Black skin cancer (malignant melanoma)

Malignant melanoma is a malignant tumor of the skin that has a rapid spread. One feature of black skin cancer that contributes to its poor prognosis is the early formation of metastases (scattered settlements) in other organs of the human body. In Europe, malignant melanoma affects approximately 12 per 100,000 people per year. A higher incidence is particularly noticeable in Australia, where the population is exposed to more sunlight.

Overall, more women than men are affected by this form of cancer. In contrast to men, who mainly develop malignant melanoma at an older age, this form of cancer also occurs more often at a younger age in women. This is also confirmed by the lower average age of onset of the disease in women (57 years) compared to men (63 years). In recent years, however, the proportion of young people with malignant melanoma has generally increased.

Black skin cancer can also develop in regions of the body that are not constantly exposed to the sun. Thus, malignant melanoma in men occurs predominantly on the trunk, while in women melanomas are relatively often found on the limbs. Occasionally, however, malignant melanomas can also develop in areas of the body where they are difficult to detect, such as in the nail bed, between the toes or even on mucous membranes.

Skin damage due to sun exposure

In most cases, malignant melanoma develops as a result of excessive sunbathing. However, the decisive factor here is not the total sun exposure in the course of a lifetime, but above all individual intensive sunburns, which are significantly involved in the development of malignant melanoma.

In addition to natural sunlight, frequent and intensive visits to solariums can also significantly increase the risk of developing black skin cancer.

Moles

People with fair skin and red hair are relatively more likely to develop melanoma. People with many moles are also particularly at risk of developing malignant melanoma. People with more than fifty moles have an increased risk of developing cancer.

Furthermore, there are genetic predispositions that can promote the development of malignant melanoma, which is why black skin cancer occurs more frequently in families with a high risk.

In about 2/3 of the cases, malignant melanoma develops on inconspicuous skin areas. Only in a smaller proportion of those affected does a malignant tumour develop from a pre-existing or abnormal mole (atypical nevus), a hairy mole that has existed since birth, or from cancerous precursors (lentigo maligna).

Degenerated melanocytes

Although a number of factors that promote the development of malignant melanoma are already known, it is not yet known exactly how the factors cause black skin cancer. However, it is known that melanoma develops from altered skin pigment cells (melanocytes). This leads to a degeneration of the growth of these melanocytes, which can then multiply unchecked. One ability of these degenerated pigment cells is that they have a high mobility within the skin and can therefore spread early into other organs of the body (metastases).

Malignant melanoma can occur in different forms. In principle, the following forms of melanoma occur most frequently:

Superficial spreading melanoma (SSM): This form of malignant melanoma affects most people worldwide. It usually develops over a period of one to four years and occurs predominantly on the back, chest, arms or legs. Usually the melanoma is flat and can be partly nodular. Furthermore, it is clearly demarcated from the surrounding skin. The melanoma can also be conspicuous due to colour changes, such as brown, pink, grey and bluish-black areas, or small white areas.

Nodular melanoma (NM): This is a very rapidly growing form of black skin cancer. Similar to superficial spreading melanoma, it most commonly occurs on the chest, back, or limbs. Nodular melanoma usually develops in just a few months. It is usually nodular and raised in structure, may bleed easily, and is usually very dark (bluish, dark brown) in color. Due to its aggressive growth, nodular melanoma has a very malignant course with poor prognosis.

Lentigo maligna melanoma (LMM): This form of malignant melanoma mainly affects older people. It develops gradually over many years from a benign precancerous stage (lentigo maligna). In most cases, lentigo maligna melanoma occurs in areas of the skin that are frequently exposed to the sun, for example on the face, neck, arms and hands.

Acral lentiginous melanoma (ALM): Acral lentiginous melanoma occurs predominantly, as the name suggests, on the acras, i.e. the ends of the extremities. It is mainly on the palm of the hand, the sole of the foot, and the fingers and toes that this form of melanoma occurs. Because it can also often grow under the nails, actral lentiginous melanoma is often mistaken for a small injury to the nail bed, a fungus or a wart. A blotchy structure with different colors and fuzzy borders is typical for this melanoma.

In addition to these forms of malignant melanoma, there are other types that are not as common. For all malignant melanomas it is true that they usually start to bleed even by small scratches.

The earliest possible diagnosis is crucial for the chances of recovery from malignant melanoma. Unlike other forms of cancer, diagnosing melanoma usually does not require extensive examination methods. A thorough inspection of the entire skin is very important to detect malignant melanoma, although the skin cancer can also be detected in time with regular checks by the patients themselves. It should be noted that the majority of moles are not malignant in most cases. However, in order to be able to detect malignant melanomas, the ABCDE rule can be helpful.

• A=Asymmetry: Healthy moles are usually circular and symmetrical.
• B=Boundary: If melanomas are not sharply demarcated from the surrounding skin, this may indicate a degenerate mole.
• C=Coloration (discoloration): Especially black melanomas, as well as moles that show several different colors, should be further clarified with the doctor.
• D=Diameter: Moles that are larger than half a centimeter or that are visibly getting larger may also be malignant.
• E=Elevation: Malignant melanomas are usually elevated and do not have a flat surface.

If 4 features of the ABCDE rule are detectable in a mole, there is an urgent suspicion that it is a malignant melanoma. In this case, the melanoma should be removed prophylactically by means of a small operation and examined under the microscope.

Furthermore, conspicuous melanomas can be examined with a dermatoscope. This is a microscope that is especially suited for the evaluation of melanomas. If conspicuous moles are discovered with the dermatoscope, these should also be removed and microscopically evaluated.

For a complete diagnosis, blood tests and ultrasound examinations should also be performed for melanomas that are thicker than 1 mm.

Metastases

If a malignant melanoma is diagnosed, it is absolutely necessary to determine or exclude the presence of malignant cells in other organs. For this purpose, various imaging procedures such as CT, MRI, X-ray and ultrasound examinations as well as bone scintigraphy can be used.

Both the type of therapy and the chances of cure depend on the progress of the cancer. Several stages are distinguished from each other:

• Stage 0:The degenerate cells of the malignant melanoma are located exclusively in the uppermost layer of the skin and have not yet grown into the depths.
• Stage I: Cells of the malignant melanoma have already penetrated the dermis. The malignant mole is larger than 1.5 millimeters, but the surrounding lymph nodes are free of cancer cells.
• Stage II:The diameter of the melanoma is larger than 1.5 millimeters but smaller than 4 millimeters. In this stage, the cancer cells have already penetrated the dermis, but neither deeper layers nor surrounding lymph nodes are affected.
• Stage III: The cancer cells have already invaded deep layers of the skin as well as surrounding lymph nodes. In addition, so-called satellite tumours may develop in the immediate vicinity and adjacent tissues and organs may be affected.
• Stage IV: The malignant melanoma has already spread to other organs and distant lymph nodes (distant metastases).

Surgical removal

The basic treatment for almost any malignant melanoma is surgical removal of the tumor. To ensure that no cancer cells remain, adjacent tissue more than one centimeter in diameter is also surgically removed.

If growth of the melanoma into deeper layers has already been diagnosed by ultrasound before the operation, the surrounding tissue within a radius of three centimetres should be cut out. If an extension of the tumour into deeper skin layers is only discovered under the microscope after the operation, the tissue within a radius of three centimetres must then be removed in a second operation.

If an infestation of the surrounding lymph accounts is detected before or during the operation, these must also be removed.

Chemotherapy and radiotherapy

If the malignant melanoma has already spread to distant organs or lymph nodes, the prognosis is considerably worse. For the time being, an attempt is made to surgically remove these metastases. However, if this is not successful, chemotherapy is added to the operation.

Radiotherapy is mainly used for malignant moles affecting the eyes, for lentigo maligna moles as well as for elderly people and metastases in the brain.

Furthermore, there are experimental studies investigating the treatment with radiation energy together with hyperthermia (heating of the body). This treatment method showed promising results in the first studies and will possibly play a role in skin cancer therapy in the future.

Drug treatment

Another option for the treatment of malignant melanoma is to influence the immune system with drugs, for example by means of interferon alpha. This active substance must be administered by means of an injection and strengthens the immune reaction against the tumour cells. This form of therapy is particularly useful for patients in stages II or III.

If a drug therapy is carried out postoperatively (adjuvant therapy), any small, invisible metastases (micrometastases) that may be present can be combated. This adjuvant treatment can normally prolong the survival time.

In this regard, of the wide variety of drugs that have been tested to date, α-2b-interferon and α-2b-interferon have performed best. For example, high-dose therapy with α-2b interferon significantly prolonged the survival of treated patients and reduced the relapse rate. Furthermore, the occurrence of micrometastases could be reduced by the therapy.

Chances of cure

Since malignant melanoma is increasingly diagnosed at earlier stages due to improvements in examination methods in recent years, the prognosis has improved significantly. However, the prospect of a cure is influenced by several factors: the type and stage of the melanoma are crucial.

For example, the prognosis is quite good for melanomas that do not grow deeper than 0.75 mm into the skin and do not yet reach the dermis. A poor prognostic sign would be metastasis to other organs or surrounding lymph nodes. On average, the 5-year survival rate of black skin cancer is 84 percent in men and about 88 percent in women.

The role of early detection

It should be emphasized that malignant melanoma is completely curable in very early stages, which is why early detection and timely treatment are very important for cure.

If the black skin cancer has already been diagnosed and treated, the aftercare is significant: the affected persons should regularly go for check-ups according to the instructions of the treating physician as the malignant melanoma may recur even after years. Such recurrences and metastases also have a better prognosis, provided they are detected in time.

Protect yourself from excessive sun exposure

One of the most important things you can do to prevent malignant melanoma is to protect yourself appropriately from excessive sun exposure. This is especially true for people with fair skin and many moles, but people with darker skin should also protect themselves from intense sun exposure.

Thus, for the prevention of black skin cancer, the use of a sunscreen with a high protection factor against both UVA and UVB radiation is recommended. Since even the best sunscreen cannot provide 100% protection against intensive sun exposure, the skin should also be protected from the sun by wearing suitable clothing. Furthermore, one should not expose oneself to the intense rays of the sun during midday. Especially children should choose a very high sun protection factor, as they are particularly at risk.

Another important preventive measure is regular visits to a dermatologist to examine existing moles. If you notice a new or changed birthmark during a self-examination of the skin, you should have it clarified immediately. Especially a rapid increase in size as well as bleeding tendencies of the skin change should be considered suspicious.

One of the most important measures in the fight against skin cancer is the skin cancer screening which is an early and regular skin examination. In Germany, these are financed by the health insurance companies from the age of 35, in some cases also in Austria. During the screening, complaints and risk factors are initially questioned in the course of an anamnesis interview and then the skin is closely examined by the doctor. If the doctor detects abnormalities in the course of the screening examination, the patient is referred to a dermatologist for further clarification.