Nucleus Fibrotic Focus Fat Invasion (NNF) Classification of Hasebe et al for Invasive Ductal Carcinoma of the Breast

 

Parameters:

(1) nuclear atypia

(2) fibrotic focus (area of sclerosis)

(3) extramammary fat invasion (This refers to the fat surrounding breast ducts, lobules and stroma.)

Parameter	Finding	Points
nuclear atypia	mild (Grade I) or moderate (Grade II)	0
	marked (Grade III)	1
fibrotic focus	absent	0
	present	1
extramammary fat invasion	none or <= 2 mm	0
	> 2 mm	1

 

where:

• The depth of fat invasion is the distance between the edge of the "mammary tissue" and the furthest edge of advancing tumor. The points chosen for the "mammary tissue" margin could vary between observers.

 

NNF score =

= SUM(points for all 3 parameters)

 

Interpretation:

• minimum score: 0

• maximum score: 3

• The higher the NNF score, the greater the chance for recurrence, the shorter the disease free survival and the worse the survival.

 

NNF Score	5 Year Disease Free Survival	5 Year Survival Rate
0 or 1	83%	97%
2	60%	79%
3	31%	64%

from Figure 6, page 1365, with 5 years = 1825 days

 

Other high risk factors associated with tumor recurrence:

(1) tumor size > 20 mm

(2) > 3 lymph nodes with metastases

(3) presence of skin invasion