Use of Mohs surgery, with and without immunohistochemistry, to treat melanoma is growing, although there is some geographic variation in surgical practices, a national cross-sectional analysis in JAMA Dermatology suggests.
Rates of melanoma treatment with Mohs surgery increased from 2.6% in 2001 to 7.9% in 2016, with the odds rising by 2% on average annually (odds ratio 1.02 per calendar year, P<0.001), reported Jeremy Etzkorn, MD, of the University of Pennsylvania in Philadelphia, and colleagues.
Immunohistochemistry was coded for just 26.8% of Mohs surgery cases, but the odds of receiving Mohs surgery with immunohistochemistry grew over the study period (OR 1.13 per calendar year, P<0.001), the researchers note.
Notably, use of Mohs surgery with immunohistochemistry and Mohs surgery alone to treat melanoma varied widely across region census divisions, with more than a three-fold variation between the areas with lowest and highest use in each period. For instance, from 2013 to 2016, the East South Central region used Mohs surgery in 8.8% of melanoma excisions versus 2.6% in the New England region, Etzkorn and colleagues state, in a media release from MedPage Today.
“Patients are getting widely variable treatments for the same kind of cancers, and we need to figure out who is getting the best treatment and try to figure out how to use these different techniques appropriately,” Etzkorn says.
Strong evidence assessing various approaches to excision instead of different excisional margins “would better inform consensus guideline statements about the role of comprehensive margin assessment surgery for melanoma and possibly reduce variations in practice patterns and care,” the authors wrote.
The National Comprehensive Cancer Network (NCCN) guidelines have suggested traditional wide local excision with prescribed surgical margins for all cutaneous melanomas, without consideration for histological subtype or anatomical location for over 20 years, noted Christopher Miller, MD, of the University of Pennsylvania in Philadelphia, and colleagues, in an accompanying viewpoint.
The use of Mohs micrographic surgery to treat melanoma is growing quickly to fill in the gaps in current melanoma excision recommendations, noted Miller’s group. “The absence of data specific to special-site melanomas in current guidelines creates problems, because anatomical location is a key determinant of complications and complexity of wide local excision.”
Miller and colleagues pointed out that Mohs micrographic surgery is beneficial in verifying clear margins for locally recurrent or special-site melanomas of all subtypes and stages, especially prior to graft or flap reconstruction, and another aspect of best practices is to establish standards for Mohs micrographic surgery to treat melanoma.
Efforts should be made to adopt standards of credentialing and training, like those used for other surgical methods like robotic surgery, they added.
Mohs surgery is being favored over conventional wide local excision due to its ability to obtain function preservation and cosmesis, notes Vinay Gupta, MD, of Willamette Valley Cancer Institute in Corvallis, Oregon, who was not involved in the study. “While there is retrospective data suggesting equivalent outcomes between the two approaches, this does not obviate the need for head-to-head clinical trials.”
“This lack of clarity is acknowledged in the NCCN guidelines, and behooves design of clinical trials to investigate unanswered questions,” Gupta states, the release continues.
The researchers evaluated melanoma patients, of whom 4,061 were treated with Mohs surgery and 75,047 with conventional excision, using claims information from the Optum Clinformatics Data Mart. The cohort had a median age of 63 and was 59.9% male.
Study limitations included uncertain trends outside of the US, and that these data may underrepresent the overall use of margin-controlled surgery to treat melanoma, as the comprehensive margin assessment surgery done with permanent sections is usually billed with excision codes for malignant neoplasms, the authors explained.
Etzkorn and colleagues stated that, although claims-based assessments may be subject to errors related to misclassification, adjusting trends in misclassification of billing practices probably would not account for the trends of excisional surgery for melanoma found in these results.
[Source: MedPage Today]