Skin cancer is one of the most common types of cancer in the world. It usually occurs because of sun’s harmful UV rays penetrating into the skin and damaging. Skin cancers have the most healing rate and are the most treatable types of cancers. However, low awareness of signs of skin cancer leads to missed opportunity for early diagnosis.

Skin cancer occurs when DNA damage occurs in cells in the skin and damage cannot be repaired, resulting in uncontrolled proliferation of damaged cells. Three types of skin cancer make up more than 99% of all skin cancers. Based on the type of cell in which they originate, skin cancers are divided into two major groups: melanoma and non-melanoma skin cancers. Basal cell carcinoma, the most common non-melanoma skin cancer, is responsible 80% of all skin cancers and 16% of squamous cell carcinoma which is the other common non-melanoma skin cancer. The least common type of skin cancer (4%) is malignant melanoma, a life-threatening malignant skin cancer.

What do non-melanoma skin cancers look like?
Basal cell cancer: This cancer is the most common but least dangerous skin cancer that develops from the basal cells in the skin. It is most common in the skin regions exposed to the sun. It usually appears like a small, red or skin-colored, bright-edged bump, and later recurrent oozing, wounding, bleeding and crusting may develop on the skin. They grow slowly and almost don't spread to the rest of the body, but if they are not treated for a long time, they can turn into a deep wound and damage the underlying tissues. This type of cancer can rarely spread to other parts of the body.

Squamous cell cancer: It is the second most common skin cancer that develops from keratinocytes on the skin. These cancers commonly appear on long-term sun-exposed areas of the body such as the head, neck and backs of the hands. It shows a sign in the form of a red-skinned, peeled, crusted, hard bump area on the skin. Often located in blood supply areas such as the nose, lips and ears, spreading rapidly to regional lymph nodes and other organs, resulting in death. Lesions, described as actinic keratosis, a cancer precursor, are considered the stage before cancer development and have the potential to turn into squamous cell cancer by 10% or 15%, so it must be treated early. Mostly, the lesions are seen in the sun-exposed areas, most often on the face and back of the hands. They may appear as reddish or brownish patches in the skin, often with a rough, scaly, or crusted surface.

Who develops non-melanoma skin cancers most frequently?
These cancers are more common in the elderly. The most important risk factor is harmful sun rays. However, although they are young, the risk is increased in construction workers, farmers, people who do outdoor sports such as surfing, sailing, golf, and those who frequently enter the solarium. It usually occurs in individuals with fair skin, dense freckles and prone to redness after sun exposure rather than tan. Skin cancer occurs more often in adulthood, especially in those with a history of freckles in childhood or are frequently or intermittently exposed to intense sun and carcinogens. Individuals with a family history of cancer or inherited skin disease (such as albinism, xeroderma pigmentosum, Gorlin Syndrome) or those using immunosuppressive medications for organ transplantation or for cancer treatment are at higher risk of developing skin cancer. Skin areas damaged by other forms of radiation, old scars, persistent chronic ulcers and wounds and burns are also at increased risk.

When should we suspect non-melanoma skin cancers?
Early diagnosis is the first and most important step of effective treatment. Visible changes in the skin can be warning sign of cancer. Such complaints like a chronic wound or puffiness, crusting, itching, bleeding in the skin are important. If a blister or blemish in the skin grows slowly, changes in shape or color, persists for more than a month or a wound does not recover, should be examined by the dermatologist.

Early diagnosis and treatment are possible in non-melanoma skin cancers
In the diagnosis of non-melanoma skin cancers, clinical examination of dermatology specialist with dermatoscopic assessment showing the changes in skin lesions in a more detailed manner and biopsy when needed are essential diagnostic practices.

The first treatment option is surgical treatment, i.e. surgical removal of the cancerous part. After the diagnosis is confirmed by biopsy, one of the non-surgical electrocauterization and curettage, cryotherapy (freezing technique), laser and photodynamic therapy (drug + specific light based therapy) methods can be applied based on the size of the tumor, the area of involvement and the need to protect the surrounding tissue. If it is too large or spread to the other regions or organs in a way that cannot be surgically removed, other methods such as radiotherapy (radiation therapy) and chemotherapy (drug therapy) are used.  

Furthermore, topical creams (Imiquimod, 5-Fluorourasil), drugs containing intra-tumor (intralesional) interferon and retinoic acid derivatives can be applied with different treatment protocols in early stage superficial skin cancers.

Basal cell cancers tend to recur within the first five years after treatment, while flat cell cancers tend to spread, therefore, skin and lymph node examination should be repeated in the years after treatment.

Malignant melanoma develops as a result of the malignant proliferation of cells called melanocytes, which give the skin its color. It can occur anywhere in the skin that covers our bodies. Melanoma can develop through a pre-existing mole or from normal skin. These moles may be moles that exist inherent or appear later in the body over the years. Melanoma usually begins as a dark brown or black stain or blister and can grow over time, pink, blue tints can be added or its color may lighten, rarely be colorless. Therefore, attention should be paid to the rapidly growing skin-colored or pinkish bumps. If diagnosed and treated early, it is possible to get rid of the disease completely. However, if diagnosed late, it can be fatal because it can spread to other organs in advanced stages. Melanoma is less common than other types of skin cancer, but the vast majority (75%) of skin cancer-related deaths are from melanoma.

Risk factors in melanoma development: The risk of melanoma is doubled in people with light eye coloration (blue/green), fair skin, light-colored hair (yellow/red), prone to freckles, easy sunburn but not tanning (skin phototype I-II). Especially those with a history of severe sunburn in childhood or those who have been exposed to intense sun throughout their life, presence of a pre-existing mole in the skin, have a family history of melanoma or skin cancer  increase the risk. The more mole a person has, the greater risk of developing cancer increases. Moreover, should be more careful if there are irregular atypical shaped, color-containing and large-scale moles. For any reason, people who use a drug that weakens the immune system or suppresses the immune system for therapeutic purposes are more likely to have melanoma. High socioeconomic level increases the risk of melanoma due to vacation habits and solarium.

In order to diagnose and treat melanoma, it is essential to remove the suspicious spot or mole after the examination and evaluate it in the light of pathological examination. Early diagnosis is the key to effective treatment. If melanoma is detected early and found superficial according to the pathology report, surgical excision is sufficient for treatment. Afterwards physical examination, dermatological examination (examination of moles and follow-up if necessary) and ultrasonographic examination of the lymph glands are required periodically. These follow-ups should be performed by the dermatologist. If melanoma is thick and deeply located, the guard lymph nodes are also examined during the surgical treatment. If cancer is also spread to lymph nodes, the body is investigated by advanced radiological imaging methods in the presence of suspicion of metastases to other organs. In addition to surgery in patients with more advanced-stage; adjuvant radiotherapy, chemotherapy, immunotherapy or gene-targeted treatments are on the agenda. Melanoma is the most malignant tumor of the skin and it has worse prognosis. Usually there is a life expectancy that parallels with the depth of the tumor's vertical line spread and stage.

Is it possible to diagnose early? Are changes in the moles a sign of skin cancer?
ABCDE criteria (asymmetry, border irregularity, color that is not uniform, diameter greater than 6 mm, evolving size, shape or color) should be considered in the clinical diagnosis of melanoma. Moles are similar lye in the same person: the same shape and the same color. If the appearance of the mole is different, it can be considered suspicious. It's called an Ugly Duckling sign. In order to be noticed early on, it is important that the individuals get into the habit of checking their skin at regular intervals.  

The person who notices any change in size, shape or elevation of a mole, or experience any new symptom such as bleeding, itching or crusting, should see a dermatologist promptly. Dermatoscopy (surface microscopy) is the most useful method of examination in early diagnosis of melanoma. This method provides early detection of melanoma, while on the other hand reduces the likelihood of misdiagnosis and unnecessary removal. This method has no risk or side effects for the patient.

Should everyone have nevus map?
Especially people with fair skin, light-colored eye, red-blond hair or skin type that can easily develop sunburn, those exposed to long or intermittent sunlight, have a family history of skin cancer or melanoma and those with numerous congenital nevi should get their moles mapped.

The naked eye alone is not enough to detect the changes in a mole.  For the purpose of early diagnosis in risky people, it is important to examine with digital dermatoscopy which can show the change in moles in detail. This method analyzes the internal structure of existing moles and determines how they change in the process whether they are good or malignant. A significant part of malignant melanoma occurs on the mole. Since this type of cancer spreads rapidly throughout the body, the chance of treatment is largely eliminated when not diagnosed early. However, it is possible to treat the disease with early diagnosis.

Point localizations are determined by creating a map of moles in the body by digital dermatoscopy method. Then the dermatoscopic image is taken and recorded for each mole.

Thus, the changes of moles are objectively compared in the next checkup with the patient. Suspected moles should be surgically removed without waiting for them to turn into skin cancer. In the risky group, dermatoscopic examination is recommended every 3-6 months if moles are changing and growing and at least once a year if there are no changes.

Is removing moles harmful in terms of skin cancer? Which methods do you recommend for removal of moles?
The healthiest and most correct method to remove mole is to remove it surgically. Removed mole must be sent to pathological examination. Non-surgical methods such as laser removal, radio frequency, freezing (cryo), shaving and cauterization (burning) in mole removal are wrong. With these methods, there are risks such as permanent skin blemishes, permanent redness, burns, activation of herpes virus, and activation of pigment cells causing to recurrent mole. Except for the surgical operation, the tissue is destroyed in all aesthetic mole removal procedures. The destroyed mole tissue cannot be examined pathologically and it cannot be detected whether the removed mole is malignant.

"If the knife touches a mole, it becomes unmanageable" opinion among the people is not true. Medical removal of mole does not pose a risk of cancer and does not harm the patient. In fact, if the mole is cancerous, removal of mole is much more beneficial for the patient. In suspicious cases, removing mole plays a crucial role in the early diagnosis and onset of treatment. Irritation of moles also increases the risk of cancer. Exposure to the sun, continual damage of the area where the moles are located with applications such as shaving, epilation or sports activities, or friction-related irritation caused by the clothes we wear causes deterioration in the cells of the moles. Care must be taken in this regard.

Why is sun protection so important and what are your suggestions?
Since sun rays are the most important cause of skin cancers, the most important protective measure in preventing skin cancer is avoiding the sun. To protect against damage from the sun's rays, it is particularly important to avoid the sun between 10:00 and 16:00, when the sun's rays are the strongest. It should be preferred to stay in the shade at all times while outdoors. 80% of ultraviolet rays reach the earth surface not only in clear and sunny weather, but also on cloudy and closed days. It should be noted that normal window glass will absorb UVB but will not prevent UVA rays from passing. Regular use of sunscreens (from infancy) (sunscreen with both UVA and UVB protection, at least 30 factors) are required in summer-winter seasons. Our clothes provide an important barrier for sun protection. Using a wide-brimmed hat and sunglasses with full UVA-UVB filter will be useful for sun protection.

In the prevention of skin cancers, it is important to perform mole checks regularly with a dermotoscopy once a year (more often in people at risk), not to perform laser or other surgical applications without dermascopic examination of pigmented lesions on the face and body, and to consult an experienced dermatologist in suspicious lesions.

Assoc. Prof. Tuba Oskay, M.D.
Dermatology Specialist, Bayındır Söğütözü Hospital