Skin cancer is a broad term that refers to any type of cancer that begins in the cells of the skin, usually developing in the top layer of skin, also known as the epidermis. More specifically according to the Skin Cancer Foundation, it is "the uncontrolled growth of abnormal skin cells," occurring when "unrepaired DNA damage to skin cells (most often caused by ultraviolet radiation from sunshine or tanning beds) triggers mutations or genetic defects that lead the skin cells to multiply rapidly and form malignant tumors."

Basal cell carcinoma

The most frequent form of skin cancer is basal cell carcinoma. BCCs are abnormal and uncontrolled lesions in the basal cells, which line the deepest layers of the epidermis. They often look like open sores, or they can be red patches, pink growths, shiny bumps, or scars. They are caused by the cumulative effect of exposure to the sun or by occasional excessive exposure. BCC rarely spreads, but it should not be taken lightly. If not treated, it can cause disfigurement. More than 4 million cases are diagnosed each year in the U.S.

Squamous cell carcinoma

The second most common form of skin cancer is squamous cell carcinoma, which is uncontrolled growth in the squamous cells, which compose most of the skin's upper layers. SCCs appear in a variety of ways -- scaly red patches, open sores, elevated growths with a central depression, or warts. They may crust over and bleed. If allowed to grow, they can disfigure and become dangerous. They can be caused by cumulative UV exposure over a lifetime. Occurring anywhere in the body, they are most often found on areas exposed to the sun-the rim of the ear, lower lip, balding scalp, neck, hands, arms, and legs.

Melanoma

Melamoma originates in the pigment-producing melanocytes in the basal layer of the epidermis and can resemble moles and sometimes develop from moles. They are generally black or brown and are usually caused by intense, occasional exposure to ultraviolent rays, often leading to sunburn especially in people with a genetic predisposition.

According to the Skin Cancer Foundation, an estimated 9,730 people will die of melanoma in 2017. An estimated 87,110 new cases will be diagnosed in the U.S. in 2017. If treated early, a melanoma is almost always curable, but if not, it can metastasize. The estimated five-year survival rate for patients whose melanoma is detected early is about 98 percent in the U.S. The survival rate falls to 62 percent when the disease reaches the lymph nodes, and 18 percent when the disease metastasizes to distant organs. On average, a person's risk for melanoma doubles if he or she has had more than five sunburns.

Genetic factors

	Atypical mole

Every article and scientific paper on skin cancer emphasizes sunlight and UV light exposure as the primary cause. But the etiology is a bit more complicated than that. According to the National Cancer Institute there are more than 100 types of tumors clinically apparent on the skin, and "many are known to have familial and/or inherited components, either in isolation or as part of a syndrome with other features." Though BCC and SCC, the most common non-melanoma skin cancers, are usually caused by the sun, there are also hereditary and genetic factors. In the case of melanoma, 5 to 10 percent of all cases arise in families where there are multiple cases. So it seems clear that there are several genes and hereditary syndromes associated with the development of skin cancer. It appears that genetics won't give you skin cancer, but they might create a predisposition.

People of color and skin cancer

Then there is a question often asked: Can people of color get skin cancer? The answer is yes, everyone can get skin cancer. It is true that many people of color are less susceptible to the UV damage of the sun and other forms of UV radiation because there are greater amounts of melanin, the protective pigment that darker skin produces. But darker skin can still be damaged by too much exposure. Further, there are other factors to consider. Darker-skinned people are more susceptible to acral lentiginous melanoma, an especially virulent form of melanoma that appears on the palms of the hands and the soles of the feet. With the more common forms of skin cancer, risk varies by ethnicity. Latinos, Chinese, and Japanese tend to develop BCC, while among African Americans and Asian Indians SCC is more frequent.

Treatment

Treatment for skin cancer varies with the form, the intensiveness, and aggressiveness of the cancer. This article lists some of the most frequently used treatment options. Surgical excision is used to treat many kinds of skin cancer. When the surgeon is experienced and the tumor is small, results are very good both medically and cosmetically. With cryosurgery, tumor tissue is destroyed by freezing. Liquid nitrogen is applied with a cotton-tipped applicator or spray device. No cutting is required. Curettage and electrodesiccation is like a combination of cutting and freezing, with a 95 percent cure rate. Radiation, for inoperable skin cancers, uses X-ray beams directed at the tumor with no need for cutting or anesthesia. Treatment continues several times a week for one to four weeks.

Mohs micrographic surgery

In the 1930s, Dr. Frederick Mohs developed a surgical technique that has stood the test of time and has come to be embraced by an increasing number of surgeons for an ever-widening variety of skin cancers. A thin layer of tissue containing the tumor is removed. While the patient waits, sections of this excised layer are mapped in detail and examined under a microscope in a laboratory on site. If cancer is present, the procedure is repeated in the area where the cancer cells were identified. The tissue mapping allows the surgeon to pinpoint where that is. Successive layers are taken until the last excised layer is cancer-free. This process has the lowest recurrence rates, highest cure rates, and best cosmetic results of any skin cancer treatment. 

Effect of the sun

But, of course the best treatment for skin cancer is prevention, and the first thing to consider is the sun, which has fallen from grace in recent decades, sadly. Once it was seen as the great bearer of light and health; now it is regarded by many as a danger. So which is it -- benefit or hazard, or both? And is the best prevention for skin cancer to make sure you are never exposed to the sun's UV rays?

Dangers

According to the information from the Skin Cancer Foundation cited earlier in this article, "about 90 percent of non-melanoma skin cancers are associated with exposure to ultraviolet radiation from the sun." And note again that "between 40 and 50 percent of Americans who live to age 65 will have either basal cell carcinoma or squamous cell carcinoma at least once." These are the two main non-melanoma skin cancers. So, almost half of all Americans living to retirement age will suffer the negative dermatological effects of the sun.

Though basal cell carcinoma and squamous cell carcinoma can be inconvenient and difficult, they are usually not killers. That distinction belongs to melanoma, which accounts for only 1 percent of cases of skin cancer but the vast majority of deaths. Again, according to the Skin Cancer Foundation, a study in the U.K. determined that about 86 percent of cases of melanoma are from exposure to the ultraviolet radiation from the sun. So there can be no denying that the sun can have a very deleterious effect on one's skin and one's health.

Benefits

But there is another side to this discussion. UVA rays, which have the longest wave length of ultraviolet rays and which are not filtered out by the atmosphere, stimulate the body to produce vitamin D. In Australia, an anti-sun-exposure campaign extended over many years has produced a populace in which 31 percent of adults now have vitamin D deficiency. When levels of this vitamin are low, the bones tend to lose calcium and become weaker. In moderate amounts, UVA rays also help prevent breast cancer, colon cancer, and prostate cancer.

The UVA rays stimulate the melanocytes in the skin to produce more of the brown pigment called melanin, which helps protect the skin against the rays and helps you tolerate more of the sun. So a tan can give protection, up to a point. Further, the sun triggers physical and psychological responses that are not fully understood. We know that people in climates where the sun rarely shines, especially in the winter, sometimes suffer from seasonal affective disorder. When they can get out into the sunlight, their spirits lift. Sunshine is often a motivator that invites people to go outdoors and be active.

Tanning

But the dangers of sunlight are real and even pervasive, and the tan that seems so healthful can be hazardous. It is the ultraviolet light that does the damage, and the evidence is so strong that many states have banned tanning salons. Tanning, or at least over-tanning, can have painful, lasting, and even life-threatening results. Prolonged exposure to the ultraviolet radiation of the sun results in burning by the ultraviolet B rays. The effect is that immune cells in the skin release histamine, which causes blood vessels to dilate and leads to acute inflammation. Anyone who has had bad sunburn knows what this looks and feels like. Some of the cells can be so badly injured that they die and flake away. Brown spots can appear. The burning can lead to basal cell carcinoma, which, while not usually malignant, can cause cosmetic problems.

But too much exposure can lead to malignant melanoma, which can spread and develop very rapidly, metastasizing to other parts of the body, becoming a killer. People who have been repeatedly over-exposed to the sun and have been sunburned from an early age are at special risk. Too much exposure over a long period of time will also speed skin aging and permanently wrinkle the skin. The blood vessels in the skin can become permanently dilated, and the skin can become thick and red.

To sun or not to sun?

So what is it to be? Well, we should all exercise more caution than we might think we should. But sun in reasonable amounts is healthful. Just don't stay out too long and don't get sunburned. Here are some things to remember in order to protect yourself against the sun: 

* Wear a hat with at least a three-inch brim.

* When outside between 10 a.m. and 4 p.m., seek out the shade.

* Cover your skin with clothing - wear a long-sleeved shirt.

* Use a broad spectrum (protecting against UVA and UVB rays) sunscreen with an SPF (sun protection factor) of 15 or higher. For extended outdoor activity use a water resistant, broad spectrum sunscreen with an SPF of 30 or higher.

* Apply two tablespoons of sunscreen to your body 30 minutes before going outside and repeat every two hours or right after swimming or heavy sweating.

* Keep newborns out of the sun.

* Always use sunscreen on children. They should never get sunburned.

* Stay away from tanning salons.

* Remember there are different "levels" of shade. You can get indirect or diffuse UV radiation even when you are in shade. Only deep shade (no sky visible, no UV penetration) gives you complete protection

* Beware of cloudy days. You can still receive UV radiation.

* Wear sunglasses year-round when you are in sunlight.

* Give yourself a head-to-toe skin examination every month.

Skin Cancer Awareness

Author Maud Hart Lovelace wrote in one of her books, "The sunshine was like powdered gold over the grassy hillside." It is unpleasant to have to acknowledge that something so rich and good, so life-giving as the sun can be the primary cause of a widespread form of cancer. But that is the reality of skin cancer. If there is anything that emerges from Skin Cancer Awareness Month, it is that the sun is not as benign as we may have wished, and that too often people forget to protect themselves from its deleterious effects. But as we admit this sobering reality, let us not forget that in proper amounts the sun can even help condition the skin to handle the sun's own rays. Of course, the sun is immutable. We cannot live without its light and warmth. So we must handle it with thoughtful attention. If we do that, we may enjoy this "powdered gold" on our skin during a long and healthy life.