Welcome back to the journal review. This is the April twenty twenty-six issue of the Journal of the American Academy of Dermatology, and we've got four pieces to get through today — a letter to the editor, a large registry-based mortality study in melanoma, a brief report mapping the entire United States dermatology workforce, and a multicenter real-world study on photodynamic therapy for facial actinic keratosis. Let's get into it.

First up is a letter to the editor — so no new data here, just correspondence responding to a prior JAAD paper on factors associated with adherence to skin self-examination, or SSE, recommendations in melanoma patients. The original study, by Nugent and colleagues, identified factors that lower the likelihood of patients performing SSE. This response letter's core critique is that the original cohort study didn't analyze sociodemographic variables — income, race and ethnicity, education level, or access to dermatologic care — any of which could meaningfully confound the relationship between whatever factors were studied and actual adherence. The authors marshal some supporting literature: education level as a marker of socioeconomic status has previously been tied to differences in how seriously patients view melanoma and how familiar they are with ABCD lesion criteria, and physicians themselves have been shown to spend less time counseling patients with only a high school education. They also raise the geographic access issue — Native American, Hispanic, and Black patients are disproportionately likely to live in areas with limited dermatologic care, which itself reduces exposure to SSE education, and there's a nod to acculturation literature showing English language fluency correlates with a higher likelihood of ever having performed SSE. Their ask is straightforward: future work should stratify by race and socioeconomic status to see whether standardized physician counseling actually closes these gaps, or whether disparities persist despite counseling — which would point toward deeper structural issues like implicit bias or unequal access rather than simple knowledge deficits. There's no methodology to critique here beyond the letter's own argument, and no new results — this is purely a call to account for unmeasured confounders. For your practice, take this as a reminder rather than a mandate: when you're counseling patients on SSE, especially in a diverse practice, don't assume your standard counseling script lands equally across literacy and access levels. It's a reasonable hypothesis-generating point, not something with data behind it yet.

Next, a full original study — a retrospective cohort analysis of primary tumor location and mortality in cutaneous melanoma, using the SEER database, that's Surveillance, Epidemiology, and End Results, the NCI-sponsored cancer registry covering roughly a third of the US population. The clinical question here has a genuinely messy literature behind it: some studies say head and neck melanoma carries worse prognosis, attributed to anatomic complexity or delayed diagnosis, while others say that effect weakens, disappears, or even reverses once you properly adjust for Breslow thickness and ulceration. One study even found the head-and-neck mortality signal loses significance after about three and a half years of follow-up. And critically, primary tumor location isn't incorporated into AJCC staging at all, so if it does carry independent prognostic weight, current staging may be missing it.

Methodologically, this is a big retrospective pull from SEER, 2000 through 2021, seventeen registries. They started with over three hundred and seventy thousand melanoma cases and whittled down through a long exclusion cascade — multiple primaries, missing histologic confirmation, missing TNM or AJCC or SEER stage, missing survival time, race, marital status, urban residence, or surgery information — landing at just under one hundred sixty-three thousand patients. That's a large final cohort, which is really the whole point of using SEER for this question: you need enough head-and-neck, trunk, and limb cases with complete staging and treatment data to run genuinely adjusted multivariable models and still have power left for subgroup analyses — something no single-institution series could offer. They ran univariate and multivariate Cox models for all-cause mortality, plus competing-risk regression for melanoma-specific mortality, with two adjustment tiers — the first for basic demographics and income and urban residence and diagnosis year, the second adding comorbidities, ulceration, laterality, histology, AJCC stage, and treatment received. One nice methodological detail worth flagging for anyone building models like this: they found extreme multicollinearity among the staging systems, with variance inflation factors as high as the thousands, so they kept only AJCC staging in the final model rather than layering in TNM or SEER stage redundantly. They also ran an extensive sensitivity battery — excluding cases with missing thickness, excluding those with missing ulceration too, building three separate one-to-one propensity-matched cohorts comparing each limb and head-neck site against trunk, propensity overlap weighting, and substituting TNM for AJCC stage — all to make sure the location signal wasn't an artifact of residual confounding or staging choice.

The results held up: compared with trunk, head and neck location was associated with a modest but statistically significant increase in both all-cause mortality, about an eight percent relative increase, and melanoma-specific mortality, about a five percent relative increase. Going the other direction, upper limb and shoulder location was associated with roughly a nine percent lower all-cause mortality and a notably larger twenty-one percent lower cancer-specific mortality relative to trunk. Lower limb and hip showed an eleven percent lower all-cause mortality, though its cancer-specific mortality reduction was borderline — the confidence interval essentially touched the null, so treat that one as a weaker, less certain signal than the others. These patterns were consistent across their subgroup and sensitivity analyses, which is reassuring for internal validity.

On limitations, the authors are appropriately brief — they flag the retrospective design and the potential for selection bias, and honestly, given how much of the original cohort got excluded through that missing-data cascade, generalizability deserves a bit more scrutiny than the paper gives it. There's also the inherent SEER problem of no central pathology review and reliance on registry-coded variables. And clinically, keep the magnitude in perspective: an eight percent and five percent relative increase in mortality, while statistically robust in a cohort this large, is not a dramatic effect at the individual patient level — this is a population-level signal, not something that should reflexively change how you counsel an individual head-and-neck melanoma patient about prognosis. The authors' own conclusion leans toward recommending more aggressive treatment and surveillance for head-and-neck melanoma, which is a reasonable extrapolation but goes a bit beyond what a hazard ratio in this range can really support on its own. The practical takeaway: this is a well-powered, methodologically careful confirmatory study that adds weight to the idea that tumor location carries independent prognostic information beyond thickness, ulceration, and stage — interesting, and probably strengthens the case for continued vigilant surveillance in head-and-neck melanoma patients that many of us already practice anatomically-informed caution around — but it's not practice-changing in the sense of altering margins, staging conversations, or referral thresholds today.

Third is a brief report — a descriptive, address-level landscape analysis of the entire US dermatology workforce, pulling from the American Academy of Dermatology's public directory cross-referenced with population data, using the Haversine formula to calculate straight-line distances between towns and the nearest dermatologist. The novelty the authors emphasize is that prior workforce studies worked at the county or state level; this is the first analysis matching individual, address-level practice locations to self-reported practitioner information nationally.

The numbers: eleven thousand six hundred fifty-six self-reported dermatologists, split about evenly with a slight majority of women at fifty-four percent versus forty-six percent men, the vast majority MD-trained at ninety-three percent versus seven percent DO, and board certification rates of ninety-five percent through the American Board of Dermatology and about four percent through the American Osteopathic Board. Subspecialty certification broke down to about seventeen percent in micrographic dermatologic surgery, under four percent in dermatopathology, and under three percent in pediatric dermatology. Geographically, they identified nearly fourteen thousand individual practice addresses, with California holding the most at about thirteen percent of all locations and North Dakota the fewest. There's a nice sex-based practice pattern here too — women dermatologists tend to practice in larger cities, with a median town population around one hundred twelve thousand versus about ninety-five thousand for men, and DOs practice in notably smaller towns than MDs. Worth flagging for our own subspecialty specifically: micrographic surgery certification showed a significant sex gap, about twenty-three percent of male dermatologists carrying that certification versus twelve percent of female dermatologists — a real demographic disparity within Mohs surgery itself. On geographic access, the median distance from a town to its nearest dermatologist was about fourteen and a half miles nationally, shortest in Washington DC at just over a mile, and longest, unsurprisingly, in Alaska at well over two hundred miles on average. Even within the contiguous states, they flagged specific towns — Presidio, Texas and Madawaska, Maine — sitting roughly one hundred seventy to two hundred miles from the nearest dermatologist.

There's no hypothesis testing or causal claim here — this is pure descriptive geospatial mapping, and the authors are upfront that the value is practical rather than mechanistic: identifying exactly which rural communities are most underserved, to guide teledermatology expansion, rural residency track programming, and loan subsidy targeting. Limitations are the ones you'd expect from any self-reported directory dataset — it doesn't capture retirements or new graduates in real time, and Haversine straight-line distance ignores actual road geography, so real-world travel burden in mountainous or poorly connected areas is probably underestimated. For practice purposes, this isn't something that changes your day-to-day, but it's a genuinely useful reference dataset if you're involved in workforce advocacy, residency recruitment, or thinking about where to expand access — and that Mohs certification sex gap is worth keeping in mind as our own subspecialty continues to diversify.

Last is a multicenter, real-world comparative study out of China looking at long-term recurrence after lesion-directed versus full-face photodynamic therapy, or PDT, for facial actinic keratosis. The background here is familiar — actinic keratosis reflects field cancerization, and full-face treatment theoretically clears subclinical disease that lesion-directed treatment leaves behind, but long-term recurrence data specific to an Asian population using this kind of intensive protocol had been lacking.

Two hundred eleven patients across five Chinese hospitals were treated with either lesion-directed PDT, one hundred thirty-one patients, or full-face PDT, eighty patients, both using ten percent aminolevulinic acid with red LED light, and both getting three to six treatment sessions spaced two weeks apart. Here's the methodological wrinkle worth flagging: this wasn't a clean randomized trial — allocation was partially based on patient preference, which meant the two groups weren't perfectly balanced at baseline, with the full-face group actually having somewhat higher lesion counts and more severe Olsen grade distribution going in. Rather than ignore that imbalance, the authors used a standardization approach — essentially the same logic as age-adjustment in epidemiology — stratifying by baseline lesion count and recalculating recurrence rates as though both groups had an identical, standard distribution of lesion burden. That's a reasonable way to partially correct for the lack of true randomization, though it's still not a substitute for it, and it's worth noting explicitly when reading the results.

After standardization, the one-year participant-level recurrence rate was significantly lower with full-face PDT than lesion-directed — about one percent versus three and a half percent — and that advantage held at two years, roughly two percent versus six percent, and at three years, roughly three percent versus nine percent. Notably, even patients with fewer than five lesions benefited from the full-face approach, supporting the field-cancerization rationale rather than just treating what's visible. Adverse events were mild across the board, with more transient erythema in the full-face group, which tracks with treating a larger surface area. One striking discussion point: these recurrence numbers are considerably lower than what's been reported in Western trials, where one-year lesion recurrence has ranged from roughly three to nineteen percent and participant-level recurrence has run thirty to forty percent. The authors' explanation is dosing intensity — Chinese protocols here used three to six sessions, compared with the one to two sessions typical in Europe and North America, and they suggest that more intensive up-front treatment may be driving the more durable clearance.

Limitations are honestly stated: the partial patient-preference design introduces selection bias that the standardization technique only partly addresses, and they note that patients with more than fifteen lesions may simply be undertreated by a three-to-six session protocol. Practically, this reinforces a treatment philosophy many of us already lean toward — treating the whole cosmetic unit rather than just visible lesions in patients with field-cancerized facial skin — and the session-intensity observation is a genuinely useful clinical pearl: if you're using PDT for facial actinic keratosis, more aggressive dosing with multiple sessions may meaningfully improve long-term durability, not just initial clearance. It's not a randomized trial, so I'd call the specific numbers here informative rather than definitive, but the overall direction — full-face beats lesion-directed, and it holds up for years, even in lower-lesion-burden patients — lines up with the broader field-cancerization literature and is reasonable to act on.

That wraps this episode. To summarize the throughline: a cautionary letter about unmeasured confounders in skin self-exam research, solid confirmatory evidence that head-and-neck location carries a modest independent mortality signal in melanoma, a useful descriptive map of where dermatologists — and Mohs surgeons specifically — actually practice in this country, and further real-world support for full-face field treatment of actinic keratosis over spot treatment alone. Thanks for listening, and I'll see you next month.