Excessive exposure to UV (ultraviolet) rays – which reach us directly from the sun’s rays and can damage skin cells – is the main cause of skin cancer, a disease that affects thousands of Brazilians every year.
Knowing how to identify possible signs of different types of skin cancer – and how to protect yourself from the disease – is essential in a country like Brazil, where the index for rays is 11 – a level considered very high and which offers a greater risk for skin cancer.
Together, non-melanoma skin cancer and melanoma account for 34% of cancer diagnoses in Brazil, with about 193,000 cases per year, according to data from INCA (National Cancer Institute).
The sooner the disease is discovered, especially in cases of melanoma, the more aggressive type, the greater the chance of successful treatment.
Common symptoms of skin cancer
Non-melanoma skin cancer is the most frequent malignant tumor in Brazil and will represent 31.3% of cancer cases between 2023 and 2025, according to an estimate by INCA (National Cancer Institute).
It can be classified into basal cell carcinoma and squamous cell carcinoma.
The first is the most frequent type, with normally slower growth, and which is usually manifested by the appearance of a lesion in the form of a pink nodule on the exposed skin of the face, neck and scalp. The mole could also be a persistent, red spot with jagged edges that bleeds easily.
In squamous cell carcinoma, more common in men, there is the formation of a nodule that grows rapidly, with ulceration (wound) that is difficult to heal even four weeks after the appearance or a reddish, raised, irritated area that can itch.
“Both types are related to high exposure to sunlight and should be prevented with sunscreen and frequent consultations with a dermatologist are important for detecting cancer in its early stages”, points out Sheila Ferreira, oncologist at Grupo OncoclÃnicas and specialist in clinical oncology by the Hospital AC Camargo Cancer Center.
The so-called melanoma skin cancer, although considered to be of low incidence – it is estimated that 8,450 new diagnoses are made per year in Brazil, about 3% of skin cancers – is the most aggressive and requires increased attention.
“Melanomas are malignant neoplasms of melanocytes, which are pigmented cells located in the layer responsible for the renewal of the epidermis (the most superficial part of the skin),” says dermatologist Bethania Cavalli of HSPE (State Public Servant Hospital).
The appearance of melanoma is also related to sun exposure and the tumor has the potential for metastasis (when cancer cells spread to other organs). This is due, explains Cavalli, to cancer cells having an unlimited potential for replication, in addition to the capacity for tissue invasion and evasion of the immune system.
These are usually the cases that begin with the appearance of dark spots on the skin, which change over time.
One way to identify whether a mole or stain may pose a danger is to use the ABCDE scale:
- Asymmetry (if you divide the mole into four parts, they are not equal)
- B for jagged edges
- C for colors, which evaluates the variation in color
- D in diameter (the mole is larger than six millimeters)
- E of evolution (change in color pattern, growth, itching and bleeding)
“Melanomas are more common on the back of men and on the legs of women. Black and Asian patients have a more common location on the feet and hands, which we call acral melanoma”, explains Bethania Cavalli.
Risk factors for skin cancer
The main risk factor for skin cancer, both melanoma and non-melanoma, is ultraviolet radiation.
This light, explains Cavalli, causes direct damage to cellular DNA and induces oxidative stress, resulting in gene mutations that trigger skin cancer.
“In addition to ultraviolet radiation, family history and the presence of multiple moles are also risk factors. Transplanted patients are at greater risk of developing skin cancer, as they use medications that interfere with immunity (immunosuppressants).”
How is skin cancer diagnosed?
Performed by the person in parallel with the health professional, regular observation of the moles on our body allows us to identify new signs or previously non-existent changes.
“Today we have a device called a dermatoscope that allows us to evaluate moles in more detail and at high magnification, complementing the assessment of skin inspection. When in doubt, we still have another exam called confocal microscopy, which allows us to obtain high-resolution images and microscopic aspects, as if it were an optical biopsy without the need for cutting.”
The doctor also highlights as an option the body mapping with dermoscopy, a technique that evaluates each mole individually with the recording of images and allows the monitoring of signs to observe possible changes.
“This exam is very useful for patients who have multiple moles and especially those who have had a history of melanoma.”
Treatment options for skin cancer
When cancer is discovered at an early stage, the indication is that the lesions be surgically resected by a qualified specialist so that an adequate approach can be taken at the margins around the tumor, without leaving parts that could be harmful.
“This applies both to cases of melanoma and non-melanoma skin cancer. Surgery is actually capable of resolving most cases, making any other complementary treatments rarely necessary”, explains Sergio Azevedo, oncologist at the Grupo OncoclÃnicas and professor at the Faculty of Medicine of UFRGS (Federal University of Rio Grande do Sul).
If the disease has a more serious stage, subtype, or extension, the specialist says that other treatment approaches can be used.
In more advanced cases and with metastasis, specifically melanoma, immunotherapy – a treatment with medication that activates the immune system so that it becomes capable of fighting malignant cells – has proven to be an alternative with good results for quality of life and patients’ well-being.
Another type of intervention in these advanced scenarios, points out the doctor, for a limited number of patients whose melanoma has a mutation in the BRAF gene, is the use of oral medications that inhibit abnormal cell proliferation.
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