Skin cancer: types, symptoms, stages, and treatment

Skin cancer is the most common cancer in the United States—over 4 million cases are diagnosed each year. The vast majority are non-melanoma skin cancers like basal cell carcinoma (BCC) and squamous cell carcinoma (SCC). Melanoma, the most dangerous form of skin cancer, only makes up only about 1% of these cases (CDC, 2021; ACS, 2021).

Sun exposure and the damage caused by its ultraviolet rays are the cause of most skin cancers. However, other risk factors also play a part. Let’s take a look at what causes skin cancer and options for treating it.

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Skin cancer comes in several forms usually divided into two main categories: melanoma and non-melanoma skin cancers. 

Melanoma

This is a type of skin cancer that forms in melanocytes, which are specialized cells that make the pigment that gives your skin color (Heistein, 2021).

Melanoma cases make up 1% of all skin cancers. However, they account for the majority of skin cancer deaths. Unlike other types, melanoma is more likely to show up earlier in life with an average age of diagnosis of 57 (Henrikson, 2018; ACS, 2021). 

Like other skin cancers, melanoma is closely linked with sun exposure. But it doesn’t always show up in sun-damaged areas (Heistein, 2021).

Non-melanoma 

Two common skin cancers make up this group––basal cell carcinoma (BCC) and squamous cell carcinoma (SCC). Like melanoma, both are named for the type of skin cells they form in (Gruber, 2021). 

Non-melanoma can occur anywhere but is often on areas most exposed to the sun like the head, face, neck, back of the hands, arms, and legs. Basal cell carcinoma is by far the most common type. BCC makes up 75–80% of all non-melanoma skin cancers. While almost never deadly, BCC can severely damage or disfigure your skin if left untreated (McDaniel, 2021; Gruber, 2021). 

Squamous cell carcinoma is the second most seen form of skin cancer. SCC often shows up on the face and other parts of the skin regularly exposed to the sun. SCC is considered more dangerous than BCC as it’s more likely to metastasize or spread to other areas of the body, though that’s still rare (Howell, 2021). 

Other types of skin cancer seen only rarely include Kaposi sarcoma and Merkel cell carcinoma (Cesarman, 2019; Becker 2017). 

The most common sign of skin cancer is an irregular mole or spot. However, it can be tricky to distinguish this from a benign (non-cancerous) mole. Usually, your medical provider needs to take a biopsy or sample of your skin cells to determine if the skin growth is cancerous.

What does a skin cancer mole look like? That depends on the type (ACS, 2021): 

• Melanoma: These spots are usually asymmetrical, brown or black discolorations with irregular borders. They tend to be larger than 6 mm––roughly the size of an eraser on the end of a pencil. In some cases, melanoma moles may itch or bleed (Heistein, 2021).

• Basal cell carcinoma: BCC spots are often pink or red patches of small, pearly pimples or raised bumps. 

• Squamous cell carcinoma: SCC moles also look like patches of pimply pink or red skin. SCC spots can be scaly, crusty, or even bloody, and may be hard or rough to the touch.

Any new or changing moles or something on your skin that looks different from your other skin spots is considered suspicious. It’s worth having a medical professional like a dermatologist (a doctor who specializes in skin health) take a look (Gruber, 2021). 

Non-melanoma skin cancers are not defined in terms of stages. 

However, squamous cell skin cancers are sometimes preceded by something called actinic keratosis. This is an irregular pink, red, or scaly patch of sun-exposed skin. Actinic keratosis is not cancerous but can turn into SCC. It can be an indicator of early-stage skin cancer (Marques, 2021).

Melanoma, on the other hand, progresses in stages. What stage the cancer is in depends on characteristics of the growth including its size, thickness, and whether it has spread to other parts of the body. 

For example, stage 0 or early melanoma refers to skin cancer that is small and confined to the surface of the skin. The 5-year survival rate for this stage of melanoma is 99%. Stage 4 melanoma, on the other hand, is much more severe and has spread organs or other parts of the body. The 5-year survival rate for stage 4 melanoma is roughly 30% (ACS, 2021). 

Cancer survival rates describe the percentage of people still alive five years after their initial diagnosis. Whatever statistics you read online, be aware that these numbers come from large studies. They can’t predict future health or well-being for just one person as each individual responds to cancer and treatments for it differently. 

While you can die from skin cancer, only a very small percentage of people do. Skin cancer is also highly treatable with early detection (Henrikson, 2018).

Unprotected sun exposure and UV radiation is the primary cause of most skin cancers. 

If you’re out in the sun without protection—like clothing or sunscreen—UV rays from the sun can damage your skin cells. Repeated exposure eventually damages DNA and promotes the growth of cancerous cells. Staying out of the sun is one of the best forms of skin cancer prevention. 

For non-melanoma cancers like BCC and SCC, your risk rises with cumulative sun exposure, which is the total amount of sun you’ve seen over time. The more sun you get, the more likely you are to develop some type of skin cancer (Gruber, 2021). 

When it comes to melanoma, researchers have found evidence that getting too much sun during childhood and adolescence—particularly bad sunburns —raises the risk of skin cancer (Wu, 2014). 

Other skin cancer risk factors include:

• A family history of skin cancer (Mucci, 2016)

• Exposure to chemicals or toxins, including cigarette smoke (Sondermeijer, 2020)

• Tanning bed use

• Fair skin (less skin pigmentation)

• A compromised immune system 

What skin cancer treatment is needed depends on the type, location, and severity. 

The standard treatment option for basal and squamous cell cancers is the surgical removal of cancerous tissue. This can be accomplished by cutting it out or freezing the affected area. Most forms of non-melanoma skin cancer can be easily treated because they grow slowly. 

A special type of surgery known as Mohs surgery is also common. This procedure uses microscopic technology to remove skin cells layer by layer. Mohs surgery can minimize scarring on the face and other areas (McDaniel, 2021). 

In some cases, surgery isn’t the best option. Radiation therapy, topical creams, and medications are sufficient for some skin cancers (Howell, 2021).

For melanoma, the right treatment depends a lot on what stage the cancer is in. Surgery is usually the first line of treatment. While it may be enough on its own, surgery is often followed by chemotherapy and drug treatments (Gruber, 2021). 

Some people report skin cancer as relatively painless, while others say the moles or lesions are painful (Howell, 2021). 

It’s also worth pointing out that the face is the most common site of skin cancer, but these spots can also show up on your scalp, ears, legs, and lips (especially your upper lip).

Current estimates are that one in five Americans will develop some form of skin cancer in their lifetime. Fortunately, most cases are treatable and non-lethal (Fontanillas, 2021).  

You can help prevent skin cancer by protecting your skin from the sun's rays. That includes:

• Staying out of the sun in the middle of the day (from 10 AM to 4 PM)

• Wearing sunscreen (with an SPF of 30 or higher) and reapplying it often. It’s important to not forget the tops of your feet, neck, ears, and top of your head.

• Avoid tanning beds

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Current version

February 24, 2022

Written by

Health Guide Team

Fact checked by

Felix Gussone, MD

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About the medical reviewer

Felix Gussone, MD, Ro

Felix Gussone is a physician, health journalist and a Manager, Medical Content & Education at Ro.