Melanoma, a serious form of skin cancer, originates in melanocytes, the cells responsible for producing skin pigment. If left untreated, this cancer can progress significantly, leading to severe and life-threatening complications. This article outlines the path that untreated melanoma can take within the body.
Initial Growth and Local Invasion
Untreated melanoma begins uncontrolled growth at its primary site on the skin. Initially, it expands horizontally across the skin surface. A more aggressive phase, the vertical growth phase, sees cancer cells penetrating deeper into the skin layers. This deeper invasion can lead to visible changes, such as the lesion becoming raised, firm, or developing an ulcerated surface that may bleed or crust. The continued proliferation of these cancerous cells locally damages surrounding healthy tissues, making the melanoma increasingly aggressive even while confined to the skin.
Spread to Lymph Nodes
From its initial site, untreated melanoma can advance by spreading to regional lymph nodes. Cancer cells detach from the primary tumor and enter the lymphatic system, a network of vessels and nodes that are part of the body’s immune system. These cells travel through lymphatic channels, often reaching the nearest lymph node, known as the sentinel lymph node. Once established in these nodes, the cancer cells can multiply, causing the lymph nodes to become swollen or painful. Involvement of lymph nodes signifies a more advanced stage, increasing the risk of the cancer spreading further throughout the body.
Distant Organ Involvement
The progression of untreated melanoma often culminates in distant metastasis, where cancer cells travel through the bloodstream or lymphatic system to establish new tumors in organs far from the original site. Common sites for these secondary tumors include the lungs, liver, brain, and bones.
If melanoma spreads to the lungs, individuals may experience a persistent cough, shortness of breath, or chest pain. Liver metastases can manifest as discomfort in the upper right abdomen, loss of appetite, fatigue, or yellowing of the skin and eyes (jaundice).
When melanoma reaches the brain, symptoms can include headaches, seizures, vision problems, or changes in mental status. Bone metastases may cause localized pain that worsens over time, or lead to weakened bones that are more prone to fractures. Melanoma can also spread to the gastrointestinal tract, causing symptoms like abdominal pain or changes in bowel habits. The development of these distant tumors indicates widespread disease and significantly complicates treatment efforts.
Impact on Overall Health and Survival
The cumulative effect of untreated, widespread melanoma significantly impacts an individual’s overall health and quality of life. The systemic burden of the disease often leads to general symptoms such as persistent fatigue, unexplained weight loss, and widespread pain. These symptoms arise as the body struggles with the growing number of cancer cells and their disruption of normal organ function. The presence of melanoma in multiple organs can also lead to organ-specific complications, such as respiratory failure from lung metastases or neurological deficits from brain tumors.
Untreated melanoma is ultimately life-threatening, as the unchecked growth and spread of cancer cells overwhelm the body’s systems. Survival rates decrease substantially as the disease progresses from localized to regional and then to distant metastasis. For instance, the five-year survival rate for localized melanoma is over 99%, but this drops to about 75% for regional spread and further to approximately 35% for distant metastasis. This decline in survival highlights the severe consequences of allowing melanoma to progress without intervention.