Predictive factors for sentinel lymph nodes and non-sentinel lymph nodes metastatic involvement: a database study of 1,041 melanoma patients

Role of Sentinel Lymph Node Biopsy for Skin Cancer Based on Clinical Studies

The sentinel lymph node is the first lymph node from the primary tumor. Sentinel lymph node biopsy (SLNB) is a surgical procedure that can detect occult nodal metastasis with relatively low morbidity. It may also have a therapeutic effect via regional disease control. The Multicenter Selective Lymphadenectomy-I (MSLT-I) trial revealed a prognostic benefit from SLNB in melanoma patients. However, it remains unclear whether there is a prognostic benefit from SLNB in patients with nonmelanoma skin cancer owing to a lack of randomized prospective studies. Nevertheless, SLNB provides important information about nodal status, which is one of the strongest factors to predict prognosis and may guide additional nodal treatment. Currently, SLNB is widely used in the management of not only patients with melanoma but also those with nonmelanoma skin cancer. However, the utilization and outcomes of SLNB differ among skin cancers. In addition, SLNB is not recommended for routine use in all patients with skin cancer. In this review, we provide a summary of the role of SLNB and of the indications for SLNB in each skin cancer based on previously published articles.

Higher polygenic risk for melanoma is associated with improved survival in a high ultraviolet radiation setting

BACKGROUND

The role of germline genetic factors in determining survival from cutaneous melanoma (CM) is not well understood.

OBJECTIVE

To perform a genome-wide association study (GWAS) meta-analysis of melanoma-specific survival (MSS), and test whether a CM-susceptibility polygenic risk score (PRS) is associated with MSS.

METHODS

We conducted two Cox proportional-hazard GWAS of MSS using data from the Melanoma Institute Australia, a high ultraviolet (UV) radiation setting (MIA; 5,762 patients with melanoma; 800 melanoma deaths) and UK Biobank (UKB: 5,220 patients with melanoma; 241 melanoma deaths), and combined them in a fixed-effects meta-analysis. Significant (P < 5 × 10-8) results were investigated in the Leeds Melanoma Cohort (LMC; 1,947 patients with melanoma; 370 melanoma deaths). We also developed a CM-susceptibility PRS using a large independent GWAS meta-analysis (23,913 cases, 342,870 controls). The PRS was tested for an association with MSS in the MIA and UKB cohorts.

RESULTS

Two loci were significantly associated with MSS in the meta-analysis of MIA and UKB with lead SNPs rs41309643 (G allele frequency 1.6%, HR = 2.09, 95%CI = 1.61-2.71, P = 2.08 × 10-8) on chromosome 1, and rs75682113 (C allele frequency 1.8%, HR = 2.38, 95%CI = 1.77-3.21, P = 1.07 × 10-8) on chromosome 7. While neither SNP replicated in the LMC, rs75682113 was significantly associated in the combined discovery and replication sets. After adjusting for age at diagnosis, sex and the first ten principal components, a one standard deviation increase in the CM-susceptibility PRS was associated with improved MSS in the discovery meta-analysis (HR = 0.88, 95% CI = 0.83-0.94, P = 6.93 × 10-5; I2 = 88%). However, this was only driven by the high UV setting cohort (MIA HR = 0.84, 95% CI = 0.78-0.90).

CONCLUSION

We found two loci potentially associated with MSS. Increased genetic susceptibility to develop CM is associated with improved MSS in a high UV setting.

Sentinel node tumor burden in cutaneous melanoma. Survival with competing risk analysis and influence in relapses and non-sentinel node status: retrospective cohort study with long follow-up in a Spanish population

Several authors have studied the potential of sentinel lymph node (SLN) tumor burden as prognostic factor but the microscopic classifications used in different study groups were variable. We examined the prognostic role of tumor burden in SLN on melanoma specific-survival and competing causes of death. We also analysed clinical and histological factors as predictors of disease relapses and additional non sentinel lymph node (NSLN) metastases. We included all patients with cutaneous melanoma that underwent SLN biopsy between 2002 and 2012 at Complejo Hospitalario de Navarra (Spain). The study end-points were death due to melanoma, melanoma relapse and involvement of NSLN. We used Fine-Gray test for competing risk analysis. A logistic regression model was performed to predict the risk of involvement of NSLN. Between 2002 and 2012, there were 348 patients who underwent SLN biopsy in our centre (308 were eligible for the study). 26.9% patients positive SLN. 88 patients died during the follow-up period and 66 (75%) died from melanoma. The 5-year cumulative incidence of melanoma death was 15.33% (95 % CI 15.25-15.42). The cumulative probability of death from melanoma was associated with gender, histological subtype, Breslow thickness, mitotic rate, ulceration and SLN tumor burden. In multivariable analysis, Breslow thickness and SLN tumor burden remained as independent prognostic factors. SLN tumor burden appears to be an important prognostic factor. It is very important reporting these characteristics in pathological reports. More prospective studies would be necessary to analyze these variables and to be able to make recommendations in management of melanoma patients.

Management of Regional Nodal Melanoma

Regional nodal melanoma management has changed substantially over the past 2 decades alongside advances in systemic therapy. Significant data from retrospective studies and from 2 randomized controlled trials show no survival benefit to completion lymph node dissection compared with observation in sentinel lymph node-positive melanoma patients. Observation is becoming the standard recommendation in these patients, whereas patients with clinically detected lymph nodes are still recommended to undergo lymph node dissection. Promising early results from a neoadjuvant approach inform the ongoing evolution of melanoma management. Recruiting patients to clinical trials is paramount to attaining evidence-based practice changes in melanoma.

Predictors of Nonsentinel Lymph Node Metastasis in Cutaneous Melanoma: A Systematic Review and Meta-Analysis

BACKGROUND

Although completion lymph node dissection (CLND) is not routinely performed for a positive sentinel lymph node (SLN) anymore, adjuvant therapy depends on the risk factors available from SLN biopsy, including the risk of nonsentinel node metastases (NSNM). A systematic review and meta-analysis was performed in an attempt to identify risk factors that could be used to predict the risk of NSNM.

MATERIALS AND METHODS

Medline, Web of Science, Embase, and Cochrane were searched for articles discussing predictive factors for NSNM. PRISMA guidelines were followed, and RevMan software was used to calculate pooled odds ratios (OR) using the Mantel-Haenszel test.

RESULTS

Fifty publications were suitable for additional analysis. The clinical and primary tumor factors that were consistently identified as risk factors for NSNMs were: age >50, T stage 3 or 4, Clark level IV/V, ulceration, microsatellitosis, lymphovascular invasion, nodular histology, and extremity versus trunk primary tumor location. SLN factors that predicted NSNMs were >1 positive SLN, SLN micrometastatic tumor burden, diameter >2 mm, extracapsular extension, nonsubcapsular location (Dewar), and Rotterdam > 1 mm or ≥ 0.1 mm.

CONCLUSIONS

The findings in this study support that many clinical and pathologic risk factors that can be assessed with SLN biopsy alone can be used to predict the risk of NSNMs. The factors identified in this review should be evaluated in clinical prediction models to predict the risk of NSNMS, a prediction that may be used to select patients for adjuvant therapy in high-risk melanoma.

Performance of models predicting residual lymph node disease in melanoma patients following sentinel lymph node biopsy

BACKGROUND

Among melanoma patients with a tumor-positive sentinel node biopsy (SNB), approximately 20% harbor disease in non-sentinel nodes (nSN), as determined by a completion lymph node dissection (CLND). CLND lacks a survival benefit and has high morbidity. This study assesses predictive factors for nSN metastasis and validates five models predicting nSN metastasis.

METHODS

Patients with invasive melanoma were identified from the BC Cancer Agency (2005-2015). Clinicopathological data were collected from 296 patients who underwent a CLND after a positive SNB. Multivariate analysis was completed to assess predictive variables in the study population. Five models were externally validated using overall model performance (Brier score [calibration and discrimination]) and discrimination (area under the ROC curve [AUC]).

RESULTS

Seventy-three patients had nSN metastasis at the time of CLND. The variable most predictive of nSN involvement was lymphovascular invasion (odds ratio [OR] 3.99; 95% confidence interval [CI] 1.67-9.54; p = 0.002). The highest discrimination was Lee et al. (2004) (AUC 0.68 [95% CI 0.61-0.75]), Rossi et al. (2018) (AUC 0.68 [95% CI 0.57-0.77]), and Bertolli et al. (2019) (AUC 0.68 [95% CI 0.60-0.75]). Rossi et al. (2018) had the lowest overall model performance (Brier score 0.44). Rossi et al. (2018) and Bertolli et al. (2019) had the ability to stratify patients to a risk of nSN involvement up to 99% and 95%, respectively.

CONCLUSION

Bertolli et al. (2019) had amongst the highest overall model performance, was the most clinically meaningful and is recommended as the preferred model for predicting nSN metastasis.

The Role and Necessity of Sentinel Lymph Node Biopsy for Invasive Melanoma

Sentinel lymph node biopsy (SLNB) is a widely accepted procedure for melanoma staging and treatment. The development of lymphatic mapping and SLNB, which was first introduced in 1992, has enabled surgeons to detect microscopic nodal metastases and stage-negative regional nodal basins with low morbidity. SLNB has also facilitated the selective application of regional lymph node dissection for patients with microscopic nodal metastases, enabling unnecessary lymph node dissection. In contrast, recent major randomized phase III trials (DeCOG-SLT and MSLT–II trial) compared the clinical benefit of early completion lymph node dissection with observation after detecting microscopic nodal disease. The results of those studies indicated that there was no significant difference in the survival between the two groups, although regional control was superior after early completion lymph node dissection compared to that obtained after observation. Thus, the role and value of early completion lymph node dissection worldwide are currently very limited for patients with microscopic nodal disease. However, the use of SLNB is still controversial. In addition, the recent approval of adjuvant therapy using novel agents, such as anti-programmed death-1 antibodies, and molecular targeted therapeutics may influence the skipping of complete lymph node dissection in patients with micrometastatic nodal disease in a real-world setting. Furthermore, modern neoadjuvant therapy, which is now under investigation, may have the potential to change the surgical procedure used for nodal disease. Herein, we describe the current role and value of SLNB and completion lymph node dissection and discuss the major controversies as well as the favorable future outlook.

Mitotic rate as an important prognostic factor in cutaneous malignant melanoma

BACKGROUND

Recently, the quantification of mitoses in cutaneous melanoma has been discharged from the main prognostic variables of the TNM classification.

OBJECTIVE

To investigate the prognostic value of the presence of mitoses in primary cutaneous melanoma and to establish the number of mitoses per mm2 that may have prognostic significance.

METHODS

A retrospective observational study was performed on 141 patients treated for cutaneous melanoma, who were assessed by the same pathologist, and who had a minimum follow-up of 2 years. Clinical, epidemiological, histopathological and follow-up variables were gathered and compared with the number of mitoses to distinguish the significance of differences by means of univariate, multivariate, and survival analyses.

RESULTS

The cut-off level related to a better sensitivity and specificity was 1.50 mitoses per mm2. The presence of two or more mitoses/mm2 showed a better relationship with prognostic variables and both the overall and disease-free survival than the presence of 1 or more mitoses/mm2. This happens especially in melanomas thicker than 0.8 mm and it could affect the staging in cases with Breslow between 1 and 2 mm.

CONCLUSIONS

A mitotic rate of two or more mitoses per mm2 in cutaneous melanoma should be considered as a more accurate prognostic factor than one or more mitoses per mm2, particularly in tumors equal or greater than 0.8 mm in thickness.

Meta-analysis of completion lymph node dissection in sentinel lymph node-positive melanoma

BACKGROUND

The role of completion lymph node dissection (CLND) in patients with sentinel lymph node (SLN)-positive melanoma continues to be debated. This systematic review and meta-analysis evaluated survival and recurrence rate in these patients who underwent CLND, compared with observation.

METHODS

A comprehensive MEDLINE and Embase database search was performed for cohort studies and RCTs published between January 2000 and June 2017 that assessed the outcomes of CLND compared with observation in patients with SLN-positive melanoma. The primary outcome was survival and the secondary outcome was recurrence rate. Studies were assessed for quality using the Cochrane risk-of-bias tool for RCTs and Newcastle-Ottawa Scale for cohort studies. Pooled relative risk or hazard ratio with 95 per cent confidence intervals were calculated for each outcome. The extent of heterogeneity between studies was assessed with the I² test. The protocol was registered in PROSPERO (CRD42017070152).

RESULTS

Fifteen studies (13 cohort studies with 7868 patients and 2 RCTs with 2228 patients) were identified for qualitative synthesis. Thirteen studies remained for quantitative meta-analysis. Survival was similar in patients who underwent CLND and those who were observed (risk ratio (RR) for death 0·85, 95 per cent c.i. 0·71 to 1·02). The recurrence rate was also similar (RR 0·91, 0·79 to 1·05).

CONCLUSION

Patients with SLN-positive melanoma do not have a significant benefit in survival or recurrence rate if they undergo CLND rather than observation.

Retrospective study of patients with cutaneous melanoma treated at the Federal University of São Paulo

OBJECTIVE

to evaluate the characteristics of the patients with cutaneous melanoma treated at the São Paulo Hospital - UNIFESP.

METHODS

we conducted a retrospective study of 184 cases of cutaneous melanoma. We analyzed information on gender, age, tumor characteristics, histological characteristics and staging.

RESULTS

mean age at diagnosis was 58.7 years, with homogeneous age distribution between genders and predominance in white individuals (70.6%). There was a predominance of trunk involvement in men (36.7%) and lower limbs in women (42%). Sun exposure, with sunburns, was more common among males (31.2%) than among females (23.5%). There was an approximately three-fold increase in lymph node involvement when the mitotic index rose from zero (11.9%) to one or more mitosis per field (36.2%). In addition, the greater the Breslow thickness, the greater the lymph node involvement and poor the outcomes: 10.2% when less than 1mm and 59.2% when greater than 4mm.

CONCLUSION

the characteristics of patients with cutaneous melanoma treated at Hospital São Paulo are similar to those found in the literature.

Essential Components of Melanoma Histopathological Reporting: The Surgical Oncologist's Perspective

Histopathological reporting plays a critical role in guiding the surgical oncologist's management plan in treatment of primary cutaneous melanoma. The International Collaboration on Cancer Reporting (ICCR) espouses various components of structured histopathological reporting as "essential" or "recommended." From a surgical oncologist's perspective, we discuss the clinical relevance of each essential component, as well as prognostic and treatment implications with regard to treatment planning.

Patients with sentinel lymph node positive melanoma: Who needs completion lymph node dissection?

INTRODUCTION

Completion lymph node dissection (CLND) for melanoma after positive sentinel lymph node biopsy (SLNB) was recently shown to improve regional but not overall survival, likely due to the majority of patients harboring no further nodal disease. We sought to determine predictors of non-sentinel node (NSN) positivity.

METHODS

Retrospective review of prospectively collected data on melanoma patients undergoing SLNB.

RESULTS

116 patients underwent 119 CLNDs. The incidence of NSN positivity was 17.6%; the average number of positive NSNs in those cases was 1.5. Cervical and inguinofemoral location were most likely to yield positive NSN(s) (40% each). Conversely, the axilla was least likely at 18% (p < 0.001). The average number of nodes harvested was 13 for NSN negative cases and 20 for NSN positive cases (p = 0.005). Tumor thickness increased the probability of positive NSN(s) (OR 1.2, p = 0.02).

CONCLUSIONS

Tumor thickness and nodal basin were predictors of NSN metastasis, factors that could help determine which patients may benefit from CLND. Further, CLNDs with fewer nodes may inadequately clear residual nodal disease.

Predictive Factors for the Positivity of the Sentinel Lymph Node in Malignant Melanoma

Malignant melanoma is a neoplasia that has its origin in the melanocytes, the melanin-synthesizing pigment cells present in the epidermis or sometimes in the dermis. Sentinel lymph node biopsy (SLNB) is the standard procedure used for staging patients with malignant melanoma in the majority of surgical centers in the world. With a probability of approximately 20% of finding positive lymph nodes, it spares a large number of patients of a complete lymphatic dissection. The aim of this study is to evaluate the factors that can predict the positivity of sentinel lymph nodes in malignant melanoma patients. We performed a retrospective study analyzing the histopathologic reports of patients who underwent SLNB for malignant melanoma between 2012 and 2015. There were 32 patients identified, out of which only three (9.37%) had positive SLN, so the majority of our patients were spared of regional lymphatic dissection. In our series, lymphatic invasion (p = 0.01), Breslow index >4 mm (p = 0.0064), AJCC staging (p = 0.0008), the presence of precursory lesions (p = 002), and microsatellitosis (p = 0.017) were predictive factors for the positivity of the SLN in malignant melanoma patients. Although our results are similar to those published in the literature, we consider that larger cohort studies should be performed to consolidate our results.

Prediction of Non-sentinel Node Status in Patients with Melanoma and Positive Sentinel Node Biopsy: An Italian Melanoma Intergroup (IMI) Study

BACKGROUND AND PURPOSE

Approximately 20% of melanoma patients harbor metastases in non-sentinel nodes (NSNs) after a positive sentinel node biopsy (SNB), and recent evidence questions the therapeutic benefit of completion lymph node dissection (CLND). We built a nomogram for prediction of NSN status in melanoma patients with positive SNB.

METHODS

Data on anthropometric and clinicopathological features of patients with cutaneous melanoma who underwent CLND after a positive SNB were collected from nine Italian centers. Multivariate logistic regression was utilized to identify predictors of NSN status in a training set, while model efficiency was validated in a validation set.

RESULTS

Data were available for 1220 patients treated from 2000 through 2016. In the training set (n = 810), the risk of NSN involvement was higher when (1) the primary melanoma is thicker or (2) sited in the trunk/head and neck; (3) fewer nodes are excised and (4) more nodes are involved; and (5) the lymph node metastasis is larger or (6) is deeply located. The model showed high discrimination (area under the receiver operating characteristic curve 0.74, 95% confidence interval [CI] 0.70-0.79) and calibration (Brier score 0.16, 95% CI 0.15-0.17) performance in the validation set (n = 410). The nomogram including these six clinicopathological variables performed significantly better than five other previously published models in terms of both discrimination and calibration.

CONCLUSIONS

Our nomogram could be useful for follow-up personalization in clinical practice, and for patient risk stratification while conducting clinical trials or analyzing their results.

Tumor Mitotic Rate and Association with Recurrence in Sentinel Lymph Node Negative Stage II Melanoma Patients

Tumor mitotic rate (TMR) is a known prognostic variable in thin melanoma patients. Its significance in stage II melanoma patients is yet to be demonstrated. Retrospective analysis of a prospective melanoma database from 9/1997 to 7/2015 was performed. All stage II melanoma, with documented TMR, and six months of follow-up were included. We evaluated the association of clinicopathologic variables, TMR, as a continuous and categorical variable with recurrence-free survival (RFS) and overall survival (OS) using Cox proportional hazards modeling. We used a statistical model, X-tile, to develop optimal categorizations of TMR. A total of 265 patient characteristics are included in this study. Recurrences occurred in 82 (30.9%) patients, including 5 local, 41 regional, and 36 distant patients. In multivariate model, ulceration, Breslow, and continuous TMR were associated with worse RFS\OS. Continuous TMR demonstrated worse RFS (hazards ratio [HR] 1.02 (1.00–1.05)) and OS (HR 1.02 (1.00–1.04)), whereas dichotomized TMR (≥1 vs <1) was not significant. TMR >10.4 mitoses/mm2 has a 5-year RFS\OS of 27.2 and 44.3 per cent, respectively, compared with 57.4 and 71.4 per cent, respectively, for TMR <3.2 mitoses/mm2. Continuous TMR predicts incidence of recurrence in stage II melanoma. We propose a new categorization method developed by statistical modeling for optimal stratification that may guide surveillance for this disparate patient population.

Sentinel node metastasis mitotic rate (SN-MMR) as a prognostic indicator of rapidly progressing disease in patients with sentinel node-positive melanomas

Risk stratification of sentinel lymph node biopsy (SNB)-positive patients with malignant melanoma differs among current classification systems. To improve classification of patients with rapidly progressive disease who may profit from adjuvant therapy with novel immune or targeted treatment modalities, a single-center retrospective analysis was performed including all melanoma patients diagnosed with a positive SN at a university-based skin cancer center over a 10-year period (2002-2012) (96 of 419 patients). Sentinel node metastasis mitotic rate (SN-MMR) and further histologic parameters were determined by blinded histological re-evaluation and correlated with clinical follow-up (overall [OS], melanoma-specific [MSS], and disease-free survival [DFS]). Median follow-up was 53 months. In univariate analyses, SN tumor penetrative depth (TPD), maximum tumor diameter (MTD), number of positive SN, SN-MMR and the S-, Rotterdam, RDC, Hannover I and II classification systems correlated with OS, MSS and DFS. Multivariate Cox regression analyses showed that a binary classification system based only on the SN-MMR (<1 vs. ≥1 mitoses/mm2 ) was the strongest independent prognostic indicator for all endpoints analyzed. Kaplan-Meier analyses confirmed binary SN-MMR to be superior to stratify patients into high- and low-risk groups (45.45% vs. 87.92% 5-yr MSS). The general prognostic validity of the published SN classification systems was confirmed. The novel SN-MMR classification system may improve discrimination of patients with slowly and rapidly progressive disease. We therefore propose its implementation into clinical practice as the SN-MMR can be easily and reliably determined in routine pathology reports. Its prognostic value for the selection of patients amenable to adjuvant therapies should be studied in clinical trials.