Squamous Cell Carcinoma: Risk Factors and Prognosis

Overview / Definition Squamous Cell Carcinoma (SCC) is a malignant tumor arising from the squamous cells, which are flat cells found in the outer layer of the skin and in mucous membranes. SCC can present as a solitary lesion or as part of a larger field of actinic damage, and it is primarily caused by cumulative sun exposure, although other risk factors also contribute. Epidemiology SCC is one of the most prevalent forms of skin cancer, accounting for about 20% of all nonmelanoma skin cancers. Its incidence has been increasing over the past few decades, particularly in fair-skinned populations. Key epidemiological factors include: Age: Most common in individuals over 50 years old. Gender: Males are more frequently affected than females. Geography: Higher incidence in regions with intense sunlight exposure. Skin Type: Individuals with fair skin, light hair, and light eyes are at higher risk. Pathophysiology / Mechanism The pathogenesis of SCC involves genetic mutations, particularly in the TP53 tumor suppressor gene, often triggered by UV radiation. The mechanism includes: UV Radiation: Causes direct DNA damage leading to mutations. Immune Suppression: UV exposure can suppress local immune responses, allowing malignant cells to proliferate. Chronic Inflammation: Conditions like actinic keratosis can predispose individuals to SCC. Clinical Presentation SCC can present in various forms, including: Common Variants: Invasive SCC, in situ SCC (Bowen's disease). Lesion Characteristics: Typically presents as a red, scaly patch, a firm nodule, or a ulcerative lesion. Location: Commonly affects sun-exposed areas such as the face, ears, neck, scalp, and back of the hands. Diagnosis / Workup The diagnosis of SCC is primarily clinical, but confirmation is achieved through: Skin Biopsy: Excisional or punch biopsy to obtain tissue for histopathological examination. Imaging Studies: CT or MRI may be indicated for advanced lesions to assess metastasis. Treatment / Management Manage