Skin Cancer Explained: Causes, Types, And Treatments

According to the American Cancer Society, skin cancer is the "most commonly diagnosed" cancer in the United States. In fact, close to 10,000 people are diagnosed daily, and two or more people die of the disease every hour (per The Skin Cancer Foundation).

More statistics from The Skin Cancer Foundation found that while at least 20% of the population will have some form of skin cancer before they turn 70 there is an almost 100% survival rate if found early.

Furthermore, figures from the American Cancer Society credit advances in treatment for lowering the number of deaths by nearly 4% between 2015-2019.

As your body's largest organ, your skin is designed to guard your body against germs. Made up of water, protein, fats, and minerals, your skin also helps your body maintain the proper temperature. At the same time, the nerves in your skin enable you to feel sensations (via the Cleveland Clinic).

Your skin has several layers; the outermost is known as the epidermis and is where most skin cancer starts, according to The Centers for Disease Control and Prevention (CDC). Skin cancer results from mutations in damaged skin DNA that causes accelerated growth that forms tumors (via the Skin Cancer Foundation).

The Mayo Clinic doctors recommend that a medical professional determine the cause of abnormal skin growths, as not all result from skin cancer. Let's take a closer look at all the types of skin cancer, as well as their available treatments and causes. 

The American Academy of Dermatology Association (AAD) reports that more than 2 million people in the United States are diagnosed with basal cell carcinoma (BCC) annually. Furthermore, according to Memorial Sloan Kettering Cancer Center, BCC accounts for nearly 80% of skin cancer diagnoses in the U.S. The majority of those diagnosed with BCC are over the age of 50 (via MedlinePlus). When you're diagnosed with BCC, the cancerous cells are found in what is known as the basal cell layer. It is the bottom part of the top section of your skin, and is known as the epidermis.

BCC is most common in those with fair skin who fail to wear either sunscreen or sun-protective clothing while outside. Precursors to a BCC diagnosis include age spots, deep wrinkles, and skin discoloration (per the AAD).

Those with BCC often notice non-painful bumps and lesions that look like scars on the parts of their body most exposed to the sun. Crusty, bleeding sores that don't heal are also common prior to diagnosis (via the Cleveland Clinic). And this type of skin cancer can also get into your nerves and bones, according to the AAD. 

According to the American Cancer Society, nearly 100,000 people get diagnosed with melanoma annually. Though that only makes up for approximately 1% of all skin cancer diagnoses in the United States, melanoma is responsible for "a large majority of skin cancer deaths." The American Society of Clinical Oncology (ASCO) puts the number of deaths yearly from melanoma at approximately 7,650 in the U.S.

The upper layer of your skin possesses cells known as melanocytes. Melanocytes give your skin its color by creating two types of the pigment known as melanin, called eumelanin and pheomelanin. According to The Skin Cancer Foundation, only eumelanin can protect you from the sun. It does so by darkening your skin. Those with less eumelanin are more susceptible to melanoma.

Doctors at the Mayo Clinic report melanoma is often caught through changing moles or discovering new ones. Most adults have an average of 10-40 moles, with most moles appearing either in childhood or after age 40. It is recommended that you have a medical professional check your moles to ensure they're not asymmetrical or have an irregular edge. Also, watch for size, shape, and color changes, and make an appointment if your moles suddenly itch or bleed.

Dermatofibrosarcoma protuberans (DFSP) is a rare form of skin cancer diagnosed in one in 100,000 to one in 1 million people annually (via MedlinePlus). Of those with this form of the disease, only around 5% see it spread from its origin. According to the Cleveland Clinic, DFSP differs from other cancers in several ways. First, "DFSP appears to affect people who are Black more often than people of other ethnicities" (via the Cleveland Clinic). And, unlike previously mentioned skin cancers, it is not attributed to sunlight or UV rays. Moreover, DFSP affects your dermis or middle layer of skin, and this type of skin cancer is known to return after surgical treatment. Finally, those between the ages of 20-50 are most likely to be diagnosed with DFSP.

Appearing mainly on your arms, legs, and torso, the rough patches of skin or pimple-like lumps associated with DFSP also develop in areas of your body damaged by burns, scars, or tattoos (per the Cleveland Clinic).

DFSP varies depending on the cell makeup of the tumor; melanin-containing Bednar tumors appear dark in color, while Myxoid DFSP's include myxoid stroma, which is "an abnormal type of connective tissue." Giant cell fibroblastoma or juvenile dermatofibrosarcoma protuberans are named as such since the cells in the tumor are much larger than those in other tumors, and this type of DFSP is more likely to affect the children and teens (via MedlinePlus).

Between 5-10% of skin cancers occur as eyelid tumors. Of those, approximately 1% are diagnosed as sebaceous carcinoma, making this type of skin cancer extremely rare (via the Cleveland Clinic). Most people with this type of skin cancer get diagnosed between the age of 60-80 and were born female. However, of those patients who received treatment early, nearly 80% survived over five years. The percentage drops to 50% once cancer metastases (per American Association for Cancer Research AACR).

SC forms in your skin's oil glands and is most often found on the eyelids (via the Mayo Clinic). It usually starts with a slow-growing, firm lump (via Stanford Health Care). Over time, it often turns yellow and, if not treated, could look like pink eye or a stye, and additional growth could lead to eyesight issues. If SC appears anywhere else on your body, it presents as a slow-growing pink or yellowish lump and could bleed. Like most other forms of skin cancer, it results from spending too much time in the sun without protection. Other contributing factors include a weakened immune system and previous radiation therapy.

Unfortunately, SC is known to be aggressive and often returns after treatment, according to the American Academy of Dermatology Association.

Surgery is one of the most common ways to treat skin cancer. However, the procedure you undergo depends on the kind of skin cancer you're diagnosed with, its location, and how far along it has developed (via Cancer Research UK).

Most skin cancer diagnoses begin with a biopsy. This procedure requires your doctor to numb the affected area and remove the diseased tissue along with some healthy tissue. This specimen is sent off to be examined, so your doctor knows what to do next (per Cancer Research UK).

Medical professionals at Johns Hopkins University remove smaller, less complicated skin tumors using cryosurgery or curettage and electrosurgery. During cryosurgery, your doctor sprays the area with liquid nitrogen to freeze and destroy the diseased cells. It takes about two weeks for the dead tissue to fall off. When curettage and electrosurgery are used, the doctor scrapes away as much cancerous tissue as possible and then uses an electric current to kill off any remaining cells and control bleeding.

During Mohs surgery, the doctors at NYU Langone numb the affected area and remove a thin layer of tissue. It is then analyzed, and if any cancer remains, the doctor goes back in to take another layer. Mohs keeps scars small and reduces the need for additional surgery.

If your doctor thinks your cancer has spread, you may undergo a lymph node biopsy wherein a sample or an entire lymph node gets removed for examination. Should cancer be found, additional steps will be taken (per NYU Langone).

AIM at Melanoma uses the term targeted therapy to describe medications specifically designed to attack molecules that help cancer cells spread. Samitivej Hospital further explains that, unlike chemo, the drugs used in targeted therapy don't destroy healthy cells. Additionally, doctors at Penn Medicine state that while chemo only kills the cancer cells you currently have, targeted therapy makes it so new cancer cells cannot develop. Regarding skin cancer, targeted therapy is used primarily for melanoma (per AIM at Melanoma).

Also, studies reported by Samitivej Hospital show that targeted therapy is much more effective at getting rid of melanoma than chemotherapy. Chemo has a 30% success rate, and targeted therapy is 80% successful. However, not everyone is a candidate for targeted therapy.

Medical professionals at Penn Medicine use one of three types of targeted therapy to treat your skin cancer. BRAF inhibitors help with melanomas associated with a mutation in the BRAF gene. Along a similar line are MEK inhibitors that work to target the protein in the BRAF gene. KIT inhibitors are used for more rare types of melanoma that have specific KIT gene mutations

Side effects related to targeted therapy depend on the medications you are given and often include rashes, dry skin, joint pain, and hair thinning. However, reactions tend to decrease when BRAF and MEK inhibitors are used together (per ASCO).

For best results, doctors at Penn Medicine often recommend using targeted therapy in conjunction with other treatments.

The American Cancer Society defines immunotherapy as using medications to stimulate one's immune system to better recognize and destroy cancer cells in the body.

Immunotherapy is most often used to treat people with advanced basal or squamous cell skin cancer (per American Cancer Society). Nearly half of those treated with immunotherapy were still alive after six and a half years, and more than one third of those who survived hadn't had their cancer worsen (via Dana-Farber Cancer Institute).

According to Healthline, doctors prescribe three types of immunotherapy drugs. The most common of which is known as a checkpoint inhibitor. Memorial Sloan Kettering Cancer Center describes this type of immunotherapy as blocking immune checkpoints by blocking the molecule that regulates T cells. T cells look for and kill tumors.

Another type of immunotherapy, cytokines, boosts your immune system's response to your cancer. It is often prescribed after you've undergone melanoma surgery to help lower your chances of recurrence. Cytokines also benefit those who haven't responded well to other treatments (per Healthline).

Another way doctors try to trigger your immune system to fight your cancer is by using oncolytic virus therapy. This type of immunotherapy uses modified viruses to infect and ultimately kill cancer cells. These viruses also prompt your immune system to attack the cancer cells (via Healthline).

Side effects are generally flu-like in nature. However, the American Cancer Society reminds you that immunotherapy suppresses your immune system and can lead to other serious health issues.