Basal Cell Carcinoma - Causes, Symptoms and Treatment

Basal cell carcinoma (BCC) is the most common type of skin cancer in humans, and it is also the one with the highest cure rate. Despite being the histological type of 3 in 4 diagnosed skin cancers, basal cell carcinoma has a mortality rate below 2%.



The epidermis is the most superficial layer of the skin (the other layers are the dermis and the hypodermis, the latter is also called subcutaneous tissue), reaching a thickness of 1.5 cm in areas of thicker skin, such as the soles of feet and the palms of the hands. The epidermis is subdivided into 5 layers, the deepest being composed of the basal cells. The basal cells are constantly multiplying, generating new skin cells, pushing the old ones upwards, in order to constantly renew the epidermis. As the old cells peel off and decay, the newer cells that are rising take up their place.

Basal cell carcinoma is cancer that arises from basal cells. Its appearance usually occurs after an injury of the DNA of this cell, causing them to change its characteristics, becoming a cancer. The main factor of aggression to the DNA of skin cells is the excess of sun exposure (we will explain better in the next part of the text).

Basal cell carcinoma is the most common and, hopefully, the least deadly type of skin cancer. Although locally an aggressive tumor capable of destroying layers of the skin and invading surrounding tissues, its relative benignity lies in the fact that it is a cancer with a low potential for metastasis. In fact, less than 1% of cases of basal cell carcinoma metastasize.

Untreated tumors continue to grow, causing significant destruction of the skin layers, which can lead to disfiguring lesions. However, even in these cases, curative treatment is possible.

Chronic exposure to the sun is the main risk factor for the development of basal cell carcinoma.

Unlike melanoma that usually arises after an episode of excessive exposure to the sun, BCC occurs in people who are often exposed to the sun for years, usually from the earliest years of life.

In relation to sun exposure, the following factors increase the risk of basal cell carcinoma:

• Have very clear skin.
• Have clear eyes.
• To be red or naturally blonde.
• Have had many episodes of sunburn throughout life.
• Be over 50 years old (DNA damage occurs in youth, but cancer only appears decades later).
• Tanning.
• Live in tropical areas and with high sun exposure throughout the year.
• Have close family members with a history of skin cancer.
• Have previously had a basal cell carcinoma (the risk of a new tumor is 40% higher than in the general population).

Excessive sunshine throughout life is an important risk factor, but there are other factors that can also lead to the appearance of basal cell carcinoma, such as:

• Excessive exposure to radiation, such as X-rays.
• Immunosuppression (due to immunosuppressive disease or drug use).
• Exposure to arsenic.
• Some rare genetic diseases facilitate the onset of BCC, such as Goltz syndrome or xeroderma pigmentosum.

Basal cell carcinoma lesions usually occur at sites of the skin most exposed to solar radiation. In most cases, the injury occurs on the face. Next, the trunk is the most affected site. Eventually the BCC may arise in areas not exposed to the sun, such as the genitals or region around the anus.

In most cases, the skin lesion of the basal cell carcinoma presents as a small nodule or papule (a raised lesion, somewhat flattened type), skin color, glossy or pearly, often with one or more tiny visible blood vessels. These lesions are easily injured and may form small ulcers. The nodular form usually appears on the face and accounts for 60% of the cases.

In 30% of cases, the BCC lesion is superficial, flat and slightly reddish. This form occurs most commonly in young people and mainly affects the trunk.

The remaining 10% of cases can come in a variety of forms. In general, they are variations of the nodular and superficial form. Some lesions may be pigmented (darker) or mildly depressed. Others look like rounded scars, as if the patient had had a previous wound in place.

It is not always easy for the lay population to notice the presence of an early basal cell carcinoma. Therefore, some warning signs should be known:

• A persistent wound, especially on the face, that does not heal after several weeks.
• A new red spot that does not go away after several weeks.
• A new shiny lump. It may be reddish, translucent or pigmented. There may also be small visible blood vessels.
• A whiter or yellowish area, with slightly defined borders, similar to a small scar.

The diagnosis of basal cell carcinoma is usually confirmed with a skin biopsy.

Treatment of basal cell carcinoma is preferably surgical, with complete removal of the lesion, but a number of other treatments are available, depending on the type, location, and severity of the tumor.

Some options include: laser therapy, curettage, cryotherapy, electrocoagulation, and radiation therapy. Very early lesions can be treated only with 5-Fluorouracil (5-FU) or Imiquimod based creams.

Regardless of the treatment chosen, virtually all cases of BCC can be cured. However, the recurrence rate is high, about 10% after 5 years.