Enhancing the prognostic role of melanoma sentinel lymph nodes through microscopic tumour burden characterization: clinical usefulness in patients who do not undergo complete lymph node dissection

Investigation of prognostic factors for non-sentinel lymph node metastasis in patients undergoing sentinel lymph node biopsy for cutaneous malignant melanoma: Experience from a reference centre in Turkey

BACKGROUND

In the light of the results of recent randomised controlled trials regarding the role of nodal observation and completion lymph node dissection (CLND), studies from different populations are needed. The aim of our study was to present our experience with sentinel lymph node biopsy (SLNB) and CLND and the clinical and histopathological factors associated with a positive non-sentinel node.

METHODS

In this single-centre, retrospective study, we reviewed histopathological reports of patients with primary cutaneous melanoma who underwent SLNB and CLND over a period of 7 years. The primary outcomes were the positivity rates of SLNBs and CLNDs. Secondary outcomes were metastatic tumour burden in positive sentinel nodes and presence of perinodal invasion.

RESULTS

Among the 110 participants who underwent SLNB (53 females, 57 males), the mean Breslow thickness of the primary tumour was 4.1 (0.3-41) mm. Ulceration appeared in 62.7% of lesions. The SLNBs were positive in 38 patients (34.5%), with 35 (92.1%) undergoing CLND, among which 9 (25.7%) showed metaNBstasis. Positive SLNB was linked to a higher Breslow thickness (p = 0.022), whereas CLND results lacked such an association (p = 0.76). Perinodal invasion (p = 0.006) and sentinel lymph node metastasis exceeding 1 mm (p = 0.017) was associated with a higher probability of non-sentinel node metastasis.

CONCLUSION

To adapt the results of the new cohort study on SLNB and melanoma to different populations, studies with different patient groups highlighting the problems and suggested solutions are needed.

Prediction of nonsentinel lymph node metastasis in acral melanoma with positive sentinel lymph nodes

BACKGROUND

Metastasis in a nonsentinel lymph node (non-SLN) is an unfavorable independent prognostic factor in cutaneous melanoma (CM). Recent data did suggest potential value of completion lymph node dissection (CLND) in CM patients with non-SLN metastasis. Prediction of non-SLN metastasis assists clinicians in deciding on adjuvant therapy without CLND. We analyzed risk factors and developed a prediction model for non-SLN status in acral melanoma (AM).

METHODS

This retrospective study enrolled 656 cases of melanoma who underwent sentinel lymph node biopsy at Fudan University Shanghai Cancer Center from 2009 to 2017. We identified 81 SLN + AM patients who underwent CLND. Clinicopathologic data, including SLN tumor burden and non-SLN status were examined with Cox and Logistics regression models.

RESULTS

Ulceration, Clark level, number of deposits in the SLN (NumDep) and maximum size of deposits (MaxSize) are independent risk factors associated with non-SLN metastases. We developed a scoring system that combines ulceration, the cutoff values of Clark level V, MaxSize of 2 mm, and NumDep of 5 to predict non-SLN metastasis with an efficiency of 85.2% and 100% positive predictive value in the high-rank group (scores of 17-24).

CONCLUSIONS

A scoring system that included ulceration, Clark level, MaxSize, and NumDep is reliable and effective for predicting non-SLN metastasis in SLN-positive AM.

A new label-free optical imaging method for the lymphatic system enhanced by deep learning

Our understanding of the lymphatic vascular system lags far behind that of the blood vascular system, limited by available imaging technologies. We present a label-free optical imaging method that visualizes the lymphatic system with high contrast. We developed an orthogonal polarization imaging (OPI) in the shortwave infrared range (SWIR) and imaged both lymph nodes and lymphatic vessels of mice and rats in vivo through intact skin, as well as human mesenteric lymph nodes in colectomy specimens. By integrating SWIR-OPI with U-Net, a deep learning image segmentation algorithm, we automated the lymph node size measurement process. Changes in lymph nodes in response to cancer progression were monitored in two separate mouse cancer models, through which we obtained insights into pre-metastatic niches and correlation between lymph node masses and many important biomarkers. In a human pilot study, we demonstrated the effectiveness of SWIR-OPI to detect human lymph nodes in real time with clinical colectomy specimens.

One Sentence Summary

We develop a real-time high contrast optical technique for imaging the lymphatic system, and apply it to anatomical pathology gross examination in a clinical setting, as well as real-time monitoring of tumor microenvironment in animal studies.

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.

Sentinel Lymph Node Tumor Burden Using Digital Cell Count Estimation Predicts Outcomes in Melanoma

BACKGROUND

Cutaneous melanoma often metastasizes in primis to sentinel lymph nodes (SLNs). Currently, there is no standardized method of characterizing micrometastatic tumor burden in SLN biopsies for melanoma. Different criteria have been developed to evaluate SLN biopsies, yet none consider the number of cells identified.

AIM

Here, we used software analysis to digitally quantify metastatic tumor burden within SLNs and correlated these data with clinicopathologic and prognostic information.

METHODS

We identified 246 cases of SLN biopsies, including 63 positive (26%) and 183 (74%) negative for metastatic melanoma. Digital cell counting was performed within the greatest metastatic focus and the entire metastatic tumor burden within the same SLN.

RESULTS

Increasing cell count in the largest metastatic deposit correlated with the previously described Rotterdam (Spearman's r = 0.91; 95% CI: 0.84, 0.94), Starz (Spearman's r = 0.78; 95% CI: 0.68, 0.87), and Dewar criteria (p < 0.01), validating our method of using cell count to define SLN tumor burden. Additionally, increasing cell count was associated with decreased metastasis free survival (HR = 2.29; 95% CI: 1.22, 4.31).

CONCLUSION

These data support the use of computerized cell count analysis for prognostication of outcomes in patients undergoing SLN biopsy.

Regional Lymph Node Metastases in Cutaneous Melanoma: A Single-Center Analysis from Southeast Europe

OBJECTIVE

Sentinel lymph node biopsy is the standard of care for nodal staging in clinically node-negative melanoma patients. Our goal was to present 10-year results of sentinel lymph node biopsy at our institution and to evaluate the clinicopathologic factors as potential predictors of sentinel lymph node and non-sentinel lymph node metastatic involvement in patients with cutaneous melanoma.

METHODS

We have analyzed clinicopathologic and lymphoscintigraphic characteristics in 420 patients with cutaneous melanoma who underwent sentinel lymph node biopsy between 2010 and 2019. In addition, we have examined the results of group of patients with positive sentinel lymph node biopsy undergoing complete lymph node dissection.

RESULTS

The overall detection rate of sentinel lymph node biopsies was 97.1%, of which 18.8% was metastatic. Drainage to one regional basin was seen in 345 patients (83.1%) and to multiple drainage regions in 71 patients (17%). In-transit lymph nodes were detected in 20 patients. On univariate logistic regression analysis, male gender, primary tumor thickness with nodular histology, acral location, presence of ulceration, and the number of nodes harvested were significantly associated with sentinel lymph node biopsy status (p < 0.05). On multivariate analysis, the Breslow thickness was the only independent predictor of sentinel lymph node biopsy status. The metastases in non-sentinel lymph node found in 26 patients with positive sentinel lymph node (35.6%) correlated on univariate, as well as on multivariate logistic regression, with tumor subtype and number of sentinel lymph node harvested.

CONCLUSION

In addition to the well-established primary tumor thickness as a predictor of sentinel lymph node biopsy positivity, we observed acral location and nodular melanoma subtype to significantly enhance the risk of metastases in sentinel lymph node(s). Primary tumor histology and number of nodes harvested were the only statistically significant variables predicting the non-sentinel lymph node status on multivariate analysis. Lymphoscintigraphy imaging characteristics were not significantly associated with sentinel lymph node status.

The sentinel node invasion level (SNIL) as a prognostic parameter in melanoma

Sentinel lymph node (SN) tumor burden is becoming increasingly important and is likely to be included in future N classifications in melanoma. Our aim was to investigate the prognostic significance of melanoma infiltration of various anatomically defined lymph node substructures. This retrospective cohort study included 1250 consecutive patients with SN biopsy. The pathology protocol required description of metastatic infiltration of each of the following lymph node substructures: intracapsular lymph vessels, subcapsular and transverse sinuses, cortex, paracortex, medulla, and capsule. Within the SN with the highest tumor burden, the SN invasion level (SNIL) was defined as follows: SNIL 1 = melanoma cells confined to intracapsular lymph vessels, subcapsular or transverse sinuses; SNIL 2 = melanoma infiltrating the cortex or paracortex; SNIL 3 = melanoma infiltrating the medulla or capsule. We classified 338 SN-positive patients according to the non-metric SNIL. Using Kaplan-Meier estimates and Cox models, recurrence-free survival (RFS), melanoma-specific survival (MSS) and nodal basin recurrence rates were analyzed. The median follow-up time was 75 months. The SNIL divided the SN-positive population into three groups with significantly different RFS, MSS, and nodal basin recurrence probabilities. The MSS of patients with SNIL 1 was virtually identical to that of SN-negative patients, whereas outgrowth of the metastasis from the parenchyma into the fibrous capsule or the medulla of the lymph node indicated a very poor prognosis. Thus, the SNIL may help to better assess the benefit-risk ratio of adjuvant therapies in patients with different SN metastasis patterns.

The prognostic significance of non-sentinel lymph node metastasis in cutaneous and acral melanoma patients-A multicenter retrospective study

Background

Whether non‐sentinel lymph node (SLN)‐positive melanoma patients can benefit from completion lymph node dissection (CLND) is still unclear. The current study was performed to identify the prognostic role of non‐SLN status in SLN‐positive melanoma and to investigate the predictive factors of non‐SLN metastasis in acral and cutaneous melanoma patients.

Methods

The records of 328 SLN‐positive melanoma patients who underwent radical surgery at four cancer centers from September 2009 to August 2017 were reviewed. Clinicopathological data including age, gender, Clark level, Breslow index, ulceration, the number of positive SLNs, non‐SLN status, and adjuvant therapy were included for survival analyses. Patients were followed up until death or June 30, 2019. Multivariable logistic regression modeling was performed to identify factors associated with non‐SLN positivity. Log‐rank analysis and Cox regression analysis were used to identify the prognostic factors for disease‐free survival (DFS) and overall survival (OS).

Results

Among all enrolled patients, 220 (67.1%) had acral melanoma and 108 (32.9%) had cutaneous melanoma. The 5‐year DFS and OS rate of the entire cohort was 31.5% and 54.1%, respectively. More than 1 positive SLNs were found in 123 (37.5%) patients. Positive non‐SLNs were found in 99 (30.2%) patients. Patients with positive non‐SLNs had significantly worse DFS and OS (log‐rank P < 0.001). Non‐SLN status (P = 0.003), number of positive SLNs (P = 0.016), and adjuvant therapy (P = 0.025) were independent prognostic factors for DFS, while non‐SLN status (P = 0.002), the Breslow index (P = 0.027), Clark level (P = 0.006), ulceration (P = 0.004), number of positive SLNs (P = 0.001), and adjuvant therapy (P = 0.007) were independent prognostic factors for OS. The Breslow index (P = 0.020), Clark level (P = 0.012), and number of positive SLNs (P = 0.031) were independently related to positive non‐SLNs and could be used to develop more personalized surgical strategy.

Conclusions

Non‐SLN‐positive melanoma patients had worse DFS and OS even after immediate CLND than those with non‐SLN‐negative melanoma. The Breslow index, Clark level, and number of positive SLNs were independent predictive factors for non‐SLN status.

Sentinel node tumor burden in prediction of prognosis in melanoma patients

Recent data have demonstrated no survival benefit to immediate completion lymph node dissection (CLND) for positive sentinel node (SN) disease in melanoma. It is important to identify parameters in positive SNs, which predict prognosis in melanoma patients. These might provide prognostic value in staging systems and risk models by guiding high-risk patients’ adjuvant therapy in clinical practice. In this retrospective study of university hospital melanoma database we analyzed tumor burden and prognosis in patients with positive SNs. Patients were stratified by the diameter of tumor deposit, distribution of metastatic focus in SN, ulceration and number of metastatic SNs. These were incorporated in Cox proportional hazard regression models. Predictive ability was assessed using Akaike information criterion and Harrell’s concordance index. A total of 110 patients had positive SN and 104 underwent CLND. Twenty-two (21%) patients had non-SN metastatic disease on CLND. The 5-year melanoma specific survival for CLND-negative patients was 5.00 years (IQR 3.23–5.00, range 0.72–5.00) compared to 3.69 (IQR 2.28–4.72, range 1.01–5.00) years in CLND-positive patients (HR 2.82 (95% CI 1.17–6.76, p = 0.020).The models incorporating distribution of metastatic focus and the largest tumor deposit in SN had highest predictive ability. According to Cox proportional hazard regression models, information criterions and c-index, the diameter of tumor deposit > 4 mm with multifocal location in SN despite of number of metastatic SN were the most important parameters. According to the diameter of tumor deposit and distribution of metastatic focus in SN, adequate stratification of positive SN patients was possible and risk classes for patients were identified.

[Sentinel node biopsy and lymph node dissection in the era of new systemic therapies for malignant melanoma]

BACKGROUND

Recently, adjuvant therapies with checkpoint inhibitors and BRAF/MEK inhibitors have become available for patients with malignant melanoma and microscopic nodal disease. Meanwhile the number of complete nodal dissections for a melanoma-positive sentinel node (SN) have decreased significantly.

OBJECTIVE

The authors discuss the significance of sentinel node biopsy (SNB) and early lymph node dissection in the era of adjuvant systemic therapy for stage III melanoma.

MATERIALS AND METHODS

Current publications and recommendations were evaluated.

RESULTS

Complete nodal dissection for a positive SN significantly reduces the risk of regional nodal relapse. However, neither SNB nor complete nodal dissection following a positive SN are associated with a benefit in survival. With the availability of novel adjuvant systemic treatment strategies for stage III melanoma, SNB has become an even more important part of modern staging diagnostics. Thus, detection of early dissemination of melanoma cells into the SN as well as the quantification of the tumor load are decisive for further therapy planning.

CONCLUSION

Accurate assessment of the regional lymph node status by SNB is becoming even more important in the era of novel effective adjuvant therapies for microscopic nodal disease. Whether complete lymph node dissection is performed in patients with a positive SN needs to be assessed individually. In the case of "active nodal surveillance" instead of surgery, long-term close follow-up in specialized centers, including ultrasonographic controls, is required.

Impact of American Joint Committee on Cancer 8th edition classification on staging and survival of patients with melanoma

OBJECTIVE

The American Joint Committee on Cancer (AJCC) 8th staging system introduced several revisions. To assess the impact of the 8th edition American Joint Committee on Cancer (AJCC8) staging system on subgrouping and survival, patients with melanoma from two tertiary skin cancer centres were classified according to both the 7th edition American Joint Committee on Cancer (AJCC7) and AJCC8.

METHODS

A total of 1948 patients aged ≥18 years with cutaneous melanoma stage II-IV were included. The impact of sex and age on reclassification was assessed by log binomial models. The inverse probability of censoring weighting method was used to compute ROC curves from time-to-event data to assess the discriminatory ability of AJCC7 and AJCC8. Melanoma-specific survival (MSS) and overall survival (OS) were calculated, and age- and sex-adjusted MSS hazard ratios were estimated using Cox proportional hazards models.

RESULTS

Of all, 23.5% of patients were assigned a different subgroup when classified according to AJCC8. Owing to upshifting to stage IIIC (AJCC7 24.8% vs. AJCC8 50.8%), patient numbers of stages IIIA and IIIB decreased from 28.7% to 16.2% and 46.5% to 28.3%. The prediction accuracy for AJCC7 and AJCC8 was comparable (integrated time-dependent area under the curve [AUC] of 0.75 and 0.74, respectively). Five-year MSS of IIB and IIC AJCC8 was poor and lower than that of IIIA AJCC8 (80%, 67% and 89%, respectively). Compared to results of the International Melanoma Database and Discovery Platform, 5-year MSS was 10-15% points lower for stages IIC, IIIB and IIIC.

CONCLUSIONS

Upshifting affects primarily stage III subgroups, while effects in stage II are minor. Stage IIB/C (AJCC8) patients have 67-80% MSS and should be considered for adjuvant treatment, while in stage IIIA, the indication of adjuvant treatment is questionable.