Photodynamic Therapy, PDT for short, is a modern process to treat skin cancer in its early stages and pathologic skin changes leading to cancer (hellen Hautkrebs?).
(Helle) skin cancer arises from gradual changes in surface layers. These occur frequently in sun-exposed skin, of the hands and face for example. Early stages show as small reddened areas with flaky exfoliation that over weeks or months tend to spontaneously regress (actinic keratosis). Others growths begin as small, pearly, skin-colored knots (basal cell carcinoma).
According to type, location and size, these diseased growths can be frozen, lasered, electrocauterized, or treated with topical chemotherapy to remove them. Harvested are both diseased and healthy tissue, whereby all diseased tissue is targeted and as little surrounding healthy tissue as possible.
PDT involves first placing a cream that contains ingredients taken up by tumor cells, over the affected area. After three to five hours, exposure to infra-red radation by special lamp activates the ingredients to kill-off the carrier cells. Thus, normal cells are left largely intact. Healing without scars usually ensues. Small scars, in exceptional cases, remain.