes+PrognosticMarkers) method reduces to:
  • the Size+Nodes method, when only size and nodal status are known.
  • the SizeOnly method, when only size is known.

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