Skin cancers

The number of skin cancer cases in France has more than tripled between 1990 and 2023.

It is estimated that between 141,200 and 243,500 cases of skin cancer are diagnosed in France each year. They include:

- Basal cell carcinomas (~70% of cases): The most common type. They progress slowly and locally, without metastasizing.

- Squamous cell carcinomas (~20% of cases): More aggressive; they can spread to the lymph nodes.

- Melanomas (~10% of cases): The most dangerous type. They can be particularly aggressive if they penetrate deeply.

Why such an increase?

- The ozone layer, damaged by human activity, offers less protection than it did 80 years ago. Consequently, more UV rays reach the Earth's surface.

- Sun exposure is more sought-after than in the past. Some people even use tanning booths, which increases the annual dose of UV radiation each individual receives.

- Increased life expectancy: as we live longer, our skin accumulates radiation exposure over a longer period. This gives DNA mutations much more time to build up and develop into carcinomas.

- Better screening: French people visit dermatologists more regularly, making it possible to detect lesions that previously went unnoticed.

Ultraviolet rays are the primary culprits:

*   UVB rays are the most energetics and cause immediate damage to the DNA within epidermal cells. Their energy is directly absorbed by DNA bases; consequently, adjacent bases on the same strand can accidentally bond together to form dimers. When these mutations affect key genes, the cell loses control over its division, leading to tumor formation.

*   UVA rays penetrate more deeply, reaching the dermis. Although less energetic, they do not alter DNA directly but instead trigger secondary chemical reactions. They generate highly unstable free radicals that attack their surroundings. These radicals oxidize cell membranes and destroy collagen and elastin—causing premature skin aging—while also damaging DNA by inducing strand breaks and altering bases.

It is therefore crucial to pay close attention to even minimal exposure; sunburns are not the only danger! You can accumulate high doses of UVA radiation through window glass, on cloudy days, and so on, without even realizing it. This causes deep damage to skin cells, which—decades later—can lead to the development of carcinoma or worse.

Effective sun protection is therefore essential, regardless of the level of exposure. Sunscreen is not merely an ordinary cosmetic product but a vital health product that should be chosen with care.