Skin Cancer (Non-Melanoma) Causes, Symptoms, Diagnosis, Treatment, Prevention

Skin Cancer Causes, Symptoms, Diagnosis, Treatment, Prevention

The Skin

The skin is the body's outer covering. It protects us against heat, light, injury, and infection. It regulates body temperature and stores water, fat, and vitamin D. Weighing about 6 pounds, the skin is the body's largest organ. It is made up of two main layers: the outer epidermis and the inner dermis.

The epidermis (outer layer of the skin) is mostly made up of flat, scale-like cells called squamous cells. Under the squamous cells are round cells called basal cells. The deepest part of the epidermis also contains melanocytes. These cells produce melanin, which gives the skin its color.

The dermis (inner layer of skin) contains blood and lymph vessels, hair follicles, and glands. These glands produce sweat, which helps regulate body temperature, and sebum, an oily substance that helps keep the skin from drying out. Sweat and sebum reach the skin's surface through tiny openings called pores.

What Is Cancer?

Cancer is a group of more than 100 diseases. Although each type of cancer differs from the others in many ways, every cancer is a disease of some of the body's cells.

Healthy cells that make up the body's tissues grow, divide, and replace themselves in an orderly way. This process keeps the body in good repair. Sometimes, however, normal cells lose their ability to limit and direct their growth. They divide too rapidly and grow without any order. Too much tissue is produced, and tumors begin to form. Tumors can be benign or malignant.

Benign tumors are not cancer. They do not spread to other parts of the body and are seldom a threat to life. Often, benign tumors can be removed by surgery, and they are not likely to return.

Malignant tumors are cancer. They can invade and destroy nearby healthy tissues and organs. Cancer cells also can spread, or metastasize, to other parts of the body and form new tumors.

What is Skin Cancer (Non-Melanoma)?

Skin cancer - the abnormal growth of skin cells - most often develops on skin exposed to the sun. But this common form of cancer can also occur on areas of your skin not ordinarily exposed to sunlight.

There are three major types of skin cancer - basal cell carcinoma, squamous cell carcinoma and melanoma.

The first sign of non-melanoma skin cancer is usually the appearance of a lump or patch on the skin that doesn't heal after a few weeks.

In most cases, cancerous lumps are red and firm, while cancerous patches are often flat and scaly.

You can reduce your risk of skin cancer by limiting or avoiding exposure to ultraviolet (UV) radiation. Checking your skin for suspicious changes can help detect skin cancer at its earliest stages. Early detection of skin cancer gives you the greatest chance for successful skin cancer treatment.

See your GP if you have any skin abnormality that hasn't healed after four weeks. Although it is unlikely to be skin cancer, it is best to be sure.

Causes of Skin Cancer (Non-Melanoma)

Skin cancer occurs when errors (mutations) occur in the DNA of skin cells. The mutations cause the cells to grow out of control and form a mass of cancer cells.

Cells involved in Skin Cancer (Non-Melanoma) 

Skin cancer begins in your skin's top layer - the epidermis. The epidermis is a thin layer that provides a protective cover of skin cells that your body continually sheds. The epidermis contains three main types of cells:

  • Squamous cells lie just below the outer surface and function as the skin's inner lining.
  • Basal cells, which produce new skin cells, sit beneath the squamous cells.
  • Melanocytes - which produce melanin, the pigment that gives skin its normal color - are located in the lower part of your epidermis. Melanocytes produce more melanin when you're in the sun to help protect the deeper layers of your skin.
Where your skin cancer begins determines its type and your treatment options.

Ultraviolet light and other potential causes

Much of the damage to DNA in skin cells results from ultraviolet (UV) radiation found in sunlight and in commercial tanning lamps and tanning beds. But sun exposure doesn't explain skin cancers that develop on skin not ordinarily exposed to sunlight. This indicates that other factors may contribute to your risk of skin cancer, such as being exposed to toxic substances or having a condition that weakens your immune system.

Who is at risk of skin cancers?

Some of the risk factors for skin cancers include:

  • Light or fair complexion, especially blonde, red or light-brown hair and blue, green or gray eyed individuals. Dark skinned individuals may develop melanoma.
  • Those with an easy tendency to burn in the sun or tan little or not at all. Early history of bad sunburns or scars from previous burns.
  • Prolonged sun exposure - especially during childhood.
  • Early history of skin cancer.
  • A family history of skin cancer especially melanomas.
  • More than normal number of moles (above 50 in number).
  • A history of atypical nevi or abnormal moles.
  • Those undergoing therapies like immunosuppressive therapy, photosensitive therapies etc.

Skin Cancer (Non-Melanoma) Symptoms

Where skin cancer develops 

Skin cancer develops primarily on areas of sun-exposed skin, including the scalp, face, lips, ears, neck, chest, arms and hands, and on the legs in women. But it can also form on areas that rarely see the light of day - your palms, beneath your fingernails or toenails, and your genital area.

Skin cancer affects people of all skin tones, including those with darker complexions. When melanoma occurs in people with dark skin tones, it's more likely to occur in areas not normally exposed to the sun.

Basal cell carcinoma signs and symptoms 

Basal cell carcinoma usually occurs in sun-exposed areas of your body, such as your neck or face.

Basal cell carcinoma may appear as:

  • A pearly or waxy bump
  • A flat, flesh-colored or brown scar-like lesion

Squamous cell carcinoma signs and symptoms 

Most often, squamous cell carcinoma occurs on sun-exposed areas of your body, such as your face, ears and hands. People with darker skin are more likely to develop squamous cell carcinoma on areas that aren't often exposed to sun, such as the legs and feet.

Squamous cell carcinoma may appear as:

  • A firm, red nodule
  • A flat lesion with a scaly, crusted surface

Melanoma signs and symptoms 

Melanoma can develop anywhere on your body, in otherwise normal skin or in an existing mole that becomes cancerous. Melanoma most often appears on the trunk, head or neck of affected men. In women, this type of cancer most often develops on the lower legs. In both men and women, melanoma can occur on skin that hasn't been exposed to the sun.

Melanoma can affect people of any skin tone. In people with darker skin tones, melanoma tends to occur on the palms or soles, or under the fingernails or toenails.

Melanoma signs include:

  • A large brownish spot with darker speckles
  • A mole that changes in color, size or feel or that bleeds
  • A small lesion with an irregular border and portions that appear red, white, blue or blue-black
  • Dark lesions on your palms, soles, fingertips or toes, or on mucous membranes lining your mouth, nose, vagina or anus

Signs and symptoms of less common skin cancers 

Other, less common types of skin cancer include:

  • Kaposi sarcoma. This rare form of skin cancer develops in the skin's blood vessels and causes red or purple patches on the skin or mucous membranes. Kaposi sarcoma mainly occurs in people with weakened immune systems, such as people with AIDS, and in people taking medications that suppress their natural immunity, such as people who've undergone organ transplants. Kaposi sarcoma can also occur in young men living in Africa or older men of Italian or eastern Jewish heritage.
  • Merkel cell carcinoma. Merkel cell carcinoma causes firm, shiny nodules that occur on or just beneath the skin and in hair follicles. Merkel cell carcinoma is usually found on sun-exposed areas on the head, neck, arms and legs.
  • Sebaceous gland carcinoma. This uncommon and aggressive cancer originates in the oil glands in the skin. Sebaceous gland carcinomas — which usually appear as hard, painless nodules — can develop anywhere, but most occur on the eyelid, where they're frequently mistaken for other eyelid problems.

Detection and Diagnosis for Skin Cancer (Non-Melanoma)

Detection for Skin Cancer (Non-Melanoma)

The cure rate for skin cancer could be 100 percent if all skin cancers were brought to a doctor's attention before they had a chance to spread. Therefore, people should check themselves regularly for new growths or other changes in the skin. Any new, colored growths or any changes in growths that are already present should be reported to the doctor without delay.

Doctors should also look at the skin during routine physical exams. People who have already had skin cancer should be sure to have regular exams so that the doctor can check the skin - both the treated areas and other places where cancer may develop.

Diagnosis for Skin Cancer (Non-Melanoma)

Basal cell carcinoma and squamous cell carcinoma are generally diagnosed and treated in the same way. When an area of skin does not look normal, the doctor may remove all or part of the growth. This is called a biopsy. To check for cancer cells, the tissue is examined under a microscope by a pathologist or a dermatologist. A biopsy is the only sure way to tell if the problem is cancer.

Doctors generally divide skin cancer into two stages: local (affecting only the skin) or metastatic (spreading beyond the skin). Because skin cancer rarely spreads, a biopsy often is the only test needed to determine the stage. In cases where the growth is very large or has been present for a long time, the doctor will carefully check the lymph nodes in the area. In addition, the patient may need to have additional tests, such as special x-rays, to find out whether the cancer has spread to other parts of the body. Knowing the stage of a skin cancer helps the doctor plan the best treatment.

Skin Cancer Treatment Planning

In treating skin cancer, the doctor's main goal is to remove or destroy the cancer completely with as small a scar as possible. To plan the best treatment for each patient, the doctor considers the location and size of the cancer, the risk of scarring, and the person's age, general health, and medical history.

It is sometimes helpful to have the advice of more than one doctor before starting treatment. It may take a week or two to arrange for a second opinion, but this short delay will not reduce the chance that treatment will be successful. There are a number of ways to find a doctor for a second opinion:

  • The patient's doctor may be able to suggest a doctor, such as a dermatologist or a plastic surgeon, who has a special interest in skin cancer.
  • The Cancer Information Service can tell callers about treatment facilities, including cancer centers and other programs that are supported by the National Cancer Institute.
  • Patients can get the names of doctors from local and national medical societies, a nearby hospital, or a medical school.
  • The Directory of Medical Specialists lists doctors' names and gives their background. It is in most public libraries.

Questions To Ask the Doctor

Skin cancer has a better prognosis, or outcome, than most other types of cancer. Although skin cancer is the most common type of cancer in this country, it accounts for much less than 1 percent of all cancer deaths. It is cured in 85 to 95 percent of all cases. Still, any diagnosis of cancer can be frightening, and it's natural to have concerns about medical tests, treatments, and doctors' bills.

Patients have many important questions to ask about cancer, and their doctor is the best person to provide answers. Most people want to know exactly what kind of cancer they have, how it can be treated, and how successful the treatment is likely to be. The following are some other questions that patients might want to ask their doctor:

  • What types of treatment are available?
  • Are there any risks or side effects of treatment?
  • Will there be a scar?
  • Will I have to change my normal activities?
  • How can I protect myself from getting skin cancer again?
  • How often will I need a checkup?

Some patients become concerned that treatment may change their appearance, especially if the skin cancer is on their face. Patients should discuss this important concern with their doctor. And they may want to have a second opinion before treatment.

Treatments and drugs for Skin Cancer (Non-Melanoma)

Treatment for skin cancer and the precancerous skin lesions known as actinic keratoses varies, depending on the size, type, depth and location of the lesions. Small skin cancers limited to the surface of the skin may not require treatment beyond an initial skin biopsy that removes the entire growth.

If additional treatment is needed, options may include:


Your doctor may destroy actinic keratoses and some small, early skin cancers by freezing them with liquid nitrogen (cryosurgery). The dead tissue sloughs off when it thaws.

Excisional surgery

This type of treatment may be appropriate for any type of skin cancer. Your doctor cuts out (excises) the cancerous tissue and a surrounding margin of healthy skin. A wide excision - removing extra normal skin around the tumor - may be recommended in some cases.

Laser therapy

A precise, intense beam of light vaporizes growths, generally with little damage to surrounding tissue. A doctor may use this therapy to treat superficial skin cancers.

Mohs surgery

This procedure is for larger, recurring or difficult-to-treat skin cancers, which may include both basal and squamous cell carcinomas. Your doctor removes the skin growth layer by layer, examining each layer under the microscope, until no abnormal cells remain. This procedure allows cancerous cells to be removed without taking an excessive amount of surrounding healthy skin.

Curettage and electrodesiccation

After removing most of a growth, your doctor scrapes away layers of cancer cells using a circular blade (curet). An electric needle destroys any remaining cancer cells. This simple, quick procedure may be used to treat small or thin basal cell cancers or squamous cell cancers.

Radiation therapy

Radiation may be used in situations when surgery isn't an option.


In chemotherapy, drugs are used to kill cancer cells. For cancers limited to the top layer of skin, creams or lotions containing anti-cancer agents may be applied directly to the skin. Systemic chemotherapy can be used to treat skin cancers that have spread to other parts of the body.

Photodynamic therapy (PDT)

This treatment destroys skin cancer cells with a combination of laser light and drugs that makes cancer cells sensitive to light. PDT makes your skin sensitive to light, so you will need to avoid direct sunlight for at least six weeks after treatment.

Biological therapy

Biological treatments stimulate your immune system in order to kill cancer cells. Biological therapy medications used to treat certain skin cancer include interferon and interleukin-2.

Skin Cancer (Non-Melanoma) Prevention

Avoid the sun during the middle of the day

For many people in North America, the sun's rays are strongest between about 10 a.m. and 4 p.m. Schedule outdoor activities for other times of the day, even in winter or when the sky is cloudy. You absorb UV radiation year-round, and clouds offer little protection from damaging rays. Avoiding the sun at its strongest helps you avoid the sunburns and suntans that cause skin damage and increase your risk of developing skin cancer. Sun exposure accumulated over time also may cause skin cancer.


Each of these measures protects against sun’s UV rays. For example, one should wear clothing that covers as much of the body as possible. Long-sleeved shirts, long pants, or skirts cover the most skin and are the most protective. Dark colors are more protective and are preferred. A tightly woven fabric and dry protects better than loosely woven cloth or wet clothes.

Some clothings are available to special UV protection. These sun-protective clothes may have a label listing the UV protection (UPF) value that ranges on a scale of 15 to 50 and over. The higher the UPF, the higher the protection from UV rays. Swimming costumes are available with UV protection. Some new laundry detergents may also increase the UV protection of clothing.

Babies less than 6 months of age should be kept out of direct sunlight and protected from the sun using hats and protective clothing.


The next important step is to use sunscreen. This is the most vital step in sun-protection. It is important to know the level of protection offered by a sunscreen. Sunscreens are available in many forms like lotions, creams, ointments, gels, sprays, wipes etc. Some are available in cosmetics as well including powders, foundation, lipsticks etc.

Most dermatology associations, including the American Academy of Dermatology, recommend using broad-spectrum sunscreen products which help protect against both UVA and UVB rays. These have a sun protection factor (SPF) of at least 30. The SPF number is the level of protection the sunscreen provides against UVB rays.

When applying a SPF30 sunscreen, it should be smeared on thickly to get approximately 1 minute of UVB rays for each 30 minutes spent in the sun. SPF 15 sunscreens filter out 93% of UVB rays, while SPF 30 sunscreens filter out 97%, SPF 50 sunscreens 98%, and SPF 100 filters around 99% of the UVB rays.

Ideally 1 ounce of sunscreen (around one palm full) should be used to cover the arms, legs, neck, and face of the average adult. Most sunscreens must be reapplied at least every 2 hours and more frequently if one is swimming or sweating. Waterproof sunscreens protect for 80 minutes while those that are not protect for 40 minutes.

Sunscreens that contain avobenzone (Parsol 1789), ecamsule, zinc oxide, or titanium dioxide protect from both UVA and UVB rays. Sunscreens past their expiry date may still be effective to a lesser extent for 2 to 3 years. Before use the bottle needs to be shaken to remix the sunscreen ingredients.

Some individuals are allergic to products used in sunscreens. To check for allergies a small amount can be applied over the soft skin on the inside of the elbow. If the skin does not turn red or itchy, the product is suitable for the individual.

Tanning beds and artificial sunlamps should be avoided

Tanning lamps give out UVA and usually UVB rays as well. These can seriously harm the skin and cause skin cancer. Tanning bed use has been linked with an increased risk of melanoma especially if used by young adults (less than 30) and adolescents.

Several tanning pills claim to give a tan without exposing a person to UV radiation. These mostly contain color additives similar to beta-carotene. The Food and Drug Administration (FDA) does not approve any of these products for tanning.

Be aware of sun-sensitizing medications

Some common prescription and over-the-counter drugs, including antibiotics, can make your skin more sensitive to sunlight. Ask your doctor or pharmacist about the side effects of any medications you take. If they increase your sensitivity to sunlight, take extra precautions to stay out of the sun in order to protect your skin.

Check your skin regularly and report changes to your doctor

Examine your skin often for new skin growths or changes in existing moles, freckles, bumps and birthmarks. With the help of mirrors, check your face, neck, ears and scalp. Examine your chest and trunk, and the tops and undersides of your arms and hands. Examine both the front and back of your legs, and your feet, including the soles and the spaces between your toes. Also check your genital area and between your buttocks.

Followup Care

Even though most skin cancers are cured, the disease can recur in the same place. Also, people who have been treated for skin cancer have a higher-than-average risk of developing a new cancer elsewhere on the skin. That's why it is so important for them to continue to examine themselves regularly, to visit their doctor for regular checkups, and to follow the doctor's instructions on how to reduce the risk of developing skin cancer again.