The Different Types of Skin Cancer and Risk Factors for Development

Skin cancer is one of the most common forms of cancer in the world today. It is estimated that in 2022, over 100,000 people were diagnosed with some type of skin cancer in the United States alone. The skin is made up of many different types of cells and whenever the DNA inside these skin cells gets damaged, they can become cancerous. The exact type of skin cancer you get depends on the type of skin cell where it started in. Let us take a closer look at the different types of skin cancer and the risk factors for the development of this type of cancer.

It is estimated that one in five people will end up developing skin cancer at some point in their life. Almost all types of skin cancers can be cured if caught early and the correct treatment is administered.^(1, 2) Skin cancer develops when the skin cells start to grow and multiply rapidly in an uncontrolled and unorderly manner. Under normal conditions, new skin cells are produced when the skin cells get old and die or when they get damaged. However, in some cases, this process fails to work properly and a rapid growth of cells takes place. This build-up of rapidly growing cells might be non-cancerous (or benign) and do not cause any harm and neither do they spread, or they can be cancerous, spreading to nearby tissues and other parts of the body if not found early and treated.^(3, 4)

Skin cancer is most commonly caused by exposure to ultraviolet (UV) light from the sun, and there are three main types of skin cancer. These include:⁽⁵⁾

• Basal cell carcinoma
• Squamous cell carcinoma
• Melanoma

Out of these three types of skin cancer, basal cell carcinoma and squamous cell carcinoma are grouped together and known as non-melanoma skin cancers. There are also some other extremely rare and unusual forms of skin cancer known as Merkel cell tumors and dermatofibrosarcoma protuberans.^(6, 7)

Let us take a closer look at the different types of skin cancer and the risk factors for their development.

1. Basal Cell Carcinoma

   Basal cell carcinoma is the most common type of skin cancer. This type of skin cancer begins in the basal cells of the skin that can be found in the lower part of the epidermis layer. The epidermis layer is the outermost layer of the skin. Basal cells are a type of cell inside the skin that is responsible for making new skin cells as the older ones die or get damaged. When the basal cells manufacture new skin cells, the older skin cells get pushed to the surface of the epidermis layer, where they eventually die and are shed off by the body.⁽⁸⁾

   Basal cell carcinoma typically begins as a slightly transparent bump on the skin. However, it is possible that it appears different than this. It can sometimes also appear like a scaly flat patch or a shiny bump on the skin that grows slowly over a period of time. This type of skin cancer tends to commonly develop on areas of the skin that are exposed to the sun, including the head and the neck.⁽⁹⁾

   Most cases of basal cell carcinomas are believed to be caused by long-term exposure to UV radiation from the sun. Using sunscreen and avoiding going out at peak sunlight hours can help keep you safe from basal cell carcinoma.

   There are four major types of basal cell carcinoma (BCC), including:

   • Nodular BCC: This is the most common type of basal cell carcinoma and it appears like a small round pimple that has blood vessels surrounding it that are quite visible. This is known as telangiectasias.⁽¹⁰⁾
   • Sclerosing or Morpheaform BCC: This type of basal cell carcinoma looks like scars that tend to expand slowly and over a long time. This type of BCC is mostly seen on the face, and it can even appear as a small red dot anywhere on the skin.⁽¹¹⁾
   • Superficial Spreading BCC: This type of basal cell carcinoma causes the appearance of lesions on the skin. These lesions look like small and shallow marks on the skin that may be slightly lighter in color than the nearby skin. These lesions can appear on the torso, legs, and arms.⁽¹²⁾
   • Pigmented BCC: This is a very rare form of basal cell carcinoma that causes hyperpigmentation on the skin. In this, a certain part of the skin turns darker than the skin surrounding the affected area.

   Basal cell carcinoma can impact anybody, though the risk of developing this type of skin cancer is higher in men and people who are assigned male at birth. Basal cell carcinoma is also more common in people above the age of 50 years, as well as those who have fair skin and light eyes. People who get basal cell carcinoma once are at a much higher risk of developing another form of non-melanoma skin cancer in the future.

   Some of the common signs of basal cell carcinoma may include:⁽¹³⁾

   • Bumps, lumps, scabs, scaly lesions, or even pimples that appear on the skin and tend to persist without getting better.
   • The lump might be slightly translucent or see-through and may appear close to your normal skin color. Or it may even differ in color and range from being white to pink, black to blue, or brown to black.
   • The lump tends to grow slowly over a period of time.
   • The lump may appear to get shinier than the skin surrounding it. Over time, small blood vessels may become visible on it.
   • The lump may become painful or itchy.
   • The lump may develop an ulcer and clear fluid or blood can ooze out of it upon touching it.

   Basal cell carcinomas tend to commonly develop on the face, scalp, nose, legs, arms, ears, or eyelids – basically those parts of the body that are most exposed to the sun.

   Once you are diagnosed with basal cell carcinoma, your doctor will treat the cancer by removing the cancerous tissues from the body. Some of the treatment options can include surgery, cryotherapy, chemotherapy, laser therapy, photodynamic therapy, or electrodesiccation and curettage in which the cancerous bump is scraped off with a curette and then burnet with a specialized electric needle.^(14, 15)

   Your doctor will select the best possible treatment plan for you depending on many factors like the stage and location of the cancer, your age, and your overall health amongst others.

   If you leave basal cell carcinoma untreated, the skin cancer will continue to grow slowly and eventually start spreading to deeper tissues of the body like muscle, cartilage, and bone. Over time, the cancer will become more painful and ulcerated, causing bleeding and increasing the risk of infection. In some rare forms of basal cell carcinoma, the cancer may spread to other parts of the body, causing fatal side effects.

2. Squamous Cell Carcinoma

   Squamous cell carcinoma is a type of skin cancer that develops in the squamous cells present in the middle and upper layers of the skin. This type of skin cancer is usually not fatal, though it is usually aggressive. Squamous cell carcinoma develops as a result of an overproduction of squamous cells in the epidermis layer of the skin. This form of skin cancer is sometimes also referred to as cutaneous squamous cell carcinoma and it is the second most common type of skin cancer, just behind basal cell carcinoma.⁽¹⁶⁾

   Similar to basal cell carcinomas, there are different kinds of squamous cell carcinomas as well, depending on which part and how much cancer is present in the body. The two most common types of squamous cell carcinoma are cutaneous squamous cell carcinoma and metastatic squamous cell carcinoma. Cutaneous only affects the topmost layers of the skin while metastatic is the stage of the cancer that has spread to other parts of the body from the skin.^(17, 18)

   While squamous cell carcinoma can affect anyone, some people are at a higher risk of developing this type of skin cancer. You are at a higher risk if you:

   • Are 65 years of age or above.
   • Have a pale complexion, blonde or red hair, and blue or green eyes.
   • Have a weak immune system.
   • Have received an organ transplant.
   • Have been exposed to the sun for a long time or experienced sun damage to the skin at a young age.
   • If you get easily sunburned.
   • If you frequently use tanning beds or regularly tan yourself under the sun.

   The common symptoms of squamous cell carcinoma appear as the following skin changes:⁽¹⁹⁾

   • A wound or sore that refuses to heal or a wound/sore that heals and then keeps coming back.
   • A feeling of roughness on the skin, or feeling a bump or growth on the skin, which may crust over. It may also bleed from time to time, especially upon touching.
   • A growth on the skin that appears to be higher than the skin surrounding it, but it sinks down in the middle.
   • A part of the skin that is scaly, flat, and red in color and the patch is larger than one inch.

   While it is possible to develop squamous cell carcinoma anywhere on the body, it is most commonly observed on the skin, the face, lips, ears, nose, eyelids, scalp, mouth, tongue, throat, anal cavity, hands, legs, arms, or the stomach.

   The treatment options for squamous cell carcinoma are very similar to basal cell carcinoma and include photodynamic therapy, cryosurgery, excision, Mohs surgery (commonly used for facial cancers), curettage and electrodessication, and systemic chemotherapy.

   In cases of invasive squamous cell carcinoma where surgically removing the cancer is not an option, your doctor could also prescribe medications for treating squamous cell carcinoma.

   Some of the medicines may include:

   • Skin creams containing 5-fluorouracil or imiquimod to treat the cancer that is present in the epidermis layer.⁽²⁰⁾
   • Pembrolizumab (brand name: Keytruda), is a type of immunotherapy for treating squamous cell carcinoma that cannot be treated with surgery.⁽²¹⁾
   • Cemiplimab-rwlc (brand name: Libtayo), is another type of immunotherapy to treat advanced stages of the cancer.⁽²²⁾

   Of course, like any other treatment options, there are several side effects associated with the treatment options for squamous cell carcinoma as well. The most common side effect is cosmetic changes to the skin, especially scarring from the removal of the cancer from the body. There can also be many side effects from the immunotherapy drugs you take for treating the cancer.

   If your squamous cell carcinoma is caught early and you start treatment right away, you have an excellent survival rate and a positive prognosis.

3. Melanoma

   Melanoma is the most aggressive and serious type of skin cancer. It also has the highest rate of death. While this is a serious and aggressive form of skin cancer, it also has a high chance of getting cured if it is detected at an early stage. Following prevention techniques and an early diagnosis are critical if you want to survive this form of cancer, especially if you have pale or fair skin, red or blonde hair, and blue eyes.⁽²³⁾

   Melanoma grows rapidly and it is also capable of spreading to any organ in the body. Melanoma arises from skin cells known as melanocytes, which are responsible for the production of melanin, the pigment in the body that lends color to our skin. Most melanomas tend to be brown or black in color, but some can be red, pink, purple, or even the same color as your skin.

   Many cases of melanomas tend to start out from existing moles, though they can also begin from normal skin. Melanomas can even appear as scaly patches, raised bumps, or open sores on the skin. This is why it is important to keep a close eye on any changes in the skin.⁽²⁴⁾

   It is possible to get melanoma on any part of the body, even on the eyes and internal organs. Women are more prone to getting melanoma on their legs while men are more likely to develop this type of skin cancer on their trunk, usually on the upper back.⁽²⁵⁾

   The biggest risk factor for developing melanoma is excessive exposure to sunlight, especially suffering sunburns at a young age. In fact, nearly 86 percent of all melanomas are caused by UV radiation from the sun and from tanning beds.^(26, 27)

   While anyone can get melanoma, some people are at a higher risk of developing this type of skin cancer. These include:

   • People with a family history of melanoma.
   • Those who have fair skin, blond or red hair, blue eyes, and freckles.
   • People who have overexposure to sunlight or have got blistering sunburns in the past, especially at a young age.
   • People with a history of regularly using tanning beds.
   • Those who have many moles on the body.
   • Those with a weakened immune system.
   • People living near the equator or in higher altitudes where your exposure to UV radiation from the sun is much higher.

   The exact treatment for melanoma depends on the stage at which the cancer is diagnosed and the patient’s overall health. Surgery is generally the most preferred form of treatment for melanoma, where the cancer is cut out along with some of the healthy tissue surrounding it. The exact amount of healthy skin or tissue that is removed along with the cancer depends on the location and size of the cancer. Usually, surgical removal of melanoma is carried out under local anesthesia. Advanced cases of melanoma require other types of treatments, along with or instead of surgery. Some other treatment options for melanoma include lymphadenectomy where the lymph nodes near the primary site of the cancer are removed along with the cancer, metastasectomy, targeted therapy, radiation therapy, and immunotherapy.^(28, 29)

   You can lower the risk of melanoma by protecting yourself from excessive sun exposure and sunburns. Also, avoid using tanning beds. As is the case with most skin cancers, they can be cured if they are detected early and before they have spread to other parts of the body. However, advanced cases of melanoma have a higher chance of being fatal. Remember that the earlier any type of skin cancer is detected and removed, the better are your chances of making a full recovery from the cancer.

Over the years, skin cancer has emerged as one of the most common types of cancer in the world. There are three main types of skin cancer. The exact type of skin cancer you have depends on the type of skin cells in which the cancer originated in. The three most common types of skin cancer are basal cell carcinoma, squamous cell carcinoma, and melanoma. Any type of skin cancer usually develops on parts of the skin that remains exposed to the UV rays of the sun, especially the scalp, face, ears, lips, neck, chest, legs, and arms, amongst others. However, this does not mean that skin cancer cannot develop in other parts of the body.

Remember that skin cancer can affect people of all skin colors, not just people with fair or lighter skin. No matter what type of skin cancer you have, an early diagnosis and proper treatment can go a long way in ensuring you make a full recovery from this type of cancer.

References:

Also Read:

• What is Skin Cancer: Signs, Symptoms, Detection & Diagnosis, Prevention, Risk Factor
• Warning Signs of Skin Cancer
• What Do The Early Stages Of Skin Cancer Look Like?
• Is Morphea A Skin Cancer?
• Why Skin Cancer Screening is Important for Men?