Late-stage skin cancer means the disease has advanced considerably beyond its original skin location. Cancer cells have either invaded deeper tissues, affected nearby structures, or traveled to other body areas.
Understanding Advanced Skin Cancer
Advanced or late-stage skin cancer is characterized by its spread or deep local invasion, meaning it has grown into underlying tissues or disseminated to distant body parts. The primary types of skin cancer that can reach advanced stages include melanoma, squamous cell carcinoma (SCC), and basal cell carcinoma (BCC). Each type exhibits different patterns of progression when advanced.
Melanoma, which originates from pigment-producing cells, is the most serious form of skin cancer due to its propensity to spread rapidly. Advanced melanoma often means the cancer has spread to distant lymph nodes or organs such as the lungs, liver, brain, or bones. This stage is often referred to as metastatic or stage IV melanoma.
Squamous cell carcinoma, the second most common skin cancer, usually remains localized but can become advanced. Advanced SCC can involve extensive local growth, penetrating deeply into underlying tissues, muscles, or nerves. If SCC metastasizes, it most commonly spreads to regional lymph nodes, and less frequently to distant organs like the lungs, liver, or bones.
Basal cell carcinoma, while the most common type, rarely spreads beyond its original site. Untreated, it can grow deeply into nearby skin, cartilage, and bone, leading to significant local destruction. In very rare cases, advanced BCC may spread to nearby lymph nodes or distant sites like the lungs.
How Skin Cancer Spreads
The process by which cancer cells detach from a primary tumor and establish new tumors elsewhere in the body is known as metastasis. Skin cancer cells accomplish this primarily by traveling through the body’s circulatory system (bloodstream) or the lymphatic system. The lymphatic system, a network of vessels and small, bean-shaped organs called lymph nodes, plays a significant role in this spread.
Melanoma cells frequently spread first to nearby lymph nodes before moving to more distant sites. Common locations for distant melanoma metastasis include the lungs, liver, brain, and bones. The lungs are often one of the first visceral sites for melanoma spread. Melanoma can also spread to the skin itself, appearing as satellite lesions or in-transit metastases.
In contrast, squamous cell carcinoma is less likely to metastasize than melanoma, but when it does, it commonly spreads to regional lymph nodes. Distant spread of SCC is less frequent but can involve the lungs and bones. Basal cell carcinoma rarely spreads, but local invasion can be extensive, affecting cartilage and bone.
Identifying Late-Stage Skin Cancer
Diagnosing late-stage skin cancer involves procedures to determine its full extent and confirm systemic spread. A physical examination inspects skin lesions for changes and palpates regional lymph nodes for enlargement or tenderness, which can signal cancer dissemination.
Various imaging tests detect cancer that might have spread to internal organs or distant lymph nodes. Computed tomography (CT) scans provide detailed cross-sectional images, often used to identify metastases in the lungs or liver. Magnetic resonance imaging (MRI) offers high-resolution views, particularly for assessing spread to the brain or soft tissues. Positron emission tomography (PET) scans can detect metabolically active cancer cells throughout the body, helping to pinpoint areas of disease activity.
Biopsies remain a definitive method for confirming the diagnosis of advanced skin cancer. An excisional biopsy involves removing the entire primary skin lesion for microscopic examination to determine its depth and other features. A sentinel lymph node biopsy assesses whether cancer cells have reached the first lymph node in the drainage pathway from the primary tumor. If imaging tests suggest distant spread, biopsies of these suspected metastatic sites are taken to confirm the presence of cancer and its origin from skin cancer.
Managing Advanced Skin Cancer
Managing advanced skin cancer involves an individualized treatment plan developed by a multidisciplinary team. Systemic therapies, which affect the entire body, address widespread disease.
Immunotherapy uses medications that stimulate the body’s own immune system to recognize and attack cancer cells. Checkpoint inhibitors like pembrolizumab and nivolumab are examples used for advanced melanoma.
Targeted therapy focuses on specific genetic mutations found within cancer cells that drive their growth. For melanomas with particular gene changes, such as in the BRAF gene, specific inhibitors like dabrafenib and trametinib can block these signals, slowing or stopping cancer progression. Chemotherapy may still be used in certain situations to kill rapidly dividing cancer cells.
Radiation therapy plays a role in managing advanced skin cancer, often used for local control or to alleviate symptoms. It can target specific areas where cancer has spread, such as the brain or bones, to reduce tumor size and manage pain. For non-melanoma skin cancers, radiation can be a primary treatment if surgery is not feasible or used after surgery to eliminate remaining cancer cells.
Surgical interventions are also part of the management strategy, especially for resectable tumors. This can involve removing the primary tumor, affected lymph nodes, or even isolated metastases in organs like the lungs or liver if resectable. The decision for surgery in advanced cases depends on various factors, including the number and location of metastases, and is often combined with other therapies.