Melanoma is a type of cancer that starts in skin cells that give skin its color. Melanoma can also form in the eyes, nose, mouth, genitalia, or, rarely, in the internal organs.
Melanoma is more dangerous than most other common skin cancers because it is more likely to spread if it isn’t found early. Melanoma has the potential to spread through the dermis to nearby tissues and other parts of the body. The deeper a melanoma grows into the dermis, the higher the risk of spreading through lymph vessels or blood vessels.
There are four major types of cutaneous melanoma:
• Superficial spreading melanoma is the most common type of melanoma. It usually looks like a brown-black stain.
• Nodular melanoma grows more quickly deeper into the dermis than other types of melanoma.
• Lentigo maligna melanoma is the slowest growing type of melanoma. It tends to develop in sites of chronic sun exposure in older adults.
• Acral lentiginous melanoma is the least common type of melanoma. This type of melanoma is not related to UV light exposure. It occurs on the palms of the hands or soles of the feet, including fingernails and toenails.
Human melanomas are immunogenic. Virtually all the major principles of “tumor immunology” have been experimentally established in this model. Although these strategies have not been uniformly successful in all cases, durable complete regressions of metastatic melanoma can at times be obtained with immunotherapy.
Treatment of melanoma
There are many treatment options for melanoma. The type of treatment depends on a number of factors – the stage of the disease, sites of metastatic disease, the patient’s overall health condition, etc. However, supportive care is an important part of the overall treatment for all patients.
Melanomas could be treated locally (drugs could be inserted into the tumor or around it), or systemically (drugs could be delivered by intramuscular or intravenous injection).
Neoadjuvant treatment is given to shrink the tumor before surgery and to minimize the spread of melanoma cells during operation.
The primary treatment for melanoma is surgery – dissection of the melanoma (tumor) and the sentinel node.
Adjuvant treatment is usually given as a systemic treatment to eradicate any remaining melanoma cells after surgery.
Palliative treatment is the treatment of advanced, relapsed or metastatic melanoma.
Immunotherapy of melanoma
Immunotherapy can be used both as a local therapy (interferon alfa, imiquimod, interleukin-2, T-VEC or ECHO-7) or systemic therapy (interferon alfa, interleukin-2, ipilimumab, nivolumab, peginterferon alfa 2B, pembrolizumab and ECHO-7).
Targeted therapy drugs are designed to specifically target cancer cells. These drugs are used as systemic therapy (cobimetinib, dabrafenib, imatinib, trametinib, vemurafenib). All four of
these drugs except cobimetinib target tumors that have a damaged BRAF gene.
Chemotherapy of melanoma
Chemotherapy is a type of drug commonly used to treat cancer, including melanoma (dacarbazine, cisplatin, paclitaxel, temozolomide, vinblastine). Many people refer to this treatment as “chemo.” Chemotherapy drugs kill fast-growing cells, including cancer cells and normal cells. Chemotherapy can be used as systemic therapy or regional therapy for melanoma, although it is not as effective as newer immunotherapies or targeted therapies.
Stereotactic radiosurgery of melanoma
Stereotactic radiosurgery is a type of external beam radiation therapy that may be used for melanoma. This type of radiation therapy is most often used to treat melanoma that has spread to the brain—called brain metastases. SRS delivers a high dose of radiation to a very specific, small area of the body.
Riga virus for effective treatment of melanoma
The best response is expected when used in the early stages of the disease (neoadjuvant and adjuvant use). Riga virus may be used either through a systemic administration intramuscularly, according to the regional principle of drug administration, or locally to bypass the tumor’s architectural barriers for locally advanced or locally recurrent melanoma and subcutaneous metastases.
After melanoma surgery, Riga virus may postpone or even protect against further progression of the disease. For patients with metastatic melanoma, Riga virus may slow down the course of the disease and improve their quality of life.