![](jpg/umbrellas-bannerbaee.jpg)
Not all skin cancers are created equal. Nonmelanoma skin cancers, while less dangerous than their melanoma counterparts, are far more common – with statistics estimating that in the United States 3 million people are diagnosed each year, and about half of Americans will have skin cancer at least once by the time they are 65.1 Don’t let this high rate of diagnoses alarm you though, the two most common forms of nonmelanoma, basal cell carcinoma and squamous cell carcinoma, are preventable and usually curable. Study our guide for a quick education on the different types, warning signs and how to distinguish between a cancerous and noncancerous spot. As with all cancers, early detection makes all the difference.
What’s the Difference? Nonmelanoma Skin Cancer vs. Melanoma Skin Cancer
To really understand skin cancer, it helps to understand skin. It is your body’s largest organ and protects against infections and injury and helps regulate temperature. The skin also stores water, fat and produces vitamin D - AKA it performs a number of important functions to keep you healthy.2
The skin is made up of three main layers:
- The epidermis - the top or outer layer. A thin, tough layer of skin that protects the body, gives skin its colour and makes new skin. It is made of several different types of cells.
- The dermis - the inner, thickest layer under the epidermis. It is filled with proteins like collagen and elastin, that give skin its strength, sturdiness, stretch and flexibility.
- The hypodermis or subcutis - the innermost layer of skin, found under the dermis. Mainly made up of fat tissue, it helps keep the body warm and protects the internal organs and delicate tissues from injury. 3
All types of cancer begin when healthy cells change and grow out of control, forming a mass called a tumour. A tumour can be either cancerous or benign, but a cancerous tumour is malignant which means it can grow and spread to other parts of the body. A benign tumour can grow, but will not spread. 4
While many assume that skin cancer is synonymous with melanoma, melanoma is actually one type of skin cancer that is known for its aggressive nature and strong ability to metastasize to other parts of the body. Melanoma forms in the melanocytes, which are the cells in the lowest layer of the epidermis that give skin and eyes their colour. Possible warning signs for melanoma can include a changing in the appearance of a mole or pigmented area of the skin. Read our full guide to melanoma here.
Nonmelanomas are all other types of skin cancer with the two most common being squamous cell carcinoma and basal cell carcinoma. These types of skin cancer form in the upper and middle layers of the epidermis, and rarely spread to other parts of the body - making them serious, but less concerning and less deadly than melanomas. Possible warning signs for nonmelanoma include unusual changes in the skin, such as small areas that are raised, smooth or red, or skin that is rough, red and scaly. 5
Basal Cell Carcinoma
Basal cell carcinoma (BCC) is the most common type of skin cancer, making up about 75% to 80% of all skin cancers and affecting 50 to 60,000 Canadians each year. 6
BCC begins in the basal cells of the skin, which are the round cells found in the epidermis. It is characterized by slow growth and very rarely spreads to other parts of the body, although it may grow into nearby tissue if left untreated. The most common place for it to develop is on the head, face and neck. 7
There are a number of subtypes of BCC detailed below:
- Nodular BCC - the most common subtype. Usually develops on areas of the face exposed to the sun and appears as a round, raised, pink, red or pearly white lump or an area with wide blood vessels showing on top.
- Superficial BCC - the second most common subtype. Usually develops on the central part of the body, arms or legs. It appears as a pink or red scaly area.
- Infiltrative and micronodular BCCs - a rarer form. Usually develops in the head or neck area and grows deeper into the dermis. It can look like nodular BCC but grows and spreads more quickly than both nodular and superficial BCC.
- Morpheaform BCC - another more rare form. Usually develops in the head or neck area and appears as a flat, firm white or yellow area that can look like a scar. It grows and spreads more quickly than nodular and superficial BCC and may also be called sclerosing or fibrosing BCC. 8
Previously, those most affected by BCC were older people, in particular men who had a history of working outdoors. But in the last few decades the number of new cases has increased sharply, with the average age of onset steadily decreasing and an increasing number of women being diagnosed. 9
Squamous Cell Carcinoma
Squamous cell carcinoma (SCC) is the second most common type of skin cancer, making up about 20% of all skin cancers and affecting more than 20,000 Canadians each year. 10
SCC begins in the squamous cells, which are the flat cells found in the outer part of the epidermis. It usually grows slowly, but at a faster rate than BCC and is more likely to grow deeper into the skin and spread. When it is found early and only in the epidermis, it is referred to as SCC in situ. At this stage it often isn’t life-threatening, but can turn into invasive SCC if left untreated. 11
SCCs can develop on all areas of the body including mucous membranes, but are most common in areas exposed to the sun such as the face, neck, bald scalp, hands, shoulders, arms, and back. The rim of the ear and the lower lip are especially vulnerable to the development of these cancers. SSCs can also occur where skin has suffered certain kinds of injury: burns, scars, long-standing sores, sites previously exposed to X-rays or certain chemicals (such as arsenic and some petroleum by-products). In addition, chronic skin inflammation or medical conditions that suppress the immune system over an extended period of time may encourage development of SCC.12
SSCs often look like scaly red patches, open sores, elevated growths with a central depression, or warts that may crust or bleed. 13
Actinic Keratosis
Actinic Keratosis is a precancerous condition of the skin that if left untreated can develop into squamous cell carcinoma. It is not yet cancer, but rather a warning sign you can easily look out for to prevent yourself from developing cancer in the future.
Also known as solar keratosis, it most often develops on areas exposed to the sun, like the face, ears, neck, bald scalp, arms and backs of hands. It usually appears as small, rough patches on the skin that feel like sandpaper and can get bigger and turn red or brown. They may be itchy or burn and a person can have many patches close together in one area. Many people have more than one area of actinic keratosis. 14 One of the benefits to how it presents itself, is that you can look out for warning signs simply by running your hands along worrisome areas to feel for the symptoms.
How to Identify a Non Cancerous Mole
With all of these warning signs and potential for cancerous spots, it’s also important to be able to recognize a healthy mole on your body. Normal moles are common on all bodies, for people of all races and they most usually appear as small brown spots in the first few decades of life. Flat or elevated, round or regularly shaped are all good signs. 15
Taking the Steps: Prevention and Monitoring
If you identify any of the changes detailed in this guide, or think you are at risk, the best course of action is to seek out a dermatologist who can address the current changes, and also document any skin irregularities for long term monitoring. One of the main unifying factors for all types of skin cancer are that they are believed to be caused by exposure to UV rays. Prevention techniques for staying out of the sun, or protecting exposed skin with sunscreen and layered clothing, greatly reduce your risk of developing both melanoma and nonmelanoma skin cancer.
References
-
Cancer.Net (2016) Skin Cancer (Non-Melanoma): Statistics. Retrieved from http://www.cancer.net/cancer-types/skin-cancer-non-melanoma/statistics
-
Cancer.Net (2016) Skin Cancer (Non-Melanoma): Introduction. Retrieved from http://www.cancer.net/cancer-types/skin-cancer-non-melanoma/introduction
-
Canadian Cancer Society (2017) The skin. Retrieved from http://www.cancer.ca/en/cancer-information/cancer-type/skin-non-melanoma/non-melanoma-skin-cancer/the-skin/?region=on
-
Cancer.Net (2016) Skin Cancer (Non-Melanoma): Introduction. Retrieved from http://www.cancer.net/cancer-types/skin-cancer-non-melanoma/introduction
-
Dana-Farber Cancer Institute (2017) What's the Difference Between Melanoma and Skin Cancer? Retrieved from http://blog.dana-farber.org/insight/2014/05/whats-the-difference-between-melanoma-and-skin-cancer/
-
Canadian Skin Cancer Foundation (2017) Basal Cell Carcinoma. Retrieved from http://www.canadianskincancerfoundation.com/basal-cell-carcinoma.html
-
Canadian Cancer Society (2017) Types of non-melanoma skin cancer. Retrieved from http://www.cancer.ca/en/cancer-information/cancer-type/skin-non-melanoma/non-melanoma-skin-cancer/types-of-non-melanoma/?region=on
-
Canadian Cancer Society (2017) Types of non-melanoma skin cancer. Retrieved from http://www.cancer.ca/en/cancer-information/cancer-type/skin-non-melanoma/non-melanoma-skin-cancer/types-of-non-melanoma/?region=on
-
Canadian Skin Cancer Foundation (2017) Basal Cell Carcinoma. Retrieved from http://www.canadianskincancerfoundation.com/basal-cell-carcinoma.html
-
Canadian Skin Cancer Foundation (2017) Squamous Cell Carcinoma. Retrieved from http://www.canadianskincancerfoundation.com/basal-cell-carcinoma.html
-
Canadian Cancer Society (2017) Types of non-melanoma skin cancer. Retrieved from http://www.cancer.ca/en/cancer-information/cancer-type/skin-non-melanoma/non-melanoma-skin-cancer/types-of-non-melanoma/?region=on
-
Canadian Skin Cancer Foundation (2017) Squamous Cell Carcinoma. Retrieved from http://www.canadianskincancerfoundation.com/basal-cell-carcinoma.html
-
Skin Cancer Foundation (2017) Squamous Cell Carcinoma. Retrieved from http://www.skincancer.org/skin-cancer-information/actinic-keratosis
-
Canadian Skin Cancer Foundation (2017) Precancerous conditions of the skin. Retrieved from http://www.cancer.ca/en/cancer-information/cancer-type/skin-non-melanoma/non-melanoma-skin-cancer/precancerous-conditions/?region=on
-
Skin Cancer Foundation (2017) How to Spot an Atypical Mole. Retrieved from http://www.skincancer.org/skin-cancer-information/atypical-moles/warning-signs-and-images