[Click! Health] Rapid Increase in Skin Cancer... Don't Overlook Even a Single Mole

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[Asia Economy Reporter Chunhee Lee] In Western countries, skin cancer is the most common cancer, with a very high incidence rate?about 1 in 7 people are diagnosed. This is because Westerners have relatively less melanin pigment to protect against ultraviolet rays compared to East Asians. However, with the aging population, the number of skin cancer patients is gradually increasing domestically as well. According to the Health Insurance Review and Assessment Service, the number of skin cancer patients increased from 20,983 in 2017 to 29,459 last year.

Professor Kwon Soon-hyo of the Department of Dermatology at Kangdong Kyung Hee University Hospital explained, "As the time exposed to sunlight increases, ultraviolet rays accumulate, leading to a rise in skin cancer incidence." Continuous exposure to ultraviolet rays damages DNA, which contains genetic information, causing mutations in cells. Among ultraviolet rays, UVA and UVB are dangerous. UVB directly causes DNA mutations, while UVA generates reactive oxygen species that not only accelerate skin aging but also indirectly damage DNA, increasing carcinogenic potential.

Skin cancer refers to malignant tumors that develop on the skin. It is classified into basal cell carcinoma, squamous cell carcinoma, malignant melanoma, Kaposi's sarcoma, Paget's disease, and mycosis fungoides, among others. The most common are basal cell carcinoma and squamous cell carcinoma (including Bowen's disease), which account for about 85% of all skin cancers, while malignant melanoma accounts for about 10%. Malignant melanoma has a high metastasis rate among skin cancers, resulting in a relatively high mortality rate. Basal cell carcinoma and squamous cell carcinoma have low metastasis rates and hardly affect survival rates. According to the Central Cancer Registry, the 5-year relative survival rates for skin cancer from 2015 to 2019 were 63.9% for malignant melanoma, 89.3% for squamous cell carcinoma, and 103.3% for basal cell carcinoma.

Basal cell carcinoma mainly occurs on the face, especially the nose and cheeks. However, 20-30% occur on other parts of the body besides the face. It mainly affects the elderly but can sometimes appear in people in their 50s. Squamous cell carcinoma commonly occurs on the face, backs of the hands, arms, lower lips, and auricles. Its appearance varies, including nodular plaques, warts, and ulcers. Melanoma frequently appears in people in their 30s and 40s. It often invades the fingers, toes, soles, face, back, and shins. Particularly, when it develops under the nails, vertical black lines appear on the nails.

It is common to mistake seborrheic keratosis (age spots) for skin cancer, but there are clear differences. Basal cell carcinoma and squamous cell carcinoma appear as ulcer-like lesions with depressed areas or bleeding and discharge. If an ulcer does not heal well despite treatment, a professional diagnosis is essential. The lesion may grow larger or take on a grayish or bluish hue. Sometimes, lesions are mistaken for moles and removed with lasers, but if they recur, skin cancer should be suspected.

Malignant melanoma is a different type of skin cancer. It appears as spots or nodules resembling black moles but is asymmetrical, has irregular borders, and varies in color. If the diameter exceeds 0.6 cm, or if the mole itches or bleeds, the likelihood of melanoma is high. If the original shape enlarges or new moles appear, an accurate diagnosis is necessary.

Professor Kwon Soon-hyo, Department of Dermatology, Kangdong Kyung Hee University Hospital (Photo by Kangdong Kyung Hee University Hospital)

Skin cancer is definitively diagnosed through a biopsy. The pathology department initially examines the tissue, but dermatologists further analyze it to diagnose the histological subtype and invasion depth of the skin cancer. The primary treatment is surgical removal of the cancerous tissue. Surgery aims to completely excise the cancer to prevent recurrence while reconstructing the skin perfectly for cosmetic and functional purposes.

Other treatments include electrocautery, curettage, cryotherapy, radiation therapy, and imiquimod ointment. These are used when surgery is difficult but have the limitation of not completely removing cancer cells. However, malignant melanoma is treated not only with surgery but also with radiation therapy and chemotherapy. Early-stage melanoma can be treated by removal alone, but if the tumor thickness exceeds 1 mm, lymph nodes around the area may be removed or chemotherapy administered considering the possibility of metastasis.

To prevent skin cancer, reducing exposure to ultraviolet rays, classified as a Group 1 carcinogen by the World Health Organization (WHO), is most important. Since outdoor activities cannot be avoided, it is essential to use sunscreen when going outside. Ultraviolet rays accumulate in the skin, so it is advisable to make sunscreen use a habit from a young age. Long-wavelength UVA can affect the skin even on cloudy days, so one should not be complacent. Professor Kwon Soon-hyo said, "Early detection is the most reliable treatment for any cancer," and recommended, "Regularly check if there are ulcer-like spots on your skin or black spots in less visible areas such as the soles or nails."

This content was produced with the assistance of AI translation services.