Collaborative Stage

Note 1: Code only regional nodes and nodes, NOS, in this field. Distant nodes are coded in the field Mets at DX.
Note 2: In-transit metastasis is defined as a tumor distinct from the primary lesion and located either between the primary lesion and the draining regional lymph nodes or distal to the primary lesion. In-transit metastasis is coded in the CS Lymph Nodes field.
Note 3: According to AJCC, "there is no lower threshold of tumor burden defining the presence of regional nodal metastasis. Specifically, nodal tumor deposits less than 0.2 mm in diameter (previously used as the threshold for defining nodal metastasis), are included in the staging of nodal disease as a result of the consensus that smaller volumes of metastatic tumor are still clinically significant". This means that any finding of Merkel cell carcinoma in lymph nodes, regardless of size and including isolated tumor cells (ITCs), should be coded positive lymph nodes in this field.

^ For codes 100, 200, 300, 400, 500 and 800 ONLY, the N category for AJCC 7th Edition is assigned based on the value of Site-Specific Factor 3, Clinical Status of Lymph Node Mets, as shown in the CS Lymph Nodes and Clinical Status table.

Code	Description	TNM 7 Map	TNM 6 Map	SS77 Map	SS2000 Map
000	None; no regional lymph node involvement	N0	N0	NONE	NONE
100	Regional lymph nodes Iliac, NOS: External Internal (hypogastric), NOS: Obturator Inguinal, NOS: Deep inguinal, NOS Node of Cloquet or Rosenmuller (highest deep inguinal) Superficial inguinal (femoral) Regional lymph node(s), NOS	^	N1	RN	RN
320	Stated as N1a with no other information on regional lymph nodes	N1a	N1	RN	RN
340	Stated as N1b with no other information on regional lymph nodes	N1b	N1	RN	RN
360	Stated as N1 [NOS] with no other information on regional lymph nodes	N1NOS	N1	RN	RN
400	In-transit metastasis WITHOUT regional lymph node involvement or involvement of regional lymph nodes not stated (see Note 2)	N2	N1	RN	RN
420	400 + 100 In-transit metastasis WITH regional lymph nodes listed in code 100 (see Note 2)	N2	N1	RN	RN
800	Lymph nodes, NOS	^	N1	RN	RN
999	Unknown; not stated Regional lymph node(s) cannot be assessed Not documented in patient record	NX	NX	U	U

CS Lymph Nodes