What makes Melanoma so deadly?

13 de julio de 2021

4 min de lectura

Melanoma is the most aggressive type of skin cancer and the type with the highest mortality rate. What makes melanoma so deadly? If not detected and treated early, it metastasizes, or spreads, quickly to other organs. Once that happens, the chances of a cure drop significantly.

Each year, approximately 75,000 people in the U.S. are diagnosed with melanoma. Roughly 10,000 people succumb to the disease. Men are at a slightly higher risk than women.

Avoiding excessive sun exposure and always wearing sunscreen with a Sun Protection Factor (SPF) of at least 30 are the best ways to protect yourself against melanoma. The sun’s ultraviolet rays are still harmful in winter and on cloudy days, so prevention is a 365-day a year venture.

Melanoma

Cells that produce pigment are called melanocytes. When melanocyte reproduction becomes out of control, melanoma results.

It is not possible to predict just how fast a melanoma will spread, but it can happen very fast.

Spotting Melanoma Early

The survival rates for melanomas discovered prior to spreading, or in situ, are far higher than those detected after metastasis occurs. That is why conducting a monthly skin check is crucial. See a doctor immediately if you notice any potential signs of melanoma. These for any changes in moles, based on the A, B, C, D, and E model:

A–Asymmetry. The halves of the mole are uneven.
B–Border irregularities
C–Color of the skin varies within the same mole. Melanomas may include shades of brown, black, or tan, and some have red, gray, or white areas.
D–Diameter. A diameter above 6 millimeters, the size of a pencil eraser, may indicate melanoma.
E–Evolving. Is the mole new or have there been recent changes in its appearance?

A bleeding mole or one with a crust-like surface is potentially a melanoma.

Schedule an annual appointment with your dermatologist to have a whole-body skin check. If there are precancerous moles or lesions, the doctor can biopsy them. A pathologist will examine the sample to determine whether it contains cancer.

Where Melanoma Spreads

Like many cancers, melanoma usually spreads first into lymph nodes near the tumor site. From there, melanoma cells pass into the bloodstream and the rest of the body. A recent study in mice funded by the National Cancer Institute found that melanoma cells passing through the lymphatic system prior to entering the bloodstream spread more easily and form new tumors more rapidly than melanoma cells entering the bloodstream directly.

Beyond the lymph nodes, melanoma most commonly spreads to the:

Lungs
Liver
Subcutaneous tissue
Brain
Gastrointestinal tract
Bones
Adrenal glands

Melanoma Prognosis

Patients diagnosed with melanoma want to know their prognosis. Prognosis and survival depend on various factors. These include:

Tumor thickness –A thicker tumor has a poorer prognosis. If the melanoma is less than 1 mm thick it is less likely to spread to other areas of the body. Those tumors above 4 mm in thickness are more likely to metastasize. These growths are also more prone to recurrence, or coming back after removal.
Location –Melanomas on the limbs have a better prognosis than those found on the trunk, neck, or head. Melanomas may also appear on the soles of the feet or palms of the hand. These melanomas generally have a poorer prognosis.
Cancer in lymph nodes –The higher the number of lymph nodes containing cancer, the poorer the prognosis. If the nodes are enlarged enough for palpation during diagnostic imaging tests, that indicates a worse prognosis than if there are only micrometastases, or tiny amounts of cancer, in the nodes.
Ulceration –An ulcerated melanoma, one with an open wound, has a less favorable prognosis than a tumor that does not ulcerate. Ulceration raises the risk of metastasis.
Mitotic rate –This is the measure of the speed of cancer cell division and growth. Mitosis is the number of cells dividing in a particular amount of cancer tissue. A high mitotic rate is associated with a poorer prognosis.
Growth pattern –A type of skin cancer known as nodular melanoma has a poor prognosis because it grows vertically into the skin. It is usually a thicker tumor.

When the melanoma has spread to distant organs, the prognosis is not good.

Survival Rates

Keep in mind that survival rates for melanoma are estimates. Much depends on the cancer’s stage, consisting of tumor size and whether it has spread. When caught early, before it has a chance to spread, the five-year survival rate for Stage 1A melanoma is 97 percent.

Survival rates are based on the percentage of patients diagnosed with melanoma who are alive X years after diagnosis. It does not necessarily mean all of those individuals died from melanoma.

For Stage 2A, the five-year survival rate is 81 percent. For stage 3A, it is 78 percent, and 59 percent for stage 3B. For stage 4, the highest stage, the rate drops to between 15 and 20 percent.

Sources

Melanoma - The Skin Cancer Foundation

Melanoma - Harvard Health

How Dangerous is Melanoma? It’s All a Matter of Timing (skincancer.org)

Melanoma Cells that Pass through Lymph More Likely to Spread - National Cancer Institute

Prognosis and survival for melanoma skin cancer - Canadian Cancer Society

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En esta página

Melanoma

Spotting Melanoma Early

Where Melanoma Spreads

Melanoma Prognosis

Survival Rates

Sources

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