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Evolution of Excisional Surgery Practices for Melanoma in the United States.

Importance
National Comprehensive Cancer Network guidelines for melanoma have consistently recommended wide local excision as the standard of care since their inception. Although surgery with more comprehensive margin assessment (eg, Mohs surgery) has been advocated for certain subsets of melanoma, how often these techniques are used in clinical practice is uncertain.


Objective
To examine trends in the use of comprehensive margin assessment surgery for melanoma by tracking claims data for Mohs surgery.


Design, Setting, and Participants
This national cross-sectional analysis examined claims data from the Optum Clinformatics Data Mart, a nationally representative database. The study cohort consisted of 79 108 patients undergoing surgical excision for melanoma from January 1, 2001, through December 31, 2016. Data were analyzed from January 1, 2001, through December 31, 2016.


Main Outcomes and Measures
The primary outcome was the likelihood of a melanoma being treated with Mohs surgery over time, evaluated by multivariable logistic regression and expressed as the odds of treatment per additional calendar year.


Results
Among 79 108 patients with melanoma (median age, 63 years [interquartile range {IQR}, 51-73]; 47 407 men [59.9%]), 75 047 were treated with conventional excision (median age, 62 years [IQR, 50-73 years]; 44 786 men [59.7%]) and 4061 with Mohs surgery (median age, 67 years [IQR, 56-76 years]; 2621 men [64.5%]). Mohs surgery was used in 5.1% of all surgical cases, with the rate of Mohs surgery increasing 304% from 2.6% in 2001 to 7.9% in 2016. Odds of receiving Mohs surgery for melanoma increased significantly in more recent calendar years (odds ratio [OR], 1.02 per calendar year; 95% CI, 1.01-1.03; P < .001). Immunohistochemistry (IHC) use was only coded with Mohs surgery in 1087 cases (26.8%), and the odds of receiving Mohs surgery with IHC increased in more recent calendar years (OR, 1.13 per calendar year; 95% CI, 1.10-1.15; P < .001). Use of Mohs surgery and Mohs surgery with IHC for melanoma differed widely across geographic census divisions with greater than 3-fold variation between the regions with highest and lowest use in every period (eg, for 2013 through 2016, the East South Central region used Mohs surgery in 8.8% of melanoma excisions compared with 2.6 in the New England region).


Conclusions and Relevance
Despite stable guidelines for melanoma surgery, the results of this study suggest that surgical practices for melanoma are evolving. Wide variations in surgical practice patterns for melanoma are present in the United States. This study's findings suggest that the effect of variations in surgical techniques on outcomes requires scrutiny and further study.