Histopathologic regression in patients with primary cutaneous melanoma undergoing sentinel lymph node biopsy is associated with favorable survival and, after metastasis, with improved progression-free survival on immune checkpoint inhibitor therapy: A single-institutional cohort study

BACKGROUND

Histopathologic regression of cutaneous melanoma is considered a favorable prognostic factor, but its significance in clinical practice remains controversial.

OBJECTIVE

To investigate the prognostic importance of regression in patients with primary cutaneous melanoma undergoing sentinel lymph node (SLN) biopsy and to assess its significance in patients progressing to an unresectable stage requiring systemic therapy.

METHODS

We retrospectively reviewed patients with newly diagnosed melanoma undergoing SLN biopsy between 2010 and 2015 and available information on histopathologic regression (n = 1179). Survival data and associations of clinical variables with SLN status were assessed.

RESULTS

Patients with regressive melanoma showed favorable relapse-free (hazard ratio [HR], 0.52; P = .00013), distant metastasis-free (HR, 0.56; P = .0020), and melanoma-specific survival (HR, 0.35; P = .00053). Regression was associated with negative SLN (odds ratio, 0.48; P = .0077). In patients who progressed to an unresectable stage, regression was associated with favorable progression-free survival under immune checkpoint inhibition (HR, 0.43; P = .031) but not under targeted therapy (HR, 1.14; P = .73) or chemotherapy (HR, 3.65; P = .0095).

LIMITATIONS

Retrospective, single-institutional design.

CONCLUSIONS

Regression of cutaneous melanoma is associated with improved prognosis in patients eligible for SLN biopsy as well as in patients with unresectable disease receiving systemic therapy with immune checkpoint inhibitors.

Sentinel lymph node assessment in melanoma: current state and future directions

Assessment of sentinel lymph node status is an important step in the evaluation of patients with melanoma for both prognosis and therapeutic management. Pathologists have an important role in this evaluation. The methodologies have varied over time, from the evaluation of dimensions of metastatic burden to determination of the location of the tumour deposits within the lymph node to precise cell counting. However, no single method of sentinel lymph node tumour burden measurement can currently be used as a sole independent predictor of prognosis. The management approach to sentinel lymph node-positive patients has also evolved over time, with a more conservative approach recently recognised for selected cases. This review gives an overview of past and current status in the field with a glimpse into future directions based on prior experiences and clinical trials.

The Importance of Immunohistochemistry in the Evaluation of Tumor Depth of Primary Cutaneous Melanoma

Primary cutaneous melanoma (PCM) is the most aggressive skin malignancy, with an increasing incidence and significant mortality. Tumoral invasion, expressed as Breslow thickness, is routinely assessed on hematoxylin and eosin (HE), although this stain may sometimes underestimate the tumoral depth. The aim of this study was to compare the efficiency of the immunohistochemical (IHC) markers S-100, SOX10, Melan-A, and HMB-45 with HE for the evaluation of the Breslow thickness and staging of PCM. This retrospective study included 46 cases of PCM diagnosed between 2015 and 2022; for each case, the Breslow thickness using HE, S-100, SOX10, Melan-A, and HMB-45 was measured and the appropriate T category was recorded. The highest values of the Breslow thickness were observed for S-100. However, S-100, SOX10, and Melan-A provided statistically significant higher values of the Breslow thickness compared to HE, but no difference was noted between HMB-45 and HE. S-100 was most frequently involved in increasing the T category (26.1%), the majority of cases being upstaged from T1a to T1b. The IHC markers S-100, SOX10, and Melan-A contributed to better evaluation of the melanoma invasion, especially in thin melanomas, but their impact on staging and consecutive treatment remains to be confirmed by future studies.

Regression in cutaneous melanoma: histological assessment, immune mechanisms and clinical implications

Tumour regression is an immunologically driven process that results in complete or partial disappearance of tumour cells. This can be observed in histological sections as replacement of tumour cells with fibrosis, angiogenesis, and a variable inflammatory infiltrate. In primary cutaneous melanoma, the prognostic significance of regression has been debated for decades, in part because inconsistent histological criteria are used in prognostication studies. It is broadly accepted that CD8+ T lymphocytes are the primary effectors of the anti-tumour response, but the interplay between melanoma and the immune system is complex, dynamic, and incompletely understood. Sustained progress in unravelling the pathogenesis of melanoma regression has led to the identification of therapeutic targets, culminating in the development of immune checkpoint inhibitors for the management of advanced disease. Modern techniques allow for high-resolution spatial analyses of the tumour microenvironment. Such studies may lead to better understanding of the immune drivers of melanoma regression, thereby facilitating the search for new prognostic and predictive biomarkers to assist clinical decision-making.

Tissue Biomarkers Predicting Lymph Node Status in Cutaneous Melanoma

Cutaneous melanoma is a severe neoplasm that shows early invasiveness of the lymph nodes draining the primary site, with increased risk of distant metastases and recurrence. The tissue biomarker identification could be a new frontier to predict the risk of early lymph node invasiveness, especially in cases considered by current guidelines to be at low risk of lymph node involvement and not requiring evaluation of the sentinel lymph node (SLN). For this reason, we present a narrative review of the literature, seeking to provide an overview of current tissue biomarkers, particularly vascular endothelium growth factors (VEGF), Tetraspanin CD9, lymphatic vessel endothelial hyaluronan receptor-1 (LYVE-1), D2-40, and gene expression profile test (31-GEP). Among these, 31-GEP seems to be able to provide a distinction between low or high risk for positive SLN classes. VEGF receptor-3 and CD9 expression may be independent predictors of positive SLN. Lastly, LYVE-1 and D2-40 allow an easier assessment of lymph vascular invasion, which can be considered a good predictor of SLN status. In conclusion, biomarkers to assess the lymph node status of cutaneous melanoma patients may play an important role in those cases where the clinician is in doubt whether or not to perform SLN biopsy.

Is the presence of tumor-infiltrating lymphocytes predictive of outcomes in patients with melanoma?

BACKGROUND

The significance of tumor-infiltrating lymphocytes (TILs) in melanoma is debated. This article presents a multicenter, retrospective study assessing the predictive and prognostic value of TILs.

METHODS

The Sentinel Lymph Node Working Group database was queried from 1993 to 2018 for cases with known TIL data. TILs were categorized as absent or present, which included nonbrisk (NB), brisk (B), and present but unspecified TIL levels. Clinicopathologic factors were correlated with TILs, sentinel lymph node (SLN) status, and melanoma-specific survival (MSS).

RESULTS

Overall, 3203 patients were included. The median thickness was 1.5 mm, and 469 cases had SLN metastases. TILs were present in 2458 cases (76.7%), with NB, B, and unspecified TILs seen in 1691 (68.8%), 691 (28.1%), and 76 (3.1%), respectively. Multivariable analysis showed that the presence of TILs significantly predicted a negative SLN biopsy (P < .05). The median follow-up was 25.2 months. MSS was significantly better for cases with TILs than cases without TILs (P < .001). According to multivariable analysis, age, gender, thickness, mitotic rate, ulceration, lymphovascular invasion, and SLN status were significantly prognostic of MSS (all P values < .05). Although TILs were not prognostic of MSS, when multiple imputation was used and the SLN status was excluded, the presence of TILs was significantly prognostic of improved MSS (hazard ratio, 0.78; 95% confidence interval, 0.64-0.95; P = .0154).

CONCLUSIONS

TILs are a favorable marker because their presence significantly predicts a negative SLN, and the absence of TILs may be a prognostic marker of worse survival in patients with a positive SLN but not a negative SLN. TILs may also serve as a prognostic marker of survival when the SLN status is not considered.

Histological regression in melanoma: impact on sentinel lymph node status and survival

Regression in melanoma is an immunological phenomenon that results in partial or complete replacement of the tumor with variably vascular fibrous tissue, often accompanied by pigment-laden macrophages and chronic inflammation. In some cases, tumor-infiltrating lymphocytes (TILs) may represent the earliest phase of this process. The prognostic significance of regression has long been a matter of debate, with inconsistent findings reported in the literature to date. This study sought to determine whether regression in primary cutaneous melanomas predicted sentinel lymph node (SLN) status and survival outcomes in a large cohort of patients managed at a single centre. Clinical and pathological parameters for 8,693 consecutive cases were retrieved. Associations between regression and SLN status, overall survival (OS), melanoma-specific survival (MSS) and recurrence-free survival (RFS) were investigated using logistic and Cox regression. Histological evidence of regression was present in 1958 cases (22.5%). Regression was significantly associated with lower Breslow thickness, lower mitotic rate, and absence of ulceration (p < 0.0001). Multivariable analysis showed that regression in combination with TILs independently predicted a negative SLN biopsy (OR 0.33; 95% C.I. 0.20-0.52; p < 0.0001). Patients whose tumors showed both regression and TILs had the highest 10-year OS (65%, 95% C.I. 59-71%), MSS (85%, 95% C.I. 81-89%), and RFS (60%, 95% C.I. 54-66%). On multivariable analyses, the concurrent presence of regression and TILs independently predicted the lowest risk of death from melanoma (HR 0.69; 95% C.I. 0.51-0.94; p = 0.0003) as well as the lowest rate of disease recurrence (HR 0.71; 95% C.I. 0.58-0.85; p < 0.0001). However, in contrast, in the subgroup analysis of Stage III patients, the presence of regression predicted the lowest OS and RFS, with MSS showing a similar trend. Overall, these findings indicate a prognostically favorable role of regression in primary cutaneous melanoma. However, in Stage III melanoma patients, regression may be a marker of more aggressive disease.

Regression in melanoma is significantly associated with a lower regional recurrence rate and better recurrence-free survival

BACKGROUND AND OBJECTIVES

The prognostic significance of regression in predicting melanoma recurrences is unknown. We present a large multicenter study correlating regression with recurrence.

METHODS

The Sentinel Lymph Node Working Group database was queried from 1993 to 2018 for cases with regression data. Clinicopathologic factors were correlated with overall and first-site of recurrence and with recurrence-free survival (RFS).

RESULTS

There were 4790 patients and the median follow-up was 39.6 months. Regression and recurrences were seen in 1081 (22.6%) and 773 (16.1%) cases, respectively. First-site locoregional and distant recurrences were seen in 412 (8.6%) and 352 (7.3%) patients, respectively. Regression was seen in 15.8% and 24.7% of all cases with and without recurrences (p < 0.0001), respectively, while regression was seen in 14.3% and 17.9% of first-site locoregional and distant recurrent cases, respectively, compared with 23.3% and 22.9% of patients with regression and without first-site locoregional and distant recurrences, respectively (p = 0.29). On multivariable analysis, after controlling for age, gender, thickness, ulceration, lymphovascular invasion, and sentinel lymph node status, regression significantly predicted improved RFS (p = 0.004) and fewer first-site regional recurrences (p = 0.017).

CONCLUSION

Our data suggest that regression is a favorable prognostic marker in melanoma and predicts significantly better RFS and decreased first-site regional recurrences.

Regression is significantly associated with outcomes for patients with melanoma

BACKGROUND

The prognostic significance of regression in melanoma is debated. We present a large multicenter study correlating regression with sentinel lymph node metastasis and melanoma-specific survival.

METHODS

The Sentinel Lymph Node Working Group database was reviewed from 1993 to 2018. Patients with known regression and sentinel lymph node status were included. Clinicopathologic factors were correlated with regression, sentinel lymph node status, and melanoma-specific survival.

RESULTS

There were 4,790 patients; median follow-up was 39.6 months. Regression was present in 1,081 (22.6%) cases, and 798 (16.7%) patients had sentinel lymph node metastases. On multivariable analysis, male sex, truncal tumors, and decreasing thickness were significantly associated with regression (P < .05), whereas head/neck or leg tumors had lower rates of regression (P < .05). Regression was significantly correlated with a decreased risk of sentinel lymph node disease on multivariable analysis (odds ratio 0.68, 95% confidence interval 0.54-0.85; P = .0008). Multivariable analysis also showed that increasing age, male sex, increasing thickness, ulceration, lymphovascular invasion, microsatellitosis, and sentinel lymph node metastasis were significantly (P < .05) associated with worse melanoma-specific survival, while regression was significantly associated with better melanoma-specific survival (hazard ratio 0.75, 95% confidence interval 0.57-0.99; P = .043).

CONCLUSION

This large study shows that regression is significantly associated with better outcomes in patients with melanoma and is correlated with a lower risk of sentinel lymph node metastasis and a better melanoma-specific survival.

Coexistence of regression and tumor infiltrating lymphocytes is associated with more favorable survival in melanoma

PURPOSE

Melanoma is one of the highly immunogenic malignancies, and histological regression (HR) and tumor infiltrating lymphocytes (TILs) represent early signs of activation of the immune system against primary melanoma. In this study we aimed to investigate the potential roles of HR and TILs on survival, as combined or separately.

METHODS

A total of 916 cutaneous melanomas were analyzed retrospectively.

RESULTS

Only minority of the lesions had HR (25.1%) and they were associated with males (p = 0.002), axial localization (p = 0.0001), non-nodular histopathology (p = 0.0001), thin Breslow depth (p = 0.01) and nevus-associated melanoma (p = 0.03). Those with TILs (48.4%) were found in association with lower Clark levels (p = 0.003), thin tumor thicknesses (p = 0.001), lower mitotic rates (p = 0.02), BRAF mutation (p = 0.03), absence of neurotropism (p = 0.03), involvement of lymph node (p = 0.0001) and relapse of disease (p = 0.04). A significant relationship was found between HR and TILs (p = 0.01). TILs were independently associated with favorable RFS (p = 0.02), whereas no relationship was observed between HR and RFS (p = 0.2). A marked favorable survival advantage was noted in the group with HR (+)/TILs (+) compared to other groups with HR (-)/TILs (-) (p = 0.007), only HR (+) and only TILs (+). Both HR (p = 0.05) and TILs (p = 0.04) were correlated with favorable OS rates. Moreover, HR (+) /TILs (+) patients had more favorable OS than other groups with HR (-)/TILs (-) (p = 0.002), only HR (+) and only TILs (+).

CONCLUSION

Only HR (+) and only TILs (+) subgroups separately were found to be associated with favorable survivals in melanoma. Furthermore, coexistence of HR and TILs, HR (+)/TILs (+) subgroup, had more favorable survival rates compared to only HR (+) and only TILs (+) subgroups.

Histological regression in primary melanoma and drug-related immune reaction towards metastatic melanoma: Are they associated??

Histologic regression has recently been associated with a more favorable prognosis in primary melanoma. historically this immune phenomenon was described as a negative prognostic factor able to substage the true Breslow thickness. Since many years we have assisted to the appearance of vitiligo in metastatic melanoma patients. This has been considered one of the explanations of the immunogenicity of this disease, as inducing a strong immune reaction against cancer cells able to kill normal melanocytes even far from the metastatic lesions, This vitiligo like reaction has been seen even stronger in patients treated with immune and target therapy. The three phenomena involve the same pattern of lymphocytes. The association between the three can explain the better prognosis of the patients with primary melanoma with histological regression as well as the longer survival of the vitiligo like immune reaction in metastatic melanoma patients.

Systemic adjuvant therapy for adult patients at high risk for recurrent melanoma: A systematic review

Cutaneous melanoma is typically treated with wide local excision and, when appropriate, a sentinel node biopsy. Many patients are cured with this approach but for patients who have cancers with high risk features there is a significant risk of local and distant relapse and death. Interferon-based adjuvant therapy was recommended in the past but had modest results with significant toxicity. Recently, new therapies (immune checkpoint inhibitors and targeted therapies) have been found to be effective in the treatment of patients with metastatic melanoma and many of these therapies have been evaluated and found to be effective in the adjuvant treatment of high risk patients with melanoma. This systematic review of adjuvant therapies for cutaneous and mucosal melanoma was conducted for Ontario Health (Cancer Care Ontario) as the basis of a clinical practice guideline to address the question of whether patients with completely resected melanoma should be considered for adjuvant systemic therapy and which adjuvant therapy should be used.

Current controversies in early-stage melanoma: Questions on incidence, screening, and histologic regression

In the first article in this continuing medical education series we review controversies and uncertainties relating to the epidemiology and initial diagnosis of localized cutaneous melanoma (ie, stage 0, I, or II). Many of these issues are unsettled because of conflicting evidence. Melanoma incidence appears to be increasing, yet its basis has not been fully explained. Despite the advantages of early detection, the US Preventive Services Task Force does not recommend skin screening for the general population. Occasionally, biopsy specimens of melanoma will show histologic regression, but the prognostic importance of this phenomenon is uncertain. Some practitioners recommend obtaining a sentinel lymph node biopsy specimen for thin melanomas showing regression, although this histologic finding is not part of the staging system for thin melanomas. Our goal is to provide the clinician who cares for patients with (or at risk for) melanoma with up-to-date contextual knowledge to appreciate the multiple sides of each controversy so that they will be better informed to discuss these issues with their patients and their families.

Epidemiological trends in the diagnosis of melanoma in a Southern European population: analysis of a large database from a tertiary referral center

The aim of this study was to present the epidemiological, clinicopathological, and treatment characteristics of patients diagnosed and treated in a tertiary referral center and to analyze independent factors associated with these characteristics. In this cohort study, epidemiological, clinicopathological, and treatment characteristics of 1461 consecutive melanoma patients diagnosed and treated in a tertiary referral center in 1987-2015 were prospectively collected in a registry. All patients underwent resection of their melanoma lesion. Multiple logistic regression analysis was used to examine independent correlations between characteristics. Internal validation of these correlations was performed by the bootstrap method. The median age of the patients was 53 years. Female sex had a slight predominance, whereas the majority were of Southern European origin. Superficial spreading melanoma was associated with younger age (P<0.001), whereas the nodular melanoma histological subtype was associated independently with indoor occupation (P=0.021) and diagnosis in the years 2004-2015 (P=0.002). Melanomas with Breslow thickness above 1.0 mm were associated with skin type III-IV (P=0.021) and diagnosis in the years 1987-2003 (P=0.046). In addition, histological ulceration was associated with older age (P=0.004) and diagnosis in the years 1987-2003 (P<0.001), whereas histological regression was associated independently with older age (P=0.001). This study presented independent associations between epidemiological, histopathological, and treatment characteristics, which might help to better understand melanoma disease and treatment practices in Southern Europe.

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.

The microenvironment in primary cutaneous melanoma with associated spontaneous tumor regression: evaluation for T-regulatory cells and the presence of an immunosuppressive microenvironment

Spontaneous tumor regression, regression in the absence of therapeutic intervention, can be identified histologically in over 25% of primary cutaneous melanomas at initial diagnosis. A unique subset of T lymphocytes found in areas of regression can be histologically distinguished from tumor-infiltrating T lymphocytes (TIL) found in areas of tumor progression. We call this unique subset of T lymphocytes regression-associated T lymphocytes (RATs). The aim of this study is to determine the phenotype of lymphocytes and the density of specific cell types linked to immunosuppression in areas of tumor progression compared with areas of tumor regression. These specific cell types include T-regulatory cells (Tregs) and S100A9 cells. A total of 14 primary cutaneous melanomas with areas of progression and regression were used. Immunohistochemistry staining was used to identify CD4 cells, CD8 cells, Tregs, and S100A9 cells. Two independent observers manually counted three high-powered ×40 fields. There was no predominance of CD4 or CD8 T lymphocytes in either RATs or TIL. We identified a lower density of Tregs in RATs compared with TIL when using the FOXP3/CD4 Treg marker (P=0.04) and a marginal difference when using our second, confirmatory Treg marker, FOXP3/CD25 (P=0.11). We observed a lower density of S100A9 cells in RATs compared with TIL (P=0.002). There was an observable difference in the tumor microenvironments of RATs and TIL, with RATs having a significantly lower density of Tregs and S100A9 cells. We deduce that the absence of immunosuppression in areas of regression allows for a more robust immune response and thus effective eradication of tumor cells.

Regression in primary cutaneous melanoma: etiopathogenesis and clinical significance

Though not required currently for staging, regression is a histopathologic parameter typically reported upon diagnosis of an invasive primary cutaneous melanoma. The studies examining the prognostic significance of regression in patient outcome have yielded controversial findings; likely because the definition and assessment of regression have not been consistent, in addition to subjectivity of pathologists' interpretation. Regression is histologically characterized by variable decrease in the number of melanoma cells accompanied by the presence of a host response consisting of dermal fibrosis, inflammatory infiltrate, melanophages, ectatic blood vessels, epidermal attenuation, and/or apoptosis of keratinocytes or melanocytes; the relative extent of these features depends on the stage of the regression. However, the magnitudes to which these individual changes must be present to meet the threshold of histologic regression have not been well defined or agreed upon, and thus, the definition and classification of histologic regression in melanoma varies considerably among institutions and even among individual pathologists. In order to determine the clinical significance of histologic analysis of regression, there is a compelling need for a universal scheme to objectively define and assess histologic regression in primary cutaneous melanoma, so that the biologic and prognostic significance of this process may be completely understood.Laboratory Investigation advance online publication, 27 February 2017; doi:10.1038/labinvest.2017.8.

Patient Symptoms Are the Most Frequent Indicators of Recurrence in Patients with American Joint Committee on Cancer Stage II Melanoma

BACKGROUND

Patients with stage II melanoma have a considerable risk for recurrence. Current guidelines are imprecise as to optimal follow-up. We hypothesized that by examining recurrence patterns, we could help to better inform guidelines.

STUDY DESIGN

We queried IRB-approved melanoma databases of Thomas Jefferson University and University of North Carolina, identifying 581 patients with stage II melanoma between 1996 and 2015 with at least 1 year of follow-up. Data included location of first recurrence and how recurrence was detected (ie patient symptom, physician examination, or routine surveillance imaging). Cox regression with backward elimination was used for multivariable analysis.

RESULTS

One hundred and seventy-one patients had a recurrence (29.4%), the incidence increased considerably by stage sub-group. Significant predictors of recurrence included male sex (p = 0.003), ulceration (p = 0.03), and stage (p < 0.001). On multivariable analysis, male sex and stage continued to be significant (p < 0.01). For overall survival, regression, ulceration, stage, and age were significant predictors of survival. Stage, regression, and age remained significant by multivariable analysis. Patient symptoms were the most frequent mode of detection (40%), followed by physician examination (30%) and surveillance imaging (26%)-this did not differ significantly by stage. Regional nodes were the most common site of recurrence (30%), followed by lung (27%) and in-transit (18%).

CONCLUSIONS

The majority of recurrences in stage II melanoma are detected by patients and their physicians and rarely by routine imaging. As such, clinical follow-up and patient education are critical factors in detection of recurrence. With the prevalence of regional nodal recurrences, ultrasound might prove to be an important strategy in early recurrence detection.

The influence of tumor regression, solar elastosis, and patient age on pathologists' interpretation of melanocytic skin lesions

It is not known whether patient age or tumor characteristics such as tumor regression or solar elastosis influence pathologists' interpretation of melanocytic skin lesions (MSLs). We undertook a study to determine the influence of these factors, and to explore pathologist's characteristics associated with the direction of diagnosis. To meet our objective, we designed a cross-sectional survey study of pathologists' clinical practices and perceptions. Pathologists were recruited from diverse practices in 10 states in the United States. We enrolled 207 pathologist participants whose practice included the interpretation of MSLs. Our findings indicated that the majority of pathologists (54.6%) were influenced toward a less severe diagnosis when patients were <30 years of age. Most pathologists were influenced toward a more severe diagnosis when patients were >70 years of age, or by the presence of tumor regression or solar elastosis (58.5%, 71.0%, and 57.0%, respectively). Generally, pathologists with dermatopathology board certification and/or a high caseload of MSLs were more likely to be influenced, whereas those with more years' experience interpreting MSL were less likely to be influenced. Our findings indicate that the interpretation of MSLs is influenced by patient age, tumor regression, and solar elastosis; such influence is associated with dermatopathology training and higher caseload, consistent with expertise and an appreciation of lesion complexity.

Tumor Thickness and Mitotic Rate Robustly Predict Melanoma-Specific Survival in Patients with Primary Vulvar Melanoma: A Retrospective Review of 100 Cases

Purpose: Primary vulvar melanoma (PVM) is the second most common vulvar malignancy. Despite their distinct anatomic site and unique molecular-genetic alterations, PVMs are staged according to the American Joint Committee on Cancer (AJCC) guidelines for primary cutaneous melanomas (PCM). However, whether parameters derived for PCM also apply to PVM remain a critical yet largely unexplored clinical question. The objective of this study was to determine the parameters predictive of survival in PVM.Experimental Design: We retrospectively reviewed 100 patients with PVM and determined associations between clinical and histopathologic parameters and disease-specific survival (DSS) and overall survival (OS).Results: Univariate Cox regression analysis demonstrated older age (>56 years), greater tumor thickness, higher dermal mitotic rate, ulceration, lymphovascular invasion, perineural invasion, microscopic satellitosis, and absence of precursor nevus associated with decreased OS. Furthermore, age, midline, and/or multifocal involvement, greater tumor thickness, higher dermal mitotic rate, ulceration, lack of regression, lymphovascular invasion, perineural invasion, and microscopic satellitosis associated with decreased DSS. Multivariate analysis demonstrated tumor thickness, dermal mitotic rate, lymphovascular invasion, microscopic satellitosis, and absence of precursor nevus independently predicted shorter OS. Only tumor thickness and increased dermal mitotic rate (≥2/mm²) independently predicted reduced DSS. In comparison with the AJCC T-category, a novel, bivariate T-category based only on tumor thickness and dermal mitotic rate robustly predicted OS and DSS in our patient cohort.Conclusions: In the largest single institutional study of PVM, we demonstrate a combination of tumor thickness and mitotic rate comprise a simple but robust T-category to direct staging and prognosis. Clin Cancer Res; 23(8); 2093-104. ©2016 AACR.

Presence of histological regression as a prognostic factor in cutaneous melanoma patients

Regression is caused by a host immunological response primarily characterized by lymphocytic infiltration directed against melanoma cells. The prognostic significance of regression remains controversial in cutaneous melanoma patients. The aim of this study was to determine the clinical significance of the histological regression status in patients with cutaneous melanoma. A total of 664 patients with a pathologically confirmed cutaneous melanoma were enrolled into this study and were investigated retrospectively. The median age of the patients was 51 years, ranging in age from 16 to 104 years. The majority of them had lesions without regression (n=495; 74.5%) and others had lesions with regression (n=169; 25.5%). Melanoma patients with regression were more frequently males (60.1 vs 51.7%; P=0.038) and had axial localized lesions (67.5 vs 53.7%; P=0.002), superficial spreading histologic subtype (73.2 vs 49.1%; P=0.000), thin Breslow depth (<2 mm) (44.6 vs 33.5%; P=0.01), and the presence of tumor-infiltrating lymphocytes (74.4 vs 60.0%; P=0.001) than those without regression. However, regression was not significantly associated with age, Clark level, mitotic rate, ulceration, vertical growth phase, neurotropism, lymphovascular invasion, nor association with a pre-existing melanocytic nevus. Similarly, no significant correlations were found between regression and lymph node involvement, recurrence, nor metastasis of disease. Patients with, nodular pathology, advanced Clark invasion level (IV-V), thick Breslow depth (≥2 mm), high mitotic rate (>3/mm), ulceration, vertical growth phase, neurotropism, lymphovascular invasion, lymph node involvement, metastasis, and recurrence of disease, and male patients had poor prognostic variables for both relapse-free survival and overall survival. However, the presence of regression was not associated with relapse-free survival (P=0.093) nor overall survival (P=0.113) similar to other factors such as age, tumor localization, tumor-infiltrating lymphocytes, and association with a pre-existing melanocytic nevus. Similar insignificant P values were also observed in multivariate analyses (P=0.115 and 0.816, respectively). In conclusion, the presence of histological regression plays no prognostic role in nodal involvement nor survival in patients with cutaneous melanoma.

Regression in cutaneous melanoma: a comprehensive review from diagnosis to prognosis

Histological regression in primary cutaneous melanoma occurs in 10-35% of cases. Although a large body of literature exists to suggest that histological regression serves very little purpose in predicting biologic behaviour with melanoma, recognizing the presence of regression at clinical and histological ground may still retain some value in grading melanoma aggressiveness. In the current review, a comprehensive overview of the main aspects of regression will be provided. Histologically, many classifications have been reported so far, but all of them only agreed on the presence of an infiltrate of lymphocytes admixed with pigment-laden macrophages underlying an atrophic epidermis with flattened rete ridges. Upon dermoscopy, regression is also named Blue White Scar-like areas and could be variably admixed with granularity or peppering. Almost fully regressed lesions represent a main diagnostic issue in dermoscopy, and thus, confocal microscopy can be of help to identify whether the tumour is melanocytic or not. The clinical utility of regression as a prognostic factor has been challenged recently. Nowadays, evidences showed that it is less likely associated to SLN metastases.

Absence of Tumor-Infiltrating Lymphocyte Is a Reproducible Predictive Factor for Sentinel Lymph Node Metastasis: A Multicenter Database Study by the Brazilian Melanoma Group

Aims

The aim of this study is to confirm the function of tumor-infiltrating lymphocytes (TILs) in sentinel lymph node (SLN) metastasis.

Materials and Methods

This retrospective study included 633 patients with invasive melanoma who underwent sentinel lymph node biopsy in 7 referral centers certified by the Brazilian Melanoma Group. Independent risk factors of sentinel node metastasis (SNL) were identified by multiple logistic regression.

Results

SLN metastasis was detected in 101 of 633 cases (16.1%) and in 93 of 428 patients (21.7%) when melanomas ≤ 1mm were excluded. By multiple logistic regression, the absence of TILs was as an independent risk factor of SLN metastasis (OR = 1.8; 95%CI: 1.1–3.0), in addition to Breslow index (greater than 2.00 mm), lymph vascular invasion, and presence of mitosis.

Conclusion

SLNB can identify patients who might benefit from immunotherapy, and the determination of predictors of SLNB positivity can help select the proper population for this type of therapy. The absence of TILs is a reproducible parameter that can predict SLNB positivity in melanoma patients, since this study was made with several centers with different dermatopathologists.

Study of the immunophenotype of the inflammatory cells in melanomas with regression and halo nevi

The pathogenesis and prognostic implications of regression in melanoma are not well understood. It has traditionally been considered an immunologically mediated phenomenon. Improvement in the knowledge of the mechanisms that lead to regression may prove to be of great value in an era in which treatments oriented to the augmentation of the host's immunity against melanoma have demonstrated excellent clinical results. This study was designed to improve the understanding of the mechanisms underlying melanoma regression and the differences between similar situations in benign melanocytic nevus. The study sample consisted of 77 lesions: 62 melanomas and 15 halo nevi. The following markers were included in the study: CD4, CD8, FoxP3, PD1, CD123, granzyme, and TIA-1. Staining was evaluated in 5 categories, according to the percentage of labeled cells. Granzyme, PD1, and TIA-1 stained significantly more cells in halo nevi than in melanomas with regression (P < 0.01). The ratio CD123/TIA-1 was higher in melanomas than in halo nevi (1 vs. 0.67, P < 0.05). Regression in the 62 melanomas was categorized as early in 14 cases and late in 48 cases. Early regression was associated with a higher percentage of CD123, CD4, and TIA-1 staining than late regression. The inflammatory infiltrate found in halo nevi is characterized by a higher number of active cytotoxic T cells and regulatory PD1-positive T cells than the infiltrate found in melanoma with regression. CD123 staining was higher in early regression than in late regression, suggesting the presence of a tolerogenic mechanism in this phenomenon's initiation phase.

Prediction of survival in patients with thin melanoma: results from a multi-institution study

PURPOSE

Cutaneous melanoma incidence is increasing. Most new cases are thin (≤ 1 mm) with favorable prognoses, but survival is nonetheless variable. Our aim was to investigate new prognostic factors and construct a nomogram for predicting survival in individual patients.

PATIENTS AND METHODS

Data from 2,243 patients with thin melanoma were retrieved from prospectively maintained databases at six centers. Kaplan-Meier survival and crude cumulative incidences of recurrence were estimated, and competing risks were taken into account. Multivariable Cox regression was used to investigate survival predictors.

RESULTS

Median follow-up was 124 months (interquartile range, 106 to 157 months); 12-year overall survival was 85.3% (95% CI, 83.4% to 87.2%). Median times to local, regional, and distant recurrence were 79, 78, and 107 months, respectively. Relapse was significantly related to age, Breslow thickness, mitotic rate (MR), ulceration, lymphovascular invasion (LVI), and regression; incidence was lower and subgroup differences were less marked for distant metastasis than for regional relapse. The worst prognosis categories were age older than 60 years, Breslow thickness more than 0.75 mm, MR ≥ 1, presence of ulceration, presence of LVI, and regression ≥ 50%. Breslow thickness more than 0.75 mm, MR ≥ 1, presence of ulceration, and LVI (all P = .001) were significantly associated with sentinel node positivity. Age, MR, ulceration, LVI, regression, and sentinel node status were independent predictors of survival and were used to construct a nomogram to predict 12-year overall survival. The nomogram was well calibrated and had good discriminative ability (adjusted Harrell C statistic, 0.88).

CONCLUSION

Our findings suggest including LVI and regression as new prognostic factors in the melanoma staging system. The nomogram appears useful for risk stratification in clinical management and for recruiting patients to clinical trials.

Tumor-infiltrating lymphocyte response in cutaneous melanoma in the elderly predicts clinical outcomes

Tumor-infiltrating lymphocytes (TILs) and regression are manifestations of the host immune response to tumor, but their influence on outcome remains undefined. There is a paucity of data on the elderly who represent a growing proportion of melanoma patients. The aim of this study was to evaluate the influence of TILs and regression as an indirect measure of immunity on outcome in elderly patients with melanoma. From a prospective database, we identified 250 consecutive cutaneous melanoma patients aged at least 65 years at the time of diagnosis. Data were verified by record review. Within the primary melanoma, a brisk TIL response was present in 66 (31%), nonbrisk TILs in 36 (17%), and absent in 111 (52%). The presence of a brisk infiltrate conferred a three-fold increased risk of sentinel lymph node (SLN) metastasis (P=0.02). Despite this, nonbrisk or absent TILs were associated with a five-fold increased risk of recurrence (P=0.0001). In multivariate analysis, nonbrisk or absent TILs were independently associated with recurrence (P<0.0001), diminished 5-year disease-free survival (76 vs. 91%, P=0.0006), and 5-year melanoma-specific survival (82 vs. 95%, P=0.0008). Regression was not an independent predictor of SLN metastasis, disease-free survival, or melanoma-specific survival. Our study demonstrates that an active antitumor immune response exists in elderly melanoma patients that, paradoxically, predicts both SLN metastasis and improved melanoma-specific outcomes. Further investigation to characterize this lymphocytic infiltrate and to confirm its clinical significance as a predictor of nodal status, patient outcome, and response to immunotherapy in elderly melanoma patients appears warranted.

Impact of the 2009 (7th edition) AJCC melanoma staging system in the classification of thin cutaneous melanomas

CONTEXT

The 7th (2009) edition of the AJCC melanoma staging system incorporates tumor (Breslow) thickness, MR, and ulceration in stratifying T1 primary melanomas. Compared to the prior 6th (2001) edition, MR has replaced CL for thin melanomas.

OBJECTIVE

We sought to identify and report differences of the classification of thin melanomas as well as outcome of SLNB in patients according to the 6th and 7th editions at our institution.

RESULTS

106 patients were identified with thin melanomas verified by wide excision. 31 of 106 thin melanomas were reclassified according to the 7th edition of the AJCC. Of those 31, 15 CL II/III patients (6th edition T1a) were reclassified as T1b based on the presence of mitoses while 16 CL IV patients (6th edition T1b) were categorized as T1a based on the absence of mitoses. 26/31 reclassified patients underwent SLNB, and all were negative. Patients with thin melanoma and a +SLNB (N = 3) were all classified as T1b according to both staging systems.

CONCLUSIONS

In our experience, 29% of thin melanomas were reclassified according to the 7th edition with similar proportions of patients re-distributed as T1a (14%) and T1b (15%). Cases with +SLN corresponded with T1b lesions in both 6th and 7th editions.