1. What is Staging?
Staging is done by gathering information regarding the thickness of the skin cancer tumor, the depth of the penetration of that tumor and the degree to which the skin cancer has spread and categorizing your disease process as a stage–I through IV. Diagnostic tests, scans and procedures are used to collect the information which is then used to decide the stage of your cancer. By staging skin cancer, communication between health care providers is made easier; also, considering the stage of your cancer will help direct doctors in how they want to treat you. The different stages of skin cancer are treated differently due to the difference in extent of the disease.
2. Breslow’s Thickness and Microscopic Ulceration
By measuring the distance between the upper layer of the epidermis and the deepest point of the tumor’s penetration will provide doctors with a measurement termed Breslow’s thickness–generally the thicker the tumor the higher the stage. Another factor considered when evaluating the stage of melanoma is microscopic ulceration. Microscopic ulceration means that the epidermis (the outer most layer of skin) covering the tumor is not in tact. If microscopic ulceration is present your cancer will be staged later and more aggressive treatments may be considered.
3. Clark’s Level of Invasion
Another piece of information that doctors gather as they begin the staging process will be Clark’s level of invasion. For very thin tumors, this classification is based on the number of layers of the skin that are penetrated by the tumor. There are five levels of invasion ranging from level 1–where the tumor is only involving the epidermis–to level 5 where the tumor is involving the subcutaneous fat.
4. Sentinel Node And Staging
Because cancer can spread through the lymphatic system your physician may choose to remove your sentinel node–the node closest to the primary tumor–and have it tested in a laboratory for melanoma cells. If there are melanoma cells present in the sentinel node, there is a chance that other lymph nodes surrounding the area and through out the body have also been infected. A number of those nodes will also be removed for careful study. If the sentinel node is negative for melanoma cells, then the surrounding lymph nodes will not be removed. The information collected by biopsies performed on the lymph nodes will help the physicians stage your melanoma correctly.
5. Numbered Stages
Breslow’s thickness and microscopic ulceration have traditionally both been used to help decide the staging of skin cancer. Stage I is subdivided according to the thickness of the primary (original) tumor. Stage II is again subdivided by the thickness of the tumor and/or the depth of the tumor. Microscopic ulceration is also a consideration in stage II. Stage III is considered a later stage skin cancer consideration of lymph node involvement. Currently, Breslow’s thickness is no longer used in staging, however microscopic ulceration is important in the staging process, progression of the disease and prognosis. Stage IV is indicative of distant metastasis–cancer found in far reaching lymph nodes or organs.