The NPI status was 1st published about 1992 as an attempt at using some fairly objective parameters to determine the odds that a newly diagnosed case of invasive ductal adenocarcinoma would benefit from adjuvant chemotherapy. By whatever means, the status of the axillary lymph nodes must be determined at least as to whether any nodes are positive for metastatic cancer (ALN+) or negative (ALN-). If any positive nodes, more details are needed. The studies looked at "overall survival" (OS) at 15 years post diagnosis. This grouping is just an initial categorization; many other patient-specific factors are taken together to make a final decision.

Decisions may have to be made prior to having the whole tumor out and size-measurable. By whatever measure, the following are the criteria for assignment of size points (such are finally, ultimately, assigned from the pathology tissue studies):

• maximum tumor size in centimeters:_____________times 0.2=________points.

• from 1 (better) to 3 (worse), by whatever system, the tumor grade=___________points

Use one of the following scoring methods:

• Classical scoring system:
  • negative nodes..............................................................................1 point
  • positive nodes, low axillary only..........................................2 points
  • positive nodes, internal mammary only..............................2 points
  • positive nodes, axillary plus internal mammary............3 points
  • positive nodes, apical axillary node positivity...............3 points
• Alternative scoring system:
  • negative nodes...............................................................................1 point
  • positive nodes, 1 to 3 positive..............................................2 points
  • positive nodes, 4 or more.........................................................3 points