Is photodynamic therapy effective pre-cancer cells?

Photodynamic therapy (PDT) is the use of a medication activated by light. PDT for treating precancerous lesions (actinic keratoses), improving skin tone and erasing sun damage utilizes a topical (on the skin) solution in conjunction with a blue light, or intense pulsed light source. This treatment acts by eliminating sun damaged and precancerous cells as well as shrinking sebaceous glands damaged by the sun.