Collaborative Stage

Note 1: Use codes 000-009 only to report results of IHC on otherwise histologically negative or that have only ITCs on routine H and E stains., i.e., only when CS Lymph Nodes is coded 000. Otherwise code 987 in this field.
Note 2: Isolated tumor cells (ITC) are defined as single tumor cells or small clusters not greater than 0.2 mm, usually detected by immunohistochemical (IHC), H and E (see code 050 of CS Lymph Nodes), or molecular methods (RT-PCR: Reverse Transcriptase Polymerase Chain Reaction) (see CS Site-Specific Factor 5). ITCs do not usually show evidence of malignant activity (e.g., proliferation or stromal reaction.) If both IHC and H and E report positive ITC findings, record as 002 or 009 depending on whether size of clusters was given.
Note 3: If it is unstated whether or not tests were done for IHC assume they were not done.
Note 4: If the record states N0(i+) and no other information, code to 009.

Code	Description
000	Regional lymph nodes negative on routine H and E, no IHC studies or Unknown if tested for ITCs by IHC studies Nodes clinically negative, not examined pathologically
001	Regional lymph nodes negative on routine H and E, IHC studies done, negative for tumor
002	Regional lymph nodes negative on routine H and E, IHC studies done, positive for ITCs (tumor cell clusters not greater than 0.2mm)
009	Regional lymph nodes negative on routine H and E, positive for tumor detected by IHC, size of tumor cell clusters or metastases not stated; stated as N0(i+) with no further information
888	OBSOLETE DATA CONVERTED V0200 See code 987 Not applicable CS Lymph Nodes not coded 000
987	Not applicable CS Lymph Nodes not coded 000

CS Site-Specific Factor 4
Immunohistochemistry (IHC) of Regional Lymph Nodes