Skin Cancer: Types, Causes and How to Protect Yourself

This post was authored by Sarah Keogh and posted to The Eye Opener on June 28th, 2011.

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From the (guest) editor:  Although today’s weather forecast is for thunderstorms, we should keep in mind that the summer season is upon us.  It is time to protect one of our largest organs — our skin!

–Jason

The news last week about the new FDA regulations on sunscreen had me prepared to write a blog article this week about the changes. I wanted to clarify what the new rules will mean for consumers – how to choose the correct product, what the various claims actually mean about protection, whether safety has been considered. However, as I delved deeper into the topic, I realized that the first concern has to be sun exposure and cancer in general. There is too much information – medical and legal – out there for one post. So, I am going to write a brief series. The first topic – today – will be about the startling statistics about various skin cancers. I will discuss various types of skin cancers, their prevalence and the survival and death rates from these cancers. In future posts, I plan to examine the original issue – whether the new regulations will help consumers choose a product that will help protect from some of these risks and how these legal steps may fall short of the final goal. Finally, I will look at the issue of tanning beds. Should children or teens be allows to use them? What about parental consent? There are medical and legal ramifications surrounding the use of tanning beds – I will look at a few of those. Along the way, please comment and let me know your thoughts. Or, if you are just daydreaming about enjoying summer…you can let us know that too (for my own personal idea of a great summer vacation see today’s photo).

Not All Skin Cancer is Created Equal

Personally, I tend to lump all skin cancer together in my mind. Unfortunately, whether you are putting yourself at risk for or are diagnosed with squamous cell, basilar cell or malignant melanoma makes a big difference. The rates of these diseases and the survival statistics are dramatically different.

So, first, what are these diseases?

Image from www.cancer.org

 

The National Cancer Institute at NIH explains the different types of skin cancers:

Skin cancer that forms in melanocytes (skin cells that make pigment) is called melanoma. Skin cancer that forms in the lower part of the epidermis (the outer layer of the skin) is called basal cell carcinoma. Skin cancer that forms in squamous cells (flat cells that form the surface of the skin) is called squamous cell carcinoma. Skin cancer that forms in neuroendocrine cells (cells that release hormones in response to signals from the nervous system) is called neuroendocrine carcinoma of the skin.

How Common are these Cancers?

According to the Skin Cancer Foundation, skin cancer is the most common form of cancer in the United States. Of the various types of skin cancer, basal cell carcinoma is the most common (2.8 million/year the US), followed by squamous cell carcinoma (700,000/year), and finally melanoma (115,000). However, the death rates caused by melanoma are much higher than the other types of cancer. The statistics on the Skin Cancer Foundation website are shocking (just a sampling):

  • One person dies of melanoma every hour (every 62 minutes).
  • One in 55 people will be diagnosed with melanoma during their lifetime.
  • Melanoma is the most common form of cancer for young adults 25-29 years old and the second most common form of cancer for young people 15-29 years old.
  • The incidence of many common cancers is falling, but the incidence of melanoma continues to rise at a rate faster than that of any of the seven most common cancers. Between 1992 and 2004, melanoma incidence increased 45 percent, or 3.1 percent annually.
  • An estimated 114,900 new cases of melanoma were diagnosed in the US in 2010 – 46,770 noninvasive (in situ) and 68,l30 invasive, with nearly 8,700 resulting in death.
  • Melanoma accounts for less than five percent of skin cancer cases, but it causes more than 75 percent of skin cancer deaths.

I was particularly taken by this last fact – while accounting for “less than five percent of skin cancer cases, [melanoma] causes more than 75 percent of skin cancer deaths.” This is startling because “[t]he survival rate for patients whose melanoma is detected early, before the tumor has penetrated the skin, is about 99 percent.” However, ‘”[t]he survival rate falls to 15 percent for those with advanced disease.” So the key here is clearly prevention and early detection.

Unfortunately, the melanoma incidence rate is rising annually. Melanoma is responsible for approximately 8,700 deaths a year in the US, as compared to rare deaths from basal cell carcinoma and approximately 2,500 deaths a year from squamous cell carcinoma.  And this is not just a problem for those with light skin – the Skin Cancer Foundation explains that “[w]hile melanoma is uncommon in African Americans, Latinos, and Asians, it is frequently fatal for these populations.”

Given the high incidence rate and the high survival rate for early-diagnosed melanomas, it seems key that people should know the risks factors and causes for melanoma. The better the prevention, the less likely that you should develop this type of cancer. Secondly, if you are in a high-risk category, you should be seeing a dermatologist regularly since the key to survival is early detection.

Causes of Melanoma

The CDC provides confirmation that “[s]kin cancer is the most common form of cancer in the United States” and that the incidence of melanoma of the skin has “increased significantly by 3.1% per year from 1986 to 2006 among men” and 3% among woman from 1993 to 2006.Yet, we know many of the risk factors for melanoma.

The CDC reports that “[a]bout 65%-90% of melanomas are caused by exposure to ultraviolet (UV) light.” This is the kind of radiation that come from the sun – and tanning beds (more on that in a later post). There are three different types of ultraviolet light and two of them have a role to play in changing and damaging skin cells.

The three types of UV rays are ultraviolet A (UVA), ultraviolet B (UVB), and ultraviolet C (UVC)-

  • UVA is the most common kind of sunlight at the earth’s surface, and reaches beyond the top layer of human skin. Scientists believe that UVA rays can damage connective tissue and increase a person’s risk of skin cancer.
  • Most UVB rays are absorbed by the ozone layer, so they are less common at the earth’s surface than UVA rays. UVB rays don’t reach as far into the skin as UVA rays, but they can still be damaging.
  • UVC rays are very dangerous, but they are absorbed by the ozone layer and do not reach the ground.

Too much exposure to UV rays can change skin texture, cause the skin to age prematurely, and can lead to skin cancer. UV rays also have been linked to eye conditions such as cataracts.

From the CDC website

In addition to sun exposure, there also additional risk factors to consider:

  • A lighter natural skin color.
  • Family history of skin cancer.
  • A personal history of skin cancer.
  • Exposure to the sun through work and play.
  • A history of sunburns early in life.
  • A history of indoor tanning.
  • Skin that burns, freckles, reddens easily, or becomes painful in the sun.
  • Blue or green eyes.
  • Blond or red hair.
  • Certain types and a large number of moles.

From the CDC website

Children and Adults are Not Doing Enough to Protect Themselves

Certainly, some of these risk factors are immutable, but others, like sun exposure and tanning are risks that can be avoided or at least minimized. The CDC says they have supported surveys that show that “U.S. youth and adults are being exposed to ultraviolet radiation and can do more to protect themselves. More than one-third of the U.S. population reported a sunburn in the previous year, with rates higher among men and the non-Hispanic white population.”

I found the CDC statistics troubling given how long it has been known that sun exposure and damage lead to skin cancer:

In 2005, only 56% of adults said they usually practice at least one of the three sun-protective behaviors (use sunscreen, wear sun-protective clothing, or seek shade).

  • 30% reported usually applying sunscreen (27% applied sunscreen with an SPF of 15 or higher).
  • 18% reported usually wearing some type of fully sun-protective clothing.
  • 33% usually sought shade.
  • Only 43% of young adults aged 18-24 used one or more sun protective methods, whereas 58% of those 25 years of age and older reported using one or more methods. Among men 18 and older, only 47% reported usually using one or more methods of sun protection, in contrast to 65% of women 18 and older.

Among high school students, when they were outside for more than an hour on a sunny day-

  • 11.7% of girls and 6.3% of boys reported they routinely used a sunscreen with an SPF of 15 or higher.
  • 15.9% of girls and 20.5% of boys reported they routinely stayed in the shade, wore long pants, wore a long-sleeved shirt, or wore a hat that shaded their face, ears, and neck.

Nearly 9% of teens aged 14-17 years used indoor tanning devices. Girls aged 14-17 years were seven times more likely than boys in the same age group to use these devices.

From the CDC – internal resources omitted.

The recommendations are clearly not being followed. To best protect yourself from sun damage, there are 3 simple steps:

  • Use Sunscreen
  • Wear Protective Clothing (including hats and sunglasses)
  • Find Shade

Do not forget that these tips are important whether you are at the beach or just around town and on both cloudy and sunny days. It is especially important to be careful during the peak times of 10 am to 4 pm.

Of course, “use sunscreen” is oversimplifying how to protect oneself. It is within this context that I will look into the various legal and marketing changes coming soon to sunscreens in my next post.

Did you know all of these facts about skin cancer? Did you know that melanoma was so common and so deadly, despite being very survivable when detected early?

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2 Responses to “Skin Cancer: Types, Causes and How to Protect Yourself”

  1. TheresaNo Gravatar says:

    The statistics really are staggering! One only has to look at your picture of the skin anatomy to understand why melanoma is so deadly. Since it develops in melanocytes, it naturally starts much deeper in the skin layers, closer to blood vessels and lymphatic channels. By the time the malignant cells reach the surface and cause surface skin changes, chances are that it has also invaded a deeper, adjacent blood vessel and spread to another part of the body like the bones or lungs. The problem with diagnosis of malignant melanoma is that it is often late, after the cancer has spread, and there are not really good chemotherapy agents that can treat it. So, yes, prevention is the key! Good post, Sarah.

  2. LoreneNo Gravatar says:

    Super inoframtive writing; keep it up.

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