Thyroid cancer stages

The article was written by Specialist Doctor I Nguyen Thi Minh Thuyen - Pathologist, Laboratory Department - Vinmec Danang International General Hospital.

After a person is diagnosed with thyroid cancer, doctors try to find out if it has spread, and if so, how far. This process, called staging, helps determine the severity of the cancer and the best treatment.
Thyroid cancer is graded from stage I (1) to IV (4). As a rule, the smaller the number, the less the cancer has spread. In the same period, the preceding letter means the lower stage. Although cancers are individualized, cancers with similar stages often have a similar prognosis and are often treated in a similar manner.

The commonly used staging system for thyroid cancer is the AJCC (American Cancer Commission) TNM system, which is based on 3 key pieces of information:
Spread (size) of the tumor (T - tumor ): How big is the cancer? Has it grown to nearby structures? Spread to nearby lymph nodes ( N - lymph nodes ): Has the cancer spread to nearby lymph nodes? Spread (metastasis) to distant sites (M - metastatis): Has the cancer spread to distant organs such as the lungs or liver? These are the latest AJCC systems that came into effect in January 2018 and apply to differentiated, undifferentiated, and myeloid thyroid cancers.
The numbers or letters after T, N and M provide more details about this information. A higher number means the cancer is more advanced. Once the T, N and M parameters are determined, they are combined to define an overall period.
>>> Defines how to stage cancer according to the TNM system
The staging system in the table below uses the pathological stage (also known as the surgical stage). It is determined by examining the surgically removed tissue.
Sometimes, if immediate or complete surgery is not possible, a clinical staging will be substituted, based on a physical exam, biopsy results, and imaging tests. Clinical staging will be used to help plan treatment. Sometimes, however, the cancer has spread more than estimated by the clinical stage and may not predict the patient's prognosis as accurately as the pathological stage.
Cancer staging can be complicated, so ask your doctor to explain it to you in a way you can understand.

Young patients have a low mortality rate from differentiated thyroid cancer (papillary or follicular). Therefore, all patients under 55 years of age with this type of cancer are in stage I if no distant metastasis and stage II if distant metastasis is present.
1. Phase I 1.1. Patient younger than 55 years T any N M0
Any tumor size (any T) ​​With or without spread to adjacent lymph nodes (any N) No spread to distant organs (M0 ) 1.2. Patients 55 years of age or older ●T1 N0/Nx M0
Tumor no larger than 2cm (0.8 inch) and limited to thyroid gland (T1) Has not spread to nearby lymph nodes (N0) Has not spread to other sites distal (M0) Or
T2 N0/Nx M0
Tumor larger than 2cm (0.8 inch) but not more than 4 cm and limited to thyroid gland (T2) Has not spread to nearby lymph nodes (N0) Has not spread to distant locations (M0) 2. Phase II 2.1. Patient younger than 55 years any N any M1
U of any size (any T) ​​With or without spread to adjacent lymph nodes (any N) Has spread to other parts of the body body, such as distant lymph nodes, internal organs, bones,... (M1) 2.2. Patient 55 years of age or older ● T1 N1 M0
Tumor not larger than 2cm (0.8 inch) and limited to thyroid gland (T1) Has spread to adjacent lymph nodes (N1) Has not spread to distant organs ( M0) Or
T2 N1 M0
Tumor larger than 2cm (0.8 inch) but not more than 4cm and limited to thyroid gland (T2) Has spread to nearby lymph nodes (N1) Has not spread to distant organs (M0) Or
T3a/T3b N any M0
Tumor larger than 4cm but limited to thyroid gland (T3a) or invade perithyroid muscle bundles (T3b) With or without spread to lymph nodes adjacent (any N) Has not spread to distant organs (M0) 3. Stage 3: for patients 55 years of age or older ●T4a N any M0
U of any size and has grown extensively extrathyroidal to adjacent tissues in the neck, such as the larynx, trachea, esophagus, or laryngeal nerve (T4a) With or without spread to adjacent lymph nodes (any N) Has not spread to other tissues distal organs (M0) 4. Stage 4: for patients 55 years of age or older ● Stage IVA: T4b N any M0
U Any size and has extended beyond the thyroid gland toward the spine or into nearby large blood vessels (T4b) With or without spread to adjacent lymph nodes (any N) Has not spread to distant organs (M0) Stage IVB: any T any N M1
U of any size (any T) ​​With or without spread to adjacent lymph nodes (any N) Has spread to other organs of the body, such as distant lymph nodes, internal organs, bones, etc. (M1)

All undifferentiated thyroid cancers are considered stage IV, reflecting a poor prognosis for this type of cancer.
Stage IVA: T1/T2/T3a N0/Nx M0 U tumor of any size but limited to thyroid gland (T1, T2 or T3a) Has not spread to nearby lymph nodes (N0) Has not spread to other lymph nodes Distant location (M0) Stage IVB: T1/T2/T3a N1 M0 U of any size but limited to thyroid gland (T1, T2 or T3a) Has spread to nearby lymph nodes (N1) No spread to distant organs (M0) Or any T3b N M0
U of any size and has invaded perithyroid muscle bundles (T3b) With or without spread to adjacent lymph nodes (N any ) Has not spread to distant organs (M0) Or any T4 N M0
U of any size and has grown beyond the thyroid gland into adjacent tissues in the neck, such as the larynx, trachea, esophagus, laryngeal nerve or larynx, or invades the spinal side or into nearby large blood vessels (T4) May or may not spread to adjacent lymph nodes (any N) Has not spread to distant organs (T4) M0) IVC stage: any T any N M1 U of any size (any T) ​​With or without spreading to nearby lymph nodes (any N) Has spread to other parts of the body, such as distant lymph nodes, internal organs, bones,.. (M1)

Age is not a factor in the staging of medullary thyroid cancer.
1. Stage I T1 N0 M0 Tumor less than or equal to 2cm (0.8 inch) and limited to thyroid gland (T1) Has not spread to nearby lymph nodes (N0) Has not spread to organs (M0) 2 Stage II T2 N0 M0 The tumor is larger than 2cm but not more than 4cm and confined to the thyroid gland (T2) Has not spread to nearby lymph nodes (N0) Has not spread to distant organs (M0) Or
T3 N0 M0 Tumor larger than 4 cm and confined to thyroid gland or any size that invades beyond the thyroid gland but does not involve adjacent structures (T3) Has not spread to adjacent lymph nodes (N0) No spread to distant organs (M0) 3. Stage III T1/T2/T3 N1a M0 The tumor is of any size and may invade beyond the thyroid gland but does not involve adjacent structures (T1, T2). , T3) Has spread to lymph nodes in the neck (paratracheal, peritracheal, pre-laryngeal, or superior mediastinum) (N1a) Has not spread to distant lymph nodes or distant organs (M0) 4 Stage IV IVA: T4a N any M0 U of any size and has grown r Extends beyond the thyroid gland into adjacent tissues in the neck, such as the larynx, trachea, esophagus, or laryngeal nerve (T4a) With or without spread to adjacent lymph nodes (any N) No to distant organs (M0). Or T1/T2/T3 N1b M0
The tumor is any size and may grow outside of the thyroid gland but does not involve adjacent structures (T1, T2, T3) Has spread to several lymph nodes in neck such as cervical or jugular lymph nodes (N1b) Has not spread to distant organs (M0) IVB: T4b N any M0 U is of any size and has invaded the spine or proximal large blood vessels there (T4b) With or without spread to adjacent lymph nodes (any N) No spread to distant organs (M0) IVC: any T any M1 U of any size and may have invaded Involved in adjacent structures (any T) ​​With or without spread to adjacent lymph nodes (any N) Has spread to distant organs such as liver, lung, bone, or brain (M1) Additional information The following are not listed in the above categories:
Tx : Primary tumor cannot be assessed due to lack of information.
T0 : No evidence of primary tumor.
Nx : Regional lymph nodes cannot be assessed due to lack of information.
When we notice abnormalities in the body, we need to go to the doctor immediately, have a general examination as well as a specialist to detect the disease as soon as possible. Doctors recommend that we go for a regular check-up once a year to understand our health status, as well as have a direction to screen for early treatment.
For thyroid cancer, we need to perform subclinical diagnostic methods such as thyroid ultrasound, cytological diagnostic tests to detect thyroid cancer.

Article referenced source: American Cancer Society