Radiation Therapy for Skin Cancer: When and How

Overview / Definition Radiation therapy (RT) is a non-invasive treatment option that utilizes high-energy radiation to destroy cancer cells. It is commonly employed in the management of various types of skin cancer, including basal cell carcinoma (BCC), squamous cell carcinoma (SCC), and melanoma. RT can be used as a primary treatment, adjuvant therapy following surgery, or in palliative care settings. Epidemiology Skin cancer is the most prevalent form of cancer in the United States, with more than 3.3 million cases of nonmelanoma skin cancer diagnosed annually. The incidence of melanoma, although less common, is rising at an alarming rate. Key epidemiological points include: Nonmelanoma skin cancers (NMSCs) account for approximately 80% of skin cancer cases. Melanoma has a lifetime risk of about 1 in 38 for Caucasians. Incidence is increasing, particularly in individuals with fair skin and those over 65 years of age. Pathophysiology / Mechanism The effectiveness of radiation therapy is based on the principle of delivering ionizing radiation that damages the DNA of cancerous cells, leading to cell death. The primary mechanisms involved include: Direct DNA damage: Radiation breaks DNA strands, triggering apoptosis. Indirect damage: Radiation generates free radicals that further damage cellular components. Cells with high proliferation rates, such as cancer cells, are more susceptible to radiation due to their inability to repair DNA damage efficiently. Clinical Presentation Patients with skin cancer may present with various clinical features depending on the type of cancer. Common manifestations include: Basal Cell Carcinoma (BCC): Pearly nodules, ulcerations, or crusting lesions. Squamous Cell Carcinoma (SCC): Red, scaly patches, or firm nodules that may ulcerate. Melanoma: Asymmetrical moles with irregular borders, color variegation, and changes in size. Diagnosis / Workup The diagnosis of skin cancer typically involves a thorough clinical examination and may requ