Types of Skin Cancer, Diagnosis, and Treatment Processes

Skin cancer occurs when DNA damage arises in the cells of the skin and this damage is not repaired, leading to uncontrolled proliferation of the damaged cells. More than 99% of skin cancers are composed of three types of cancer.

Skin cancers are classified into two categories based on the cells from which they originate: melanoma and non-melanoma skin cancers. The most common type of non-melanoma skin cancer is basal cell carcinoma, which accounts for 80% of all skin cancers. Another frequently encountered non-melanoma skin cancer is squamous cell carcinoma, responsible for 16% of all skin cancers. Melanoma, on the other hand, accounts for 4% of all skin cancers.

SQUAMOUS CELL CARCINOMA

What are the risk factors?

The most important risk factor is exposure to sunlight and tanning beds. Excessive exposure to ultraviolet light leads to the uncontrolled proliferation of keratinocytes located in the epidermis layer of the skin. It is more commonly seen in the elderly. However, there is an increased risk among younger individuals, such as construction workers, farmers, and those who engage in outdoor sports like surfing, sailing, and golf, as well as frequent tanning bed users. The risk is also increased for individuals who have undergone long-term ultraviolet therapy for skin diseases like psoriasis. It is more common in people with fair skin, dense freckles, and a tendency to redden rather than tan after sun exposure. Areas of the skin that have experienced radiation damage, old scar tissue, chronic wounds, ulcers, and burn sites are also considered high-risk regions. The risk is elevated for individuals taking immunosuppressive medications due to organ transplants or cancer treatment.

What are the symptoms?

Symptoms can manifest as bleeding, growing lesions, and non-healing wounds. The face and lips are frequently affected, starting with a skin-colored bump. This bump may appear as a firm growth or sometimes resemble a wart. As it progresses, this bump can expand into a crater-like growth in advanced stages. If neglected, the bump can turn into a bleeding open sore. Squamous cell carcinoma (SCC) needs to be taken more seriously. It can easily settle in highly vascular areas like the nose, lips, and ears and spreads rapidly. Regional lymph nodes also need to be monitored for signs of disease. A rarely encountered form, known as "vegetant," which has a cauliflower appearance, can be seen on the soles of the feet.

Is early diagnosis possible?

Yes, early diagnosis and treatment are possible. However, if left untreated for a long time, it can spread to other parts of the body.

How is the diagnosis made?

Diagnosis is made through pathological examination following a small biopsy taken from the abnormally appearing area of the skin under local anesthesia or after the complete removal of the lesion. The biopsy is performed to assess the depth of the carcinoma and determine the width of the area. Treatment is planned accordingly.

How is it treated?

The first treatment option is surgical. The lesion is completely removed under local anesthesia. Other treatment options that may be applicable include:

• Electrocoagulation for small lesions.
• Cryotherapy.
• Mohs surgery.
• Removal of lymph nodes (in cases where spread is suspected).
• Radiation therapy is preferred for areas where surgical intervention is challenging and for very large lesions. It can be used alone or in addition to surgery. If there is spread to other organs outside the skin, it may also be used for pain relief.

Chemotherapy is only administered when there is spread to other parts of the body.

Is it possible to prevent squamous cell carcinoma?

It is especially important to stay in the shade between 10:00 AM and 2:00 PM. However, it should be remembered that sunlight can reach us in the shade by reflecting off surfaces. It should be noted that exposure to the sun can occur during any outdoor activity, not just at the beach. Protective measures should include wearing clothing, hats, and sunglasses.

Additionally, starting from childhood, a habit similar to brushing teeth should be established by using a sunscreen product with at least 15 SPF daily. It should be understood that sunscreens do not provide 100% protection and cannot be an alternative to seeking shade and wearing protective clothing; they should only be used in addition to these measures.

BASAL CELL CARCINOMA

Definition

Basal cell carcinoma (BCC) is the most commonly observed skin tumor and can even be considered the most frequently seen tumor in humans. It is more prevalent in individuals with fair skin (skin phototypes I and II). The likelihood of developing BCC increases with age, and it is most commonly observed between the ages of 60 and 80. In younger individuals, it can rarely be seen as a component of certain syndromes (such as Basal Cell Nevus Syndrome, Rombo syndrome, etc.).

What are the risk factors?

The causative factors (etiology) are categorized into two groups: genetic (hereditary) and environmental. Among environmental factors, the following are important:

• Ultraviolet radiation, particularly UVB rays from sunlight.
• Ionizing radiation, especially in genetically predisposed individuals (e.g., those with Basal Cell Nevus Syndrome).
• Carcinogens, such as inorganic arsenic, from long-term exposure.
• Immunosuppression.
• Certain chronic skin diseases (like lupus vulgaris) and the contributions of long-term skin damage such as radiation therapy.

What are the symptoms?

Basal cell carcinoma (BCC) is observed in the facial region in 80% of cases and on the nose in 30% of cases. The upper area above a line drawn from below the ear to the upper lip is a frequent site. BCC often starts as a skin-colored, pearly 2-4 mm bump (in the initial stage), which over time can change to a purplish-red color. The growth phase can be very long, with slow growth expected over years; this growth and color change should be a warning for the patient and should be discussed with a physician.

BCC can present in various forms besides a single bump (nodular form), including cystic, ulcerated, pigmented, sclerosing, keloidal, and superficial spreading types. A biopsy taken from the tumor in different forms can be helpful for diagnosis and guiding treatment.

Is early diagnosis possible?

While it may be overlooked in the initial stages, early diagnosis and simple treatment methods are possible with the help of a specialist and dermoscopy.

How is the diagnosis made?

Expert examination, dermoscopy, and biopsy when necessary are diagnostic methods.

How is it treated?

Medication treatments include Imiquimod, intralesional interferon, and retinoic acid derivatives, applied according to different treatment protocols.

Surgical methods may include electrocoagulation, laser therapy, cryotherapy (freezing), photodynamic therapy (medication + special light), radiation therapy, and surgical excision. The choice of method depends on the tumor size, the area affected, and the need to preserve surrounding tissue.

Is it possible to prevent basal cell carcinoma?

Prevention of BCC is primarily based on sun protection, similar to the prevention of squamous cell carcinoma.

MELANOMA

Definition

Melanoma is the most malignant skin tumor originating from melanocytes or nevus cells found in the upper and lower layers of the skin.

Cutaneous melanoma accounts for 3% of all skin cancers. It ranks fifth among all cancers in men and sixth in women. It appears in 2% of individuals under the age of 20 and in 0.3-0.4% of prepubescent individuals. It is most commonly observed in individuals aged 45-55. In men, the most frequently affected area is the back, while in women, it is the lower leg.

Today, it is believed that increasing public awareness of melanoma, rising rates of physician consultations, and imaging options such as dermoscopy have contributed to the relatively higher incidence of melanoma.

What are the risk factors?

Sunlight (ultraviolet): The development of melanoma in Caucasians is directly related to exposure to sunlight (especially wavelengths between 280-320 nm). Artificial ultraviolet sources (such as tanning beds) are also dangerous. Severe sunburns caused by intense sunlight exposure during childhood are a risk factor. Chronic accumulated sun damage is influential in the development of lentigo maligna melanoma.

Phenotypic characteristics: Individuals with light-colored eyes (blue/green), fair skin, light-colored hair (blonde/red), who are prone to freckling, easily develop sunburns but do not tan (phototype I-II), have double the risk of developing melanoma.

Gender and hormonal factors: Estrogen and estrogen-progesterone preparations affect the number of melanocytes and the melanin content of pigment cells. The reduced frequency of occurrence during menopause, better prognosis in women than men, higher incidence in women with breast cancer, and lower incidence before puberty suggest that hormonal factors contribute to the risk. Studies have shown that those who start using oral contraceptives at an early age and those who use them for a long duration (over 5-10 years) have an increased risk.

Family history: Family history is one of the most significant risk factors. Having melanoma in a first-degree relative triples the risk, while having more than three first-degree relatives with a history of melanoma increases the risk by 35-70 times. The most crucial or sole factor in etiology is not genetic predisposition. In familial cases, the number of nevi, phenotypic characteristics, and shared environmental factors also play a role.

Immunosuppression: In patients who have undergone organ transplantation, those with hematological malignancies (such as lymphoma), and patients with immunodeficiency, the risk of melanoma is increased.

Other risk factors: In obese individuals, there is a relatively higher risk of melanoma due to larger surface areas and greater sun exposure. Higher socioeconomic levels and vacation habits also increase the risk of melanoma.

What are the symptoms?

Symptoms of melanoma vary according to clinical types. The symptoms of the four main clinical types of cutaneous melanoma are summarized below:

Superficial spreading melanoma: It typically develops on melanocytic nevi. Changes in color, blue-gray mottling, and shape asymmetry in nevi are situations that require careful attention in early diagnosis.

Nodular melanoma: It mainly occurs in sun-exposed areas such as the head and neck. Most often, it develops on healthy skin. However, in children, it can also develop on congenital nevi. Clinically, it appears as rapidly growing, often blue-black, sometimes colorless, dome-shaped ulcerated, firm nodules.

Acral lentiginous melanoma: The most common sites are the soles of the feet (especially the heel), palms, and nail beds. It usually starts as a blackish-brown discoloration under the nail. Discoloration in the skin adjacent to the nail (Hutchinson's sign) is an important clinical indicator.

Lentigo maligna melanoma: This type is most commonly seen in sun-exposed areas such as the cheeks, nose, forehead, ears, and neck. Clinically, it presents as lesions that are not sharply defined, containing various colors including brown and black, ranging in size from a few centimeters to 10-15 centimeters. Accumulated sun exposure plays a role in its formation.

Is early diagnosis possible?

In the clinical diagnosis of melanoma, the ABCDE criteria (asymmetry, border irregularity, variegated or very dark pigmentation, diameter greater than 5 mm, and sudden, rapid changes in color, size, or topography (evolution)) should be considered. Dermoscopy (surface microscopy) is the most useful examination method for the early diagnosis of melanomas.

How is the diagnosis made?

The definitive diagnosis of melanoma is made through histopathological examination. Complete excision of the suspicious lesion is preferred. However, if complete excision is not possible in some anatomical sites, a deep biopsy of 5-6 mm from the highest point of the lesion is appropriate.

Staging melanoma:

Like other tumors, melanoma can spread to lymph nodes, internal organs, bones, the brain, and skin. Initial spread is limited to lymph nodes in two-thirds of cases. Lymph node involvement can be detected with sentinel lymph node biopsy. The sentinel lymph node is the first lymph node to receive lymph fluid from the melanoma area.

Melanoma staging is performed according to the system defined by the American Joint Committee on Cancer (AJCC).

• Stage 0: Early in situ. 5-year survival rate: 9.3%
• Stage 1: Tumor with thickness equal to or less than 1 mm, either ulcerated or not, or tumor without ulceration between 1-2 mm thick. 5-year survival rate: 90%
• Stage 2: Ulcerated tumor with a thickness of 1-2 mm without lymph node involvement or tumor thicker than 2 mm, ulcerated or not. 5-year survival rate: 78.7%
• Stage 3: Any thickness tumor with regional lymph node involvement and/or in-transit metastasis (lymph node involvement more than 2 cm away from the tumor). 5-year survival rate: 63.3%
• Stage 4: Presence of distant metastasis. 5-year survival rate: 6.7-18.8%

Melanoma is the most aggressive skin tumor, and the prognosis is poor. Generally, the lifespan is proportional to the tumor's vertical depth of spread and stage.

How is it treated?

Early diagnosis is key to effective treatment. Stages 1 and 2 patients (i.e., those without regional or distant spread) are the group for whom surgery can yield good results.

Surgical treatment:
How much tissue should be removed?

• Melanoma type:
  • In situ melanoma: Should include healthy tissue 0.5 cm away from the tumor.
  • If melanoma is less than 2 mm: Should include healthy tissue 1 cm away from the tumor.
  • If melanoma is 2 mm or greater: Should include healthy tissue 2 cm away from the tumor, deeply (including healthy tissue).

Drug treatment:
In advanced stage patients, in addition to surgery:

• Immunotherapies (BCG vaccine and tumor vaccines, monoclonal antibodies, biological response modifiers)
• Chemotherapy (dacarbazine)
• Radiotherapy

Can melanoma be prevented?

• Regular use of sunscreens (both UVA and UVB protection) from infancy, throughout the year.
• Regular dermoscopy of nevi at least once a year (more frequently if there is a family history of melanoma).
• Consultation with a dermatologist for suspicious lesions.
• Avoiding laser or other surgical procedures on pigmented lesions of the face and body without dermoscopic examination.
• Drug treatments such as imiquimod, intralesional interferon, and retinoic acid derivatives can be administered with different treatment protocols.

Surgical methods: Electrocauterization, laser, cryotherapy (freezing), photodynamic therapy (drug + special light), radiotherapy (radiation treatment), and surgical excision methods can be applied depending on the size of the tumor, the area of involvement, and the need to protect surrounding tissue.