Skin cancer is a disease caused by the abnormal proliferation of skin cells, primarily divided into two main categories: non-melanoma skin cancer and melanoma. According to statistics from the World Health Organization, skin cancer accounts for a significant proportion of new cancer cases globally, with even higher incidence rates in areas with strong sunlight. Early detection and treatment can greatly improve the cure rate, but public awareness of its symptoms and preventive measures remains insufficient.
This article will systematically analyze the causes, clinical manifestations, diagnostic methods, and treatment strategies for skin cancer, and provide practical prevention advice. Understanding this information can help readers identify risks, seek medical attention early, and establish proper skin health management concepts. The key lies in recognizing the multifaceted knowledge encompassed in the "Overview of Skin Cancer," from cellular mechanisms to daily protective measures, to comprehensively understand the characteristics and countermeasures of this disease.
The occurrence of skin cancer is related to various intrinsic and extrinsic factors. Ultraviolet (UV) radiation is the primary environmental trigger, with UVB rays causing damage to the DNA of the epidermis, leading to dysfunction in cellular repair mechanisms. Prolonged exposure and a history of sunburn (especially during childhood) accumulate DNA damage, increasing the risk of malignant transformation. Occupational exposure to UV radiation (such as agricultural workers) or populations living in high-altitude, low-latitude areas have an incidence rate 2-3 times higher than the general population.
Genetic factors play a key role in specific types of skin cancer. Individuals with a family history of melanoma have a 5-10 times higher risk of developing the disease, which is associated with specific gene mutations (such as CDKN2A and BRAF mutations). A weakened immune system (such as those using immunosuppressants after organ transplants) or human papillomavirus (HPV) infection is also associated with certain subtypes of skin cancer. Additionally, chronic skin damage (such as long-term exposure to arsenic or tar) and immunosuppressive states can weaken cellular surveillance mechanisms, promoting the progression of precancerous lesions to malignant tumors.
Symptoms of different types of skin cancer vary significantly. Basal cell carcinoma often presents as pearly nodules on the skin surface, with raised edges and a central depression, commonly exhibiting telangiectasia. Lesions are frequently found on the face, ears, and other areas commonly exposed to UV radiation. Initially, patients may experience only mild itching, but if left untreated, the lesions can invade deeper tissues, causing tissue destruction.
Melanoma symptoms are characterized by the "ABCDE criteria":
Squamous cell carcinoma typically presents as hard nodules or scaly plaques, commonly found on the backs of the hands, lips, etc., and may be accompanied by bleeding or ulceration. Patients may experience localized pain or tenderness, and there may be scaly desquamation around the lesions. When cancer cells metastasize to lymph nodes, local swelling or lymphadenopathy may occur.
The diagnostic process begins with visual and tactile examination, where the physician carefully observes the shape, color, and borders of the lesions. A dermatoscopic examination may follow, using a special light source to magnify and observe skin structures; the reticular structure or pigmentation patterns of melanoma can be captured at this stage. If a malignant lesion is suspected, a tissue biopsy is necessary to obtain samples for histological analysis.
Imaging studies are used to assess the stage of the disease. Computed tomography (CT) and magnetic resonance imaging (MRI) are used to evaluate tumor depth and whether there is lymph node metastasis. Positron emission tomography-computed tomography (PET-CT) is used in advanced cases to look for distant metastases. Blood tests can assess liver and kidney function, providing references for subsequent treatment plans.
Emerging diagnostic techniques include:
Treatment strategies depend on the type and stage of cancer. Surgical excision is the first choice for early skin cancer, with Mohs surgery allowing for layer-by-layer removal and immediate pathological analysis, maximizing the preservation of normal tissue. For patients who cannot undergo surgery, radiation therapy can effectively control local lesions, especially suitable for older patients or those with comorbidities.
In terms of pharmacological treatment, immune checkpoint inhibitors (such as anti-PD-1 monoclonal antibodies) have shown significant efficacy in advanced melanoma, increasing the 2-year survival rate to over 60%. Targeted therapy for patients with BRAF gene mutations, using a combination of dabrafenib and trametinib, can achieve a tumor shrinkage rate of up to 60%. Chemotherapy remains a supplementary option in advanced cases, often used in combination with targeted drugs.
Photodynamic therapy combines specific photosensitizers with light exposure to selectively destroy cancer cells, suitable for treating extensive actinic keratosis. Gene therapy and cell therapy are still in clinical trial stages, with CAR-T cell therapy showing potential efficacy against specific subtypes in laboratory studies.
The core of preventing skin cancer lies in reducing UV exposure. Daily sun protection should combine physical protection (such as broad-spectrum sun-protective clothing and sun hats) with chemical protection (sunscreen with SPF 30 or higher). Avoid outdoor activities during peak sunlight hours from 10 AM to 4 PM, and reapply sunscreen every two hours to reduce UV damage.
Self-skin examinations should be conducted monthly, using a "top mirror" to check hard-to-see areas like the scalp. High-risk groups (such as those with multiple moles or family history) should undergo professional skin examinations every six months. Quitting smoking can reduce the risk of squamous cell carcinoma, as the tar components in tobacco can directly damage the DNA of epidermal cells.
Choosing UPF (Ultraviolet Protection Factor) 50+ sun-protective clothing can block 98% of UV rays. Installing UV-blocking window films in the home environment can reduce UVA penetration through windows. Outdoor workers can use portable UV index monitors to keep track of environmental UV intensity in real-time.
Seek medical attention immediately if you notice the following abnormalities on your skin: a new mole larger than 6 millimeters, uneven color in a mole, abnormal symmetry in shape, or blurred borders. If an existing mole shows rapid enlargement, non-healing ulceration, or bleeding, a dermatological examination should be arranged within three days.
High-risk groups with unexplained localized skin hardening, persistent itching, or tenderness should undergo professional evaluation. Individuals over 60 who develop unexplained facial ulcers, even if painless or itch-free, should be evaluated to rule out basal cell carcinoma. If more than two abnormalities from the "ABCDE criteria" are found during regular self-examinations, immediate medical attention for a tissue biopsy is warranted.
During self-examination, pay attention to abnormal lesions on the skin, including asymmetrical shapes of moles or patches, blurred borders, uneven colors, diameters exceeding 6 millimeters, or rapid changes within a short time. It is recommended to check hard-to-see areas, such as the back and scalp, using a mirror each month, and seek professional diagnosis promptly if abnormalities are found.
How should I choose daily sunscreen products to effectively reduce the risk of skin cancer?Select products with a sun protection factor (SPF) of 30 or higher that offer broad-spectrum protection (UVA/UVB), and reapply every two hours, especially after outdoor activities or swimming. Physical sunblock ingredients like zinc oxide or titanium dioxide are more suitable for sensitive skin, while chemical sunscreens require attention to potential allergic reactions. Wearing wide-brimmed hats, long-sleeved clothing, and seeking shade can enhance protective effects.
If diagnosed with early skin cancer, is surgery always necessary?Early skin cancers (such as actinic keratosis) can be controlled with topical medications or cryotherapy (liquid nitrogen), but if the lesions are deep or rapidly spreading, surgical excision remains the preferred option. Physicians will develop personalized treatment plans based on tumor size, location, and the patient's health status; some cases may combine radiation therapy or immunotherapy.
Is the risk of recurrence high for patients with non-melanoma skin cancer after treatment?The recurrence rate of non-melanoma skin cancers (such as basal cell carcinoma or squamous cell carcinoma) is related to the treatment method and tumor characteristics. If the initial treatment involves complete excision with clear margins, the recurrence probability is about less than 5%. However, if the tumor is deep, has a high degree of malignancy, or the patient has a weakened immune system, regular follow-up examinations are necessary, typically every 3 to 6 months for dermatoscopic checks.
Is it true that skin cancer only affects people with fair skin?This statement is not entirely accurate. While individuals with fair skin are at higher risk due to weaker melanin protection, darker-skinned populations can also develop skin cancer due to prolonged UV exposure or genetic factors, often occurring in less sun-exposed areas like the soles of the feet and nails. All groups should conduct regular self-examinations and avoid using UV lamps or excessive sun exposure.
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