Endocrine > Thyroid > Neoplasms

Staging Criteria for Thyroid Cancer

[Radiology 2008; Donahue KP, et al. Initial staging of differentiated thyroid carcinoma: continued utility of posttherapy ¹³¹I whole-body scintigraphy. 246: 887-894]

Age and Stage	Size	Location	Metastases	Survival % Papillary	Survival % Follicular
Under 45 years			0
I	Any	Any	0	97	95
II	Any	Any	(+)	93	90
≥ 45 years
I	Less than 2 cm	0	0	97	95
II	2-4 cm	0	0	93	90
III	Any size	Spread to nodes around the thyroid- prelaryngeal and or Delphian pre and or paratracheal nodes (N1a)	0	83	69
	Tumor larger than 4 cm	0	0
IVa	Any size	Spread to nodes lateral cervical or superior mediastinal nodes (N1b)	0
	Any size tumor with local invasion into subcutaneous soft tissues, larynx, trachea, esophagus, or recurrent laryngeal nerves	0	0
IVb	Tumor invades mediastinum or prevertebral fascia or encases carotid artery	Any	0	39	41
IVc	Any	Any	(+)

TNM Classification System for Differentiated Thyroid Cancer

[AJR 2009; Park JS, et al. Performance of preoperative sonographic staging of papillary thyroid carcinoma based on the sixth edition of the AJCC/UICC TNM classification system. 192: 66-72]

Category	Description
Tx	Primary tumor cannot be assessed
T0	No evidence of primary tumor
T1	Tumor is ≤ 2cm in greatest dimension and is limited to the thyroid; T1a 1cm, but ≤ 2cm
T2	Tumor is >2 cm but ≤ 4cm in greatest dimension and is limited to the thyroid
T3	Tumor is > 4 cm in greatest dimension and limited to the thyroid or any tumor with minimal extrathyroid extension such as extension to the sternothyroid muscle or perithyroid soft tissues
T4a	Tumor of any size extends beyond the thyroid capsule to invade subcutaneous tissues, larynx, trachea, esophagus, or recurrent laryngeal nerve
T4b	Tumor invades prevertebral fascia or encases carotid artery or mediastinal vessels
Nx	Regional lymph nodes cannot be assessed
N0	No regional lymph node mets
N1a	Metastases to level VI (pretracheal, paratracheal, and prelaryngeal or Delphian nodes)
N1b	Metastases to unilateral or bilateral cervical or superior mediastinal lymph nodes
Mx	Distant metastases cannot be assessed
M0	No distant metastases
M1	Distant metastases

TNM Staging System [From: J Nucl Med 2012; Avram AM. Radioiodine scintigraphy with SPECT/CT: an important diagnostic tool for thyroid cancer staging and risk stratification. 53: 754-764]

Patients under 45 years of age

Stage	T	N	M
Stage I	Any T	Any N	M0
Stage II	Any T	Any N	M1

Patients 45 years or older

Stage	T	N	M
Stage I	T1	N0	M0
Stage II	T2	N0	M0
Stage III	T3 T1/T2/T3	N0 N1a	M0 M0
Stage IVA	T1/T2/T3 T4a	N1b Any N	M0 M0
Stage IVB	T4b	Any N	M0
Stage IVC	Any T	Any N	M1

Thyroid Cancer Risk Assessment

	ATA	Thyroid Cancer Risk Stratification
Very low risk		Unifocal or multifocal microcarcinomas (< 1cm)
		MACIS score < 6, or TNM score: T1?2, N0, M0 (MACIS= (metastases, Age, Completeness of resection, invasiveness, size of tumor, staging system devloped at the Mayo Clinic)
		In patients < 45 years old: tumors < 4 cm confined to the thyroid
		Excludes tumors with aggressive histology* (tall cell, insular, columnar, diffuse sclerosing, trabecular solid, poorly differentiated variants of papillary carcinoma, Hurthle cell variant of follicular thyroid carcinoma) or vascular invasion
Low-risk (all criteria must be met)		In patients < 45 years old: MACIS < 6, or TNM score: any T any N, M0
		In patients ≥ 45 years old: MACIS < 6, or TNM score: T2, N0, M0
	√	No local or distant metastases
	√	All macroscopic tumor has been resected
	√	There is no tumor invasion of locoregional tissues or structures
	√	The tumor does not have aggressive histology* or vascular invasion
	√	If 131I is given, there is no 131I uptake outside the thyroid bed on the first post-therapy scan
Intermediate/Moderate risk (any criteria)		In patients < 45 years old: tumors > 4 cm; macroscopic (> 1cm) N1a or N1b; T1?3, N1b, M0
		In patients ≥ 45 years old: T3, N0, M0 or T1?3, N1a, M0
		MACIS score > 6
		Minimally invasive (microscopic capsular, but not vascular invasion) FTC < 4 cm
	√	Tumor with aggressive histology* or vascular invasion
	√	Microscopic invasion of tumor into the perithyroidal soft tissues at initial surgery
	√	Cervical lymph node metastases, or 131I uptake outside the thyroid bed on the post-therapy scan
High-risk (any criteria)		In patients < 45 years old: T4a?4b, any N, M0, or any T, any N, M1
		In patients ≥ 45 years old: any T, N1a?1b, M0, AJCC Stages IVA, IVB, IVC
		FTC > 4 cm, or macroscopic invasive FTC
	√	Distant metastases
	√	Macroscopic tumor invasion
	√	Incomplete tumor resection
	√	Thyroglobulinemia out of proportion to what is seen on the post-therapy scan