skin cancer

Description

The skin cancer is the cancer most common in Canada. It is estimated that each year about 75,000 people in Canada are diagnosed with skin cancer in non-melanoma, and this number continues to rise.

The skin cancers are classified into three types: basal cell carcinoma, squamous cell carcinoma, and melanoma. This article focuses on the first two forms of skin cancer, known both as the "cancer of the skin non-melanoma". Unlike melanoma, the mortality rate for cancer of the skin of non-melanoma is low and is often treated very easily. For information on melanoma, please see our Melanoma article.

Basal cell carcinoma (BCC) is the only skin cancer the most common, but also the most common form of cancer. It grows from the basal (deepest) of the epidermis (the outer layer of skin). Cancer cells almost always appears on sun-exposed skin areas like the forehead, hands, lips, or the top of the pinna. BCC makes up about 75% of all skin cancers non-melanoma. There are three main types of BCC:

superficial basal cell carcinoma (CBS): This type of cancer often appears on the chest and upper body (torso) and possibly in the face. In most cases, it is a well-circumscribed scaly patch that looks like eczema. It is often surrounded by a raised edge of pearly color.
Nodular basal cell carcinoma: This type of CB appears on areas exposed to sunlight, including the head and neck. It has the form of a lump usually pink or pearly.
morpheaform basal cell carcinoma: This type of CB appears as ivory scar in areas that have never undergone surgery or injury. The tumor is slightly raised and waxy, often white or yellowish. The outline of the tumor is not accurate.
There are also two more unusual types of BCC: pigmented (tattoo) (similar to nodular BCC, but with white and brown pigmentation) and cystic BCC (bluish-gray with liquid center).

Squamous cell carcinoma is less common than basal cell carcinoma, but still represents the second form of skin cancer the most common. It grows from the top layers of the skin, and it occurs most often on sun-exposed surfaces.

Other cancers such as Merkel cell carcinoma, Kaposi's sarcoma or cutaneous T-cell lymphoma are cancers of the skin very rare, representing approximately 1% of cancers of non-melanoma.


Causes

Like melanoma, basal and squamous cell carcinomas are associated with a significant exposure to sunlight. Most people accumulate the majority of their total exposure to sunlight during childhood, and studies have shown that even a single sunburn in childhood increases the risk of skin cancer later in of life. But there is no need to catch a sunburn to suffer skin lesions. A tan is a sign of skin damage caused by ultraviolet (UV).

In Canada, skin cancer is rare in people under 40. Sunbathing at the origin of skin tumors were taken mostly 30, 40 or 50 years ago. In Australia, where people are much more exposed to ultraviolet radiation from an early age, skin cancer strikes people in their twenties and thirties.

People with fair skin, blond or red hair, blue eyes or green, who have freckles, or who tan easily are at higher risk of cancer of the skin because their skin is less pigmented and they are less well protected from the sun.

In general, tumors are formed when the DNA of a healthy cell undergoes a mutation that causes deregulated cell proliferation. Scientists now believe that in basal cell carcinoma, a gene called PTC is damaged by UV radiation. Under normal conditions, this gene induces the production by the cell of a protein that prevents reproduction of adjustment. A similar scenario may be at work in the case of squamous cell carcinoma.

Other causes of skin cancer, stress X-rays, skin contact with arsenic or radium, or simply bad luck. Even if a person is poorly exposed to sunlight, an error can occur spontaneously in cell division. We also know that a sexually transmitted cancer-causing virus, human papillomavirus (HPV) can cause a rare form of squamous cell carcinoma.


Symptoms and Complications

Basal cell carcinoma (BC) generally appears to skin sites exposed to sunlight. It first appears as a small blister pink and round, but that depends on the type of CB (eg. Superficial, nodular or morpheaform). Over time, the tumor can continue to grow and after a few months or years, it is sometimes surrounded by tiny blood vessels, but visible. The lesion often forms crusts repeatedly, and then cured, forming new crust. The crust formation is sometimes accompanied by bleeding.

If the lesion is not treated, its appearance can be very different, because cancer cells destroy the skin. The lesion takes the appearance of a bite, in which case, the tumor is called a rodent ulcer.

The CB is the type of superficial basal cell carcinoma the least aggressive, whereas the CB morpheaform is the most aggressive and most dangerous of these cancers. The CB surface develops outside its border (edge) and damage over time, the surrounding tissue. Since the CB surface develops slowly, people do not always consult their doctor immediately. Detection and early treatment are often the best way to increase its chances of survival in many types of cancer. The CB nodules have irregular contours and often remain flat. This type of cancer often causes bleeding followed by crusting or flaking. The CB morpheaform develop rapidly and are more difficult to treat.

Squamous cell carcinoma usually begins with a small hard mass. In most cases it develops from actinic keratosis (AK), a rough, scaly lesions of the skin that appears on the surface of the skin exposed to sunlight. It can be the same color as the surrounding skin, but it can also be brown, pink or red. The KA is simply an alteration of the size, shape and organization of skin cells. Because they can cause skin cancer, we recommend screening and treatment of KA as soon as possible.

Squamous cell carcinoma is characterized by redness, scaling, crusting or ulcers. In addition, it can cause itching and be slow to heal. Gradually, as the tumor of squamous cell carcinoma grows, the skin tends to degenerate and becomes scarred tissue. The tumor bleed easily if scratched, without it being painful so far. Squamous cell carcinoma is more likely to develop in the form of metastases (spread to other parts of the body) that the CB. Fortunately, early treatment increases survival and healing.

Complications arise when the tumor invades the tissues that have other functions, such as tissues of the mouth, anus or eye. In general, cancers of the mucous membranes (eg. The lips) are more likely to develop into metastases (spread of the disease to other organs). Similarly, cancerous tumors that sit between your fingers or between the index finger and thumb or the first phalanx (before the first joint of a finger) may also be further developed in the form of metastases. Metastases are unlikely in these cancers.

Although basal cell carcinoma or squamous cell carcinomas rarely cause death, these tumors can disfigure the patient. Untreated, cancer can develop and cause disfigurement. Treatment can sometimes disfiguring the patient if a large amount of skin tissue to be excised.

diagnosis

The skin cancer is diagnosed by microscopic analysis of a sample of skin taken from the bump or spot suspicious. This is called a biopsy. Under normal conditions, it is not necessary to perform complex tests to determine if the cancer has spread to other parts of the body as it rarely happens.

There are three types of biopsies to confirm the diagnosis of cancer of the skin non-melanoma. They include:

biopsy surface

biopsy punch,

excision.

Depending on the biopsy, removing a portion or all of the tumor. All of these biopsies require local anesthesia.

Treatment and Prevention

Is usually treated skin cancer by surgery. However, the doctor never told the patient that the cancer is completely cured, because there is always a risk that the cancer will return if cancer cells have invaded parts and tissues adjacent to the tumor. Surgeons typically cut an extra margin around skin tumors to reduce the risk of recurrence.

Tumors at high risk, such as tumors of the hand or lip, is often excised by Mohs micrographic surgery, which allows a surgeon to remove skin layer by using a microscope to accurately follow the contour the cancer. This technique reduces the risk of recurrence.

Sometimes the tumors are destroyed by the application of liquid nitrogen (cryogenic) or using a laser that burns the tumor. In addition to surgery, radiotherapy and chemotherapy are suitable for the treatment of cancer has recurred or in the case of metastatic potential.

Topical medications (applied to the skin) are sometimes used to treat basal cell carcinoma (BC). Topical medications include 5-fluorouracil (also known as fluorouracil) and imiquimod. 5-fluorouracil (5-FU) belongs to the group of medicines known as topical antineoplastics. It works by inhibiting the growth of cancer cells. Imiquimod belongs to a new group of topical medications called biological response modifiers. This type of drug works by stimulating the immune system to produce substances that fight cancer.

In cases where the cancer has spread to other parts of the body, chemotherapy may be used in combination with other treatments such as radiotherapy and surgery. The doctor decides on the appropriate mix for each individual based on their medical history.

To prevent skin cancer, protect your skin against the sun by wearing long clothing and using sunscreen with an SPF of at least 15 (SPF 15) that filters out UVA and UVB rays. Apply a generous amount of sunscreen on your body at least half an hour before going outside. Check your skin every month to detect changes, growths or sores that do not heal. If necessary, consult a doctor as soon as possible.