黑料网

Skin Cancer; Basal cell carcinoma (BCC); Squamous cell carcinoma (SCC); Melanoma; Dermoscopy; Confocal laser scanning microscopy; Optical coherence tomography; Artificial intelligence (AI); Machine learning (ML); Diagnostic techniques; Biomarkers; Genomics; Proteomics; Personalized medicine; Public health initiatives

Introduction

Skin cancer is one of the most common types of cancer worldwide, with millions of cases diagnosed each year. It occurs when there is an uncontrolled growth of abnormal skin cells, which can invade and damage surrounding tissues [1]. The primary types of skin cancer include basal cell carcinoma (BCC), squamous cell carcinoma (SCC), and melanoma. Early diagnosis is crucial as it significantly improves the chances of successful treatment and can prevent the cancer from spreading to other parts of the body [2]. Skin cancer, a term encompassing various malignancies that originate in the skin's tissues, represents the most common form of cancer globally [3]. The primary types of skin cancer are basal cell carcinoma (BCC), squamous cell carcinoma (SCC), and melanoma, each differing significantly in prevalence, etiology, and prognosis. Basal cell carcinoma, the most frequent, is typically less aggressive, while melanoma, though less common, is notably more lethal due to its potential for rapid metastasis [4]. The rising incidence of skin cancer can be attributed to increased ultraviolet (UV) radiation exposure, changes in lifestyle, and improved detection methods. Understanding the complexities of skin cancer diagnosis is critical for early detection and effective treatment [5]. The diagnostic process involves a multifaceted approach, integrating clinical evaluation, dermatoscopic examination, and histopathological analysis. Advances in technology have also introduced innovative diagnostic tools such as digital dermoscopy, reflectance confocal microscopy (RCM), and artificial intelligence (AI)-based systems, enhancing diagnostic accuracy and aiding in early intervention [6].

The clinical evaluation begins with a thorough patient history and a physical examination, focusing on the identification of suspicious lesions. Dermoscopy, a non-invasive technique, allows for the magnification and illumination of skin structures, providing detailed visualization of pigmentation patterns and vascular structures [7]. This method has significantly improved the diagnostic accuracy for melanoma and other pigmented lesions. However, definitive diagnosis often requires histopathological confirmation through biopsy, where tissue samples are examined under a microscope to identify malignant cells and determine the cancer type [8].

Recent advancements in imaging techniques and molecular diagnostics have revolutionized skin cancer diagnosis [9]. Technologies such as RCM provide real-time, in vivo visualization of skin layers at a cellular resolution, facilitating the identification of malignancies without the need for invasive procedures. Additionally, AI and machine learning algorithms have shown promise in analyzing dermoscopic images, offering high sensitivity and specificity rates, and assisting clinicians in making informed decisions [10].

Public awareness and regular screening play pivotal roles in the early detection of skin cancer. Educating individuals about the risks of UV exposure, encouraging protective measures, and promoting self-examination and routine dermatological check-ups can significantly reduce the burden of this disease. Moreover, understanding the genetic and environmental factors contributing to skin cancer development is crucial for devising targeted prevention strategies and personalized treatment plans.

Types of skin cancer

Basal cell carcinoma (BCC)

BCC is the most common form of skin cancer, accounting for about 80% of cases. It originates in the basal cells, which are found in the lower part of the epidermis. BCC often appears as a painless raised area of skin, which may be shiny with small blood vessels running over it. It can also manifest as a red patch, a sore that doesn’t heal, or a scar-like area.

Squamous cell carcinoma (SCC)

SCC is the second most common type of skin cancer, making up about 20% of cases. It arises from squamous cells, which are flat cells found in the outer part of the epidermis. SCC often appears as a rough, scaly red patch, an open sore, a wart-like growth, or a raised growth with a central depression. Unlike BCC, SCC can metastasize if not treated promptly.

Melanoma

Melanoma is the most dangerous form of skin cancer, although it is less common than BCC and SCC. It develops in the melanocytes, the cells responsible for producing melanin, the pigment that gives skin its color. Melanoma can appear as a new dark spot on the skin or develop from an existing mole. It is characterized by the ABCDE rule: Asymmetry, Border irregularity, Color variation, Diameter greater than 6mm, and Evolving shape and size. Early detection is critical, as melanoma can quickly spread to other parts of the body.

Risk factors

Several factors can increase the risk of developing skin cancer, including:

Ultraviolet (UV) radiation: Prolonged exposure to UV radiation from the sun or tanning beds is the primary risk factor for skin cancer.

Fair skin: Individuals with fair skin, light hair, and blue or green eyes are at higher risk.

Family history: A family history of skin cancer increases the likelihood of developing the disease.

Personal history: Having had skin cancer once increases the risk of developing it again.

Age: The risk of skin cancer increases with age.

Weakened immune system: Individuals with weakened immune systems, such as those who have undergone organ transplants, are at higher risk.

Exposure to certain chemicals: Exposure to substances like arsenic can increase the risk of skin cancer.

Diagnosis of skin cancer

Self-examination

Regular self-examination of the skin is crucial for early detection. Individuals should check their skin monthly, looking for any new growths, changes in existing moles, or any other unusual changes. The ABCDE rule can be a helpful guide in identifying potential melanomas.

Clinical examination

If an individual notices any suspicious changes, they should consult a healthcare professional. The clinician will perform a thorough skin examination, looking for any abnormal growths or changes.

Dermoscopy

Dermoscopy is a non-invasive diagnostic tool that allows healthcare providers to examine skin lesions with greater detail. It involves the use of a dermatoscope, a handheld device that magnifies the skin and illuminates it with polarized light. Dermoscopy can help differentiate between benign and malignant lesions, improving diagnostic accuracy.

Biopsy

If a suspicious lesion is identified, a biopsy is performed to confirm the diagnosis. There are several types of biopsies:

Shave biopsy: A thin layer of skin is shaved off the lesion.

Punch biopsy: A circular tool is used to remove a small core of skin, including deeper layers.

Excisional biopsy: The entire lesion is removed, along with a margin of normal skin.

Incisional biopsy: A portion of the lesion is removed.

The tissue sample is then examined under a microscope by a pathologist to determine if cancer cells are present.

Imaging tests

In cases where skin cancer is suspected to have spread, imaging tests such as X-rays, CT scans, MRI, or PET scans may be performed to evaluate the extent of the disease.

Staging

Once skin cancer is diagnosed, it is staged to determine the extent of the disease. The staging system varies depending on the type of skin cancer but generally involves evaluating the size of the tumor, the involvement of nearby lymph nodes, and the presence of metastasis. The most common staging system for melanoma is the American Joint Committee on Cancer (AJCC) TNM system, which stands for Tumor, Node, and Metastasis.

Treatment

The treatment of skin cancer depends on the type, stage, and location of the cancer, as well as the patient’s overall health. Common treatment options include:

Surgical treatment

Excisional surgery: The cancerous tissue is surgically removed along with a margin of healthy tissue.

Mohs surgery: This precise surgical technique involves removing the cancer layer by layer and examining each layer under a microscope until no abnormal cells remain.

Curettage and electrodessication: The tumor is scraped away with a curette, and the area is treated with an electric needle to destroy any remaining cancer cells.

Non-surgical treatments

Radiation therapy: High-energy radiation is used to kill cancer cells. It is often used for cancers that are difficult to treat surgically.

Cryotherapy: Liquid nitrogen is used to freeze and destroy abnormal cells.

Topical treatments: Medications such as imiquimod or 5-fluorouracil can be applied to the skin to treat superficial skin cancers.

Photodynamic therapy: A photosensitizing agent is applied to the skin and activated by light, destroying cancer cells.

Systemic treatments

Chemotherapy: Drugs are used to kill cancer cells. It is often used for advanced skin cancers.

Targeted therapy: Drugs that target specific molecules involved in cancer growth, such as BRAF inhibitors for melanoma, are used to treat certain types of skin cancer.

Immunotherapy: Drugs that enhance the body’s immune system to fight cancer, such as checkpoint inhibitors, are used for advanced melanomas and other skin cancers.

Prevention

Preventing skin cancer involves several key strategies:

Sun protection: Wearing protective clothing, using broad-spectrum sunscreen with an SPF of 30 or higher, seeking shade, and avoiding tanning beds.

Regular skin checks: Performing monthly self-examinations and getting annual skin checks by a dermatologist.

Education and awareness: Understanding the risk factors and early signs of skin cancer.

Conclusion

Skin cancer is a significant health concern, but early diagnosis and treatment can greatly improve outcomes. Regular self-examinations, professional skin checks, and protective measures against UV radiation are essential in the fight against skin cancer. Advances in diagnostic tools and treatments continue to enhance the ability to detect and treat skin cancer effectively, offering hope for better patient outcomes. Skin cancer diagnosis is a dynamic and evolving field, reflecting ongoing advancements in medical technology and a deeper understanding of the disease's pathophysiology. The comprehensive approach to diagnosing skin cancer, incorporating clinical assessment, dermatoscopic analysis, histopathology, and innovative imaging techniques, underscores the importance of early and accurate detection. Emerging technologies, particularly in the realm of AI and molecular diagnostics, hold promise for enhancing diagnostic precision and tailoring individualized treatment plans.

The diagnosis of skin cancer encompasses a blend of traditional methods and cutting-edge technologies, each contributing to a more thorough understanding and management of the disease. Continued innovation and collaboration in the medical community are vital to advancing diagnostic techniques and ultimately reducing the incidence and mortality associated with skin cancer. By prioritizing early detection and prevention, we can make significant strides in combating this prevalent and potentially deadly condition.

1. Kyrgiou M, Koliopoulos G, Martin-Hirsch P, Arbyn M, Prendiville W, et al. (2006) Lancet 367: 489-98.

, ,

2. Kyrgiou M, Athanasiou A, Kalliala IE, Paraskevaidi M, Mitra A, et al. (2017 The Cochrane Database of Systematic Reviews 11: 12847.

, ,

3. Massad LS, Einstein MH, Huh WK, Katki HA, Kinney WK, et al. (2013) Journal of Lower Genital Tract Disease 17: 1-27.

, ,

4. Rapp L, Chen JJ (1998) Biochimica et Biophysica Acta (BBA)-Reviews on Cancer 1378: 1-19.

, ,

5. Monnier-Benoit S, Dalstein V, Riethmuller D, Lalaoui N, Mougin C, et al. (2006) Journal of Clinical Virology. 35: 270-7.

, ,

6. Lowy DR, Schiller JT (2006) The Journal of Clinical Investigation 116: 1167-73.

, ,

7. Gajjar K, Martin-Hirsch PP, Bryant A, Owens GL (2016) The Cochrane Database of Systematic Reviews 7: 6120.

, ,

8. Nagi CS, Schlosshauer PW (2006) Gynecologic Oncology 102 (2): 240-3.

, ,

9. Melnikow J, Nuovo J, Willan AR, Chan BK, Howell LP (1998) Obstetrics and Gynecology 92: 727-35.

, ,

10. Solomon D, Davey D, Kurman R, Moriarty A, Prey M, et al. (2002) JAMA 287 (16): 2114-9.

, ,