CS Extension

Notes

**Note 1**: AJCC considers all anaplastic carcinomas to be T4. **Note 2**: AJCC considers "in situ carcinoma of thyroid gland" an impossible diagnosis. Any case so coded is mapped to TX for AJCC stage and in situ Summary Stage. **Note 3**: The assignment of T1 and T2 categories for carcinoma of the thyroid is based on tumor size. A physician's statement of the T category may be used to code both CS Tumor Size and/or CS Extension if this is the only information in the medical record regarding one or both of these fields. However the two fields are coded independently; for example, the record may document size but not extension. Use codes 405, 410, 415, 420, 490, 560, 810, and 815 as appropriate to code CS Extension based on a statement of T when no other extension information is available. **Note 4**: Use code 300 for localized tumor only if no information is available to assign codes 100, 200, 400, 405, 410, 415, 420, or 490. **Note 5**: Extension codes 405, 410, 415, 420, and 490 are not compatible with anaplastic carcinomas of the thyroid.

Code	Description	AJCC 7 T	AJCC 6 T	Summary Stage 1977 T	Summary Stage 2000 T
000	In situ, intraepithelial, noninvasive	Determine Correct Table for T	Determine Correct Table for T	IS	IS
100	Single invasive tumor confined to thyroid	Determine Correct Table for T	Determine Correct Table for T	L	L
200	Multiple foci confined to thyroid	Determine Correct Table for T	Determine Correct Table for T	L	L
300	Localized, NOS	Determine Correct Table for T	Determine Correct Table for T	L	L
400	Into thyroid capsule, but not beyond	Determine Correct Table for T	Determine Correct Table for T	L	L
405	Stated as T1a with no other information on extension	Determine Correct Table for T	Determine Correct Table for T	L	L
410	Stated as T1b with no other information on extension	Determine Correct Table for T	Determine Correct Table for T	L	L
415	Stated as T1 [NOS] with no other information on extension	Determine Correct Table for T	Determine Correct Table for T	L	L
420	Stated as T2 with no other information on extension	Determine Correct Table for T	Determine Correct Table for T	L	L
450	Minimal extrathyroid extension including: Strap muscle(s): Omohyoid Sternohyoid Sternothyroid Thyrohyoid	Determine Correct Table for T	Determine Correct Table for T	RE	RE
480	Pericapsular soft tissue/connective tissue	Determine Correct Table for T	Determine Correct Table for T	RE	RE
490	Stated as T3 with no other information on extension	Determine Correct Table for T	Determine Correct Table for T	L	L
500	Parathyroid Nerves: Recurrent laryngeal Vagus	Determine Correct Table for T	Determine Correct Table for T	RE	RE
520	Cricoid cartilage Esophagus Larynx Sternocleidomastoid muscle	Determine Correct Table for T	Determine Correct Table for T	RE	RE
550	Trachea	Determine Correct Table for T	Determine Correct Table for T	D	D
560	Stated as T4a with no other information on extension	Extension T4 SSF1 AJCC7	T4a	Histology Grade Extension Summary Stage	Histology Grade Extension Summary Stage
600	Thyroid cartilage Tumor described as "FIXED to adjacent tissues"	Extension T4 SSF1 AJCC7	T4b	RE	RE
620	Blood vessel(s) (major): Carotid artery (encased) Jugular vein Thyroid artery or vein	Extension T4 SSF1 AJCC7	T4b	RE	RE
650	(600 or 620) + 550 Any structures in code 600 or 620 plus trachea	Extension T4 SSF1 AJCC7	T4b	D	D
700	Bone Skeletal muscle, other than strap or sternocleidomastoid muscle	Extension T4 SSF1 AJCC7	T4b	D	D
720	OBSOLETE DATA CONVERTED V0200 See code 550 Trachea	ERROR:	ERROR:	ERROR:	ERROR:
730	700 + 550 Any structures in code 700 plus trachea	Extension T4 SSF1 AJCC7	T4b	D	D
800	Further contiguous extension including: Mediastinal tissues Prevertebral fascia	Extension T4 SSF1 AJCC7	T4b	D	D
810	Stated as T4b with no other information on extension	Extension T4 SSF1 AJCC7	T4b	D	D
815	Stated as T4 [NOS] with no other information on extension	Extension T4 SSF1 AJCC7	T4NOS	RE	RE
950	No evidence of primary tumor	Determine Correct Table for T	Determine Correct Table for T	U	U
999	Unknown; extension not stated Primary tumor cannot be assessed Not documented in patient record	Determine Correct Table for T	Determine Correct Table for T	U	U

- For CS Extension codes 000, 100-550, 950, and 999 ONLY, the T category for AJCC 7 staging is assigned based on the value of CS Tumor Size and/or CS Extension and CS Site-Specific Factor 1 as shown in the Extension Size SSF 1 AJCC 7 Table for all histologies except 8020, 8021, 8030, 8031, and 8032, or any other histology with grade equal to 4. For these histologies or grade 4, the T category for AJCC 7 staging is assigned based on the value of CS Extension and CS Site-Specific Factor 1 as shown in the Histology Grade Extension SSF 1 AJCC 7 Table. - For CS Extension codes 560-700 and 730-815 ONLY, the T category for AJCC 7 staging is assigned based on the value of CS Extension and CS Site-Specific Factor 1 as shown in the Extension T4 SSF 1 AJCC 7 Table. - For CS Extension codes 000, 100-550, 950, and 999 ONLY, the T category for AJCC 6 staging is assigned based on the value of CS Tumor Size and/or CS Extension as shown in the Extension Size AJCC 6 Table for all histologies except 8020, 8021, 8030, 8031, and 8032, or any other histology with grade equal to 4. For these histologies or grade 4, the T category for AJCC 6 staging is assigned based on the value of CS Extension as shown in the Histology Grade Extension AJCC 6 Table. - For CS Extension code 560 ONLY, the value for SS1977 and SS2000 is assigned based on the value of histology and grade as shown in the Histology Grade Extension Summary Stage Table.