The most common and most overlooked precursor to skin cancer! Talk about actinic keratosis

The most common and most overlooked precursor to skin cancer! handheld dermatoscopeTalk about actinic keratosis

As the gentle and worldly steps of spring fade away, the passionate summer is coming.electronic dermatoscope During the season closest to the sun each year, we don't see the roaring UV rays relentlessly destroying every piece of DNA in our skin cells. In the 21st century, global warming is becoming more and more serious, and the protection of the ozone layer against ultraviolet rays is becoming stronger and stronger. Even if we haven't seen the shadow of summer yet, we can feel her enthusiasm with ultraviolet light first. Today, I share with readers a preskin cancer caused by UV exposure: solar keratosis.

Solar keratosis and cutaneous squamous cell carcinoma

Actinic keratosis (AK), also known as Actinic keratosis, tends to occur in the elderly.365nm UV Lamp The disease is a precancerous keratinosis caused by genetic damage caused by excessive ultraviolet light accumulated in the skin during prolonged exposure to sunlight.

When AK is present in the skin (Figure 1), the site may have entered the clinical stage of early cancer. According to the study, 60% of squamous cell cancers were converted by the AKP. On the other hand, AK changes were present around 97% of solar squamous cell carcinomas. Therefore, AK is closely related to cutaneous squamous cell carcinoma.

Studies have shown that if a patient has more than 7 episodes of solar keratosis, the risk of developing skin squamous cell carcinoma within 10 years is up to more than 10% [c]. Since it is a disease that easily occurs in middle-aged and elderly people, it will become a disease worthy of attention in the society of Taiwan Province, where the average life expectancy is gradually increasing and the elderly population is rapidly increasing. [d]

Figure 1. Solar keratosis often occurs in areas that are exposed to the sun for a long time, such as the face. [E]

The culprit behind one solar keratosis: ultraviolet light

Ultraviolet radiation is classified as a Class 1 carcinogen by the International Agency for Research on Cancer (IARC). Ultraviolet light causes genetic damage to cells, which in turn leads to a series of cytopathological processes called photocarcinogenesis. Photocarcinogenesis in actinic keratosis is divided into initiation, initiation and progression stages [F].

Priming: UV-damaged skin cells activate self-repair mechanisms, while some severely damaged cells self-induce apoptosis and die, but some cells escape apoptosis mechanisms and survive with abnormal genes to form tumor-initiating stem cells.

Initiation period: If these cells continue to be exposed to ultraviolet light, it will cause the accumulation of more mutations in the chromosomal DNA of the initial tumor stem cells, which may induce the cells to enter the cancerous initiation period, resulting in an increasing rate of cell growth.

Progression: When large numbers of diseased cells continue to grow uncontrollably, the disease will officially turn into cancer.

Once it becomes cancer, if not treated in time, skin cancer may also enter the "metastatic stage", cancer cells gain the ability to move, can metastasize to other parts of the body and even endanger the life of the enterprise.