Skin Cancer Basics

What is "skin cancer"?

Skin cancer is an abnormality of the cells of the skin or cells that reside in the skin. It's an abnormality of the way the cells either grow or behave. In the vernacular, when we speak of skin cancer, we talk about three different types of skin cancer. The first is basal cell carcinoma, the second is squamous cell carcinoma, and there's malignant melanoma. These are the most frequent cancers in humankind and are prevalent throughout the United States.

What are the stages of melanoma skin cancer?

Malignant melanoma is staged in 5 different stages. There is stage 0, where the abnormal cells are located entirely within the epidermis. There are stages 1 and 2. Stage 1 is how deep the melanoma cells have gone and invaded into the dermis. Stage 2 is where they've invaded deeper and therefore are more aggressive. Stage 3 is where the cells are located in the lymph nodes or in certain sections of the skin. Stage 4 is where those cells have metastasised or travelled to other organs of the body including distant site of the skin, the lung, the brain, and other internal organs.

Why is the sun harmful to my skin?

The sun is harmful to us because of the radiation that it emits. The sun's radiation is also known as ultraviolet rays, which break down the skin, which in turn causes abnormal behaviour and growth in the skin.

What are "benign skin tumors" and what types are there?

The skin is the surface of our body, much like the roof is the surface of your house. In the same way that it's not abnormal to have a leaf on your roof, it's really not abnormal to have growths on our skin. It's got a tremendous amount of environmental damage and mechanical changes and, so, many things occur on the skin which are not malignant. On a daily basis, I will see thousands of benign lesions for every, occasional, malignant one.

What are the main layers of my skin and what functions do they perform?

There are three layers of the skin. The first and outermost layer is the epidermis. The middle layer is the dermis, and the layer underneath the dermis is the subcutaneous layer or the fat layer. The epidermis has many functions, but it's major function is to keep the outside world out and the inside world in. The dermis is where the blood vessels, the immune system, where the structure and the pliability of the skin lies. In addition, what are known as the adnexal structures live there, which are the hair follicles, the sweat glands, and also some of the nerves live as well in the dermis. Then there's the fat layer, which primarily, again gives pliability and heat retention as well.

What is "melanoma" skin cancer?

Malignant melanoma, which is the third most common skin cancer, is an abnormality of the growth of the pigment cells of the skin, called the melanocytes. It occurs in about fifty to sixty thousand cases per year in the United States, and of the three most common skin cancers is the one with the most significant possibility of metastasis. Therefore, it entails the greatest danger to our health. Malignant melanoma probably accounts for about ten to fifteen thousand deaths in the United States every year, which far outnumbers any of the other fatalities from any other form of skin cancer.

What is "nonmelanoma" skin cancer?

Nonmelanoma skin cancer encompasses both basal cell carcinomas as well as squamous cell carcinomas. Basal cell carcinomas probably account for approximately one million instances per year of skin cancer in the United States. Squamous cell carcinomas probably approach around five hundred thousand cases in the United States. nonmelanoma skin cancers are obviously are the most common skin cancers, the most common cancers in mankind. Both of them are virtually 100% caused by ultraviolet radiation. Both in terms of type and quantity, and if one were more careful probably the incidence of nonmelanoma skin cancer would go down by 90%.

What is an "actinic keratoses" or "early cancer"?

The term, pre-cancers, are usually used to explain a type of lesion on the skin called an actinic keratoses; actinic keratoses are really baby little squamous cell carcinomas that given enough time will start behaving biologically like a squamous cell carcinoma. That amount of time may be thirty years, forty years, we don't really know. As a result of that, actinic keratoses are treated by destroying them to try to prevent the transformation that they have the ability to make into squamous cell carcinomas. The intervention for actinic keratoses is much more benevolent than to have to take out a squamous cell carcinoma, which almost always entails some destructive or surgical event.

Is melanoma skin cancer worse than nonmelanoma?

Malignant melanoma skin cancer is by far the most dangerous of all the skin cancers that we see, commonly anyway. It unfortunately results in about 15,000 deaths every year in the United States, which is far greater than all the other skin cancers combined. It has the ability, after its growth pattern, to go into the lymphatics and the blood system, and then transfer those cells to other parts of the body. The more common skin cancers virtually never, or very rarely, do so. Therefore, malignant melanoma is by far the most serious skin cancer that we see.

What does "in situ" mean when talking about skin cancer?

"In situ" skin cancers are those skin cancers which are still located only within the epidermis. A squamous cell carcinoma in situ would be those cells that are abnormal; that are just in the outermost layer of the skin and have not reached into the epidermis. The malignant melanoma in situ, as well, means that those cells still remain in the epidermis and have not grown into the dermis. These are what would be called "non-invasive" forms of these skin cancers and because of this, their risk to the patient approaches zero from a mortality standpoint. They still have to be removed because by their nature, it's just a matter of time before their invasiveness does occur and that their aggressiveness is manifested.

What is a "sentinel lymph node" and how is it related to skin cancer?

In malignant melanoma, when those cells do spread to other organs, usually the first organ that they do so is to the lymphatic system, and that would include a lymph node. The first lymph node that the malignant melanoma goes to is called the sentinel lymph node, as in a sentry, or the lymph node that is first approached before other lymph nodes are addressed. If one finds that the sentinel lymph node has no involvement with the malignant melanoma, the inference is that the other lymph nodes would not as well. So, the sentinel lymph node is often removed and looked at microscopically to see whether or not there is any micrometastases in that lymph node. Absence of micrometastases is felt to be a very good prognostic sign for the melanoma that the lymph node was draining.