Lymph Node Ratio (LNR)

Parameters:

(1) number of examined lymph nodes

(2) number of lymph nodes containing metastases

lymph node ratio =

= (number of lymph nodes with metastatic tumor) / (number of examined lymph nodes)

Sources of variability:

(1) amount of resected tissue

(2) effort made to find lymph nodes

(3) therapy causing lymphopenia

(4) factors contributing to lymphoid hyperplasia

For a specific site a number of lymph nodes may be given as an indication of an adequate exam.

Interpretation:

• minimum ratio: 0

• maximum ratio: 1

• The lower the ratio the better.