Staging is a way of describing where the cancer is located, if or where it has spread, and whether it is affecting the functions of other organs in the body. Doctors use diagnostic tests to determine the cancer's stage, so staging may not be complete until all tests are finished. Knowing the stage helps the doctor to decide what kind of treatment is best and can help predict a patient's prognosis (chance of recovery). There are different stage descriptions for different types of cancer.
Along with staging, the type of tumor is important for a patient's prognosis. For example, a basal cell carcinoma has a more favorable prognosis than a Merkel cell carcinoma. Staging for eyelid carcinoma includes the following types of tumors:
- Basal cell carcinoma
- Squamous cell carcinoma
- Mucoepidermoid carcinoma
- Sebaceous carcinoma
- Primary eccrine adenocarcinoma
- Primary apocrine adenocarcinoma
- Adenoid cystic carcinoma
- Merkel cell carcinoma
For eyelid melanoma staging, read the melanoma  staging section.
Staging of non-melanoma eyelid carcinoma
One tool that doctors use to describe the stage is the TNM system. This system judges three factors: the tumor itself, the lymph nodes around the tumor, and whether the tumor has spread to other parts of the body. The results are combined to determine the stage of cancer for each person. There are five stages: stage 0 (zero) and stages I through IV (one through four). The stage provides a common way of describing the cancer so doctors can work together to plan the best treatments. Not all doctors may use this staging system for eyelid carcinoma; talk with your doctor for more information about staging.
TNM is an abbreviation for tumor (T), node (N), and metastasis (M). Doctors look at these three factors to determine the stage of cancer:
- How large is the primary tumor and where is it located? (Tumor, T)
- Has the tumor spread to the lymph nodes? (Node, N)
- Has the cancer metastasized to other parts of the body? (Metastasis, M)
Tumor. Using the TNM system, the "T" plus a letter and/or number (0 to 4) is used to describe the stage of eyelid cancer. Some stages are also divided into smaller groups that help describe the tumor in even more detail. This helps the doctor develop the best treatment plan for each patient. Specific tumor stage information is listed below.
TX: The primary tumor cannot be evaluated.
T0 (T plus zero): There is no tumor.
Tis: This refers to carcinoma in situ, which is a tumor that has the potential to invade nearby tissues but hasn't yet.
T1: The tumor is 5 millimeters (mm) or smaller in diameter, or it is not invading the tarsal plate (the supporting structure of the eyelid).
T2a: The tumor is larger than 5 mm but not more than 10 mm in greatest diameter, or it has invaded the tarsal plate.
T2b: The tumor is larger than 10 mm but not more than 20 mm in greatest diameter, or it has spread into the full thickness of the eyelid.
T3a: The tumor is larger than 20 mm in greatest diameter or has spread to nearby parts of the eye.
T3b: The tumor has spread to a point where complete removal of the tumor requires removing the eye and/or adjacent structures.
T4: The tumor cannot be removed with surgery because it has spread extensively.
Node. The “N” in the TNM staging system stands for lymph nodes, the tiny, bean-shaped organs that help fight infection. Lymph nodes near the eyelid are called regional lymph nodes. Lymph nodes in other parts of the body are called distant lymph nodes.
NX: The regional lymph nodes cannot be evaluated.
N0 (N plus zero): There is no regional lymph node metastasis.
N1: There is regional lymph node metastasis.
Distant metastasis. The “M” in the TNM system indicates whether the cancer has spread from the eyelid to other parts of the body.
MX: Distant metastasis cannot be evaluated.
M0 (M plus zero): There is no distant metastasis.
M1: There is metastasis to other parts of the body.
Cancer stage grouping
Doctors assign the stage of the cancer by combining the T, N, and M classifications.
Stage 0: This is carcinoma in situ, meaning the tumor has the potential to be an invasive cancer, but it hasn't become one yet (Tis, N0, M0).
Stage IA: The tumor is 5 mm or smaller in diameter or has not invaded the tarsal plate (the supporting structure of the eyelid), and the tumor has not spread to the regional lymph nodes or to other areas in the body (T1, N0, M0).
Stage IB: The tumor is larger than 5 mm but not more than 10 mm in greatest diameter, or it has invaded the tarsal plate. The tumor has not spread to the regional lymph nodes or to other areas in the body (T2a, N0, M0).
Stage IC: The tumor is between 10 mm and 20 mm in greatest diameter or has spread into the full thickness of the eyelid, but it has not spread to the regional lymph nodes or to other areas in the body (T2b, N0, M0).
Stage II: The tumor is larger than 20 mm in greatest diameter or has spread to nearby parts of the eye, but it has not spread to the regional lymph nodes or to other areas of the body. (T3a, N0, M0).
Stage IIIA: The tumor is large enough or has spread enough so that the surgeon will need to remove the eye and nearby structures to get rid of the tumor, but it has not spread to the regional lymph nodes or to other areas of the body (T3b, N0, M0).
Stage IIIB: The tumor is of any size and has spread to the regional lymph nodes, but not to other areas of the body (any T, N1, M0).
Stage IIIC: The tumor has spread outside of the eye, with or without spread to the regional lymph nodes, and cannot be surgically removed due to extensive invasion in structures near the eye. The tumor has not spread to distant parts of the body (T4, any N, M0).
Stage IV: A tumor of any size has spread outside of the eye to distant areas of the body (any T, any N, M1).
Histopathology and grading
Histology describes how closely the cancer cells resemble normal tissue under a microscope. A tumor's grade is described using the letter G and a number.
GX: The tumor grade cannot be identified.
G1: Describes cells that look more like normal tissue cells (well differentiated).
G2: Describes cells that look somewhat different from normal cells (moderately differentiated).
G3: Describes tumor cells that look very much unlike normal cells (poorly differentiated).
G4: The tumor cells barely resemble normal cells (undifferentiated).
Recurrent: Recurrent cancer is cancer that comes back after treatment. It may return in the eye or another part of the body. If there is a recurrence, the cancer may need to be staged again (called re-staging) using the system above.
Used with permission of the American Joint Committee on Cancer (AJCC), Chicago, Illinois. The original source for this material is the AJCC Cancer Staging Manual, Seventh Edition(2010) published by Springer-Verlag New York, www.cancerstaging.net .