Watch: the CureRays® explainer series
Prefer to read? The full guide below is complete on its own, with tables you can revisit any time.
What is extramammary paget disease?
Extramammary Paget disease (EMPD) is an uncommon cancer that grows within the upper layer of skin in areas dense with apocrine sweat glands — most often the vulva, scrotum, penis, groin, or around the anus. It usually appears as a red, scaly, itchy patch that is mistaken for eczema or a fungal infection for months or years. Most cases stay confined to the skin surface (in situ) and are slow-moving, but the disease tends to extend microscopically well beyond the visible patch, which makes complete removal difficult and recurrence common. In a minority, it becomes invasive or signals an underlying internal cancer, so evaluation looks for both.
The main types
Doctors group extramammary paget disease by where it starts and how it behaves:
| Type | What it means, simply |
|---|---|
| Primary EMPD (in situ) | Arises in the skin itself and stays in the surface layer; the most common form, slow-growing and highly treatable. |
| Invasive EMPD | Has grown deeper into the skin, with a higher risk of reaching lymph nodes; needs more aggressive treatment. |
| Secondary EMPD | Reflects spread from an underlying cancer nearby (such as bladder, anorectal, or other gland cancer), which must be found and treated. |
Staging, in plain terms
Because EMPD often hugs the skin surface, doctors focus on whether it is in situ (surface only) or invasive (deeper), whether it has reached lymph nodes, and whether an underlying internal cancer is driving it.
| In situ vs. invasive + node status (no single formal TNM) | What it generally means |
|---|---|
| In situ (surface only) | Confined to the top layer of skin. Excellent outlook; the challenge is treating the full, often-larger-than-it-looks area. |
| Invasive | Has grown into deeper skin, raising the chance of spread to nearby lymph nodes. |
| Node-positive | Has reached the groin or nearby lymph nodes; treatment then targets the nodes as well. |
| Secondary / associated cancer | Linked to an underlying gland or organ cancer that determines the overall plan. |
The standard of care
Extramammary Paget Disease is almost always treated by a team that may include a surgeon, a medical oncologist, and a radiation oncologist, combining therapies for the best result. The usual building blocks are:
Surgery (Mohs or wide excision)
The main treatment for the skin disease. Mohs micrographic surgery checks margins under the microscope as it goes, important because EMPD extends invisibly beyond the visible edge.
Radiation therapy
A curative option for people who aren't surgical candidates and a valuable add-on after surgery for recurrent, persistent, or incompletely removed disease.
Topical and other skin treatments
Imiquimod cream, photodynamic therapy, or laser can treat surface (in situ) disease, especially in delicate areas where surgery would be disfiguring.
How radiation treatment works
Radiation delivers focused energy that damages the DNA of the abnormal skin cells so they can no longer divide, clearing the patch over the weeks following treatment. EMPD is well suited to radiation because the disease lives in the skin where a broad, even surface dose can cover the wide microscopic spread that makes surgery hard. The beam is shaped to the affected area — useful in the groin and genital region where surgery can be disfiguring — and given as a series of short, painless daily sessions. The main side effect is a temporary skin reaction in the treated area.
The main ways radiation is delivered for extramammary paget disease:
Definitive (radical) radiation
For inoperable disease or patients who decline surgery, external-beam radiation to the affected skin (often 60-70 Gy) can control or cure the tumor while preserving sensitive anatomy.
Adjuvant radiation
Given after surgery when margins are positive or the disease keeps recurring, treating the broad at-risk skin field that surgery may have missed.
Nodal radiation
When lymph nodes are involved, the draining groin nodes are included; treating only the skin and ignoring at-risk nodes is linked to worse outcomes.
Latest studies shaping care
Care keeps improving — often toward getting the same excellent results with less burden on patients. A few developments:
Radiation in 106 patients with EMPD: 2025 retrospective study reported strong tumor control with radiation — both after surgery and as the sole treatment for inoperable disease — with mostly mild side effects.[1]
Advances in Radiation Oncology (2025)
Multi-institutional radiation outcomes: Across institutions, three-year local control, progression-free, and overall survival were about 75%, 52%, and 80%; node spread and treating skin only (without at-risk nodes) predicted worse results.[2]
Cancers (MDPI, 2025; 17:1507)
Mohs surgery pooled analysis: Pooled patient data confirm Mohs micrographic surgery lowers local recurrence versus standard excision by tracing EMPD's invisible margins.[3]
DARE/NCBI pooled analysis
Common questions
I was told it looked like eczema for a long time — is that normal? Yes. EMPD is famous for mimicking eczema or a fungal rash, so diagnosis is often delayed. A skin biopsy of a patch that won't clear with creams is what makes the diagnosis.
Can radiation cure it without surgery? It can. For people who aren't good surgical candidates or who want to avoid disfiguring surgery in the genital area, radiation alone can control or cure the disease, and it's also used after surgery for stubborn cases.
Why are my doctors checking for another cancer? A minority of EMPD cases are linked to an underlying gland or organ cancer (secondary EMPD). Checking for one ensures the whole problem is treated, not just the skin patch.
References
Numbered sources for the studies cited above. Links open the primary publication on PubMed or the publisher’s site.