What is Photodynamic Therapy?

A treatment successfully used for pre-malignant skin conditions is now accomplishing wonders for patients who suffer from severe acne or sun damage. Photodynamic therapy, initially used to treat certain types of pre-cancerous skin lesions, worked so well on damage from the sun that it is now also used for cosmetic applications.

Overview

According to the National Cancer Institute, the type of treatment uses a drug known as a photosensitizer or photosensitizing agent with a particular type of light. When exposed to a specific wavelength of light, photosensitizers manufacture a type of oxygen that kills nearby cells.

Because each photosensitizer works at a certain wavelength, doctors use specific agents and wavelengths to treat the various areas of the patient's body with photodynamic therapy (PDT).

History

Initial use of PDT was to treat certain pre-cancerous skin lesions. The Mayo Clinic reports that this treatment can be used by itself or with other treatments like chemotherapy or radiation. The conditions that the Mayo Clinic currently treats with photodynamic therapy include Barrett's esophagus; early esophageal cancer, specifically, adenocarcinoma or squamous cell carcinoma; obstructing esophageal cancer; and persistent or recurring esophageal cancer following surgery, chemotherapy or radiation.

Other diseases the clinic treats with PDT include gastric cancer; lung cancer; and macular degeneration, in which the therapy destroys abnormal blood vessels.

According to MedicineNet.com, health care professionals have used photodynamic therapy since the 1990s.

How PDT Works

Photodynamic therapy is currently utilized in oncology, dermatology and cosmetic surgery. Regardless of the application, its effectiveness is limited by the fact that it can only target cells at most one-third of an inch (1 cm) from the light source.

When used to treat severe acne or sun damage, PDT is a two-step process. According to Your Health Magazine, the treatment utilizes a topical drug called Levulan and a laser or light treatment like Intense Pulsed Light (IPL).

Levulan is found naturally in the body. When a doctor applies it to the skin, it's quickly absorbed by skin cells such as those in oil glands, hair follicles and sun-damaged skin. Once the cells absorb it, the drug is processed into a photosensitizer that attracts the light from the laser or IPL. The medication comes in stick form.

Photodynamic therapy was approved by the FDA to treat severely sun-damaged skin with pre-malignant lesions. According to the magazine, it might actually reverse certain pre-cancerous skin lesions.

Patients with cosmetic changes related to sun damage, among them skin thinning, fine lines, brown spots, red vessels and large pores, can profit from this treatment. Because the skin's oil glands absorb the Levulan, the treatment helps reduce severe acne and cut the level of oiliness in the patient's skin. During the process, patients also experience some regeneration of collagen, which can minimize scarring from acne.

Once a dermatologist has evaluated a patient's skin and determined that photodynamic therapy is an appropriate treatment, the skin is cleaned and prepped. After the Levulan has been applied, there is a wait of 30 to 60 minutes while it's absorbed. The medication is washed off, and the practitioner treats the affected area with a laser, IPL or other light.

Doctors repeat PDT every two to four weeks, depending on the patient's needs and response to the procedure. About half of patients who undergo photodynamic therapy develop redness and some degree of peeling that lasts three to seven days.

Sources:

http://www.cancer.gov/cancertopics/factsheet/Therapy/photodynamic

http://www.mayoclinic.org/photodynamic-therapy/

http://www.medicinenet.com/photodynamic_therapy/article.htm

Nicole Hayre, MD, FAAD, "'Hope in a Stick' For Sun Damage and Acne?" in Your Health Magazine, Loudoun-West Fairfax Edition, February 2011, p. 27.