Skin Cancer: Frequently Asked Questions

1. What do Actinic Keratoses evolve into?

Actinic keratoses evolve into squamous cell carcinomas.

2. What is the commonest type of skin cancer?

Basal cell carcinomas are the commonest human skin cancer.

3. Does the incidence of carcinomas increase with age?

Yes, the incidence of both basal cell and squamous cell carcinomas increase with age.

4. What are the current statistics for how many people have non-melanoma skin cancer?

There are about 230 non-melanoma skin cancers per 100,000 population in light colored skin as opposed to approximately 3.5 per 100,000 in darkly pigmented individuals. There are approximately four basal cell carcinomas to every one squamous cell carcinoma. The incidence has more than doubled in the last 20 years.

5. In the majority of deaths from non-melanoma skin cancer, where does skin cancer occur?

Squamous Cell Carcinoma is the most common form of non-melanoma cancer that causes death. The majority of deaths from squamous cell carcinoma are those arising from the ear, the lip, or in the setting of immune suppression (for example renal transplant patients). Basal cell carcinoma rarely eventuates in death.

6. Is there a standard skin type that the most common cancers affect? What other factors come into play?

These skin cancers most commonly occur in fair-skinned individuals on sun-damaged skin. Genetic factors play a role: people with red or blonde hair, and those who burn easily without tanning are at significant risk. Sun exposure is the main environmental cause of skin cancer. Both intermittent and chronic exposure to the sun increase one’s risk for skin cancer. Repeated sunburns seems to play a part in the development of all types of skin cancer.

7. What are the layers of the epidermis and how do they relate to the types of skin cancers?

The epidermis is the top layer of skin (the lower layer is the dermis) and is comprised of these sections:

Stratum corneum. Dense protein layer made up of keratin. This layer will shed on a daily basis. Granular layer. This layer moves the dead keratin cells to the surface of the epidermis. Squamous cell layer. This layer produces keratin for the stratum corneum and also transports water. Blisters originate in the squamous cell layer.

Basal cell layer. The lowest layer of the epidermis, the basal cell layer is where skin cells originate and where the cells that produce melanin, or skin pigment, reside. Malignant melanoma and basal cell carcinomas arise from the cells in the epidermis' basal layer.

8. How many people die from skin cancer?

At least 2 people die from skin cancer every day in Canada. In North America, someone dies from skin cancer every hour.