Skin cancer is the most common form of cancer with more than 600,000 new cases diagnosed each year with basal cell and squamous cell being the most common. The third type, melanoma, is more rare but is the most aggressive.
According to the American Cancer Society, there will be more than 76,000 new cases of melanoma projected for 2016. The incidences of melanoma have increased over the last 30 years. For those using indoor tanning methods, the chances of developing this disease are further increased.
The National Cancer Institute defines a number of risk factors for developing melanoma, including: unusual moles; excessive exposure to natural sunlight or artificial ultraviolet light; family or personal history of the disease; having a fair complexion; and being older than 20 years of age.
Superficial spreading melanoma is the most common type of melanoma (accounting for about 70 percent of all cases). This type travels along the top layer of the skin for a fairly long time before penetrating more deeply.
Lentigo maligna is similar to the superficial spreading type, as it also grows close to the skin surface before penetrating more deeply. It usually appears as a flat or mildly elevated mottled tan, brown or dark brown discoloration.
Acral lentiginous melanoma also spreads superficially before penetrating more deeply. It is different from the others, as it usually appears as a black or brown discoloration under the nails, on the sole of a foot or the palm of a hand. It is the most common type of melanoma in African-Americans and Asians and the least common among Caucasians.
Nodular melanoma has usually spread by the time it is first diagnosed. The malignancy is typically recognized when it becomes a colored bump.
Although surgery is the most effective way to treat melanoma, many patients present with advanced or metastatic disease.
Newer options for these patients include the use of immunological therapies like interferon, interleukin-2 and, more recently, the anti-CTL4 antibody, as well as Ipilimumab. In select cases, Imatinib has also shown efficacy. Newer classes of agents that target the Braf gene are also in development.
Chemotherapy does not always work as well for melanoma as it does for some other types of cancer, but it may relieve symptoms or help people with advanced disease live longer. Several drugs and combinations of drugs can be used to treat advanced melanoma.
The most commonly used chemotherapies for the disease are dacarbazine used either alone or in combination with other chemotherapy drugs such as carmustine and cisplatin. The combination of these three drugs, together with tamoxifen is called the "Dartmouth regimen."
Temozolomide works similarly to dacarbazine, but it can be given in pill form. Paclitaxel is administered either alone or combined with drugs such as cisplatin or carboplatin. Additional drugs with activity include alkylating agents (Melphalan), vinca alkaloids (Vinblastine) and Bleomycin.
The graph below is excerpted from a clinical trial that compared empiric chemotherapy with assay-directed chemotherapy in patients with advanced melanoma. The data illustrates a statistically significant survival advantage for patients receiving assay-directed therapy.
Despite melanoma’s drug refractory (resistant to treatment) nature, novel drug combinations have the potential to provide durable responses in some patients.