## **Supplementary Online Content**

Cheraghlou S, Doudican NA, Criscito MC, Stevenson ML, Carucci JA. Overall survival after Mohs surgery for early-stage Merkel cell carcinoma. *JAMA Dermatol.* Published online August 23, 2023. doi:10.1001/jamadermatol.2023.2822

**eTable.** Factors Associated With Overall Survival After Excision for Patients With 1+ Risk Factors

**eFigure.** Kaplan-Meier Survival Curves Stratified According to Excision Modality for Cases With 1+ Baseline Risk Factors

This supplementary material has been provided by the authors to give readers additional information about their work.

| Variable                          | Hazard Ratio (p-value) | 95% CI      |
|-----------------------------------|------------------------|-------------|
| Age                               | 1.078 (<0.001)         | 1.066-1.090 |
| Sex                               |                        |             |
| Female                            | 1 [Reference]          | -           |
| Male                              | 1.814 (<0.001)         | 1.470-2.238 |
| Race                              |                        |             |
| White                             | 1 [Reference]          | -           |
| Black                             | 1.002 (0.996)          | 0.371-2.710 |
| Hispanic                          | 0.097 (0.020)          | 0.014-0.692 |
| Asian/Pacific Islander            | 0.600 (0.611)          | 0.084-4.290 |
| Other/Unknown                     | 1.193 (0.646)          | 0.562-2.533 |
| Charlson-Deyo Comorbidity Score   |                        |             |
| 0                                 | 1 [Reference]          | -           |
| 1                                 | 1.494 (0.001)          | 1.183-1.886 |
| 2                                 | 1.472 (0.057)          | 0.988-2.191 |
| 3                                 | 2.190 (<0.001)         | 1.410-3.402 |
| Facility Type                     |                        |             |
| Non-Academic                      | 1 [Reference]          | -           |
| Academic                          | 0.801 (0.045)          | 0.645-0.995 |
| Facility Volume                   |                        |             |
| Low-Intermediate                  | 1 [Reference]          | -           |
| High                              | 0.774 (0.084)          | 0.579-1.035 |
| Tumor Pathologic T Stage          |                        |             |
| T1                                | 1 [Reference]          | -           |
| T2                                | 1.352 (0.005)          | 1.097-1.667 |
| Radiation Therapy to Primary Site |                        |             |
| No                                | 1 [Reference]          | -           |
| Yes                               | 0.836 (0.076)          | 0.686-1.019 |
| Surgical Approach                 |                        |             |
| Wide Local Excision               | 1 [Reference]          | -           |
| Mohs Micrographic Surgery         | 0.530 (0.026)          | 0.303-0.927 |
| Narrow Margin Excision            | 1.074 (0.515)          | 0.866-1.333 |

*Note: Patient insurance status and lymphovascular invasion were excluded from the model after Akaike information criterion minimization*

![](https://assets.reachrx.ai/images/10.1001%E2%98%8Djamadermatol.2023.2822/_page_2_Figure_0.jpeg)

**eFigure.** Kaplan-Meier survival curves stratified according to excision modality for cases with 1+ baseline risk factors.

© 2023 American Medical Association. All rights reserved.

JAMA Dermatology

<jats:sec id="ab-doi230036-4"><jats:title>Importance</jats:title><jats:p>Merkel cell carcinoma (MCC) is a rare cutaneous malignant neoplasm with increasing incidence and high mortality. Although it is accepted that the optimal treatment for localized tumors is surgical, the data surrounding the optimal surgical approach are mixed, and current National Comprehensive Cancer Network guidelines state that Mohs micrographic surgery (MMS) and wide local excision (WLE) can both be used. The current National Comprehensive Cancer Network guidelines do not advocate a preference for MMS or WLE and suggest that they can be used interchangeably.</jats:p></jats:sec><jats:sec id="ab-doi230036-5"><jats:title>Objective</jats:title><jats:p>To evaluate the association of surgical approach with overall survival after excision of localized T1/T2 MCC.</jats:p></jats:sec><jats:sec id="ab-doi230036-6"><jats:title>Design, Setting, and Participants</jats:title><jats:p>This retrospective cohort study used the National Cancer Database to assess adults with T1/T2 MCC who were diagnosed between January 1, 2004, and December 31, 2018, with pathologically confirmed, negative regional lymph nodes and treated with surgery. The National Cancer Database includes all reportable cases from Commission on Cancer–accredited facilities. Data analysis was performed from October 2022 to May 2023.</jats:p></jats:sec><jats:sec id="ab-doi230036-7"><jats:title>Exposure</jats:title><jats:p>Surgical approach.</jats:p></jats:sec><jats:sec id="ab-doi230036-8"><jats:title>Main Outcomes and Measures</jats:title><jats:p>Overall survival.</jats:p></jats:sec><jats:sec id="ab-doi230036-9"><jats:title>Results</jats:title><jats:p>A total of 2313 patients (mean [SD] age, 71 [10.6] years; 1340 [57.9%] male) were included in the study. Excision with MMS had the best unadjusted survival, with mean (SE) survival rates of 87.4% (3.4%) at 3 years, 84.5% (3.9%) at 5 years, and 81.8% (4.6%) at 10 years vs 86.1% (0.9%) at 3 years, 76.9% (1.2%) at 5 years, and 60.9% (2.0%) at 10 years for patients treated with WLE. Patients treated with narrow-margin excision had similar survival as those treated with WLE, with mean (SE) survival rates of 84.8% (1.4%) at 3 years, 78.3% (1.7%) at 5 years, and 60.8% (3.6%) at 10 years. On multivariable survival analysis, excision with MMS was associated with significantly improved survival compared with WLE (hazard ratio, 0.59; 95% CI, 0.36-0.97; <jats:italic>P</jats:italic> = .04). High-volume MCC centers were significantly more likely to use MMS over WLE compared with other centers (odds ratio, 1.99; 95% CI, 1.63-2.44; <jats:italic>P</jats:italic> &amp;amp;lt; .001).</jats:p></jats:sec><jats:sec id="ab-doi230036-10"><jats:title>Conclusions and Relevance</jats:title><jats:p>In this cohort study, the use of MMS (compared with WLE) was associated with significantly improved survival for patients with localized MCC with pathologically confirmed negative lymph nodes treated with surgery. These data suggest that Mohs surgery may provide a more effective treatment for MCC primary tumors than conventional WLE, although the lack of randomization and potential for selection bias in this study highlight the need for future prospective work evaluating this issue.</jats:p></jats:sec>

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Merkel cell carcinoma (MCC) is a rare cutaneous malignant neoplasm with increasing incidence and high mortality. Although it is accepted that the optimal treatment for localized tumors is surgical, the data surrounding the optimal surgical approach are mixed, and current National Comprehensive Cancer Network guidelines state that Mohs micrographic surgery (MMS) and wide local excision (WLE) can both be used. The current National Comprehensive Cancer Network guidelines do not advocate a preference for MMS or WLE and suggest that they can be used interchangeably.
To evaluate the association of surgical approach with overall survival after excision of localized T1/T2 MCC.
This retrospective cohort study used the National Cancer Database to assess adults with T1/T2 MCC who were diagnosed between January 1, 2004, and December 31, 2018, with pathologically confirmed, negative regional lymph nodes and treated with surgery. The National Cancer Database includes all reportable cases from Commission on Cancer-accredited facilities. Data analysis was performed from October 2022 to May 2023.
Surgical approach.
Overall survival.
A total of 2313 patients (mean [SD] age, 71 [10.6] years; 1340 [57.9%] male) were included in the study. Excision with MMS had the best unadjusted survival, with mean (SE) survival rates of 87.4% (3.4%) at 3 years, 84.5% (3.9%) at 5 years, and 81.8% (4.6%) at 10 years vs 86.1% (0.9%) at 3 years, 76.9% (1.2%) at 5 years, and 60.9% (2.0%) at 10 years for patients treated with WLE. Patients treated with narrow-margin excision had similar survival as those treated with WLE, with mean (SE) survival rates of 84.8% (1.4%) at 3 years, 78.3% (1.7%) at 5 years, and 60.8% (3.6%) at 10 years. On multivariable survival analysis, excision with MMS was associated with significantly improved survival compared with WLE (hazard ratio, 0.59; 95% CI, 0.36-0.97; P = .04). High-volume MCC centers were significantly more likely to use MMS over WLE compared with other centers (odds ratio, 1.99; 95% CI, 1.63-2.44; P < .001).
In this cohort study, the use of MMS (compared with WLE) was associated with significantly improved survival for patients with localized MCC with pathologically confirmed negative lymph nodes treated with surgery. These data suggest that Mohs surgery may provide a more effective treatment for MCC primary tumors than conventional WLE, although the lack of randomization and potential for selection bias in this study highlight the need for future prospective work evaluating this issue.

Overall Survival After Mohs Surgery for Early-Stage Merkel Cell Carcinoma.

Overall Survival After Mohs Surgery for Early-Stage Merkel Cell Carcinoma

Overall Survival After Mohs Surgery for Early-Stage Merkel Cell Carcinoma

Clinical Summary

What was studied

Key findings

Study limitations

Clinical implications

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