Extramammary Paget’s Disease or EMPD is a very rare condition, and physicians need to depend on research studies for updated information on treating their patients. Both surgical and nonsurgical treatment options are available for the treatment of this condition. Treatment methods may vary from region to region. As in all cancers, diagnosing EMPD early gives the most successful results.
Surgical Treatment
Surgical resection is the usual method of treatment for EMPD.
Mohs Surgery
With this technique, the lesion is removed and sliced horizontally into thin slices for examination under the microscope. The dermatologist then inspects the margins of the tissues to find out if cancerous cells are present, in which case more tissue is removed according to the markings on the excised specimen. This process works well in the case of small areas of EMPD; when the area is larger, “slow Mohs” is mostly used.
Depending on how small or how large the area of cancer removal is, specialist surgeons may be involved in performing the surgery. For instance, if a surgery is required in the anal region, a colorectal surgeon is needed; in EMPD involving the penis, scrotum, and other male genital areas, a reconstructive urologic surgeon may be required; for women with EMPD, consultation with a Mohs surgeon and a gynecologic oncologist may be necessary.
Studies have found that when Mohs surgery is performed with cytokeratin-7 immunohistochemistry stain, the treatment is more likely to result in complete eradication of the EMPD with a 95% recurrence-free cure rate over a 5-year period.
Split-Thickness Skin Grafts
When a large area of skin and tissue is removed to treat EMPD, a split-thickness skin graft (STSG) is performed to close the defect. The chances of rejection are low. Unlike a full-thickness skin graft where the epidermis and the dermis (entire thickness) are removed from one place to be placed over a defect in another, in STSG a thin layer only is removed, which includes both the epidermis and a small portion of the dermis is removed similar to a vegetable peeling. Physicians use a dermatome to carefully create thin skin slices from the donor area. Individuals often experience pain in the donor area.
Among male patients, when EMPD involves larger areas in the scrotum, the scrotum is rebuilt entirely using split-thickness skin grafts.
Additionally, skin flaps are also used after EMPD surgery when excess tissue is present near the defect. Healthy tissue is extended to create a skin flap on the portion removed for EMPD.
Nonsurgical Treatment
When surgical treatment is not desired or is impossible because of widespread involvement, nonsurgical treatments are advised.
Radiation therapy disrupts the DNA present in the cells present in the lesion as well as nearby healthy cells.
Carbon dioxide (CO2) laser is used in the treatment of EMPD patients, to ablate the EMPD cells, but is associated with significant scarring. This therapy is often combined with photodynamic therapy (PDT) in some patients with EMPD.
In photodynamic therapy, oxygen, photosensitizing drugs, and light are used to create a photochemical reaction that selectively destroys cancer cells. Photosensitizing drugs are administered either orally, or through topical or intravenous methods. Methyl aminolevulinic acid cream is activated using red light; aminolevulinic acid hydrochloride topical solution is activated by blue light.
The treatment time varies between 5 and 45 min. Depending upon the lesion type and the photosensitizing drugs used in the treatment, sometimes a second round of treatment is carried out about 7–10 days after the first round.
The affected area is sensitive to light, and side-effects occur such as crusting, a burning sensation, redness, swelling, itchiness, skin infections, blisters, and skin peeling. Depending on the drugs used in the therapy, the photosensitivity tends to persists for around 24 hrs or more.
A topical cream such as imiquimod (generally used for treating actinic keratosis, genital warts, and basal cell carcinoma) is often used for treatment of EMPD. It functions as an immune response modifier, to stimulate the immune system against the abnormal cell growth. The duration of use may vary from a few weeks to even months. In some patients, imiquimod use may cause swelling, redness, itching, blisters, burning, tenderness, sores, pain, and even changes in skin color. The success of the treatment varies across patients. Imiquimod is more commonly used among women.
The use of a topical cream affects only the treated area. In the case of PDT, the photosensitizing drugs are sequestered in both cancerous and noncancerous healthy cells, and all of them become sensitive to light. Furthermore, when the photosensitizing drugs are administered systemically, there is a risk of generalized photosensitivity.
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Further Reading