Skin cancer accounts for 33% of all diagnoses of this disease in Brazil, and the National Cancer Institute (INCA) registers around 185,000 new cases each year. The most common type, non-melanoma skin cancer, has a low lethality, but its numbers are very high. The disease is caused by the abnormal and uncontrolled growth of the cells that make up the skin. These cells are arranged in layers and, according to which are affected, the different types of cancer are defined. The most common are basal cell and squamous cell carcinomas, responsible for 177,000 new cases of the disease per year. More rare and lethal than carcinomas, melanoma is the most aggressive type of skin cancer and accounts for 8,400 cases annually.

Types of skin cancer:

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Basal cell carcinoma (BCC): the most prevalent of all types. BCC arises in basal cells, which are found in the deepest layer of the epidermis (the top layer of the skin). It has low lethality and can be cured in case of early detection. BCCs most often appear on sun-exposed regions such as the face, ears, neck, scalp, shoulders, and back. They can also develop in unexposed areas, although more rarely. In some cases, in addition to sun exposure, there are other factors that trigger their appearance. Certain manifestations of BCC can resemble non-cancerous lesions, such as eczema or psoriasis. Only a specialist doctor can diagnose and prescribe the most appropriate treatment option. The most common type is nodular-ulcerative BCC, which translates as a red, shiny papule with a central crust that can bleed easily.

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Squamous cell carcinoma (SCC):  second most prevalent among all types of cancer. It manifests itself in the squamous cells, which make up most of the upper layers of the skin. It can develop on all parts of the body, although it is more common on areas exposed to the sun such as ears, face, scalp, neck, etc. The skin in these regions typically shows signs of sun damage, such as wrinkling, changes in pigmentation, and loss of elasticity. SCC is twice as common in men as in women. As with other types of skin cancer, excessive sun exposure is the main cause of SCC, but not the only one. Some cases of the disease are associated with chronic wounds and scarring of the skin, use of anti-rejection drugs for transplanted organs, and exposure to certain chemical agents or radiation. SCCs are typically reddish in color and present as thick, scaly sores or sores that do not heal and bleed occasionally. They may look similar to warts. Only a specialized doctor can make the correct diagnosis.

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Melanoma: The least frequent type of all skin cancers, melanoma has the worst prognosis and the highest mortality rate. Although the diagnosis of melanoma usually brings fear and apprehension to patients, the chances of cure are more than 90%, when there is early detection of the disease. Melanoma usually looks like a mole or mole on the skin, in brownish or blackish tones. However, the "spot" or "mark" usually changes color, shape, or size, and can cause bleeding. That's why it's important to constantly observe your own skin, and immediately seek a dermatologist if you detect any suspicious lesions. These lesions can appear in areas that are difficult for the patient to see, although they are more common on the legs in women; in trunks, in men; and neck and face in both sexes. In addition, it is worth remembering that an injury considered “normal” for a layperson may be suspicious for a doctor.

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Light-skinned people who burn easily when exposed to the sun, with phototypes I and II, are at greater risk of developing the disease, which can also manifest itself in black individuals or with higher phototypes, although more rarely. Melanoma originates from melanocytes, the cells that produce melanin, the pigment that gives skin its color. It usually appears in the areas of the body most exposed to solar radiation. In early stages, melanoma only develops in the topmost layer of the skin, which makes it easier to surgically remove and heal the tumor. In more advanced stages, the lesion is deeper and thicker, which increases the chance of spreading to other organs (metastasis) and decreases the chances of healing. Therefore, early diagnosis of melanoma is essential. Although it has a worse prognosis, advances in medicine and the recent understanding of genetic mutations, which lead to the development of melanomas, have enabled people with advanced melanoma today to have an increase in survival and quality of life.

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Heredity plays a central role in the development of melanoma. Therefore, family members of patients diagnosed with the disease should undergo preventive examinations regularly. The risk increases when there are cases registered in first-degree relatives.

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Currently, genetic tests are able to determine which mutations lead to the development of advanced melanoma (such as BRAF, cKIT, NRAS, CDKN2A, CDK4) and thus make it possible to choose the best treatment for each patient. Despite being rarely curable, it is already possible to live with quality, controlling metastatic melanoma for the long term.