INTRODUCTION
Based on surveys by Robinson1 in 2001 and Trimble and Cherpeli2 in 2013, Immunohistochemistry (IHC) utilization in Mohs micrographic surgery (MMS) has been rising. Although these surveys provided important subjective data regarding IHC use in MMS, there is a paucity of objective data describing its current utilization patterns. The objective of this study is to characterize IHC utilization during MMS by Mohs surgeons in the treatment of Medicare beneficiaries from 2012-2017.
The 2012-2017 Medicare Provider Utilization and Payment Data, www.certificationmatters.org, www.npidb.org, and www. mohscollege.org/surgeon-finder served as the primary data sources. Mohs surgeons were defined as dermatologists with at least 150 annual claims for Current Procedural Terminology (CPT) code 17311. In order to further specify IHC use in the setting of MMS, we excluded Mohs surgeons who were also board-certified in dermatopathology and/or associated with a dermatopathology taxonomy code. The annual number of IHC services per day was identified by CPT codes 88342 or G0461, taking into consideration scenarios where multiple CPT units for a given excision may have been claimed.
Between 2012-2017, 156 Mohs surgeons (75% fellowship trained (n = 117/156)) reported 29,294 IHC services and 336,118 stage 1 Mohs claims. In this time frame, the percentage of Mohs surgeons utilizing IHC increased by 1.7% (n = 42), the annual number of IHC services increased by 2,600 cases, and the annual number of stage 1 Mohs claims increased by 27,430 claims (Table 1). Using a linear regression analysis, there was a significant increase in the number of Mohs surgeons utilizing IHC (P=.016) and a significant increase in the annual number of stage 1 Mohs claims (P=.010). While there was also a positive trend in the annual number of IHC services, the linear regression analysis approached, but did not meet significance (P=.075). Adjusting for volume of MMS, the median percentage of annual IHC services per stage 1 Mohs claims was similar between 2012-2017, at 5.2% (IQR; Interquartile range, 2.2-6.6%) in 2012 and 4.3% (IQR, 2.9-8.2%) in 2017 (Table 1). Lastly, across the US, there was no significant geospatial clustering of Mohs surgeons who utilized IHC (Moran’s I = .131, P=.101) (Figure 1).
The 2012-2017 Medicare Provider Utilization and Payment Data, www.certificationmatters.org, www.npidb.org, and www. mohscollege.org/surgeon-finder served as the primary data sources. Mohs surgeons were defined as dermatologists with at least 150 annual claims for Current Procedural Terminology (CPT) code 17311. In order to further specify IHC use in the setting of MMS, we excluded Mohs surgeons who were also board-certified in dermatopathology and/or associated with a dermatopathology taxonomy code. The annual number of IHC services per day was identified by CPT codes 88342 or G0461, taking into consideration scenarios where multiple CPT units for a given excision may have been claimed.
Between 2012-2017, 156 Mohs surgeons (75% fellowship trained (n = 117/156)) reported 29,294 IHC services and 336,118 stage 1 Mohs claims. In this time frame, the percentage of Mohs surgeons utilizing IHC increased by 1.7% (n = 42), the annual number of IHC services increased by 2,600 cases, and the annual number of stage 1 Mohs claims increased by 27,430 claims (Table 1). Using a linear regression analysis, there was a significant increase in the number of Mohs surgeons utilizing IHC (P=.016) and a significant increase in the annual number of stage 1 Mohs claims (P=.010). While there was also a positive trend in the annual number of IHC services, the linear regression analysis approached, but did not meet significance (P=.075). Adjusting for volume of MMS, the median percentage of annual IHC services per stage 1 Mohs claims was similar between 2012-2017, at 5.2% (IQR; Interquartile range, 2.2-6.6%) in 2012 and 4.3% (IQR, 2.9-8.2%) in 2017 (Table 1). Lastly, across the US, there was no significant geospatial clustering of Mohs surgeons who utilized IHC (Moran’s I = .131, P=.101) (Figure 1).
