Systematic Review of Technical Variations for Mohs Micrographic Surgery for Melanoma

Mohs micrographic surgery in the surgical treatment paradigm of melanoma in situ and invasive melanoma: A clinical review of treatment efficacy and ongoing controversies

Mohs Micrographic Surgery (MMS) for treatment of melanoma offers several advantages over wide local excision (WLE), including complete histologic margin evaluation, same-day resection and closure, and sparing of healthy tissue in critical anatomic sites. Recently, a large volume of clinical data demonstrating efficacy in MMS treatment of melanoma was published, leading to emerging patient safety considerations of incurred treatment costs, risk of tumor upstaging, and failure of care coordination for sentinel lymph node biopsy (SLNB). MMS offers a safe, effective, and value-based treatment for both melanoma in situ (MIS) and invasive melanoma (IM), particularly with immunohistochemistry use on frozen sections. Compared to wide local excision, MMS treatment demonstrates similar or improved outcomes for local tumor recurrence, melanoma-specific survival, and overall survival at long-term follow-up. Tumor upstaging risk is low, and if present, alteration to clinical management is minimal. Discussion of SLNB for eligible head and neck IM cases should be done prior to MMS. Though challenging, successful multidisciplinary coordination of SLNB with MMS has been demonstrated. Herein, we provide a detailed clinical review of evidence for MMS treatment of cutaneous melanoma and offer recommendations to address current controversies surrounding the evolving paradigm of surgical management for both MIS and invasive melanoma (IM).

Mohs for Melanoma: A Review of MART-1 Frozen Section Interpretation

BACKGROUND

Mohs surgery for melanoma has been performed for many decades, but advances in the use of immunohistochemistry with frozen sections during Mohs surgery have allowed for more accurate, reliable, and efficient margin assessment with improved local control of the disease.

OBJECTIVE

To describe the use of MART-1 in treating melanoma with Mohs surgery and serve as a primer for the Mohs surgeon adding melanoma cases to their repertoire.

MATERIALS AND METHODS

Review of the literature and discussion of experience with Mohs for melanoma.

RESULTS

Practical approach and pitfalls when assessing margins using MART-1 immunohistochemistry during Mohs surgery for the treatment of melanoma.

CONCLUSION

Mohs for melanoma is an expanding field-education of Mohs surgeons and increasing the practice of this technique has the potential to improve patient outcomes.

Intraoperative Immunohistochemistry During Mohs Micrographic Surgery and Staged Excision Decreases Local Recurrence Rates for Invasive Cutaneous Melanoma: A Systematic Review and Meta-Analysis

BACKGROUND

Mohs micrographic surgery (MMS) is increasingly used to treat cutaneous melanoma. However, it is unclear whether intraoperative immunohistochemistry (IHC) improves surgical outcomes.

OBJECTIVE

To determine whether intraoperative IHC during MMS and staged excision is associated with a decreased risk of poor surgical outcomes.

MATERIALS AND METHODS

Search of 6 databases identified comparative and noncomparative studies that reported local recurrence after MMS or staged excision with or without IHC for melanoma. Random-effects meta-analysis was used to estimate pooled local recurrence rates, nodal recurrence, distant recurrence, and disease-specific mortality.

RESULTS

Overall, 57 studies representing 12,043 patients with cutaneous melanoma and 12,590 tumors met inclusion criteria. Combined MMS and staged excision with IHC was associated with decreased local recurrence in patients with invasive melanoma (0.3%, 95% CI: 0-0.6) versus hematoxylin and eosin alone (1.8%, 95% CI: 0.8%-2.8%) [ p < .001]. Secondary outcomes including nodal recurrence, distant recurrence, and disease-specific mortality were not significantly different between these 2 groups. Study heterogeneity was moderately-high.

CONCLUSION

Local recurrence of invasive melanoma is significantly lower after MMS and staged excision with IHC as opposed to without IHC. These findings suggest that the use of intraoperative IHC during MMS or staged excision should strongly be considered, particularly for invasive melanoma.Trial Registration PROSPERO Identifier: CRD42023435630.

Mohs micrographic surgery for the treatment of invasive melanoma: A systematic review with meta-analyses

BACKGROUND

The use of Mohs micrographic surgery (MMS) in melanoma treatment has divided opinion and evidence-based guidelines are lacking.

OBJECTIVES

This systematic review aimed to analyse clinical outcomes for patients with invasive melanomas treated with Mohs rather than wide local excision (WLE).

METHODS

Embase, MEDLINE and Cochrane databases (to 30 August 2023) were searched for studies using Mohs to treat invasive melanoma. Outcomes of interest were local recurrence and death from melanoma.

RESULTS

Thirty-five articles involving 41,499 patients with invasive melanoma treated with Mohs were identified. Sixteen studies compared Mohs with WLE and 19 were Mohs-only, non-comparative studies. Patients treated with Mohs differed significantly from those undergoing WLE, in particular Mohs patients were older and had thinner melanomas. Two comparative studies using the same data source reported adjusted hazard ratios for melanoma-specific death and both showed no significant difference between Mohs and WLE-treated patients; 0.87 (95% CI 0.55-1.35) and 1.20 (95% CI 0.71-20.36). There was also no statistically significant difference in local recurrence risk; the unadjusted risk ratio for patients treated with Mohs was 0.46 (95% CI 0.14-1.51 p = 0.20) with moderate heterogeneity (I2 = 62%). No studies reported multivariable analyses for risk of local recurrence. Many studies generated from relatively few and often overlapping data sets have reported the use of Mohs to treat patients with invasive melanoma. Fewer studies were comparative between Mohs and WLE and these reported substantially different baseline risks of recurrence and death from melanoma between the groups. Mohs has generally been used for thinner melanomas in older patients; therefore, comparisons based on univariable analyses are likely to have been misleading.

CONCLUSIONS

On the basis of currently available data, it is not possible to reliably assess whether outcomes differ if invasive melanomas with comparable features are treated with Mohs or WLE, and randomized trial evidence will be required for reliable conclusions to be reached.

Lentigo Maligna Treatment-An Update

Lentigo maligna (LM) is a melanoma in situ that is prevalent in chronically sun-damaged skin. Characterized by a slow growth pattern and high mutation rates due to chronic UV exposure, LM poses diagnostic and therapeutic challenges, particularly given its tendency to mimic other skin lesions and its occurrence in cosmetically sensitive areas. Its diagnosis is based on an integrated approach using dermoscopy and reflectance confocal microscopy (RCM). Despite its slow progression, LM can evolve into lentigo maligna melanoma (LMM), making its treatment necessary. Treatment modalities encompass both surgical and non-surgical methods. Surgical treatments like Wide Local Excision (WLE) and Mohs Micrographic Surgery (MMS) aim for clear histological margins. WLE, a standard melanoma surgery, faces challenges from LM's subclinical extensions, which increase the recurrence risk. MMS, effective for large or poorly defined lesions, is defined by precise margin control while considering cosmetic outcomes. Non-surgical options, including radiotherapy and imiquimod, are alternatives for non-surgical candidates. Radiotherapy has been effective since the 1950s, offering good control and cosmetic results, especially for older patients. Imiquimod, an immunomodulator, shows promise in treating LM, though its application remains off-label. The increasing incidence of LM/LMM necessitates a balance in treatment choices to minimize recurrence and maintain cosmetic integrity. A multidisciplinary approach, integrating clinical examination with dermoscopy and RCM and histological assessment, is essential for accurate diagnosis and effective LM management.

Disease-specific survival of malignant melanoma after Mohs micrographic surgery is not impacted by initial margins: A systematic review and meta-analysis

Background

During Mohs surgery for melanoma, evidence has demonstrated that many surgeons opt for smaller initial margins than traditionally recommended (0.5 cm for in situ and 1 cm for invasive). Literature regarding surgical outcomes based on initial margin is sparse.

Objective

To determine differences in disease-specific survival of melanoma after Mohs micrographic surgery for varied initial surgical margins.

Methods

A literature search was conducted on February 14, 2022, from MEDLINE via PubMed (1946-present), Embase (1974-present), Central (1991-present), and Scopus (1960-present). The primary outcome was disease-specific mortality.

Results

Nineteen studies were included for final analysis. The overall disease-specific mortality rate of melanoma in all included studies was 0.5% (CI, 0.1-0.8; P, .010). Disease-specific mortality for 1 to 5, 5, and 6 to 10 mm categories were 0.4% (CI, 0.0-0.9; P, .074), 0.7% (CI, 0.2-1.3; P, .2-1.3), and 0.4% (CI, -0.9 to 1.8; P, .524), respectively. None of the variances across initial margin categories were statistically significant.

Limitations

Early-stage melanomas have low overall mortality rates. In our associated article, initial margins of 5 to 10 mm were shown to have the lowest rates of local recurrence.

Conclusions

In this systematic review and meta-analysis, melanoma-specific mortality was not significantly impacted by the initial surgical margin taken during Mohs micrographic surgery.

Understanding melanoma in situ: Lentigo maligna surgical treatment terminology and guideline adherence, a targeted review

BACKGROUND

Malignant melanoma in-situ, lentigo maligna (MMIS-LM) can be successfully treated with several different surgical techniques; however, the literature is inconsistent in defining them.

OBJECTIVE

To comprehensively define and describe the national guideline recommended surgical techniques used to treat MMIS-LM to help clarify and standardize this terminology to ensure compliance with the guidelines.

METHODS

A targeted literature review was performed from 1990 to 2022 focusing on articles that discussed the national guideline recommended surgical techniques of wide local excision, Mohs micrographic surgery (MMS), modified Mohs surgery, and staged excision/Slow-Mohs for MMIS-LM, as well as the related methods of tissue processing. National Comprehensive Cancer Network and American Academy of Dermatology guidelines were reviewed to identify how the techniques need to be employed to be compliant with guideline recommendations.

RESULTS

We describe the various surgical and tissue processing techniques and discuss advantages and disadvantages of each.

LIMITATIONS

This paper was styled as a narrative review defining and clarifying terminology and technique and does not investigate these topics more broadly.

CONCLUSION

Understanding the methodology and terminology for these surgical procedures and tissue processing methods is critical so that both general dermatologists and surgeons can employ these techniques effectively for optimal patient care.

Assessing Rates of Positive Surgical Margins After Standard Excision of Vulvar Melanomas

BACKGROUND

Vulvar melanoma is a rare malignancy with frequent recurrence and poor prognosis. National guidelines recommend wide local excision of these tumors with allowances for narrower margins for anatomic and functional limitations, which are common on specialty sites. There is presently a lack of data of margin positivity after standard excision of vulvar melanomas.

OBJECTIVE

We aim to evaluate the rate of positive margins after standard excision of vulvar melanomas.

MATERIALS AND METHODS

Retrospective cohort study of surgically excised vulvar melanomas from the NCDB diagnosed from 2004 to 2019.

RESULTS

We identified a total of 2,226 cases. Across surgical approaches and tumor stages, 17.2% (Standard Error [SE]: 0.8%) of cases had positive surgical margins. Among tumor stages, T4 tumors were most commonly excised with positive margins (22.9%, SE: 1.5%). On multivariable survival analysis, excision with positive margins was associated with significantly poorer survival (Hazard Ratio 1.299, p = .015).

CONCLUSION

We find that positive margin rates after standard excision of vulvar malignancies are higher than for other specialty site melanomas. Our data suggest that use of surgical approaches with complete margin assessment may improve local control and functional outcomes for patients with vulvar melanoma as they have for patients with other specialty site melanomas.

Local Recurrence Rates of Malignant Melanoma After Mohs Micrographic Surgery Are Lowest With 5- to 10-mm Initial Margins: A Systematic Review and Meta-Analysis

BACKGROUND

Current consensus guidelines have discouraged the use of sub-0.5-cm (in situ) and sub-1-cm (invasive) margins when performing Mohs micrographic surgery (Mohs) for melanoma, with minimal evidence to guide this recommendation.

OBJECTIVE

To compare melanoma local recurrence rates after Mohs based on initial margin size.

MATERIALS AND METHODS

A systematic review and meta-analysis was conducted with search terms including Mohs micrographic surgery, surgical margin, recurrent disease, and melanoma.

RESULTS

Forty-three studies were included. The 5- to 10-mm margin category had a statistically significant lower local recurrence compared with 1- to 5-mm and 5-mm categories. Recurrence for 1- to 5-mm, 5-mm, 5- to 10-mm, and 10-mm categories were 2.3% (CI 0.8-3.5, p < .001), 1.4% (CI 0.6-2.2, p < .001), 0.3% (CI 0.2-0.5, p < .001), and 6.1% (CI -6.7 - 18.8, p = .349), respectively. Number of stages for 1 to 5, 5, 5 to 10, and 10-mm categories were 1.8, 1.8, 1.6, and 1.6, respectively. There was no statistically significant difference between the groups (p = .694).

CONCLUSION

Five- to 10-mm margins were associated with the lowest local recurrence rates. A 5- to 10-mm initial margin should be considered where other factors (tumor characteristics, anatomical or functional considerations) allow.

Surgical Management of Melanoma: Advances and Updates

PURPOSE OF REVIEW

To review and update surgeons about the evolving complexities in the surgical management of melanoma including lymph node staging and treatment.

RECENT FINDINGS

Primary resection with adequate margins continues to be the standard of care for localized cutaneous melanoma. Sentinel lymph node biopsy is confirmed to be a powerful tool due to its prognostic value and informative guidance for adjuvant treatments and surveillance. Due to the lack of benefit in melanoma-specific survival and distant metastasis-free survival, completion lymph node dissection is not performed routinely after a positive sentinel lymph node biopsy. Neoadjuvant systemic treatment approaches for advanced loco-regional disease show promise in phase I and II clinical trial data, and phase III studies. The surgical management of cutaneous melanoma continues to evolve with further de-escalation of the extent of excision of primary melanomas and the management of lymph node disease.

European consensus-based interdisciplinary guideline for melanoma. Part 2: Treatment - Update 2022

A unique collaboration of multidisciplinary experts from the European Dermatology Forum (EDF), the European Association of Dermato-Oncology (EADO), and the European Organization of Research and Treatment of Cancer (EORTC) was formed to make recommendations on cutaneous melanoma diagnosis and treatment, based on the systematic literature reviews and the experts' experience. Cutaneous melanomas are excised with one to 2-cm safety margins. Sentinel lymph node dissection shall be performed as a staging procedure in patients with tumor thickness ≥1.0 mm or ≥0.8 mm with additional histological risk factors, although there is as yet no clear survival benefit for this approach. Therapeutic decisions in stage III/IV patients should be primarily made by an interdisciplinary oncology team ("tumor board"). Adjuvant therapies can be proposed in stage III/completely resected stage IV patients and are primarily anti-PD-1, independent of mutational status, or alternatively dabrafenib plus trametinib for BRAF mutant patients. In distant metastases (stage IV), either resected or not, systemic treatment is always indicated. For first-line treatment particularly in BRAF wild-type patients, immunotherapy with PD-1 antibodies alone or in combination with CTLA-4 antibodies shall be considered. In stage IV melanoma with a BRAF-V600  E/K mutation, first-line therapy with BRAF/MEK inhibitors can be offered as an alternative to immunotherapy. In patients with primary resistance to immunotherapy and harboring a BRAF-V600  E/K mutation, this therapy shall be offered as second-line therapy. Systemic therapy in stage III/IV melanoma is a rapidly changing landscape, and it is likely that these recommendations may change in the near future.