Update and Review on the Surgical Management of Primary Cutaneous Melanoma

The Challenging Melanoma Landscape: From Early Drug Discovery to Clinical Approval

Melanoma is recognized as the most dangerous type of skin cancer, with high mortality and resistance to currently used treatments. To overcome the limitations of the available therapeutic options, the discovery and development of new, more effective, and safer therapies is required. In this review, the different research steps involved in the process of antimelanoma drug evaluation and selection are explored, including information regarding in silico, in vitro, and in vivo experiments, as well as clinical trial phases. Details are given about the most used cell lines and assays to perform both two- and three-dimensional in vitro screening of drug candidates towards melanoma. For in vivo studies, murine models are, undoubtedly, the most widely used for assessing the therapeutic potential of new compounds and to study the underlying mechanisms of action. Here, the main melanoma murine models are described as well as other animal species. A section is dedicated to ongoing clinical studies, demonstrating the wide interest and successful efforts devoted to melanoma therapy, in particular at advanced stages of the disease, and a final section includes some considerations regarding approval for marketing by regulatory agencies. Overall, considerable commitment is being directed to the continuous development of optimized experimental models, important for the understanding of melanoma biology and for the evaluation and validation of novel therapeutic strategies.

Recognition, Staging, and Management of Melanoma

Melanoma accounts for approximately 1% of all skin cancers but contributes to almost all skin cancer deaths. The developing picture suggests that melanoma phenotypes are driven by epigenetic mechanisms that reflect a complex interplay between genotype and environment. Furthermore, the growing consensus is that current classification standards, notwithstanding pertinent clinical history and appropriate biopsy, fall short of capturing the vast complexity of the disease. This article summarizes the current understanding of the clinical picture of melanoma, with a focus on the tremendous breakthroughs in molecular classification and therapeutics.

Acral malignant melanoma; emphasis on the primary metastasis and the usefulness of preoperative ultrasound for sentinel lymph node metastasis

This study aimed to evaluate the most common primary metastatic location of acral malignant melanoma and to evaluate the usefulness of preoperative ultrasound for sentinel lymph node metastasis. Ninety-eight Korean acral malignant melanoma patients were enrolled. Acral malignant melanoma was present in 76 lower limbs and in 22 upper limbs. The most common origin location was the sole (33.7%). The most common location of primary metastasis was loco-regional recurrence (22/34, 64.7%). The sensitivity, specificity, positive predictive value, and negative predictive value of preoperative sentinel lymph node ultrasound was 29.1%, 94.6%, 63.6%, and 80.5%, respectively. We postulate the unusefulness of preoperative ultrasound for sentinel lymph node metastasis in acral malignant melanoma.

Association between tumor-infiltrating lymphocytes and sentinel lymph node positivity in thin melanoma

BACKGROUND

Sentinel lymph node biopsy in thin invasive primary cutaneous melanoma (up to 1mm thick) is a controversial subject. The presence of tumor-infiltrating lymphocytes could be a factor to be considered in the decision to perform this procedure.

OBJECTIVE

To evaluate the association between the presence of tumor-infiltrating lymphocytes and lymph node metastases caused by thin primary cutaneous melanoma.

METHODS

Cross-sectional study with 137 records of thin invasive primary cutaneous melanoma submitted to sentinel lymph node biopsy from 2003 to 2015. The clinical variables considered were age, sex and topography of the lesion. The histopathological variables assessed were: tumor-infiltrating lymphocytes, melanoma subtype, Breslow thickness, Clark levels, number of mitoses per mm2, ulceration, regression and satellitosis. Univariate analyzes and logistic regression tests were performed as well the odds ratio and statistical relevance was considered when p <0.05.

RESULTS

Among the 137 cases of thin primary cutaneous melanoma submitted to sentinel lymph node biopsy, 10 (7.3%) had metastatic involvement. Ulceration on histopathology was positively associated with the presence of metastatic lymph node, with odds ratio =12.8 (2.77-59.4 95% CI, p=0.001). The presence of moderate/marked tumor-infiltrating lymphocytes was shown to be a protective factor for the presence of metastatic lymph node, with OR=0.20 (0.05-0.72 95% CI, p=0.014). The other variables - clinical and histopathological - were not associated with the outcome.

STUDY LIMITATIONS

The relatively small number of positive sentinel lymph node biopsy may explain such an expressive association of ulceration with metastatization.

CONCLUSIONS

In patients with thin invasive primary cutaneous melanoma, few or absent tumor-infiltrating lymphocytes, as well as ulceration, represent independent risk factors for lymph node metastasis.

Comparative Analysis of the "Scholastic" Recommendations of the AJCC From 2011 for the Surgical Treatment of Cutaneous Melanoma with the Newly Suggested Guidelines for OSMS From the Bulgarian Society For Dermatologic Surgery!

BACKGROUND:

The American Joint Committee on Cancer (AJCC) offers a two-stage, often insufficient or so-called variable model of cutaneous melanoma treatment. This model starts with primary excision and an initial operational safety margin of 0.5 cm in all directions, followed by a re-excision with an additional field of operational security, determined by histologically established tumor thickness (with or without removal of SLN). We present a brand new method of melanoma surgery, the so-called One Step melanoma surgery (OSMS), in which cutaneous melanomas (regardless of their thickness) could be removed by single surgical intervention.

CASE REPORT:

We describe a case of a patient with cutaneous melanoma, with postoperatively established Breslow’s tumor thickness of 6 mm, operated on the AJCC model within two surgical sessions. The usual primary excision was performed with a surgical safety margin of 0.5 cm in all directions, followed by a secondary excision with an additional surgical security field of 1.2 cm in all directions (due to the patient’s wish for the optimal cosmetic result, agreed and approved by the dermatosurgeon performing the manipulation).

CONCLUSION:

The two-stage method for the treatment of melanomas is often insufficient due to: 1) the inability (in this case) secondary excision in the face area to be conducted with an additional recommended operational security field of 1.5 cm in all directions; and 2) the patient’s wish for a better cosmetic result, which should be achieved with less surgical security field, resulting in a compromise solution for re-excision with an additional surgical field of 1.2 cm in all directions.

Multiple Primary Cutaneous Melanomas in a Bulgarian Patient: The Possible Role of One Step Melanoma Surgery (OSMS) As the Most Adequate Treatment Approach!

BACKGROUND:

Simultaneous occurrence of multiple primary melanomas is a rare, however possible phenomenon, and it is believed that older, male, white, Atypical Mole Syndrome carriers (sporadic and familial) are part of the possible risk factors for its occurrence. In these patients, it is possible to observe involutional changes or (partial/complete) regression of melanocytic lesions, which are likely to be caused by the generation of a spontaneous immune reaction against specific tumour antigens.

CASE REPORT:

A 58-year-old male patient is presented with two melanocytic lesions located in the right clavicle (subclavicular area) and left the scapular area that meets clinically and dermatoscopically the requirements for malignant melanoma. The lesions were removed by a radical excision with 0.5 cm surgical safety margin in all directions. During the subsequent histological verification it was established it was melanoma with a tumour thickness of 1 mm that in one case, and the other 2 mm. A week later, according to the recommendations of the current guidelines, a re-excision was performed with a surgical safety margin of 1.5 cm in all directions. Considering the complications that are possible during the parallel removal of a draining lymph node recommended for these tumour thicknesses, the patient definitively refused its detection and removal.

CONCLUSION:

A rare case of a Bulgarian patient with multiple primary, however partially involutional melanomas existing for over 20 years, is described. The individual recommendations of dermato-oncologists for the patient (according to AJCC) were not in favour of radicality but of a more sparing, individualised approach, appropriate for that patient. Unfortunately, the approach we used, in this case, was inconsistent with the AJCC or OSMS guidelines. The reason for individualising the approach in the case we have described is due to the variability of the recommendations for surgical treatment of melanomas laid down in the AJCC.

One Step Melanoma Surgery (OSMS) Without Using Ultrasonography for Preoperative Tumour Thickness Measurement? - "A Question that Sometimes Drives Me Hazy: Am I or Are the Others Crazy!"

BACKGROUND:

One step melanoma surgery is a new surgical approach by which specific groups of patients with cutaneous melanoma may be operated only by or within a single surgical session. Until now, the Bulgarian Society for Dermatologic Surgery (BULSDS) has presented models of clinical behaviour, in which preoperative measurement of tumour thickness in combination with echographic measurement of the locoregional lymph nodes could lead to the conduct of the so-called one-step melanoma surgery. Although this one step surgery currently does not fit in the recommended guidelines, it ensures compliance of the recommended boundaries of operational security while saving patients a repeated excision and relieves the healthcare institutions or the patients themselves financially.

CASE REPORT:

We at this moment present another case from the Bulgarian Society for Dermatologic Surgery (BULSDS) of one step melanoma surgery with a perfect end result, where the tumour thickness was not preoperatively determined by high-frequency echography. Preoperative assessment of tumour thickness was performed based on the clinical picture and dermatoscopy. The histologically established tumour thickness was identical to the preoperative assessment, i.e. <1 mm. Removal of the melanocytic lesion was performed with operational security field of 1cm in all directions, where, as a rule, no further removal of the draining lymph nodes is required.

CONCLUSION:

One step melanoma surgery has two significant advantages: 1) it saves a re-excision in certain groups of patients, which in turn is 2) significantly more favourable from a financial point of view. Its applicability in the appropriate groups of patients and the postoperative (although in a limited number of patients) results achieved indicate the need to optimise the current algorithms and direct them individually to each patient. Guidelines may not and should not be unified or set strict limits given the fact that they show a significant level of variability themselves regarding some key moments in the initial surgical treatment of melanoma. More than 10% of the primary melanoma cases refer to thin melanomas, and dermatoscopy and clinics are a sufficient method of optimising the planned surgical excision.

Single-stage excision and sentinel lymph node biopsy in cutaneous melanoma in selected patients: a retrospective case-control study

Sometimes, diagnostic excision of a primary melanoma would already necessitate skin grafting or transposition skin flaps, especially in areas with an esthetic or functional importance. The utility of sentinel lymph node biopsy (SLNB) after skin reconstruction is controversial. We carried out a single-institution retrospective case-control study. In patients with a wide primary lesion at high clinical-dermatoscopic suspicion for invasive melanoma in anatomical region in which a reconstruction with a skin graft or a flap is required, we proposed the performance of a confocal microscopy examination and an incisional biopsy of the primary lesion. If these diagnostic methodologies confirmed the suspicion of melanoma, lymphatic mapping was performed before the wide excision (WE) of the primary lesion, and WE and SLNB were performed during the same operative procedure. The database evaluation showed 496 patients who had undergone a previous complete local excision and a subsequent SLNB (two-stage group), whereas 61 patients underwent WE and SLNB during the same surgical time (one-stage group). Histological results of the excisional biopsy confirmed the diagnosis of melanoma in all patients of the one-stage group. The false-negative rate was lower in the one-stage group (5.5%) than in the two-stage group (16.7%). Patients of the two groups showed a similar recurrence-free and overall survival period even when corrected for clinic-demographical variables. The concomitant execution of SLNB and WE after confocal microscopy examination and incisional biopsy appears to be a safe and accurate procedure in patients with a wide primary melanoma that requires a skin flaps or a skin graft to cover the residual defect.

An assessment of histological margins and recurrence of melanoma in situ

Background:

Melanoma in situ (MIS) accounts for up to 27% of all melanomas. MIS has no metastatic potential and the aim should be to excise the lesion completely with a clear histological margin, although margin clearance remains undefined. We aimed to assess the relation of histological excision margins of MIS to recurrence and progression to invasive disease.

Methods:

We analyzed all patients with MIS excised by wide local excision or staged excision in our institution over a 5-year period from December 2008 to January 2014 using a prospectively maintained database. Clinicopathologic details included patient demographics, anatomical site of lesion, melanoma subtype, histological excision margin, and recurrence.

Results:

A total of 410 patients had MIS excised during this time, the majority of which were lentigo maligna subtype (79%). The average histological excision margin was 3.7 mm. The rate of recurrence was 2.2% (9/410), with a median follow-up of 23 months. Lentigo maligna had a similar rate of recurrence to non-lentigo MIS (2.3% vs 1.2%) (P = 0.69). The mean excision margin of those that recurred was 1.9 mm compared with an average of 3.8 mm in those that did not. The rate of recurrence of MIS with histological excision margin ≤3.00 mm was 3.8% compared with 0.5% in those with a histological margin >3.00 mm (P = 0.03). One case of MIS recurred as invasive disease.

Conclusion:

At institutions using wide local excision or staged excision for MIS, a histological margin of >3.0 mm is required to achieve a low recurrence rate.