The increasing incidence of melanoma appears to beryllium much related to accrued diagnostic scrutiny from clinicians than to accrued UV radiation exposure, a caller investigation suggests.
More specifically, the researchers recovered that the correlations betwixt UV-related variables and melanoma were inconsistent and anemic portion the correlations betwixt diagnostic scrutiny variables and melanoma were consistently affirmative and stronger.
Dr Adewole Adamson
"As physicians, contempt our champion intentions, we whitethorn beryllium the root of the epidemic of melanoma diagnosis," archetypal writer Adewole S. Adamson, MD, an adjunct prof with the Department of Internal Medicine astatine Dell Medical School, The University of Texas astatine Austin, told Medscape Medical News. "The existent signifier of melanoma incidence successful the US is little associated with UV radiation exposure, and much associated with aesculapian practice."
Cutaneous melanoma, erstwhile a uncommon cancer, has go the 3rd astir diagnosed crab successful the US successful caller years, with an incidence complaint present six times higher than it was 40 years ago, the authors noted.
Adamson and colleagues questioned whether this summation mightiness beryllium owed to greater UV radiation vulnerability oregon overdiagnosis — the effect of accrued diagnostic scrutiny.
Consistent with overdiagnosis patterns observed with different cancers, determination has been nary corresponding summation successful mortality from melanoma.
To investigate, Adamson and his squad conducted a cross-sectional ecological study, published this period successful JAMA Internal Medicine, exploring Surveillance, Epidemiology, and End Results (SEER) information from 727 US counties betwixt January 2020 and July 2022.
The full dataset included 10 variables related to UV vulnerability and 8 variables related to diagnostic scrutiny, but the squad presented 3 for each class successful the main analysis. The 3 proxies for UV radiation were UV regular dose, variability successful cloudiness, and variability successful somesthesia crossed the counties, and the 3 for diagnostic scrutiny were median household income arsenic good arsenic concentrations of dermatologists and superior attraction physicians.
With a full of 235,333 melanomas diagnosed during the survey period, the results showed nary correlation betwixt the mean UV regular dose and the incidence of melanoma (P = .42).
However, melanoma incidence did importantly correlate with the 3 proxies of diagnostic scrutiny. The incidence of melanoma did importantly correlate with median household income (P < .001). In addition, counties with the highest concentrations of dermatologists and superior attraction physicians had the highest incidence rates of melanoma, contempt having little mean regular UV exposure, portion counties with shortages of dermatologists and superior attraction physicians had the lowest incidence of melanoma.
In fact, arsenic Adamson explained successful a tweet, "because of reviewer petition we adjacent took it a measurement further and added different investigation successful the supplement to amusement that counties that gained dermatologists had HIGHER increases successful melanoma incidence implicit time."
The observed trends tin beryllium seen successful 2 communities. Orange County, California, and Puget Sound, Washington, had astir identical melanoma incidence rates — 73 and 72 per 100,000, respectively; however, the 2 communities beryllium connected opposing extremes of UV radiation vulnerability with Orange County astatine the apical decile and Puget Sound astatine the bottom.
The authors besides pointed to southeastern New Mexico, which has among the highest UV regular doses successful the country, but among the lowest melanoma incidence.
Another origin pointing to overdiagnosis: The authors recovered lone a tiny relation betwixt melanoma incidence and melanoma mortality.
For context, the authors noted that the prevalence of smoking was highly correlated with lung crab incidence and mortality successful the aforesaid counties.
While erstwhile studies person shown conflicting results successful presumption of UV vulnerability and melanoma incidence, "this is the archetypal survey that examined proxies for UV vulnerability and proxies for diagnostic scrutiny broadside by side," Adamson said.
Among factors that could beryllium viewed arsenic confounders, Adamson and colleagues pointed to the anticipation that those surviving successful higher-income counties mightiness person greater UV vulnerability from traveling to warmer upwind destinations, peculiarly during the winter; however, that mentation would not explicate akin patterns crossed full region populations, the authors noted.
In addition, higher income counties besides person higher incidence rates of breast, prostate, and thyroid cancer, suggesting that "unless 1 argues that these cancers are besides caused by abrogation travel, the much parsimonious mentation is that each 4 cancers are delicate to diagnostic scrutiny," the authors said.
Given the evidence, immoderate of the much exaggerated nationalist messaging connected sunlight vulnerability should beryllium toned down. For instance, the thought that 95% of melanomas are caused by the prima is "particularly troubling," they wrote.
This proposition would mean that the "sun is simply a carcinogen much tied to melanoma than smoking is to lung cancer," Adamson noted. "That defies communal sense."
"Advising radical to beryllium prima harmless is important, peculiarly for children, adolescents, and young adults," helium added. "However, phobia of the prima should not get successful the mode of radical engaging successful the galore beneficial aspects of starring an active, societal manner extracurricular successful the sun."
Douglas Grossman, MD, PhD, who was not progressive successful the study, noted that "the proxies utilized for UV vulnerability and diagnostic scrutiny are indirect, and weaker than much nonstop indicators not evaluated successful the investigation — specified arsenic idiosyncratic prima vulnerability information for UV vulnerability and screening visits and biopsies performed for diagnostic scrutiny."
Due to the indirect proxies, "we request to beryllium cautious successful drafting conclusions of causality from the study," said Grossman, a prof of dermatology and co-leader of the HCI Melanoma Center astatine the University of Utah, successful Salt Lake City.
However, adjacent if causality is confirmed, trends down overdiagnosis whitethorn beryllium hard to change, Grossman added. "As agelong arsenic determination are fiscal incentives to execute biopsies, and continued hazard of aesculapian liability for missing a melanoma, it is apt that screening practices volition continue," helium explained.
Adamson is an subordinate and web exertion astatine JAMA Dermatology and reported nary different disclosures. Grossman reported nary disclosures.
JAMA Internal Medicine. Published Oct. 3, 2022. Abstract.
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