Melanoma is a dangerous type of skin cancer. Most melanoma is treated surgically, and in many cases this surgery is curative. Through numerous clinical trials, the surgery that is required to treat melanoma has become less invasive. A number of these less radical procedures were pioneered at the John Wayne Cancer Institute Melanoma Program.
Early melanomas (Stages 1 and 2) are localized, and more advanced melanomas (Stages 3 and 4) have spread (metastasized) to other parts of the body. There are also subdivisions within stages. The lower or earlier the stage the more likely it is that a patient will be cured of it. It is important to remember that there are many numbering systems within melanoma evaluation. These can be confusing, and it is often helpful to have a physician explain the meaning of all of the numbers. For example a Stage 3 melanoma is very different from a melanoma with Level III invasion.
In Stage 3 melanoma, cancer cells have spread from the primary tumor site through small channels in the tissue (“lymphatics”). These tumor cells can be detected as metastases in lymph nodes in the region of the primary melanoma, or as nodules of melanoma in the nearby skin (“in-transit metastases). If melanoma spreads this way, the risk of it spreading further in the body is greatly increased.
If the disease has advanced to Stage 4, the melanoma cells have traveled through the body via the bloodstream or lymph vessels and have settled into another area of the body, likely far from the original tumor site. These cells may have reached distant lymph nodes or invaded the internal organs. This can be in addition to or instead of the lymphatic spread.
Cutaneous melanomas usually begin in cells known as the epidermal melanocyte:
If you’ve been identified as being at a higher risk for a melanoma diagnosis, you may be a candidate for melanoma screening if you:
Anything that increases your chance of getting melanoma is a risk factor. Sun damage, especially a history of peeling or blistering sunburns, is the main risk factor for melanoma. Artificial sunlight from tanning beds causes the same risk for melanoma as natural sunlight. Tanning in the sun or in tanning beds always involves radiation damage to the skin and increases the risk of skin cancer.
Not everyone with risk factors gets melanoma. Individuals are encouraged to visit with their primary care doctor or a dermatologist if there is any concern or suspicion about melanoma. Early detection is vital to treating and surviving cancer.
Diagnosis of melanoma is most often done by a simple skin exam. The exam should be thorough, as melanoma can occur in any part of the skin. Some tools can aid in the diagnosis, such as magnification or special types of light, and photographs are often helpful for follow up exams of the skin over time. The most important part of the evaluation, though, is the experience of the examiner and the dedication to doing a thorough job. Most often, this is done by a dermatologist or primary care physician, and when in doubt a biopsy with evaluation by an experienced pathologist is recommended.
Once a melanoma has been found, a great deal of information can be obtained by a full assessment of the skin biopsy. At the Melanoma Program at Providence Saint John’s, our pathologists are very practiced in evaluating melanomas and provide all of the relevant information to help guide treatment decisions in a standard synoptic report. If the initial biopsy was done elsewhere, they are able to provide an expert review rapidly upon receipt of the biopsy slides.
Skin cancer can’t be diagnosed just by looking at it. If a mole or pigmented area of the skin changes or looks abnormal, a doctor may biopsy the mark, taking a tissue sample for a pathologist to examine. Suspicious areas should not simply be shaved off or destroyed with a hot instrument, an electrical current or a caustic substance. A biopsy should be performed first to determine if the area is malignant.
Medical treatments for melanoma are rapidly evolving, and a great deal of progress has been made in recent years. Our physicians are at the forefront of many of these new therapies and can help patients sort through the complex and changing information about established treatments, such as interferon, and newer, recently developed drugs.
Although several noninvasive diagnostic techniques for evaluation of skin lesions exist, biopsy is indicated for all suspicious pigmented lesions. Because tumor thickness is often what determines prognosis and treatment, the biopsy technique is critical. For most small and medium-sized lesions the ideal biopsy technique is complete full thickness excision of the lesion
Accurate pathologic interpretation of the biopsy specimen is what helps determines treatment and prognosis.
Several characteristic of primary melanoma tumors help predict the prognosis and risk of metastases. Tumor thickness is the strongest predictive characteristic for recurrence in patients with primary cutaneous melanoma.
Because thickness is so important, melanomas are commonly referred to as thin (generally less than 1.0 mm thick), intermediate (1.0 to 4.0 mm thick) and thick (greater than 4 mm thick).
Melanomas on the arms and legs generally have a better prognosis than those on the head and neck or trunk. Mucosal melanomas have an overall poor prognosis, often because they are detected late. Numerous studies have shown women fare somewhat better than men with melanoma, though the reasons for this are unclear.