Diagnosis & Staging
How is the diagnosis of melanoma made?
The diagnosis of melanoma requires a biopsy. There is no blood test for melanoma. Either all or part of the suspicious lesion is removed and taken to the pathologist so he can look at it under the microscope. The pathologist can then relay not only the diagnosis but also important information used for treatment to the doctors who will be treating the patient.
What is the depth or thickness that everyone is talking about? What is a Breslow thickness or Clark’s level?
The likelihood of melanoma spreading is based on how deep it invades below the surface of the skin. The depth of invasion is the most predictable factor we have for melanoma even today. Two people named Breslow and Clark recognized this over 50 years ago and their systems are still used today. Clark looked at levels of the skin and labeled melanoma based on which level I-V it invaded. Please be careful not to confuse Clarks levels with stages of melanoma; they are not the same. Breslow took it another step and just did measurements in millimeters below the skin. He learned that small increases within layers or levels were also important. It is not a bad idea for a patient to ask about their Breslow depth.
What kinds of test do I need when I am diagnosed with melanoma? Do I need x-rays or PET scan?
Other tests such a PET scans are used for the workup of melanoma but only in the situation of a deep melanoma or melanoma that has already spread to other sites such as the lymph nodes. Although these tests sound attractive to “rule out” melanoma spread or metastasis they are not very sensitive and can have a high false positive rate. This can lead to unnecessary tests or procedures. The sentinel lymph node biopsy has been the only test shown to improve patient’s outcome and give more information in the intermediate risk melanomas. Studies clearly show that doctors learn the most from talking to patients and doing an exam. Usually, when melanoma spreads it will cause symptoms or show a sign on the exam that will alert the physician to investigate more.
What are the stages of melanoma?
Stages of melanoma are often confused with levels of invasion. These levels call Clark’s levels are part of the depth mentioned above to predict melanoma. Stages are a classification system used by physicians to communicate how advanced the cancer is and how best to treat it. Melanoma that is isolated to the original site is a stage I or II. Melanoma that has spread to lymph nodes will be a stage III. Melanoma that has spread beyond lymph nodes to other organs is a stage IV.