Minimum Safe Pathologic Excision Margins for Primary Cutaneous Melanomas (1-2 mm in Thickness): Analysis of 2131 Patients Treated at a Single Center

Deep Margins Melanoma: How Deep Is Deep Enough?

BACKGROUND

Wide excision (WE) to muscular fascia for invasive melanoma is common practice but excision to subcutaneous tissue may be adequate. We evaluated practice patterns regarding depth of biopsy and excision as well as risks for recurrence.

METHODS

Retrospective review of patients with pT1-4 melanoma (cN0) treated with WE at a single institution was performed. Patient factors were evaluated. Biopsy and excision techniques were compared to pathology and reviewed for recurrence.

RESULTS

385 patients from 2006 to 2020 were included. Lesions were on the extremity (n = 189), head/neck (n = 48), trunk (n = 148). Biopsy techniques included shave (n = 330), excisional (n = 36), punch (n = 10), incisional (n = 9). Deep biopsy margins were positive for IM/melanoma in situ in 139 patients. WE specimens were taken to muscular fascia (n = 218) or mid/deep fat (n = 144). 51 patients had recurrent disease or a new primary lesion: locoregional (n = 31), distant (3), or new lesions (n = 17).

DISCUSSION

Patient characteristics associated with recurrence include older age and female gender. Tumor characteristics associated with recurrence include lesions located on the trunk, superficial spreading melanoma, ulceration, perineural invasion, and clinical T and P stage. Patients that recurred were more likely to have WE taken to or including muscular fascia. Biopsy type, deep margin on biopsy, and depth of dissection was not associated with recurrence.

Dermatosurgery - from surgical option to integral part of dermatologic therapy

Dermatosurgery was long considered an isolated, and not always important, discipline within dermatology. As a therapeutic option, it was considered either the gold standard of first-line therapy, for example in basal cell carcinoma surgery and treatment of early-stage melanoma, or the last option, for instance in the treatment of warts. The fact that a profound change has taken place and that dermatosurgery is now an integral, equal, sometimes leading and always significant component of dermatology will be demonstrated in this review using three examples from geriatric dermatology, the treatment of hidradenitis suppurativa (acne inversa), and melanoma therapy. This review is supplemented by a section on the most important technique in dermatosurgery: microscopic (micrographic) surgery or Mohs Surgery.

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.

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.

Fractal Dimension Analysis of Melanocytic Nevi and Melanomas in Normal and Polarized Light-A Preliminary Report

Clinical diagnosis of pigmented lesions can be a challenge in everyday practice. Benign and dysplastic nevi and melanomas may have similar clinical presentations, but completely different prognoses. Fractal dimensions of shape and texture can describe the complexity of the pigmented lesion structure. This study aims to apply fractal dimension analysis to differentiate melanomas, dysplastic nevi, and benign nevi in polarized and non-polarized light. A total of 87 Eighty-four patients with 97 lesions were included in this study. All examined lesions were photographed under polarized and non-polarized light, surgically removed, and examined by a histopathologist to establish the correct diagnosis. The obtained images were then processed and analyzed. Area, perimeter, and fractal dimensions of shape and texture were calculated for all the lesions under polarized and non-polarized light. The fractal dimension of shape in polarized light enables differentiating melanomas, dysplastic nevi, and benign nevi. It also makes it possible to distinguish melanomas from benign and dysplastic nevi under non-polarized light. The fractal dimension of texture allows distinguishing melanomas from benign and dysplastic nevi under polarized light. All examined parameters of shape and texture can be used for developing an automatic computer-aided diagnosis system. Polarized light is superior to non-polarized light for imaging texture details.

Appraisal of International Guidelines for Cutaneous Melanoma Management using the AGREE II assessment tool

BACKGROUND

The evidence base behind new melanoma treatments is rapidly accumulating. This is not necessarily reflected in current guidance. A recent UK-based expert consensus statement, published in JPRAS, has called for updates to the widely accepted 2015 National Institute for Health and Care Excellence (NICE) guideline for melanoma (NG14). We aimed to compare the quality of NG14 to all other melanoma guidelines published since.

METHODS

We conducted a systematic search of PubMed, Medline, and online clinical practice guideline databases to identify melanoma guidelines published between 29th July 2015 and 23rd August 2021 providing recommendations for adjuvant treatment, radiotherapy, surgical management, or follow-up care. Three authors independently assessed the quality of identified guidelines using the Appraisal of Guidelines for Research & Evaluation Instrument II (AGREE II) assessment tool, which measures six domains of guideline development. Inter-rater reliability was assessed by Kendall's coefficient of concordance (W).

RESULTS

Twenty-nine guidelines were included and appraised with excellent concordance (Kendall's W for overall guideline score 0.88, p<0.001). Overall, melanoma guidelines scored highly in the domains of 'Scope and purpose' and 'Clarity of presentation', but poorly in the 'Applicability' domain. The NICE guideline on melanoma (NG14) achieved the best overall scores.

CONCLUSION

Melanoma treatment has advanced since NG14 was published, however, the NICE melanoma guideline is of higher quality than more recent alternatives. The planned update of NG14 in 2022 is in demand.

Differences Between Recommended Surgical Margins and Measured Histological Margins in Malignant Melanoma In Situ and Malignant Melanomas

ABSTRACT

Wide local excision (WLE) using appropriate surgical margins is the standard surgical management for malignant melanoma in situ (MMIS) and primary cutaneous malignant melanoma (MM). The actual width of the histologic margins is frequently not assessed, whereas narrow histologic margins are associated with an increase in local melanoma recurrence. Our objective was to analyze the actual measured histological margins of WLE specimens of MMIS and MM cases and compare them with their recommended surgical margins. A retrospective study of formalin fixed specimens of MMIS and invasive MM treated with WLE from a large university-affiliated dermatopathology laboratory was conducted. Among a total of 164 MMIS and 128 MM cases, 14 MMIS (8.5%) and 7 MM (5.9%) had positive lateral margins. The median histologic margin for MMIS, after a 15% tissue shrinkage adjusted, was 2.7 mm [1.3-3.9] for LM type and 3.9 mm [2.3-5.6] for non-LM type, in contrast to the recommended 5-mm margin. In 96 MM of T1 type (≤1.0 mm), the median adjusted histologic margin was 6.7 mm [3.5-9.1] in contrast to the recommended 10-mm margin. These results show that measured and adjusted median histologic margins in WLE specimens in both MMIS and MM of T1 type were significantly narrower than the recommended surgical margins, regardless of anatomic location. These differences are concerning, whether they reflect clinicians' intentional or unintentional deviation from recommended guidelines.

Systematic Review of Technical Variations for Mohs Micrographic Surgery for Melanoma

BACKGROUND

Mohs micrographic surgery (MMS) for cutaneous melanoma is becoming more prevalent, but surgical technique varies.

OBJECTIVE

To define variations in published techniques for MMS for melanoma.

METHODS AND MATERIALS

A systematic review was performed of PubMed, EMBASE, and Scopus databases to identify all articles describing surgical techniques for MMS for melanoma. Technical details were recorded for the preoperative, intraoperative, and postoperative phases of MMS.

RESULTS

Twenty-four articles were included. Mohs surgeons vary in how they assess clinical margins, how wide a margin they excise on the first MMS layer, and how they process tissue to determine tumor stage and margin clearance during MMS for melanoma.

CONCLUSION

Mohs micrographic surgery for melanoma is performed with varied surgical techniques. To establish best practices, additional research is necessary to determine how different techniques affect outcomes.

Fine Needle Aspiration Cytology (FNAC) for Chinese Patients With Acral and Cutaneous Melanoma: Accuracy and Safety Analysis From a Single Institution

This study aimed to investigate the accuracy and safety of fine-needle aspiration cytology (FNAC) in Chinese patients with acral and cutaneous melanoma, and also to evaluate the influencing factors and their impact on prognosis. Data of 128 patients with stage 0-III acral and cutaneous melanoma treated in Fudan University Shanghai Cancer Center from 2009 to 2016 were collected from a prospective database. Further, 128 patients who did not undergo FNAC but had similar parameters were recruited as the matched group. Clinical features, FNAC status, and recurrence or metastasis status of patients were analyzed for overall survival (OS), melanoma-specific survival (MSS), recurrence-free survival (RFS), and metastasis-free survival (MFS). Of the 128 patients with FNAC, 5.5% (7/128) had a negative cytological diagnosis, 12.2% (5/41) had primary lesions, and 2.3% (2/87) had lesions in lymph nodes. Tumor thickness, status of ulceration, and subtype were not associated with accuracy for both primary and lymph node FNAC. With a median follow-up of 40 months in all patients, 55 had melanoma-specific death; the median OS and MSS were 95 months and 104 months, respectively. Patients with FNAC had significantly worse OS. Tumor progression occurred in 130 patients. The survival analysis revealed differences in OS and disease-free survival between the two groups. FNAC impacted patients' RFS and MFS; the difference in survival curves of RFS and MFS was also statistically significant. FNAC on primary or superficial lymphatic lesions was a good diagnostic tool for Chinese patients with acral and cutaneous melanoma, but it adversely impacted prognosis.

Clinical outcomes following surgical treatment of lentigo maligna of the head and neck

INTRODUCTION

Lentigo maligna (LM), a subtype of melanoma in-situ commonly occurring in the head and neck region, often presents a treatment challenge due to anatomical constraints, particularly on the face of mostly elderly patients. This study sought to assess the clinical outcomes of wide local excision of head and neck LM, identify predictors of recurrence and define optimal excision margins.

MATERIALS AND METHODS

Patients with LM treated between January 1997 and December 2012 were identified from the large institutional database of a tertiary center and their data were analyzed.

RESULTS

In 379 patients, 382 lesions were eligible for analysis. Median maximal lesion diameter was 10.5 mm. The mean surgical excision and histopathological clearance margins were 6.2 mm and 4.0 mm, respectively. Median follow-up was 32 months. The LM recurrence rate was 9.9%, and subsequent invasive melanoma developed in 2.3% of cases (mean Breslow thickness 0.7 mm). The recurrence rate was 27.2% if the histological margin was <3.0 mm (median time to recurrence 46.5 months) compared with 2.6% if the margin was ≥3.0 mm. The mean surgical margin required to achieve a histological clearance of ≥3.0 mm was 6.5 mm.

CONCLUSIONS

Our data suggest that to minimize recurrence, a histological margin of ≥3.0 mm is required. To achieve this, a surgical margin of ≥6.5 mm was required. This is greater than the 5 mm margin recommended in some national guidelines. Careful long-term follow-up is required for all patients because of the risk of recurrence.

Immunohistochemical Staining in the Assessment of Melanoma Tumor Thickness

Vertical tumor thickness has great influence in the prognosis and staging of melanoma. The aim of this study was determination of the differences between melanoma tumor thickness in conventional hematoxylin and eosin (H&E) and immunohistochemical techniques. Thirty-six biopsy specimens were included in our study. For each sample, four adjacent tissue sections were stained with H&E, in addition S-100, Melan- A and HMB-45 staining was performed on the next serial sections. The mean thickness of tumor invasion was 2.16, 2.38, 2.22 and 2.29 mm in H&E, S-100, HMB45 and Melan-A sections evaluation, respectively. The mean difference of the Breslow thickness between H&E and S-100 and also, between H&E and Melan-A stained slides were statistically significant (p˂0.05) while no difference was found in the tumor thickness of the H&E and HMB45 staining evaluation (p = 0.278). Greater tumor thickness was observed in 25 lesions (69.4%) with S-100, 20 lesions (55.5%) with Melan-A and 17 (47.2%) lesions in HMB-45 rather than H&E staining. Conclusively, it appears that H&E staining cannot prove the actual size of melanoma invasion in some cases and immunohistochemical examination can be a complementary method in this situations. Of the melanoma associated immunomarkers, the combination of S-100 and Melan-A staining may suffice to measure depth of tumor invasion.

Guidelines of care for the management of primary cutaneous melanoma

The incidence of primary cutaneous melanoma continues to increase each year. Melanoma accounts for the majority of skin cancer-related deaths, but treatment is usually curative following early detection of disease. In this American Academy of Dermatology clinical practice guideline, updated treatment recommendations are provided for patients with primary cutaneous melanoma (American Joint Committee on Cancer stages 0-IIC and pathologic stage III by virtue of a positive sentinel lymph node biopsy). Biopsy techniques for a lesion that is clinically suggestive of melanoma are reviewed, as are recommendations for the histopathologic interpretation of cutaneous melanoma. The use of laboratory, molecular, and imaging tests is examined in the initial work-up of patients with newly diagnosed melanoma and for follow-up of asymptomatic patients. With regard to treatment of primary cutaneous melanoma, recommendations for surgical margins and the concepts of staged excision (including Mohs micrographic surgery) and nonsurgical treatments for melanoma in situ, lentigo maligna type (including topical imiquimod and radiation therapy), are updated. The role of sentinel lymph node biopsy as a staging technique for cutaneous melanoma is described, with recommendations for its use in clinical practice. Finally, current data regarding pregnancy and melanoma, genetic testing for familial melanoma, and management of dermatologic toxicities related to novel targeted agents and immunotherapies for patients with advanced disease are summarized.

Suboptimal Compliance With National Comprehensive Cancer Network Melanoma Guidelines: Who Is at Risk?

BACKGROUND

National Comprehensive Cancer Network (NCCN) melanoma treatment guidelines are based on best available literature. We evaluated NCCN excision margin and sentinel lymph node biopsy (SLNB) guideline adherence to identify patient populations at risk for suboptimal care.

METHODS

Retrospective review of prospectively maintained database of all patients who underwent operation for invasive melanoma from January 2005 to 2015.

RESULTS

In total, 865 patients underwent operation for 522 thin (60.3%), 268 intermediate-thickness (31.0%), and 75 thick (8.7%) melanomas. Tumor location was 349 extremity (40.4%), 348 trunk (40.2%), and 168 head/neck (19.4%). SLNB was performed in 422 patients (48.8%); 75 (17.8%) were positive, and 67 (15.9%) underwent therapeutic lymphadenectomy. A total of 154 lesions (17.8%) were ulcerated; 444 had mitotic rate ≥1 (51.3%). In total, 788 patients (91.1%) fulfilled both NCCN guidelines. Recommended surgical margins were achieved in 837 patients (96.8%) and SLNB was performed as appropriate in 806 patients (93.2%); 10 patients (1.2%) were deficient for both. Deficient margins and lack of SLNB were associated with increased invasion depth and head/neck location; deficient SLNB was associated with age 80 and above (P<0.0001). Overall recurrence was 7.1%: 15 local (1.7%), 23 regional (2.7%), and 23 distant (2.7%) failures. Local recurrence was associated with head/neck location (P=0.031); all recurrence types were associated with increased tumor thickness.

CONCLUSIONS

NCCN excision and SLNB guidelines were almost always met. Patients at risk for not meeting criteria included the elderly and those with head/neck tumors. Failure to meet NCCN criteria was not associated with increased disease recurrence. Surgeons must carefully balance the risks of not pursuing NCCN guidelines with treatment goals.

Updated evidence-based clinical practice guidelines for the diagnosis and management of melanoma: definitive excision margins for primary cutaneous melanoma

INTRODUCTION

Definitive management of primary cutaneous melanoma consists of surgical excision of the melanoma with the aim of curing the patient. The melanoma is widely excised together with a safety margin of surrounding skin and subcutaneous tissue, after the diagnosis and Breslow thickness have been established by histological assessment of the initial excision biopsy specimen. Sentinel lymph node biopsy should be discussed for melanomas ≥ 1 mm thickness (≥ 0.8 mm if other high risk features) in which case lymphoscintigraphy must be performed before wider excision of the primary melanoma site. The 2008 evidence-based clinical practice guidelines for the management of melanoma (http://www.cancer.org.au/content/pdf/HealthProfessionals/ClinicalGuidelines/ClinicalPracticeGuidelines-ManagementofMelanoma.pdf) are currently being revised and updated in a staged process by a multidisciplinary working party established by Cancer Council Australia. The guidelines for definitive excision margins for primary melanomas have been revised as part of this process. Main recommendations: The recommendations for definitive wide local excision of primary cutaneous melanoma are: melanoma in situ: 5-10 mm margins invasive melanoma (pT1) ≤ 1.0 mm thick: 1 cm margins invasive melanoma (pT2) 1.01-2.00 mm thick: 1-2 cm margins invasive melanoma (pT3) 2.01-4.00 mm thick: 1-2 cm margins invasive melanoma (pT4) > 4.0 mm thick: 2 cm margins Changes in management as a result of the guideline: Based on currently available evidence, excision margins for invasive melanoma have been left unchanged compared with the 2008 guidelines. However, melanoma in situ should be excised with 5-10 mm margins, with the aim of achieving complete histological clearance. Minimum clearances from all margins should be assessed and stated. Consideration should be given to further excision if necessary; positive or close histological margins are unacceptable.

Neurotropic melanoma: an analysis of the clinicopathological features, management strategies and survival outcomes for 671 patients treated at a tertiary referral center

Neurotropic cutaneous melanoma is a rare melanoma subtype that invades nerves and is often associated with desmoplastic melanoma. Limited data suggest that it has a greater propensity to recur locally, but it is unknown whether its behavior differs from that of other melanoma subtypes, including desmoplastic melanoma. We investigated clinicopathological predictors of outcome in a cohort of 671 patients with neurotropic melanoma to develop evidence-based management recommendations. Patients with primary neurotropic melanoma diagnosed from 1985 to 2013 were identified from the Melanoma Institute Australia database, along with a control cohort of 718 non-neurotropic melanoma patients. Features predictive of sentinel lymph node status, recurrence, melanoma-specific survival and response to adjuvant radiotherapy were sought. Neither local recurrence (hazard ratio: 1.28 (0.73-2.25) P=0.39) nor melanoma-specific survival (hazard ratio: 0.79 (0.55-1.15) P=0.22) were significantly affected by the presence of neurotropism on multivariate analysis. However, there was a markedly reduced likelihood of sentinel node positivity (hazard ratio: 0.61 (0.41-0.89) P=0.01) in neurotropic melanoma patients. Surgical margins ≥8mm halved the recurrence risk compared with <2 mm margins (hazard ratio: 0.46 (0.31-0.68) P<0.001). Additionally, in neurotropic melanoma patients with <8 mm margins, adjuvant radiotherapy halved the recurrence risk (hazard ratio: 0.48 (0.27-0.87) P=0.02). This, the largest study of neurotropic melanoma reported to date, has demonstrated that the presence of neurotropism does not alter the risk of melanoma recurrence or survival but does reduce the likelihood of sentinel node positivity. For successful treatment of neurotropic melanoma, adequate excision margins are of paramount importance. However, when adequate margins cannot be achieved, adjuvant radiotherapy reduces the risk of recurrence.

Is a Wider Margin (2 cm vs. 1 cm) for a 1.01-2.0 mm Melanoma Necessary?

BACKGROUND

The current NCCN recommendation for resection margins in patients with melanomas between 1.01 and 2 mm deep is a 1-2 cm radial margin. We sought to determine whether margin width had an impact on local recurrence (LR), disease-specific survival (DSS), and type of wound closure.

METHODS

Melanomas measuring 1.01-2.0 mm were evaluated at a single institution between 2008 and 2013. All patients had a 1 or 2 cm margin.

RESULTS

We identified 965 patients who had a 1 cm (n = 302, 31.3 %) or 2 cm margin (n = 663, 68.7 %). Median age was 64 years, and 592 (61.3 %) were male; 32.5 and 48.7 % of head and neck and extremity patients had a 1 cm margin versus 18.9 % of trunk patients (p < 0.001). LR was 2.0 and  2.1 % for a 1 and 2 cm margin, respectively (p = not significant). Five-year DSS was 87 % for a 1 cm margin and 85 % for a 2 cm margin (p = not significant). Breslow thickness, melanoma on the head and neck, lymphovascular invasion, and sentinel lymph node biopsy (SLNB) status significantly predicted LR on univariate analysis; however, only location and SLNB status were associated with LR on multivariate analysis. Margin width was not significant for LR or DSS. Wider margins were associated with more frequent graft or flap use only on the head and neck (p = 0.025).

CONCLUSIONS

Our data show that selectively using a narrower margin of 1 cm did not increase the risk of LR or decrease DSS. Avoiding a 2 cm margin may decrease the need for graft/flap use on the head and neck.

Surgical excision margins in primary cutaneous melanoma: A meta-analysis and Bayesian probability evaluation

BACKGROUND

Surgery is the only curative treatment for primary cutaneous melanoma, therefore it is important to determine excision margins that minimise risk of local recurrence, distant recurrence and death.

METHODS

MEDLINE, EMBASE and Cochrane CENTRAL were searched from 2009 to 2015. Inclusion criteria were: population/setting - patients with primary melanoma; comparison - narrow versus wide margins; outcomes - overall survival, melanoma-specific survival, recurrence-free survival, and loco-regional recurrence; design - randomized controlled trials (RCTs). Results were pooled using meta-analysis and data explored using likelihood Bayesian probability plots.

RESULTS

Six RCTs with 4233 patients were included. Narrow margins were defined as 1 or 2 cm of clinically normal skin around the melanoma; wide margins as 3, 4 or 5 cm. Hazard ratios (HR) were as follows (HR>1 indicates wide margin better): overall survival 1.09 (95% CI 0.98-1.22; p=0.1); melanoma-specific survival 1.17 (CI 1.03-1.34; p=0.02); recurrence-free survival 1.08 (CI 0.97-1.20; p=0.2); loco-regional recurrence 1.10 (CI 0.96-1.26; p=0.2), with no evidence of heterogeneity between trials for any end point or within subgroup analyses. There was an 94% probability that overall survival was worse with a narrow margin and a 43% probability that it was more than 10% worse in proportional terms (i.e. HR>1.1). Probabilities that narrow margins were worse were 99%, 92% and 92% for melanoma-specific survival, recurrence-free survival and loco-regional recurrence respectively.

CONCLUSIONS

Contrary to recommendations in several national guidelines that narrow margins are safe, this systematic review and meta-analysis provides evidence that a narrow margin may lead to a worse outcome than a wide margin.