Skin cancer is still a relatively unknown cancer in Korea, but it actually occurs in quite a few cases. According to the Central Cancer Registry, there were 7,174 cases of skin cancer (2.8% of all cancers) in 2019. In the West, the incidence of skin cancer is the highest, and is expected to continue to increase in Korea because of the aging population. Kwon Soon-hyo, professor of dermatology at Kyunghee University Gangdong Hospital, is helping to discover skin cancer.
◇ Skin cancer, 40% increase in 5 years
Skin cancer is more than doubling worldwide due to the aging population, and Korea is no exception. According to Health Insurance Review and Assessment Service statistics on diseases of public concern, the number of patients visiting hospitals due to skin cancer increased by 40% in five years from 20,983 in 2017 to 29,459 in 2021. Po the longer you are exposed to the sun, the more UV rays accumulate and the risk of skin cancer increases.
Continuous exposure to UV rays damages DNA, which contains genetic information, causing mutations in cells. Ultraviolet rays are largely divided into ultraviolet A, B, and C rays, and among them, A and B have a detrimental effect on the occurrence of skin cancer. UV-C has a shorter wavelength and is not included in sunlight. UVB directly causes DNA denaturation, and UVA produces active oxygen, which not only causes skin aging but also indirectly damages DNA, increasing the possibility of carcinogenesis.
◇ Need to identify benign and malignant tumors correctly
There are benign and malignant tumors in the skin, and knowing how to differentiate between them is very useful in detecting and curing skin cancer early.
Malignant tumors include basal cell carcinoma, squamous cell carcinoma, malignant melanoma, Kaposi’s sarcoma, Paget’s disease, and mycosis fungoides, but the first three cancers are the most common. Of all skin cancers, basal cell carcinoma and squamous cell carcinoma (including Bowen’s disease) account for 85% and malignant melanoma accounts for 10%. Malignant melanoma has a relatively high mortality rate because it has a high metastasis rate among skin cancers.
On the other hand, basal cell carcinoma and squamous cell carcinoma have a low rate of metastasis and little impact on survival. According to data from the Central Cancer Registry, the 5-year relative survival rates for skin cancer between 2015 and 2019 were 63.9% for malignant melanoma, 103.3% for basal cell carcinoma, and 89.3% for squamous cell carcinoma.
◇ Malignant melanoma often occurs on the hands, toes, soles and face
Basal cell carcinoma is characterized by many on the face, especially the nose and cheeks. The problem is that basal cell carcinoma doesn’t just occur on the face. 20 to 30 out of every 100 people develop it in areas other than the face that are exposed to ultraviolet rays. It can also occur on a hairy scalp. It mostly occurs in the elderly, but sometimes appears in people in their 50s.
Squamous cell carcinoma often develops on the face, back of the hand, arm, lower lip, and auricle. It can take many forms, such as nodules, warts, and ulcers. On the other hand, melanoma often attacks the hands, toes, soles, face, back, and shins. Specifically, when it occurs under the nail, vertical black lines appear on the nail. Melanoma is most common in people in their 30s and 40s.
◇ Similar to a point, but asymmetry and irregular boundaries
In general, there are many causes for concern that seborrheic keratosis, or age spots, are skin cancer. However, skin cancer has its own characteristics. Basal cell carcinoma or squamous cell carcinoma is very different from ordinary ones. The tumor looks like an ulcer, fades, bleeds or oozes. If these ulcers do not heal well with treatment, a professional diagnosis is necessary.
Also, as the size increases, or if you look closely, it may turn blue grey. In addition, if it is mistaken for a mole and recurs after laser removal, skin cancer should be suspected.
Malignant melanoma is a different type of these skin cancers. It appears as spots or nodules, similar to black spots, but the lesions are not symmetrical and the borders are irregular. If the color is variable, the diameter is more than 0.6 cm, or the area with the mole is itchy, it is likely to be melanoma. In particular, if it grows larger or has a point different from its original shape, you should get a proper diagnosis.
◇ Complete excision and skin reconstruction is important to prevent recurrence
A biopsy confirms skin cancer. The pathology department checks the tissue first, but the dermatologist also checks the tissue and diagnoses the histological subtype and the depth of invasion of the skin cancer.
Treatment is mainly surgical removal of cancerous tissue. At this point, two things must be satisfied. First, it is completely resected so that the cancer does not return. The second is to completely reconstruct the skin both cosmetically and functionally.
Apart from surgery, there are electrical burns or curettage, cryotherapy, radiation therapy, and imiquimod ointment. It is mainly performed when surgery is difficult, but has a limitation because cancer cells cannot be completely removed. However, in addition to surgery, malignant melanoma requires radiation therapy and chemotherapy. In the early stages, it is fine to remove only the tumor, but if the thickness of the tumor is more than 1 mm, considering the possibility of metastasis, the nearby lymph nodes can be removed or anticancer drugs can be used.
◇ The key is to reduce exposure to UV rays, and sunscreen is essential
Ultraviolet rays are classified as a first class carcinogen by the World Health Organization (WHO). Therefore, the most important thing is to reduce UV exposure. As outdoor activities are unavoidable, you must use sunscreen (sunscreen) when going out.
UV rays accumulate on the skin, so it’s good to make it a habit to use sunscreen from a young age. In addition, long-wavelength UVA can affect the skin even on a cloudy day, so don’t worry.
Daeik Kwon Medical Specialist Reporter >
