Welcome back to the journal review. This is our walkthrough of the October twenty twenty-six issue of Dermatologic Surgery — two pieces today, a commentary on sustainability in Mohs practice, and an original database analysis on margin positivity in extramammary Paget disease that has real implications for your appropriate-use conversations.

Let's start with the commentary. This is an invited commentary by Rachel Abbott, responding to a review article by Abdelwahab and colleagues on environmental sustainability in Mohs micrographic surgery. It's not a primary research piece, so there's no methods or results section to walk through — it's a synthesis and call to action, and I'll treat it that way.

The core message is that the carbon footprint of Mohs surgery is an emerging but increasingly legitimate quality-of-care issue, and that most of the fixes being proposed are low-cost and don't compromise oncologic or reconstructive outcomes. The commentary situates the reviewed article within a lineage of prior pieces — Leonard and colleagues, and Scott and colleagues, both from around twenty twenty-two — that first floated practical measures: using a hyfrecator rather than firing up a full electrosurgical unit for simple hemostasis, switching to clean gloves instead of sterile gloves where appropriate, using a single surgical tray per case, and generally trimming surgical waste. The new review builds on that by flagging additional interventions — microtubules for chromocoding dyes instead of more wasteful marking methods, streamlined surgical sets, waterless scrubbing protocols, more judicious use of personal protective equipment, drapes, and dressings, and simply placing recycling bins in procedure rooms, particularly for the soft plastic packaging that generates so much of the waste stream in a Mohs suite.

The point Abbott makes that I think is worth sitting with is the travel data: patient and staff travel to and from the surgical visit is often the single largest contributor to the carbon footprint of a skin cancer removal episode — larger than the disposables used in the room itself. That reframes where the highest-yield interventions actually sit. Things like virtual presurgical consultations, and defaulting to dissolvable sutures to eliminate a dedicated suture-removal visit, do more for the carbon ledger than swapping out gauze brands.

There's an honest tension raised here too — the concern that a sustainability push could be used to justify cutting corners, shortcuts dressed up as environmentalism, and the commentary explicitly says safeguards need to stay in place so that "low consumption" never slides into compromising sterile technique or oncologic thoroughness. The suggested answer is collaborative data collection through formal quality-improvement frameworks — she references the British Society for Dermatological Surgery's national sustainable skin surgery audit standards as a model — so that environmental impact is actually measured rather than assumed.

Practical takeaway: this isn't practice-changing in the sense of altering how you perform Mohs stages, but it's directly actionable at the practice-operations level. If you're looking for where to start, the travel-reduction and dissolvable-suture points are probably your best return on effort, and tray standardization and recycling infrastructure are easy, low-friction next steps. Nothing here should change your margin technique or your indications.

Now to the main original research article — this is a retrospective database study, an analysis of the National Cancer Database, looking at margin positivity rates after standard excision of extramammary Paget disease.

Background first. Extramammary Paget disease is rare, arises in apocrine-gland-rich skin, and has long been recognized as having a high recurrence rate after wide local excision — historically cited at over fifty percent. Current evidence-based guidelines already recommend surgery with comprehensive margin assessment, meaning Mohs or similar en-face peripheral-and-deep techniques, as first-line, and the appropriate use criteria endorse Mohs for extramammary Paget disease at every anatomic site, including low-risk extragenital skin. Despite that, actual practice patterns lag — wide local excision and radical excision remain the most commonly used approaches in the real world. What hadn't been well quantified is exactly how often those conventional excisions leave positive margins. That's the gap this paper fills.

Methodologically, this is a straightforward retrospective registry study, pulling patients from the National Cancer Database between two thousand four and twenty twenty-two using the pathology code for extramammary Paget disease along with topography codes covering extragenital skin, vulva, penis, and scrotum. They restricted to histologically confirmed cases that underwent surgery with known margin status. A registry design makes sense here for the obvious reason that this is a rare disease — you simply cannot power a meaningful analysis of margin outcomes by anatomic subsite and surgical approach from a single institution's experience, so pooling a national database across nearly two decades is really the only practical way to get stratified numbers with any stability.

On the statistics side, this paper is intentionally descriptive rather than inferential — there's no Cox model, no logistic regression hunting for independent predictors of margin positivity. The entire analysis is built on stratified proportions: margin positivity rates broken down by anatomic site, by specific surgical procedure within each site, and by whether disease was in-situ versus dermal-invasive. That's a reasonable choice given the study's actual question. When your goal is simply to describe how often an outcome occurs across defined subgroups — not to control for confounders or isolate which variable independently drives risk — a multivariable model adds complexity without adding insight. Stratified descriptive rates are the right tool when you want a clean, clinically interpretable number for each specific scenario, like "partial vulvectomy for in-situ disease," that a surgeon can actually map onto a patient in front of them. The tradeoff, and it's a real one, is that stratification alone can't tell you whether site, procedure type, or histology is the dominant driver when several differ at once, and small subgroups — the registry suppressed any cell under ten patients for privacy — limit how far you can stratify before the numbers become unstable.

Now the results, and these are the numbers worth remembering. Out of about four thousand two hundred patients, overall margin positivity after excision was essentially one in two — forty-nine percent. Broken down by site, vulvar disease had the highest positivity rate at roughly fifty-four percent, followed by penile at about forty percent, scrotal at about a third, and extragenital skin also at about a third, specifically thirty-two percent.

Here's the finding that should reset any intuition that a bigger operation fixes the margin problem: within vulvar disease, partial vulvectomy had the highest positivity rate, but total and radical vulvectomy — genuinely more extensive surgery — still left margins positive forty-five to forty-seven percent of the time. And for extragenital skin, going from excision margins of a centimeter or less to margins greater than a centimeter only dropped positivity from thirty-eight percent to twenty-seven percent — a real but modest reduction, nowhere close to solving the problem. Across every site and every surgical approach the authors examined, margin positivity never dropped below twenty-five percent.

Maybe the most clinically sobering piece: this isn't just a problem of occult invasive extension being missed. Even purely in-situ, epidermis-confined disease had strikingly high positivity — about fifty-four percent for vulvar in-situ disease, forty-two percent for scrotal, and thirty-nine percent for extragenital in-situ disease. So this is a disease where the subclinical extension itself, not depth of invasion, is driving margin failure.

In their discussion, the authors connect this directly back to the known high recurrence rates after wide local excision — framing this analysis as finally quantifying, at a national scale, the margin positivity that likely underlies those recurrences. They argue this is direct empirical support for the existing guideline and appropriate-use-criteria recommendations favoring Mohs or other comprehensive en-face margin assessment, including at extragenital sites, which are sometimes treated as "lower risk" and therefore deprioritized for Mohs referral — this data pushes back on that assumption. They also note the tissue-conservation advantage of Mohs is especially relevant here given how often extramammary Paget disease involves genital skin, where every centimeter of preserved tissue matters for function and reconstruction.

The honest limitation, which the authors state plainly, is that conventional margin assessment in this cohort relied on vertical sectioning — bread-loafing — which samples well under one percent of the actual surgical margin. That means the true rate of residual disease along the entire margin is almost certainly higher than the forty-nine percent reported here; if anything, this analysis understates the problem. Other standard registry caveats apply too — no central pathology review, no standardization of exactly how margins were taken or interpreted across contributing centers, and no recurrence or survival data linked to margin status in this particular analysis.

Practical takeaway, and I'd call this genuinely practice-affirming if not entirely new: this is strong, large-scale, quantitative backing for what the guidelines already say — extramammary Paget disease, at essentially any site and regardless of whether disease appears confined to the epidermis, should be routed toward Mohs or other comprehensive margin-controlled surgery rather than conventional wide local excision, because conventional excision is failing to clear margins roughly one in three to one in two times no matter how aggressively you widen the margin or escalate the procedure. The one practical caveat worth voicing to patients and referring colleagues: for extensive perineal or multi-quadrant disease, Mohs can be time- and resource-intensive, and tolerance of a long awake procedure is a real logistical consideration that belongs in your preoperative planning conversation.

That's the issue — a sustainability commentary worth operationalizing at the practice level, and a database study that gives you a hard number to put behind why extramammary Paget disease belongs on the Mohs table rather than in the general surgery or gynecologic oncology excision queue. Thanks for listening, and I'll see you next issue.