Is Radiation Therapy Used to Treat EMPD?

Radiation therapy, also known as radiotherapy, is a cancer treatment that uses high-energy radiation to damage the DNA in cancer cells. This prevents the cells from continuing to grow and divide. Over time, the damaged cells break down and are cleared from the body.

Radiation therapy has been used in some cases of extramammary Paget’s disease (EMPD), a rare skin cancer that typically appears in areas such as the vulva, scrotum, groin, perianal region, or armpits. Surgery is the most common treatment for EMPD. However, radiation may be considered when surgery is not appropriate, such as when the tumor is in a difficult location or the patient has other medical concerns that make surgery unsuitable.

Treatment is typically given over several sessions, over the course of a few weeks or months. This approach allows normal tissue to recover between treatments. Modern radiation planning techniques, such as intensity-modulated radiation therapy, may help focus the dose more precisely and limit exposure to surrounding areas, particularly in sensitive regions.

While radiation is sometimes described as a less invasive option than surgery, current evidence remains limited. Most studies on the use of radiation for EMPD involve small groups of patients and do not include long-term follow-up. In addition, treatment approaches vary, making it difficult to compare outcomes across different reports. Radiation has been associated with side effects such as skin darkening, swelling, or nerve irritation, and it may affect the skin’s ability to heal. This can influence future treatment options.

Types of Radiation Therapy

There are two main types of radiation therapy used in cancer care. One is external beam radiation therapy, which involves a machine that directs radiation to a specific area from outside the body. This method is the most commonly used and can involve different types of particles, including photons, protons, or electrons. Electron beam therapy is often used for skin cancers like EMPD because it does not travel deeply into the body and is suited for treating surface-level tumors.

The other type is internal radiation therapy, also known as brachytherapy. In this method, a radioactive source is placed directly on or near the tumor. This allows a high dose of radiation to be delivered to a small, targeted area while reducing exposure to nearby tissue. One specialized form of brachytherapy, called dermo-beta-brachytherapy, has been studied for EMPD.

Dermo-beta-brachytherapy involves the use of a mold or patch containing a radioactive material that emits beta radiation. This mold is shaped to fit the affected area of the skin and is applied for a short time, typically between 30 and 60 minutes. After treatment, the mold is removed and handled as radioactive waste.

Materials used in this approach have included rhenium-188 and holmium-166. These isotopes release beta particles, which have limited penetration and are well-suited for treating superficial lesions. The treatment is localized, affecting only the area in direct contact with the radioactive material, while limiting exposure to surrounding skin and tissue.

EMPD Treatment

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.