The stages of eye cancer help determine the tumor’s location and metastasis. The staging system of eyelid cancer uses diagnostic tests. A TNM staging system is used to identify the different stages of eyelid cancer. There are four stages of eye cancer – stages I through IV (one through four). Cancer’s grade helps the doctor predict how quickly cancer will spread. In general, the lower the tumor’s grade, the better the prognosis. Along with staging, the type of tumor is essential for a patient’s prognosis. Staging for eyelid carcinoma includes melanoma, basal cell carcinoma, squamous cell carcinoma, mucoepidermoid carcinoma, sebaceous carcinoma, primary eccrine adenocarcinoma, primary apocrine adenocarcinoma, adenoid cystic carcinoma, and merkel cell carcinoma. The eyelid tumors are given a grade (G) to describe the composition of their cells involving GX, G1, G2, and G3. Staging of eyelid cancer includes four stages involving stage I (IA, IB, IC), stage II, stage III (IIIA, IIIB, IIIC), and stage IV. The recurrent stage of eyelid cancer is the stage that comes back after treatment.
Stages of Eyelid Cancer
Staging is the procedure of determining where the tumor is located, whether it has spread or not, and how it grows. While assessing the eyelid cancer stages, many factors are taken into account.
Doctors use diagnostic tests to discover eyelid cancer stages, so staging may not be complete until all tests are finished.
Along with staging, the type of tumor is essential for a patient’s prognosis. For instance, a basal cell carcinoma has a more favourable prognosis than a Merkel cell carcinoma. Staging for eyelid carcinoma includes the following types of tumors 1:
- Basal cell carcinoma
- Squamous cell carcinoma
- Mucoepidermoid carcinoma
- Sebaceous carcinoma
- Primary eccrine adenocarcinoma
- Primary apocrine adenocarcinoma
- Adenoid cystic carcinoma
- Merkel cell carcinoma
Staging of Non- melanoma eyelid cancer
The TNM system is the tool doctors use to describe the stage of Eyelid cancer.
- T is for tumour – How large the tumour is and where is its location
- N is for nodes – Has cancer spread to lymph nodes, and if so, where and how many?
- M is for metastasis – Whether cancer has metastasized to other parts of the body.
There are five stages of eyelid cancer – stage 0 and stages I through IV (one through four) 2.
TX- The primary tumour cannot be evaluated.
T0 (T plus zero) –There is no tumour.
Tis – This refers to carcinoma in situ, which is a tumour that can invade nearby tissues but hasn’t yet.
T1 – The tumour is 5 millimetres (mm) or smaller in diameter, or it is not invading the tarsal plate, the supporting structure of the eyelid.
T2a – The tumour is larger than 5 mm but not more than 10 mm in greatest diameter, or it has invaded the tarsal plate.
T2b – The tumour is larger than 10 mm but not more than 20 mm in greatest diameter, or it has spread into the total thickness of the eyelid.
T3a – The tumour is larger than 20 mm in greatest diameter or has spread to nearby parts of the eye.
T3b – The tumour has spread to a point where complete removal of the tumour requires removing the eye or adjacent structures.
T4 – The tumour cannot be removed with surgery because it has spread extensively.
The ‘N’ in the TNM staging system represents lymph nodes, the tiny, bean-shaped organs that help fight infection. Lymph nodes near the eyelid are the regional lymph nodes. Lymph nodes present in other body parts 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.
The ‘M’ in the TNM system indicates whether cancer has spread from the eyelid to other parts of the body, called distant metastasis.
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.
Doctors describe eyelid cancer by its grade (G), which tells how much cancer cells look like healthy cells when viewed using a microscope. The doctor compares the cancerous tissue with healthy tissue. Healthy tissue contains various types of cells grouped.
If cancer looks similar to healthy tissue and contains different cell groupings, it is differentiated or low-grade tumours. If the cancerous tissue looks much different from healthy tissue, it is poorly differentiated or a high-grade tumour.
Eyelid cancer grade helps the doctor predict how quickly cancer will spread. In general, the lower the tumour’s grade, the better the prognosis.
GX – The eyelid cancer grade cannot be identified.
G1 – Describes cells that look more like healthy tissue cells (well-differentiated).
G2 – Describes cells that look somewhat different from healthy cells (moderately differentiated).
G3 – Describes tumour cells that look very unlike healthy cells (poorly differentiated).
G4- The tumour cells barely resemble healthy cells (undifferentiated).
Eyelid Cancer stages grouping
Doctors assign the cancer stage by combining the T, N, M, and G classifications.
Stage 0 – This is carcinoma in situ, meaning the tumour has the potential to be invasive cancer, but it hasn’t become one yet (Tis, N0, M0).
Stage IA – The tumour is 5 mm or smaller in diameter or has not invaded the tarsal plate (the supporting structure of the eyelid). The tumour has not spread to the regional lymph nodes or other areas in the body (T1, N0, M0).
Stage IB – The tumour is larger than 5 mm but not more than 10 mm in greatest diameter, or it has invaded the tarsal plate. The tumour has not spread to the regional lymph nodes or other areas in the body (T2a, N0, M0).
Stage IC – The tumour is between 10 mm and 20 mm in greatest diameter or has spread into the total thickness of the eyelid, but it has not spread to the regional lymph nodes or other areas in the body (T2b, N0, M0).
Stage II – The tumour 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 other areas of the body. (T3a, N0, M0).
Stage IIIA- The tumour 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 tumour, but it has not spread to the regional lymph nodes or other areas of the body (T3b, N0, M0).
Stage IIIB- The tumour is of any size and has spread to the regional lymph nodes but not to other body areas (any T, N1, M0).
Stage IIIC- The tumour 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 tumour has not spread to distant body parts(T4, any N, M0).
Stage IV- A tumour of any size has spread outside of the eye to distant areas of the body (any T, any N, M1).
Recurrent – Cancer that has come back after treatment is called recurrent cancer. It may come back in the eye or another part of the body. If cancer returns, the doctor performs another round of tests to know the extent of the recurrence. These tests and scans are mainly similar to those done at the original diagnosis.