PHOTODYNAMIC THERAPY (PDT)

Photodynamic therapy, or PDT, is a noninvasive treatment that uses a special light-sensitive medication along with a specific type of light to help destroy abnormal skin cells. It has been used in treating extramammary Paget’s disease (EMPD), a rare skin condition often found in areas such as the groin, genitals, or armpits. PDT may be offered in certain cases where surgery isn’t the best option, or it may be used after surgery to treat remaining or recurring areas of disease.

The treatment takes place in three main steps. First, a photosensitizing medication is applied to the affected skin. A commonly used drug is aminolevulinic acid, available under the name Levulan Kerastick. Once applied, the medication is left on the skin for a period of time, usually a few hours and sometimes up to 18 hours. This allows it to be absorbed into the abnormal cells. After the incubation period, the area is exposed to a special blue or red light. The light activates the medication, which then produces a reaction that helps destroy the damaged or diseased cells.

Photodynamic therapy is most effective for superficial cases of EMPD, where the disease is limited to the upper layers of the skin. It does not reach deeper tissues, so careful evaluation is important before choosing this treatment. In many cases, PDT is used after surgery, especially when there is concern about small areas of disease that remain or come back.

During the light treatment, it is common to feel some stinging, burning, or itching in the treated area. These effects usually improve by the end of the session. After treatment, the skin may be red, swollen, or flaky for a few days. Patients are often advised to protect the treated area from sunlight for at least 24 to 48 hours.

Although PDT is not a cure for all cases of EMPD, it offers a way to treat select areas without surgery and can help manage the condition over time. It is typically done in an outpatient setting and allows patients to avoid more invasive procedures when appropriate. As with any treatment, a careful discussion between the patient and care team is important to decide whether PDT is the right approach based on the extent and behavior of the disease.

Treatments for extramammary Paget’s disease (EMPD) often differ but frequently include one or more of the following: Mohs surgery, wide local excision (WLE) surgery, topical creams, carbon dioxide (CO2) laser, photodynamic therapy (PDT), cavitational ultrasonic surgical aspiration (CUSA), radiation therapy, skin grafts, and chemotherapy.