Actinic Keratosis-The Most Common Pre-Cancer

My face Day 10 (of 21) of topical 5FU treatment
I thought I had dry skin. This winter has been particularly cold so our wood stove has been running really hot 24/7. I had a scaly patch of skin above my upper lip in November/December so I made a Dermatology appointment at Dartmouth Hitchcock Medical Center. At my appointment a few weeks ago, my doctor made the diagnosis of actinic keratoses. She recommended a 21 day topical treatment to stop the cell growth and prevent further damage.

Yes-I have gone outside without sunscreen.
Yes-I've sat out in the sun ALL DAY, A LOT in the summer.
Yes-I work in the garden in summer in my bathing suit, without a hat.
Yes-I go south once, sometimes twice a year during the winter to dive in the Caribbean.
Yes-I have used tanning beds A LOT.

I have been just plain DUMB when it comes to UV exposure.

What is Actinic Keratosis:
Scaly or crusty growths (lesions) caused by damage from the sun’s ultraviolet (UV) rays, actinic keratosis (AK) is also known as solar keratoses. They typically appear on sun-exposed areas such as the face, bald scalp, lips, and the back of the hands, and are often elevated, rough in texture, and resemble warts. Most become red, but some will be tan, pink, red, and/or flesh-toned. Untreated AKs can advance to squamous cell carcinoma (SCC), the second most common form of skin cancer, and some experts believe they are actually the earliest stage of SCC.

Who had been diagnosed-more than 58 Million
This figure is generally accepted as the best current estimate of the number of Americans with actinic keratosis (AK). People with a fair complexion, blond or red hair, and blue, green or grey eyes have a high likelihood of developing one or more of these common precancers if they spend time in the sun and live long enough. Location makes a difference: The closer to the equator you live, the more likely you are to have actinic keratoses. The incidence is slightly higher in men, because they tend to spend more time in the sun and use less sun protection than women do. African-Americans, Hispanics, Asians and others with darker skin are not as susceptible as Caucasians.

My Treatment:
5-fluorouracil (5-FU) ointment or liquid in concentrations from 0.5 to 5 percent has FDA approval and is the most widely used topical treatment for actinic keratoses. It is effective against not only the surface lesions but also the subclinical ones. Rubbed gently onto the lesions once or twice a day for two to four weeks, it produces cure rates of up to 93 percent. Reddening, swelling and crusting may occur, but they are temporary. The lesions usually heal within two weeks of stopping treatment. There is rarely scarring and the cosmetic result is good.

How 5-FU works: 
The chemotherapy agent 5-FU, which has been used against cancer for about 40 years, acts in several ways, but principally as a thymidylate synthase (TS) inhibitor. Interrupting the action of this enzyme blocks synthesis of the pyrimidine thymidine, which is a nucleoside required for DNA replication. Thymidylate synthase methylates deoxyuridine monophosphate (dUMP) into thymidine monophosphate (dTMP). Administration of 5-FU causes a scarcity in dTMP, so rapidly dividing cancerous cells undergo cell death via thymineless death. Calcium folinate provides an exogenous source of reduced folinates and hence stabilize the 5-FU-TS complex hence enhancing 5-FU's cytotoxicity. 5-FU was designed, synthesized and patented by Charles Heidelberger in 1957.

Since uracil is a normal component of RNA, the rationale behind the development of the drug was that cancer cells, with their increased genetic instability, might be more sensitive to 'decoy' molecules that mimic the natural compound than normal cells. The scientific goal in this case was to synthesize a drug which demonstrated specific uracil antagonism. The drug proved to have anti-tumor capabilities.

When elemental fluorine is reacted with uracil, 5-fluorouracil is produced. 5-Fluorouracil masquerades as uracil during the nucleic acid replication process. Because 5-fluorouracil is similar in shape to but does not perform the same chemistry as uracil, the drug inhibits RNA replication enzymes, thereby eliminating RNA synthesis and stopping the growth of cancerous cells. As a scientist and former laboratory technician who used to work with RNA/DNA, this information fascinates me.

The best way to prevent actinic keratosis is to protect yourself from the sun. Here are some sun-safety habits that really work.
  • Seek the shade, especially between 10 AM and 4 PM.
  • Do not burn.
  • Use a broad spectrum (UVA/UVB) sunscreen with an SPF of 15 or higher every day. For extended outdoor activity, use a water-resistant, broad spectrum (UVA/UVB sunscreen with an SPF of 30 or higher.
  • Apply 1 ounce (2 tablespoons) of sunscreen to your entire body 30 minutes before going outside. Reapply every two hours or immediately after swimming or excessive sweating.
  • Cover up with clothing, including a broad-brimmed hat and UV-blocking sunglasses.
  • Keep newborns out of the sun. Sunscreens should be used on babies over the age of six months.
  • Examine your skin head-to-toe every month.
  • See your doctor every year for a professional skin exam.
  • Avoid tanning and UV tanning booths.
What Causes Actinic Keratosis
Chronic sun exposure is the cause of almost all actinic keratoses. Sun damage to the skin is cumulative, so even a brief period in the sun adds to the lifetime total. Cloudy days aren’t safe either, because 70-80 percent of solar ultraviolet (UV) rays can pass through clouds. These harmful rays can also bounce off sand, snow and other reflective surfaces, giving you extra exposure.

The ultraviolet radiation given off by the lamps in a tanning salon can be even more dangerous than the sun, so dermatologists warn against indoor tanning.

Occasionally, actinic keratoses may be caused by extensive exposure to X-rays or a number of industrial chemicals.

Because the total amount of time spent in the sun adds up year by year, older people are most likely to develop actinic keratoses. However, nowadays, some individuals in their 20s are affected. Still, actinic keratoses become much more common in people over the age of 50. Some experts believe almost everyone over 80 has actinic keratoses.

Also, individuals whose immune defenses are weakened by cancer chemotherapy, AIDS, organ transplantation or excessive UV exposure are less able to fight off the effects of the radiation and thus more likely to develop actinic keratoses.

While actinic keratosis is the most common precancer, not all keratoses turn into cancers. Unfortunately, there is no way to know ahead of time which actinic keratoses are precursors of squamous cell carcinoma. That is why it is fortunate that there are so many effective treatments for eliminating actinic keratoses.

When an actinic keratisis is suspected to be an early cancer, the physician may take tissue for biopsy. This is done by shaving off the top of the lesion with a scalpel or scraping it off with a curette. Local anesthesia is required. Bleeding is usually stopped with a styptic agent.

In the beginning, actinic keratoses are frequently so small that they are recognized by touch rather than sight. It feels as if you were running a finger over sandpaper. There are many times the number of invisible (subclinical) lesions as visible ones on the skin surface.

Most often, actinic keratoses develop slowly and reach a size from an eighth to a quarter of an inch. Early on, they may disappear only to reappear later. Most become red, but some will be light or dark tan, pink, red, a combination of these, or the same color as your skin. Occasionally they itch or produce a pricking or tender sensation. They can also become inflamed and surrounded by redness. In rare instances, actinic keratoses can even bleed.

If you have actinic keratoses, it indicates that you have sustained sun damage and could develop any kind of skin cancer – not just squamous cell carcinoma.

For more info Google Actinic Keratosis or visit WebMD:

I plan to change my attitude towards UV rays and I hope after reading this and seeing the pictures of my face you will too!

Blog Archive

Show more