Welcome back to the journal review. This is your walkthrough of the September 2026 issue of the Journal of the American Academy of Dermatology, and we've got four pieces worth your time today — two letters to the editor engaging in some real scientific back-and-forth, a health policy piece on a sunscreen ingredient that's been a long time coming, and a brief report using SEER data to look at rural-urban disparities in melanoma surgery. Let's get into it.

First up is a letter to the editor, a response to the Ran et al brief report on integrated multidisciplinary care in advanced cutaneous squamous cell carcinoma. If you didn't catch the original piece, the gist was that when dermatology, surgical oncology, radiation oncology, and medical oncology are co-located and coordinated — what the authors call integrated multidisciplinary care — time to treatment initiation drops significantly compared to a more fragmented referral model. This letter, from Adler and colleagues, doesn't dispute that finding at all. Instead, it pushes on an important equity question: that kind of integrated infrastructure, with co-located specialists and recurring tumor boards, is basically a feature of well-resourced academic medical centers. It's simply not available to community practices, safety-net hospitals, or rural health systems, where subspecialty access is limited and referral networks are fragmented to begin with. The authors point out that reducing the number of pretreatment visits isn't just a convenience metric — it directly addresses the travel burden, missed work, childcare logistics, and general care fragmentation that disproportionately fall on underserved patients, and they note prior literature tying dermatologist density to melanoma prognosis as supporting evidence that geographic access really does move outcomes. Rather than just naming the problem, though, the letter offers concrete workarounds for those of us not sitting inside a big academic multidisciplinary machine — structured, proactive communication pathways between specialties, virtual tumor boards that don't require physical proximity, hub-and-spoke telementorship models like Project ECHO connecting regional physicians to specialist expertise, telemedicine for pretreatment consults to cut down unnecessary travel, and the simple but underrated value of having one trusted local coordinating clinician who can shepherd a patient through a complex care pathway. Nothing here is a randomized trial or a new dataset — it's a call to action layered onto someone else's findings — but for those of you practicing outside a tertiary academic center, or referring patients into one, it's a useful reminder that the benefits of coordinated care aren't purely a function of infrastructure you don't have. Some of it can be replicated with intentional communication and existing telehealth tools.

Next, a Health Policy and Practice piece that's genuinely going to matter for how you counsel patients on sun protection, even though there's no data analysis to walk through here — it's a regulatory update. In December of 2025, the FDA proposed adding bemotrizinol, abbreviated B-E-M-T, to the approved list of sunscreen active ingredients in the United States, with formal approval anticipated as early as this past summer. If and when that happens, this would be the first new organic, or chemical, UV filter added to the US sunscreen armamentarium since ensulizole back in 1999 — so we're talking about a genuinely rare event in US sunscreen regulation. Why does this matter clinically? Right now, avobenzone is the only FDA-monographed long-wavelength UV-A filter available in the US, and it has real formulation baggage — it's photounstable, needs to be paired with octocrylene for stabilization, and it can't be combined with zinc oxide or titanium dioxide, which meaningfully limits what a mineral-forward formulation can do. Bemotrizinol, which has been used globally since the year 2000, is photostable on its own, covers both UV-A2 and UV-A1, and also contributes some UV-B coverage, which specifically closes what the authors call the three-twenty nanometer gap — the transition zone between UV-B and UV-A2 that's poorly covered by our current filter lineup. There's also a safety angle worth knowing for patient conversations: bemotrizinol has a molecular weight of about six hundred twenty-eight grams per mole, well above the so-called five-hundred Dalton rule of thumb for stratum corneum penetration, and consistent with that, FDA maximal-usage trials showed negligible systemic absorption, staying under the half-nanogram-per-liter threshold — in contrast to smaller filters like oxybenzone and avobenzone, which have exceeded that systemic absorption threshold under similar testing conditions. From a formulation standpoint, bemotrizinol plays well with everything, including zinc oxide and titanium dioxide, which means formulators could lower the overall mineral filter concentration needed, improving photostability while reducing the visible white cast — a real practical benefit for patients with darker skin phototypes who've historically been underserved by mineral sunscreen cosmetics. The bigger-picture point the authors make is that the US currently relies on only seven commonly used UV filters, compared to twenty-nine available in the European Union, and this ingredient took nearly seven years and substantial investment to work through the approval pathway despite decades of established international use — which the authors frame as an argument for a more efficient regulatory pathway going forward, not a loosening of rigor. Nothing for you to change in practice yet since it isn't approved, but this is worth flagging to patients and worth watching for when it actually hits the shelves.

Third is another letter to the editor, and this one is a nice case study in how reanalysis and methodological transparency should work in our literature. It's a response from Zhou and colleagues to a group led by Zheng, who had reanalyzed a SEER-based cohort of sebaceous carcinoma patients using propensity score matching and found that wide local excision was associated with significantly better overall and cancer-specific survival compared to Mohs micrographic surgery — with hazard ratios suggesting a meaningful survival advantage for wide excision. That directly contradicted Zhou's group's own earlier work using the National Cancer Database, which had found the two approaches comparable. Rather than just arguing back in prose, Zhou's team went and re-ran their own National Cancer Database cohort using the same propensity score matching approach Zheng's group had used, specifically to make the two analyses more comparable. This is worth pausing on methodologically: propensity score matching is a technique for observational data where you can't randomize — it estimates each patient's probability of receiving one treatment versus the other based on their measured characteristics, like age, stage, comorbidities, and socioeconomic factors, and then pairs treated and untreated patients who had similar predicted probabilities. The goal is to mimic what randomization would have done, balancing the two groups on measured confounders so that the surgery type itself is more plausibly driving any survival difference you see, rather than the fact that, say, sicker or older patients were preferentially getting wide excision to begin with. After matching close to seven hundred patients per arm, with covariate balance confirmed by small standardized mean differences, Zhou's group's Cox multivariate analysis showed no significant survival difference between Mohs surgery and wide local excision — a hazard ratio right around 0.84, not statistically significant, essentially reproducing their original unmatched finding. Their Kaplan-Meier curve also showed a difference favoring Mohs surgery, but it didn't cross the significance threshold either. So why the discrepancy with Zheng's SEER analysis? The letter walks through some genuinely instructive reasons: the SEER database only allowed comparison of overall and cancer-specific survival, while the National Cancer Database doesn't capture cancer-specific survival at all, limiting apples-to-apples comparison; the covariates differed, with Zhou's analysis incorporating more granular TNM staging, insurance status, and facility type; and critically, the SEER cohort was considerably smaller, under six hundred patients total versus close to fourteen hundred in the matched National Cancer Database cohort, raising the possibility of selection bias or reduced statistical stability in the smaller sample. The letter also notes that other published SEER analyses have landed on the side of no significant difference between the two approaches, muddying the picture further. The authors' bottom line, and it's a reasonable one: taken together with prior literature, Mohs surgery appears non-inferior to wide local excision for sebaceous carcinoma survival, but this is squarely an area where retrospective database limitations are the whole story, and prospective, larger-scale study is genuinely needed before anyone changes practice based on database signal alone.

Last, and the one with the most substantive new data, is a brief report — a genuine original study using the SEER database to examine rural-urban disparities in melanoma surgical management and outcomes. The clinical problem here is well established: rural melanoma patients have higher melanoma-specific mortality, likely driven by delayed diagnosis and limited access to dermatologic care, and current NCCN guidelines don't recommend Mohs micrographic surgery for invasive melanoma when standard clinical margins can be achieved with wide local excision — even though some recent literature suggests Mohs surgery may offer a disease-specific survival benefit in certain contexts. The gap this study is chasing is whether access to Mohs surgery itself differs by rural versus urban residence, and whether that access gap translates into a measurable survival difference.

Methodologically, the authors pulled biopsy-confirmed invasive cutaneous melanoma cases treated with either wide local excision or Mohs surgery from SEER, covering the years 2000 through 2021 across seventeen registries, which represent roughly a quarter of the US population — a reasonable and common way to get a large enough sample to detect what are likely to be modest disparity effects that a single-institution series never could. Rural versus urban residence was classified using SEER's standard Rural-Urban Continuum Codes. For the outcome analysis, they used Kaplan-Meier curves to visualize survival over time, a log-rank test to assess whether those curves differed significantly, and — the main analytic engine here — a multivariable Cox proportional hazards model. It's worth spending a moment on why Cox regression is the right tool for a question like this. Unlike a simple comparison of raw survival percentages, a Cox model handles the fact that patients enter the cohort at different times and are followed for different lengths of time before either dying, being censored, or the study period ending — it compares the instantaneous risk of death at any given moment between groups, while allowing you to simultaneously adjust for multiple confounders like age, stage, tumor thickness, and income, all at once, rather than needing to stratify the data into ever-smaller subgroups. It's the same reason it's the standard tool across oncology survival literature, and it lets the authors report an adjusted hazard ratio that tells you the relative risk of melanoma-specific death for one group versus another, holding other measured factors constant. One important methodologic limitation the authors flag themselves: SEER's coding could not distinguish staged excisions with formal margin control from standard wide local excision, meaning some patients coded as WLE may actually have received more aggressive margin assessment, which blurs the comparison somewhat.

Onto results. Of just over one hundred thirty-six thousand patients, the vast majority — about nine in ten — resided in urban areas. Rural patients presented with a higher burden of aggressive disease features across the board: more regional or distant stage at diagnosis, more nodular subtype, more ulceration, and greater Breslow thickness, all significant differences. Overall, the great majority of patients, over ninety percent, were treated with wide local excision, with only about seven percent receiving Mohs surgery — and rural patients were significantly less likely to get Mohs surgery than urban patients, six percent versus just over seven percent. Encouragingly, Mohs utilization increased over the study period in both rural and urban populations while wide excision use declined, suggesting some closing of the gap over time, though the disparity at any given time point remained.

On the outcomes side, rural patients overall had lower disease-specific survival than urban patients — eighty-four percent versus eighty-seven percent at five years, and seventy-seven percent versus eighty-one percent at ten years — and this difference persisted after full multivariable adjustment, with an adjusted hazard ratio around 1.08. That's statistically significant, but it's worth naming explicitly: an eight percent relative increase in hazard is a real, detectable signal, not a huge one, and the absolute survival gap of a few percentage points, while clinically noticeable at a population level, is modest for an individual patient conversation. The more interesting result is what happens when you split by treatment type. Among patients treated with wide local excision, the rural survival disadvantage was clearly present and, if anything, a bit larger — eighty-four versus eighty-seven percent at five years, seventy-five versus eighty percent at ten years, with a significant adjusted hazard ratio of about 1.11. But among patients who received Mohs surgery, there was no significant rural-urban survival difference at all.

Now, how the authors interpret that last finding is the crux of the discussion, and they're admirably cautious about it. The tempting read is that Mohs surgery is protective for rural patients and erases the disparity. But the authors themselves push back on that interpretation, and I think correctly: rural patients who manage to access and undergo Mohs surgery likely represent a highly selected subset — healthier, more resourced, with fewer comorbidities, greater health literacy, and the means to travel to a fellowship-trained Mohs surgeon in the first place. In other words, this is very plausibly a selection effect rather than a treatment effect, and the authors say so directly rather than overclaiming a causal benefit of Mohs surgery itself. They also note that among wide-excision patients, the persistent rural disadvantage may reflect broader differences in procedural resources, pathology support, and follow-up infrastructure that have nothing to do with the excision technique itself. Limitations here are the usual retrospective-registry set — unmeasured confounding around comorbidity and access, the inability to separate staged excision from standard wide local excision in the coding, and no ability to capture the granular reasons an individual patient did or didn't receive Mohs surgery.

So where does this leave you practically? This is not practice-changing in the sense of altering surgical selection for melanoma — NCCN guidance still doesn't support routine Mohs surgery over wide local excision when standard margins are achievable, and this study's design can't support a causal claim that Mohs surgery improves survival for rural patients, given the obvious selection bias the authors themselves acknowledge. What it is useful for is naming, with real numbers, a disparity you may already suspect anecdotally: rural patients are getting less access to fellowship-trained Mohs surgeons, presenting with more advanced disease, and dying of melanoma at higher rates even after adjusting for stage and other measured factors. If you practice anywhere near a rural catchment area, or take referrals from one, this is a data point supporting outreach, tele-triage, or expedited referral pathways for rural patients with concerning lesions — echoing, actually, the same access themes raised in that first letter on multidisciplinary care. Interesting and worth citing when you're making the case for expanded access; not a reason to change who you put under the microscope.

That wraps our four pieces for this issue. Thanks for listening, and we'll see you next month.