New Approach Prevents Skin Cancer Using Photodynamic Therapy (PDT)

Every year there are more new cases of skin cancer than breast, prostate, lung and

colon cancers combined. One in 5 Americans will get skin cancer in their lifetime.

90% of skin cancers are caused by excessive sun exposure, yet fewer than 33

percent of adults, adolescents, and children routinely use sun protection.

Cancer prevention and early detection techniques could eliminate up to 100,000

cancer cases and 60,000 US cancer deaths each year. New technologies in the

evaluation and treatment of sun damaged skin could have a positive impact on

changing these statistics.

The same sunny weather that attracts so many tourists and new residents to the

sun-belt also increases the risk of skin cancer. The effects of chronic sun exposure

result in superficial sun spots that are visible and also invisible changes that occur

under the skin’s surface. Ultraviolet photography and photodynamic therapy (PDT)

are two recent developments that should help in the early detection and treatment

of both types of pre-cancerous skin lesions.

Early Detection with UV Photography

Ultraviolet (UV) photography offers a very useful screening tool to help the skilled

physician detect sun damaged skin that may not be visible upon a routine


Visual inspection can only detect changes on the skin’s surface, but damage due to

sun exposure occurs beneath the outer layer of skin,

The UV camera briefly shines ultraviolet light on the face. UV light is able to

penetrate 1.5-2.0 millimeters under the visible dead layer of skin and focus on the

actual living portion where sun damage originates. The advantage to the doctor and

the patient is that this technology allows for much earlier detection of skin problems

before they develop into pre-cancers that are visible on the skins surface. After

finishing the treatment plan, the doctor should take another UV photo to verify the

treatment efficacy. UV photography also helps evaluate other skin conditions

including acne, oil balance, hydration, inflammation, growths, fungi, pH, and thin

skin due to reduced collagen which makes it an ideal tool to evaluate all problem


After the damage to the deeper layers of skin, superficial signs of sun damage may

eventually appear on the surface. The most common surface lesion is known as

actinic keratoses (AK). AKs usually appear as rough or scaly patches. They may also

flake, crust, and may temporarily disappear and then return.

An AK is most likely to appear on the face, ears, scalp, neck, backs of the hands and

forearms, shoulders, and lips – the parts of the body most often exposed to

sunshine. The scaly patch may be light or dark, tan, pink, red, or a combination of

these…or the same color as your skin.

It is estimated that 10-20% of untreated AKs will develop into squamous cell

cancers. If treated early, almost all AKs can be eliminated without becoming skin

cancers. If you have AKs, it indicates that you have sustained sun damage and have

a higher risk for developing all types of skin cancer – not just squamous cell


The more keratoses a person has, the greater the chance that one or more may turn

into skin cancer. People may also have up to 10 times as many subclinical (invisible)

lesions as visible, surface lesions. These invisible lesions were undetectable until

the development of the UV camera.

Treatment options

The most common treatment options for AKs have traditionally involved topical

ointment 5-FU (Effudex), laser resurfacing, or chemical peels. To avoid the

prolonged recovery period and possible scarring associated with these techniques,

photodynamic therapy has been developed.

Photodynamic therapy (PDT) is the treatment of choice for the invisible deeper sun

damage as well as the visible pre-cancerous AK lesions. PDT involves a two step

process that has been proven effective in clinical testing. This treatment cleared

100% of the AKs in 2/3 of the patients after one treatment.

The first step is the application of a topical solution called Levulan. Abnormal cells

have a much greater affinity for the solution and absorb it while the healthy cells do

not. The solution is left on for an incubation period lasting anywhere from 15

minutes to 18 hours.

The second step of PDT is to apply a concentrated light source to activate the

chemical reaction which destroys the abnormal cells. Since the solution is absorbed

only in the damaged cells, the healthy cells are not affected. This process can cause

a mild burning sensation during the treatment. Usually, this improves immediately

after treatment and ends within 24 hours.

Following the treatment, most patients experience mild swelling, redness, and a

peeling of the AK lesions and the surrounding tissue. Patients choosing a more

aggressive treatment will experience more peeling and/or crusting of the damaged

skin that resolves within in one or two weeks. The doctor can easily control the

severity of these reactions by limiting the incubation period and the amount of

exposure to the light source.

Patients not willing to experience a prolonged recovery time after the procedure

may choose a more mild treatment and return to work after a day or two. The

tradeoff is that they will require more treatments to achieve the same clinical


In addition to eliminating AKs and the subsurface skin damage, PDT has also been

effective in improving the appearance of the skin by greatly reducing moderate to

severe acne (including cystic acne), reducing color splotches, lessening the fine

lines, and decreasing pore size.

Anyone who currently has, has had, or wants to prevent AKs or pre-cancerous skin

lesions should be evaluated and treated using UV photography and photodynamic

therapy (PDT).” Once a person has been successfully treated using this approach, it

is recommended they return for a yearly follow up to prevent future problems.

by William Nelson


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