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STAGING AND PROGNOSIS According to the American Cancer Society, staging is the process of finding out how widespread the cancer is. This includes describing its size as well as whether it has spread to any organs. This is very important because both treatment and the outlook for recovery depend on the stage of the cancer. Melanoma is divided into 5 stages referred to by 0 and the Roman numerals I - IV. The lower the stage, the better the prognosis (prediction of longevity relative to the progress of the cancer) will be. To understand this, a quick lesson in anatomy helps. The skin is divided into layers three layers. The thinnest outermost layer is called the epidermis, this is where the melanocytes are located. Just beneath the epidermis is the thickest layer of the skin, called the dermis. The bottom layer, called adipose tissue, is a layer of fat that provides insulation (some of us have more insulation than others). The risk of melanoma is directly related to the depth it invades from the epidermis into the dermis and fat. The following is an introduction to staging in melanoma. This staging overview should not be used to calculate your own stage. To determine your stage of melanoma, please consult your physician who is familiar with the specifics of your individual situation. Stage 0:When a melanoma starts, it usually starts growing in the epidermis and starts to spread out like an oil slick. If it has not crossed the border into the dermis, it is a melanoma in situ (Latin for ¿in its place) and is a stage 0 lesion. Adequate surgical excision with 0.5 cm margins gives a 100% cure rate in theory.
Treatment: melanoma in situ or non-invasive melanomaTreatment is to remove the tumor with 5 mm (a mm is about the thickness of a dime) margins with the excision taken down to the level of the fat. Barring other risk factors for skin cancer, follow-up is recommended to be twice a year for the first year and then yearly for life. Stage IAs the melanoma grows, it can invade the underlying
dermis. When melanoma has become invasive, it is no longer
classified as stage 0, but is rather stage 1. 5-year survival does not mean the patient is expected to live 5 more years. It means that if, for example, 100 patients with stage I melanomma 5 years after their diagnosis and surgery, we would expect that on average 89-95 people would still be alive, but 5-11 might have died from the melanoma progressing to stage IV. The 5-year survival says nothing about the individual patient but rather gives a relative idea of future risk of melanoma coming back and progressing.
Treatment: melanomas up to 2.0 mm in depthThe recommended treatment is to remove the tumor with 1.0-2.0 cm margins down to and including the underlying fat. In general, for lesions > 1.0 mm in depth, lymphatic mapping and sentinel lymph node biopsy is offered to the patient. Stage IIIf the melanoma has invaded to a depth of more than 2.0 mm, it qualifies as a stage II melanoma and the 5-year survival ranges between 50-80%. The treatment for stage II melanoma is surgical excision with 2 cm margins down to the fascia. Melanomas deeper than 4 mm are still stage II lesions but have a 5-year survival of around 50%.
Treatment:The treatment for stage II lesions is to use 2.0 cm margins when removing the tumor and fat. For lesions deeper than 4 mm, in addition to surgery, the doctor may offer some treatments to hopefully prevent the melanoma from coming back in the future (such as interferon), a clinical trial that might include an experimental vaccine, or other approaches to coax the immune system into fighting melanoma cells that may have escaped the skin and found their way into internal organs. Stage IIIA melanoma is considered stage III if it has invaded the regional lymph nodes. For example, if the melanoma is on the left foot, the regional lymph nodes are under the left groin. If a distant lymph node basin has been infiltrated, (e.g. the left groin in the example above) then the melanoma is stage IV. A lymph node is about the size of a kidney bean and functions a bit like a filter in a swimming pool that collects debris. The lymph nodes catch bacteria and viruses and in some cases, tumor cells. The lymph nodes are located in the axillae and groins, the head and neck areas, and internally as well. When the regional lymph nodes are involved, the estimated 5-year survival is about 30-70% depending on how many of the lymph nodes are involved and how many melanoma cells are found in each node. For example, some lymph nodes may have only a few hundred cells, while others may be packed so full of melanoma cells that the lymph node may actually split its outer cover (capsule).
Treatment:The treatment for stage III melanoma is to remove all of the lymph nodes in the affected region, e.g. if there is a positive lymph node in the right axilla then all of the lymph nodes in that area are removed, about 20 on average. Some people worry about having their lymph nodes removed and ask about subsequent increased risk of infection or swelling. First, there are hundreds of lymph nodes in the body so if you lose 20 or more, it rarely presents any sort of problem since there are many other nodes in reserve (the tonsils, for example, are types of big lymph nodes that many of us are happy not to have anymore). The second concern with removing all of the lymph nodes under the arm or in the groin is the risk of a swollen arm or leg after the surgery. This can happen but is quite rare these days. Swollen arms frequently occurred with women who had breast cancer and had radical mastectomies where the breast was removed along with the underlying muscles and lymph nodes under the arm. This procedure was often followed by radiation to the axilla that greatly increased the risk of a permanently swollen arm. Fortunately with melanoma, the surgeries to remove the lymph nodes are not as aggressive and getting a swollen limb after lymph node dissection is an infrequent complication. Because the 5-year survival for stage III melanoma is between 30-70%, the doctor may offer the patient the option to take some additional therapy in the hope of preventing the melanoma from coming back in the future. To date, the only FDA-approved therapy for stage III melanoma is interferon-alpha. There are many types of investigational (experimental) therapies offered around the country and may include vaccines or other types of medications. To date, none of these experimental therapies have definitively proven to prolong life, but progress is being made yearly. Stage IVMost melanomas will travel to lymph nodes and later leave those lymph nodes to invade internal organs. Rarely some melanomas bypass the lymph nodes altogether and attack internal organs via the bloodstream. Melanoma that has spread to remote organs is classified as stage IV. The 5-year survival for stage IV tumors invading internal organs is about 7-10%. If the melanoma spreads to other areas of the skin away from the melanoma and has not invaded internal organs, the 5-year survival is 10-20%
Treatment:The treatment for stage IV disease is generally considered to be palliative rather than curative. Palliative treatment means that the treatment can reduce symptoms of a cancer, such as pain or shortness of breath, but usually doesn't predictably prolong life. The most commonly used treatment for stage IV disease is a chemotherapeutic agent called dacarbazine, or DTIC. However, because chemotherapy has been mostly disappointing in melanoma, there are numerous clinical trials being conducted across the country that are testing combination therapies such as bio-chemotherapy. Bio-chemotherapy is a term that implies the combination of a chemotherapeutic agent such as DTIC and an immunotherapy agent such as interferon and/or interleukin-2. Some cancer centers also offer various types of gene therapies and vaccines. Patients with stage IV disease are encouraged to enter into clinical trials because traditional chemotherapy doesn't prolong survival. Other Staging FactorsBreslow Depth - Breslow Depth is simply how thick a melanoma is from top to bottom. It is measured in millimeters by the pathologist who examines the original biopsy specimen under the microscope. Clark Level - Clark Level I through V describes which layers of the skin are invaded by the melanoma. It is important not to confuse the Clark level Roman numerals with general cancer stage Roman numerals. For example, Clark level III of invasion is not the same as stage III melanoma. Both Breslow depth and Clark level are usually used to interpret the severity of a melanoma because skin varies in thickness across the body surface, with some skin being quite thin (inner forearm, neck) and other skin being quite thick (back, legs). Example: a melanoma in an area with very thin skin may have a Breslow Depth of 1 mm and may penetrate as deeply as just above the fat (Clark Level IV), or it may have the same Breslow Depth of 1 mm but penetrate down only into the first layer of very thick skin (Clark Level I). The second melanoma would have a much better prognosis than the first, even though they have the same Breslow depth. This is why your doctor will take both factors into account when evaluating the severity of your melanoma. Ulceration - When a pathologist looks at a biopsy of a melanoma they look for evidence of ulceration of the overlying epidermis. If the epidermis is ulcerated, meaning part of it is eroded, the prognosis for that patient is more guarded. It is not clear why ulceration increases risk in melanoma, but it may have something to do with the cancers ability to erode blood or lymph vessel walls. This erosive ability may provide cancer cells better chances for hitch hiking to distant sites from the original melanoma. If ulceration is present on your pathology report, please have your physician interpret its specific meaning in your case. |
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