Tumor-infiltrating lymphocytes as a prognostic and predictive factor for Melanoma

INTRODUCTION

Tumor-infiltrating lymphocytes (TILs) have been investigated as prognostic factors in melanoma. Recent advancements in assessing the tumor microenvironment in the setting of more widespread use of immune checkpoint blockade have reignited interest in identifying predictive biomarkers. This review examines the function and significance of TILs in cutaneous melanoma, evaluating their potential as prognostic and predictive markers.

AREAS COVERED

A literature search was conducted on papers covering tumor infiltrating lymphocytes in cutaneous melanoma available online in PubMed and Web of Science from inception to 1 December 2023, supplemented by citation searching. This article encompasses the assessment of TILs, the role of TILs in the immune microenvironment, TILs as a prognostic factor, TILs as a predictive factor for immunotherapy response, and clinical applications of TILs in the treatment of cutaneous melanoma.

EXPERT OPINION

Tumor-infiltrating lymphocytes play a heterogeneous role in cutaneous melanoma. While they have historically been associated with improved survival, their status as independent prognostic or predictive factors remains uncertain. Novel methods of TIL assessment, such as determination of TIL subtypes and molecular signaling, demonstrate potential for predicting therapeutic response. Further, while their clinical utility in risk-stratification in melanoma treatment shows promise, a lack of consensus data hinders standardized application.

Lymphadenectomy After Melanoma-A National Analysis of Recurrence Rates and Risk of Lymphedema

INTRODUCTION

Treatment for melanoma after a positive sentinel lymph node biopsy includes nodal observation or lymphadenectomy. Important considerations for management, however, involve balancing the risk of recurrence and the risk of lymphedema after lymphadenectomy.

METHODS

From the Merative MarketScan Research Databases, adult patients were queried from 2007 to 2021. International Classification of Disease, Ninth (ICD-9) and Tenth (ICD-10) Editions, diagnosis codes and Current Procedural Terminology codes were used to identify patients with melanoma diagnoses who underwent an index melanoma excision with a positive sentinel lymph node biopsy (SLNB). Main outcomes were completion lymph node dissection (CLND) utilization after a positive SLNB, developing lymphedema with or without CLND, and nodal basin recurrence 3 months or more after index excision. Subanalyses stratified by index excision year (2007-2017 and 2018-2021) and propensity score matched were additionally conducted. Demographics and comorbidities (measured by Elixhauser index) were recorded.

RESULTS

A total of 153,085,453 patients were identified. Of those, 359,298 had a diagnosis of melanoma, and 202,456 patients underwent an excision procedure. The study cohort comprised 3717 patients with a melanoma diagnosis who underwent an excision procedure and had a positive SLNB. The mean age of the study cohort was 49 years, 57% were male, 41% were geographically located in the South, and 24% had an Elixhauser index of 4+. Among the 350 patients who did not undergo CLND, 10% experienced recurrence and 22% developed lymphedema. A total of 3367 patients underwent CLND, of which 8% experienced recurrence and 20% developed lymphedema. Completion lymph node dissection did not significantly affect risk of recurrence [odds ratio (OR), 1.370, P = 0.090] or lymphedema (OR, 1.114, P = 0.438). After stratification and propensity score matching, odds of experiencing lymphedema (OR, 1.604, P = 0.058) and recurrence (OR, 1.825, P = 0.058) after CLND were not significantly affected. Rates of CLND had significantly decreased (P < 0.001) overtime, without change in recurrence rate (P = 0.063).

CONCLUSIONS

Electing for nodal observation does not increase the risk of recurrence or reduce risk of lymphedema. Just as CLND does not confer survival benefit, its decreased utilization has not increased recurrence rate.

Prognostic Factors and Clinical Outcomes of Clinical Node-Negative Cutaneous Malignant Melanoma Patients: An Asian Single Institute Study

INTRODUCTION

Cutaneous malignant melanoma is notorious for its aggressive behavior and relatively poor outcome compared with other common skin malignancies. Acral lentiginous melanoma (ALM) accounts for at least 50% of melanoma in the Asian population and has a significantly lower survival rate. However, previous studies of the prognostic factors of melanoma-specific survival were all conducted from Western institutions. Here, we performed a retrospective analysis to investigate this issue.

METHODS

Fifty patients diagnosed as having clinical node-negative cutaneous malignant melanoma who underwent sentinel lymph node (SLN) biopsy at Taipei Veterans General Hospital between January 2007 and December 2018 were enrolled. Patient demographics, tumor characteristics, and lymph node characteristics were evaluated by chart review.

RESULTS

Eighty-two percent of the melanoma in the sample population was ALM. Twelve patients (24.0%) presented at least 1 metastatic sentinel node, and the average number of retrieved SLNs was 3. Of the patients with positive SLNs who proceeded to completion lymph node dissection, only 2 (16.7%) had metastatic nonsentinel nodes (NSNs). The average follow-up time for all patients was 45 months. Recurrence and melanoma-specific death occurred in 21 patients (42.0%) and 15 patients (30.0%), respectively. Melanoma-specific survival was significantly lower in patients with ulcerative lesions (P = 0.005) and more metastatic SLNs (P = 0.036). The overall morbidity rate of completion lymph node dissection was 66.7%.

CONCLUSIONS

The presence of ulcerations and number of metastatic SLNs were the most important prognostic factors in this ALM-dominant Asian cohort. Among patients with clinically negative nodes but positive SLNs, less than one-fourth of patients harbored metastatic NSNs. Completion lymph node dissection carries a relatively high risk of morbidity; therefore, further research regarding predictors of positive NSNs in the Asian population is necessary.

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.

Characterization of Sentinel Lymph Node Immune Signatures and Implications for Risk Stratification for Adjuvant Therapy in Melanoma

BACKGROUND

Although sentinel lymph node (SLN) biopsy is a standard procedure used to identify patients at risk for melanoma recurrence, it fails to risk-stratify certain patients accurately. Because processes in SLNs regulate anti-tumor immune responses, the authors hypothesized that SLN gene expression may be used for risk stratification.

METHODS

The Nanostring nCounter PanCancer Immune Profiling Panel was used to quantify expression of 730 immune-related genes in 60 SLN specimens (31 positive [pSLNs], 29 negative [nSLNs]) from a retrospective melanoma cohort. A multivariate prediction model for recurrence-free survival (RFS) was created by applying stepwise variable selection to Cox regression models. Risk scores calculated on the basis of the model were used to stratify patients into low- and high-risk groups. The predictive power of the model was assessed using the Kaplan-Meier and log-rank tests.

RESULTS

During a median follow-up period of 6.3 years, 20 patients (33.3%) experienced recurrence (pSLN, 45.2% [14/31] vs nSLN, 20.7% [6/29]; p = 0.0445). A fitted Cox regression model incorporating 12 genes accurately predicted RFS (C-index, 0.9919). Improved RFS was associated with increased expression of TIGIT (p = 0.0326), an immune checkpoint, and decreased expression of CXCL16 (p = 0.0273), a cytokine important in promoting dendritic and T cell interactions. Independent of SLN status, the model in this study was able to stratify patients into cohorts at high and low risk for recurrence (p < 0.001, log-rank).

CONCLUSIONS

Expression profiles of the SLN gene are associated with melanoma recurrence and may be able to identify patients as high or low risk regardless of SLN status, potentially enhancing patient selection for adjuvant therapy.

Expression of IMP3 in a retrospective cohort of melanomas with selective lymph node biopsy

Insulin-like growth factor-II mRNA-binding protein 3 (IMP-3), which is a member of the insulin-like growth factor mRNA-binding protein family, is expressed at high levels in many types of cancer, where it plays an important role in cell proliferation, as well as in the processes of invasion, migration, and metastasis. Its expression has also been demonstrated in malignant melanoma, but not in other benign skin lesions, which has raised the possibility of using it as a predictive and prognosis marker. Its relationship with sentinel lymph node biopsy, however, has not been explored yet. A retrospective study including 120 histological samples of patients diagnosed with malignant cutaneous melanoma in Granada, between 2012 and 2018, was developed. All patients had had a sentinel lymph node biopsy (SLNB) performed at Hospital Universitario San Cecilio. IMP3 immunostaining was simultaneously carried out in the cutaneous lesion. We observed a significant difference regarding the percentage of cells expressing IMP3 (29.73 ± 3.81 for negative SLNB vs 44.86 ± 5.91 for positive SLNB, P = .020). Our endpoint calculated according to the ROC curve of 35% was significant with P = .007. H (P = .013) and AR (P = .016) indexes, created by the percentage of positive tumor cells and the intensity of the IMP3 expression, were also statistically significant. The most optimal cut-off points to predict the positivity of the SLNB were 35 for the percentage of positive tumor cells and 70 for the H score. We found a significant association between the expression of IMP3 and the regional nodal status defined by the SLNB on malignant melanomas in our series.

Nodal and systemic recurrence following observation of a positive sentinel lymph node in melanoma

BACKGROUND

Two RCTs found no survival benefit for completion lymphadenectomy after positive sentinel lymph node biopsy compared with observation with ultrasound in patients with melanoma. Recurrence patterns and regional control are not well described for patients undergoing observation alone.

METHODS

All patients with a positive sentinel node biopsy who did not have immediate completion lymphadenectomy were identified from a single-institution database (1995-2018). First recurrences were classified as node only, local and in-transit (LCIT) only, LCIT and nodal, or systemic. Regional control and factors associated with recurrence survival were analysed.

RESULTS

Median follow-up was 33 months. Of 370 patients, 158 (42·7 per cent) had a recurrence. The sites of first recurrence were node only (13·2 per cent), LCIT only (11·9 per cent), LCIT and nodal (3·5 per cent), and systemic (13·8 per cent). The 3-year postrecurrence melanoma-specific survival rate was 73 (95 per cent c.i. 54 to 86) per cent for patients with node-only first recurrence, and 51 (31 to 68) per cent for those with initial systemic recurrence. In multivariable analysis, ulceration in the primary lesion (hazard ratio (HR) 2·53, 95 per cent c.i. 1·27 to 5·04), disease-free interval 12 months or less (HR 2·38, 1·28 to 4·35), and systemic (HR 2·57, 1·16 to 5·65) or LCIT and nodal (HR 2·94, 1·11 to 7·79) first recurrence were associated significantly with decreased postrecurrence survival. Maintenance of regional control required therapeutic lymphadenectomy in 13·0 per cent of patients during follow-up.

CONCLUSION

Observation after a positive sentinel lymph node biopsy is associated with good regional control, permits assessment of the time to and pattern of recurrence, and spares lymphadenectomy-related morbidity in patients with 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.

Nonsurgical Management of Lymph Node Basins in Melanoma

In this article we provide a critical review of the evidence available for surgical management of the nodal basin in melanoma, with an aim to ensure an understanding of risks and benefits for all lymph node surgery offered to patients, and alternatives to surgical management where appropriate.

Factors associated with sentinel lymph node status and prognostic role of completion lymph node dissection for thick melanoma

INTRODUCTION

Sentinel lymph node (SLN) biopsy is useful for the prognostic stratification of patients with thick melanoma. Identifying which variables are associated with SLN involvement and establishing risk in different subgroups of patients could be useful for guiding the indication of SLN biopsy. The value of complete lymph node dissection (CLND) in patients with a positive SLN biopsy is currently under debate.

MATERIALS AND METHODS

To identify factors associated with SLN involvement in thick melanoma we performed a multicentric retrospective cohort study involving 660 patients with thick melanoma who had undergone SLN biopsy. To analyze the role of CLND in thick melanoma patients with a positive SLN biopsy, we built a multivariate Cox proportional hazards model for melanoma-specific survival (MSS) and disease-free survival (DFS) and compared 217 patients who had undergone CLND with 44 who had not.

RESULTS

The logistic regression analysis showed that age, histologic subtype, ulceration, microscopic satellitosis, and lymphovascular invasion were associated with nodal disease. The CHAID (Chi-squared Automatic Interaction Detection) decision tree showed ulceration to be the most important predictor of lymphatic involvement. For nonulcerated melanomas, the histologic subtype lentigo maligna melanoma was associated with a low rate of SLN involvement (4.3%). No significant differences were observed for DFS and MSS between the CLND performed and not-performed groups. Nodal status on CLND was associated with differences in DFS and MSS rates.

CONCLUSION

We identified subgroups of thick melanoma patients with a low likelihood of SLN involvement. CLND does not offer survival benefit, but provides prognostic information.

Prophylactic incisional negative pressure wound therapy shows promising results in prevention of wound complications following inguinal lymph node dissection for Melanoma: A retrospective case-control series

BACKGROUND

Inguinal lymphadenectomy (ILND) for melanoma is associated with a number of complications including seroma, surgical site infection (SSI), and lymphedema. Incisional negative pressure wound therapy (iNPWT) has shown promising results in preventing postoperative morbidity across a wide variety of surgical procedures, but these results are yet to be investigated in patients undergoing ILND for melanoma.

METHODS

In this study, we reviewed the data of 55 melanoma patients treated with ILND between January 2015 and January 2017 at Odense University Hospital. Patients were followed up until April 2018 for the occurrence of seroma, SSI, and lymphedema. We used prophylactic iNPWT after ILND in 14 patients and compared their morbidity outcomes with the 41 patients receiving standard postoperative wound care in the same period.

RESULTS

The iNPWT intervention significantly reduced seroma compared to the control group (28.6% vs. 90.3%, p < 0.001) and had a trending impact on wound infection (42.9% vs. 65.9%, p = 0.13). The effect was not significant for the prevention of lymphedema (35.7% vs. 51.2%, p = 0.33). Because the iNPWT group had relatively fewer incidences of seroma, SSI, and lymphedema, the iNPWT intervention was more cost-effective than conventional wound care (US$911.2 vs. US$2542.7, p < 0.05).

CONCLUSION

The use of prophylactic iNPWT significantly reduced seroma formation following ILND. These promising results, however, need to be confirmed in a future prospective randomized trial.