Metastatic Melanoma - Causes, Symptoms, Diagnosis, and Treatment

Introduction

Cancer has become a global burden and has affected millions of people worldwide. Cancers can originate from any part of the body, including the brain, lungs, pancreas, and skin. However, even with the advancement of medical technology, researchers have not been able to determine the exact reason for cancer. Unfortunately, most cancers do not show symptoms in the initial stages making the diagnosis unworkable.

What Is Metastatic Melanoma?

Before digging into metastatic melanoma, it is essential to understand what melanoma is.

Melanoma-

Melanoma is a type of skin cancer that arises from melanocytes, cells that produce a pigment called melanin. Melanin is responsible for determining the color of skin, hair, and eyes. Melanocytes are usually located in the bottom layer of the skin. Melanomas can develop in any part of the body, but the sun-exposed areas are at higher risk.

When the cancerous cells of melanoma grow uncontrollably, the tumor cells spread to other parts of the body. These cells travel through the lymph nodes or blood and invade a distant organ. This distant spreading of the primary tumor is known as metastasis, and this usually occurs in the advanced stages of cancer. Metastatic melanoma usually affects the lungs, liver, and brain. According to the American society of clinical oncology (ASCO), 4 % of people diagnosed with melanoma show distant metastasis.

Stages of Metastatic Melanoma-

Stage 0, stage 1, and stage 2 of melanoma are localized and are not spread to distant organs. However, stage 3 (some cases) and stage 4 melanomas show distant metastasis. Specifically, stage 4 melanoma spreads to various organs like the lungs, brain, bones, and liver.

How Do You Get Metastatic Melanoma?

Exposure to UV (ultraviolet) light causes the most type of skin cancers. The UV rays from the sun damage the DNA (deoxyribonucleic acid), and eventually, cells lose their ability to divide in a controlled and coordinated manner. Tanning beds and the sun are the two primary sources of UV light. At first, the melanoma (the primary tumor) develops due to DNA damage and later spreads to other organs. Sometimes the primary tumor may be so small that it goes unnoticed until the symptoms from metastasis develop.

Risk Factors Associated With Melanoma-

• Light skin, eyes, and hair color.

• Skin that is prone to sunburns.

• Multiple episodes of sunburns and blistering during childhood.

• History of melanoma running in the family.

• Exposure to UV light from the sun or tanning beds frequently.

• Mutations in certain genes.

Risk Factors Associated With Metastatic Melanoma-

• Males are more likely to develop metastatic melanoma.

• A type of melanoma called nodular (raised bump on the skin) melanoma is likely to metastasize.

• If the primary melanoma is ulcerated, it will likely spread to other organs.

What Are the Signs and Symptoms of Metastatic Melanoma?

Melanoma presents as an abnormal discoloration of the skin in the early stages. They are usually detected before they become metastatic. Any abnormal changes in the already existing mole or discoloration also indicate melanoma. People with risk factors for melanoma must be careful to identify these changes. It is also likely that sometimes the primary melanoma goes undetected. The signs and symptoms of metastatic melanoma include:

A. Changes in the lesion-

• A - Asymmetry or irregular shape of the lesion.

• B - The borders of the lesion are irregular or notched.

• C - Changes in the color of the lesion or uneven color.

• D - Changes in the diameter by one-fourth of the initial size.

• E - The evolution of the lesion, including changes in the size, shape, color, elevation, etc.

B. General Symptoms-

• Unexplained weight loss.

• Fatigue and loss of appetite.

• Swollen lymph nodes that hurt.

Signs and Symptoms of Metastatic Melanoma Depending on the Organ Affected-

A. Lung Metastasis-

• Pain in the chest.

• Difficulty breathing.

• Accumulation of fluid around the lungs.

• Coughing.

• Coughing up blood from the lungs.

B. Liver Metastasis-

• Fatigue and general discomfort.

• Loss of appetite.

• Abdominal pain and swelling.

• Swelling in the legs.

• Liver enlargement.

• Itchy skin.

• Yellowish discoloration of the skin and eyes (jaundice).

C. Brain Metastasis-

• Nausea, vomiting, and general discomfort.

• Persistent headache.

• Drowsiness.

• Transient memory loss.

• Seizures.

• Sensory changes like impaired vision, hearing, etc.

• Emotional and behavioral changes.

• Paralysis of hands and legs.

D. Bone Metastasis-

• Weak and brittle bones that are prone to fracture.

• Pain in the bones.

• Numbness and pain in various body parts.

• Changes in calcium metabolism cause symptoms like drowsiness, confusion, etc.

How Is Metastatic Melanoma Diagnosed?

• Biopsy- A biopsy is taken using a scalpel or a punch tool if there is evidence of primary melanoma. The obtained tissues are studied under a microscope for cancerous changes.

• Sentinel Lymph Node Biopsy (SLNB)- If the tumor has spread through the lymph nodes, the doctor will physically examine it to determine the associated changes. SLNB is a procedure carried out to trace the primary tumor by injecting a radioactive dye.

• Advanced Imaging- These techniques include MRI (magnetic resonance imaging), CT (computed tomography), PET (positron emission tomography), and ultrasound scans. The spreading tumor can be visualized in a non-invasive way.

• Blood Tests- Certain chemicals known as tumor markers are elevated in the blood. Studying the blood chemistry to detect these markers will help in the diagnosis.

What Is the Treatment of Metastatic Melanoma?

Treatment of melanoma is difficult because of the inability to locate the tumor. For metastatic melanoma, the following treatment modalities (individual or combination) are considered:

• Surgery- Surgical removal of the tumor is carried out under anesthesia. Along with the primary tumor, the affected lymph nodes are also removed. The distant metastasized melanoma can also be removed by surgery, thereby increasing the survival rate of the patients.

• Radiation Therapy- This is achieved by using ionizing radiation beams to target cancer cells. Radiation therapy helps in preventing the recurrence and management of metastatic melanoma.

• Immunotherapy- Utilizes drugs that help the body’s immune system to target and kill the cancer cells.

• Chemotherapy- These drugs kill cancer cells by interfering with the cell cycle. However, chemotherapy is seldom used in the treatment of metastatic melanoma.

What Is the Prognosis and Survival Rate of Metastatic Melanoma?

• The five-year survival rate of melanoma that has spread to distant organs is 27 %.

• The five-year survival rate of melanoma that has spread to a local lymph node is 66 %.

• Stage 3 and stage 4 melanoma are more likely to recur even after the treatment.

Conclusion

This distant spreading of the primary melanoma is known as metastasis, and this usually occurs in the advanced stages of cancer. Metastatic melanoma usually affects the lungs, liver, and brain. The symptoms mainly depend on the type of organ involved. The diagnosis of metastatic melanoma is made after studying the biopsy, blood tests, and advanced imaging. Surgery, immunotherapy, and radiotherapy are the primary treatment modalities. The five-year survival rate of stage 3 and stage 4 metastatic melanoma is 27 %. Therefore, with the advancement in treatment modalities, improvement in the prognosis and lifespan can be expected.