MACIS calculator

The most common system used to describe the stages of cancers is the American Joint Committee on Cancer (AJCC) TNM system. The TNM system describes 3 key pieces of information:

  • T indicates the size of the main (primary) tumor and whether it has grown into nearby areas.
  • N describes the extent of spread to nearby (regional) lymph nodes.
  • M indicates whether the cancer has metastasized to other organs of the body. (The most common site of spread of thyroid cancer is to the lungs. The next most common sites are the liver and bones.)

T CATEGORIES FOR THYROID CANCER

TX: Primary tumor cannot be assessed

T0: No evidence of primary tumor

T1: The tumor is 2 cm across or smaller

T2: Tumor is between 2 cm and 4 cm across

T3: Tumor is larger than 4 cm or has begun to grow into nearby tissues outside the thyroid

T4a: Tumor of any size and has grown extensively beyond the thyroid gland into nearby tissues of the neck

T4b: Tumor has grown either back toward the spine or into nearby large blood vessels

T CATEGORIES FOR ANAPLASTIC THYROID CANCERS:

T4a: Tumor is still within the thyroid and may be resectable (removable by surgery)

T4b: Tumor has grown outside of the thyroid and is not resectable

N CATEGORIES FOR THYROID CANCER:

NX: Regional lymph nodes cannot be assessed

N0: No spread to nearby lymph nodes

N1: Spread to nearby lymph nodes

N1a: Spread to lymph nodes around the thyroid in the neck

N1b: Spread to lymph nodes in the sides of the neck (lateral cervical) or the upper chest (upper mediastinal)

M CATEGORIES FOR THYROID CANCER:

MX: Presence of distant metastasis cannot be assessed

M0: No distant metastasis

M1: Distant metastasis is present, involving distant lymph nodes, internal organs, bones, etc.

STAGING FOR FOLLICULAR THYROID CANCER (FTC) AND PAPILLARY THYROID CANCER (PTC)

PATIENTS YOUNGER THAN 45 YEARS:

Stage I (any T, any N, M0): The tumor can be any size and may or may not have spread to nearby lymph nodes. It has not spread to distant sites.

Stage II (any T, any N, M1): The tumor can be any size and may or may not have spread to nearby lymph nodes. It has spread to distant sites.

PATIENTS 45 YEARS AND OLDER:

Stage I (T1, N0, M0): The tumor is less than 2 cm across and has not spread to nearby lymph nodes or distant sites.

Stage II (T2, N0, M0): The tumor is 2 to 4 cm across and has not spread to nearby lymph nodes or distant sites.

Stage III (T3, N0, M0 or T1 to T3, N1a, M0): One of the following applies:

  • The tumor is larger than 4 cm or has grown slightly outside the thyroid, but it has not spread to nearby lymph nodes or distant sites.
  • The tumor is any size and has spread to lymph nodes around the thyroid in the neck (cervical nodes) but not to distant sites.

Stage IVA (T4a, N0 to N1a, M0 or T1 to T4, N1b, M0): One of the following applies:

  • The tumor is any size and has grown beyond the thyroid gland to invade nearby tissues of the neck. It may or may not have spread to lymph nodes around the thyroid in the neck (cervical nodes). It has not spread to distant sites.
  • The tumor is any size and may have grown outside the thyroid gland. It has spread to lymph nodes in the side of the neck (lateral cervical nodes) or upper chest (upper mediastinal nodes) but not to distant sites.

Stage IVB (T4b, any N, M0): The tumor is any size and has grown either back to the spine or into nearby large blood vessels. It may or may not have spread to nearby lymph nodes, but it has not spread to distant sites.

Stage IVC (any T, any N, M1): The tumor is any size and may or may not have grown outside the thyroid. It may or may not have spread to nearby lymph nodes. It has spread to distant sites.

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