Non-proportional hazards model with a PVF frailty term: application with a melanoma dataset

Survival data analysis often uses the Cox proportional hazards (PH) model. This model is widely applied due to its straightforward interpretation of the hazard ratio under the assumption that the hazard rates for two subjects remain constant over time. However, in several randomized clinical trials with long-term survival data comparing two new treatments, it is frequently observed that Kaplan-Meier plots exhibit crossing survival curves. This violation of the PH assumption of the Cox PH model can not be applied to evaluate the treatment's effect on survival. This paper introduces a novel long-term survival model with non-PH that incorporates a frailty term into the hazard function. This model allows us to examine the effect of prognostic factors on survival and quantify the degree of unobservable heterogeneity. The model parameters are estimated using the maximum likelihood estimation procedure, and we evaluate the performance of the proposed models through simulation studies. Additionally, we demonstrate the applicability of our approach by fitting the models to a real skin cancer dataset.

Recurrence Patterns and Clinical Management after a Positive Sentinel Node Biopsy in Melanoma Patients

Introduction melanoma patients who become stage III after a positive sentinel node biopsy (SNB) may have several patterns of recurrence patients and methods retrospective analysis of melanoma patients who have undergone SNB in a single institution from 2000 to 2015. Results There were 111 recurrences (45.1%) among 246 (20.3%) SNB positive patients and median DRFS was 77.7 months. After initial treatment, further recurrences occurred in 68 (77.3%) patients, regardless the site of initial recurrence conclusions multimodal strategies are recommended to achieve better results when managing stage III melanoma patients after a positive SNB.

Modern Approach to Melanoma Adjuvant Treatment with Anti-PD1 Immune Check Point Inhibitors or BRAF/MEK Targeted Therapy: Multicenter Real-World Report

BACKGROUND

The landscape of melanoma management changed as randomized trials have launched adjuvant treatment.

MATERIALS AND METHODS

An analysis of data on 248 consecutive melanoma stage III and IV patients given adjuvant therapy in eight centers (February 2019 to January 2021) was conducted.

RESULTS

The analyzed cohort comprised 147 melanoma patients given anti-PD1 (33% nivolumab, 26% pembrolizumab), and 101 (41%) were given dabrafenib plus trametinib (DT). The 2-year overall survival (OS), relapse-free survival (RFS), and distant-metastases-free survival (DMFS) rates were 86.7%, 61.4%, and 70.2%, respectively. The disease stage affected only the RFS rate; for stage IV, it was 52.2% (95% CI: 33.4-81.5%) vs. 62.5% (95% CI: 52.3-74.8%) for IIIA-D, p = 0.0033. The type of lymph node surgery before adjuvant therapy did not influence the outcomes. Completion of lymph node dissection cessation after positive SLNB did not affect the results in terms of RFS or OS. Treatment-related adverse events (TRAE) were associated with longer 24-month RFS, with a rate of 68.7% (55.5-84.9%) for TRAE vs. 56.6% (45.8-70%) without TRAE, p = 0.0031. For TRAE of grade ≥ 3, a significant decline in OS to 60.6% (26.9-100%; p = 0.004) was observed.

CONCLUSIONS

Melanoma adjuvant therapy with anti-PD1 or DT outside clinical trials appears to be effective and comparable with the results of registration studies. Our data support a de-escalating surgery approach in melanoma treatment.

International Center-Level Variation in Utilization of Completion Lymph Node Dissection and Adjuvant Systemic Therapy for Sentinel Lymph Node-Positive Melanoma at Major Referral Centers

OBJECTIVE

The aim of this study was to determine overall trends and center-level variation in utilization of completion lymph node dissection (CLND) and adjuvant systemic therapy for sentinel lymph node (SLN)-positive melanoma.

SUMMARY BACKGROUND DATA

Based on recent clinical trials, management options for SLN-positive melanoma now include effective adjuvant systemic therapy and nodal observation instead of CLND. It is unknown how these findings have shaped practice or how these contemporaneous developments have influenced their respective utilization.

METHODS

We performed an international cohort study at 21 melanoma referral centers in Australia, Europe, and the United States that treated adults with SLN-positive melanoma and negative distant staging from July 2017 to June 2019. We used generalized linear and multinomial logistic regression models with random intercepts for each center to assess center-level variation in CLND and adjuvant systemic treatment, adjusting for patient and disease-specific characteristics.

RESULTS

Among 1109 patients, performance of CLND decreased from 28% to 8% and adjuvant systemic therapy use increased from 29 to 60%. For both CLND and adjuvant systemic treatment, the most influential factors were nodal tumor size, stage, and location of treating center. There was notable variation among treating centers in management of stage IIIA patients and use of CLND with adjuvant systemic therapy versus nodal observation alone for similar risk patients.

CONCLUSIONS

There has been an overall decline in CLND and simultaneous adoption of adjuvant systemic therapy for patients with SLN-positive melanoma though wide variation in practice remains. Accounting for differences in patient mix, location of care contributed significantly to the observed variation.

Evidence and implementation gaps in management of sentinel node-positive melanoma in the United States

BACKGROUND

Melanoma clinical trials demonstrated that completion lymph node dissection is low value for most sentinel lymph node-positive patients. Contemporaneous trials of adjuvant systemic immunotherapy and BRAF/MEK targeted therapy showed improved recurrence-free survival in high-risk sentinel lymph node-positive patients. To better understand how oncologic evidence is incorporated into practice (implementation), we evaluated factors associated with discontinuation of completion lymph node dissection and adoption of systemic treatment at United States Commission on Cancer-accredited centers.

METHODS

In a retrospective cohort study of adults with sentinel lymph node-positive melanoma treated from 2012 to 2017 using the National Cancer Database, we evaluated use of completion lymph node dissection and adjuvant systemic treatment using mixed-effects logistic regression, reporting results as odds ratios with 95% confidence intervals.

RESULTS

Among 10,240 sentinel lymph node-positive melanoma patients, performance of completion lymph node dissection declined from 60% to 27%. Adjuvant systemic treatment increased from 29% to 43% (37% in stage IIIA patients, 46% in IIIB-C). Completion lymph node dissection was less common with lower extremity tumors (odds ratio = 0.53, 95% confidence interval = 0.44-0.64) and more common with multiple positive sentinel lymph nodes (odds ratio = 2.36, 95% confidence interval = 2.08-2.67), treatment at a high- or moderate-volume center (odds ratiohigh = 1.49, 95% confidence interval = 1.05-2.12; odds ratiomoderate = 1.32, 95% confidence interval = 1.05-1.64), and receipt of systemic therapy (odds ratio = 1.44, 95% confidence interval = 1.27-1.63). The increased likelihood of completion lymph node dissection in patients receiving adjuvant systemic treatment persisted in the most recent study years and in patients with a single positive sentinel lymph node.

CONCLUSION

At a population level, completion lymph node dissection declined and adjuvant systemic treatment increased, reflecting evidence-responsive care. Variation in persistent use of completion lymph node dissection and in provision of adjuvant treatment for lower risk patients highlights residual gaps in both evidence and implementation.

Clinicopathologic models predicting non-sentinel lymph node metastasis in cutaneous melanoma patients: Are they useful for patients with a single positive sentinel node?

Background and Objectives

Of clinically node‐negative (cN0) cutaneous melanoma patients with sentinel lymph node (SLN) metastasis, between 10% and 30% harbor additional metastases in non‐sentinel lymph nodes (NSLNs). Approximately 80% of SLN‐positive patients have a single positive SLN.

Methods

To assess whether state‐of‐the‐art clinicopathologic models predicting NSLN metastasis had adequate performance, we studied a single‐institution cohort of 143 patients with cN0 SLN‐positive primary melanoma who underwent subsequent completion lymph node dissection. We used sensitivity (SE) and positive predictive value (PPV) to characterize the ability of the models to identify patients at high risk for NSLN disease.

Results

Across Stage III patients, all clinicopathologic models tested had comparable performances. The best performing model identified 52% of NSLN‐positive patients (SE = 52%, PPV = 37%). However, for the single SLN‐positive subgroup (78% of cohort), none of the models identified high‐risk patients (SE > 20%, PPV > 20%) irrespective of the chosen probability threshold used to define the binary risk labels. Thus, we designed a new model to identify high‐risk patients with a single positive SLN, which achieved a sensitivity of 49% (PPV = 26%).

Conclusion

For the largest SLN‐positive subgroup, those with a single positive SLN, current model performance is inadequate. New approaches are needed to better estimate nodal disease burden of these patients.

Surveillance of Sentinel Node-Positive Melanoma Patients with Reasons for Exclusion from MSLT-II: Multi-Institutional Propensity Score Matched Analysis

BACKGROUND

In sentinel lymph node (SLN)-positive melanoma, two randomized trials demonstrated equivalent melanoma-specific survival with nodal surveillance vs completion lymph node dissection (CLND). Patients with microsatellites, extranodal extension (ENE) in the SLN, or >3 positive SLNs constitute a high-risk group largely excluded from the randomized trials, for whom appropriate management remains unknown.

STUDY DESIGN

SLN-positive patients with any of the three high-risk features were identified from an international cohort. CLND patients were matched 1:1 with surveillance patients using propensity scores. Risk of any-site recurrence, SLN-basin-only recurrence, and melanoma-specific mortality were compared.

RESULTS

Among 1,154 SLN-positive patients, 166 had ENE, microsatellites, and/or >3 positive SLN. At 18.5 months median follow-up, 49% had recurrence (vs 26% in patients without high-risk features, p < 0.01). Among high-risk patients, 52 (31%) underwent CLND and 114 (69%) received surveillance. Fifty-one CLND patients were matched to 51 surveillance patients. The matched cohort was balanced on tumor, nodal, and adjuvant treatment factors. There were no significant differences in any-site recurrence (CLND 49%, surveillance 45%, p = 0.99), SLN-basin-only recurrence (CLND 6%, surveillance 14%, p = 0.20), or melanoma-specific mortality (CLND 14%, surveillance 12%, p = 0.86).

CONCLUSIONS

SLN-positive patients with microsatellites, ENE, or >3 positive SLN constitute a high-risk group with a 2-fold greater recurrence risk. For those managed with nodal surveillance, SLN-basin recurrences were more frequent, but all-site recurrence and melanoma-specific mortality were comparable to patients treated with CLND. Most recurrences were outside the SLN-basin, supporting use of nodal surveillance for SLN-positive patients with microsatellites, ENE, and/or >3 positive SLN.

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.

Surgeon decision-making for management of positive sentinel lymph nodes in the post-Multicenter Selective Lymphadenectomy Trial II era: A survey study

BACKGROUND AND OBJECTIVES

Completion lymph node dissection (CLND) did not improve melanoma-specific survival for patients with sentinel lymph node (SLN)-positive melanoma in the second Multicenter Selective Lymphadenectomy Trial (MSLT-II). We assessed surgeons' awareness of MSLT-II and its impact on CLND recommendations.

METHODS

An anonymous online cross-sectional survey of the Society of Surgical Oncology membership evaluated surgeon thresholds in offering CLND using patient scenarios and clinicopathologic characteristics ranking.

RESULTS

Of the 2881 e-mails delivered, 146 surgeons (5.1%) completed all seven scenarios. Most (129 of 131, 98%) were aware of MSLT-II and 125 (95%) found it practice-changing. Specifically, 52% (65 of 125) always, 40% usually, 6% rarely, and 3% never offered CLND before MSLT-II. Meanwhile, 4% always, 9% usually, 78% rarely, and 8% never offer CLND now, after MSLT-II (p < .0001). The most important clinicopathologic factors in determining CLND recommendations were extracapsular extension, number of positive SLN, and SLN tumor deposit size, while primary tumor mitotic index and nodal basin location were the least important. Surgical oncology fellowship training, melanoma patient volume, and academic center practice also influenced CLND recommendations.

CONCLUSIONS

Most surgeon respondents are aware of MSLT-II, but its application in practice varies according to several clinicopathologic and surgeon factors.

Construction and validation of a nomogram for patients with skin cancer

Skin cancer is a common malignant tumor in human beings. At present, the construction of clinical prediction models mainly focuses on malignant melanoma and no researchers have constructed clinical prediction models for all kind of skin cancer to predict the prognosis of skin cancer. We used patient data collected from the surveillance, epidemiology, and end results program database to construct and validate our model for clinical prediction of skin cancer, hoping to provide a reference for clinical treatment of skin cancer.R software was used for univariate and multivariate Cox regression analysis of variables to screen out factors that have an impact on the survival of skin cancer patients. Then the prognostic model of skin cancer patients was constructed and the nomogram was drawn. Concordance Index (C-index), receiver operating characteristic (ROC) curve and calibration curve were used to evaluate the clinical prediction model.A total of 3180 skin cancer patients were included in this study. We constructed nomogram, a 3-year and 5-year clinical prediction model for skin cancer patients. We used C-index to evaluate the accuracy of nomogram model, and the result of C-index was 0.728, 95%CI (0.703-0.753). The nomogram model was evaluated by ROC curve. The area under the curve values of the ROC curve for 3-year survival rate and 5-year survival rate were 0.732 and 0.768 respectively. The model calibration diagram of the modeling group also shows that the model exhibits high accuracy.The nomogram model of postoperative survival of patients with skin cancer, based on the surveillance, epidemiology, and end results program database of patients with skin cancer, has shown good stability and accuracy in multi-method validation.

Development and validation of a Brazilian nomogram to assess sentinel node biopsy positivity in melanoma

BACKGROUND

Although well-established, sentinel node biopsy (SNB) for melanoma is not free from controversies and sometimes it can be questionable if SNB should be considered even for patients who meet the criteria for the procedure. Mathematical tools such as nomograms can be helpful and give more precise answers for both clinicians and patients. We present a nomogram for SNB positivity that has been internally validated.

METHODS

Retrospective analysis of patients who underwent SNB from 2000 to 2015 in a single institution. Single logistic regressions were used to identify variables that were associated to SNB positivity. All variables with a p value < 0.05 were included in the final model. Overall performance, calibration, and discriminatory power of the final multiple logistic regression model were all assessed. Internal validation of the multiple logistic regression model was performed via bootstrap analysis based on 1000 replications.

RESULTS

Site of primary lesion, Breslow thickness, mitotic rate, histologic regression, lymphatic invasion, and Clark level were statistically related to SNB positivity. After internal validation, a good performance was observed as well as an adequate power of discrimination (area under the curve 0.751).

CONCLUSIONS

We have presented a nomogram that can be helpful and easily used in daily practice for assessing SNB positivity.

How does the mitotic index impact patients with T1 melanoma? Comparison between the 7th and 8th edition of the American Joint Committee on Cancer melanoma staging system

Background

The mitotic index is no longer used to classify T1 melanoma patients into T1a and T1b, so it should not be used to indicate sentinel node biopsy in these patients.

Objectives

To evaluate patients with T1 melanoma who underwent sentinel lymph node biopsy and to compare those who were classified as T1a with those classified T1b, according to the 7th and 8th Edition of the melanoma staging system, regarding a positive biopsy result. The authors also aimed to assess whether there is any difference in the results in both staging systems.

Material and methods

This was a retrospective analysis of 1213 patients who underwent sentinel lymph node biopsy for melanoma, from 2000 to 2015, in a single institution.

Results

Of 399 patients with thin melanomas, 27 (6.7%) presented positive sentinel lymph nodes; there was no difference in positivity for sentinel node biopsy when comparing T1a vs. T1b in both staging systems. Furthermore, the clinical results were also similar between the two groups. However, in the complete cohort analysis, the mitotic index was associated with positivity for sentinel lymph node biopsy (p < 0.0001), positivity for non-sentinel lymph node (p < 0.0001), recurrence-free survival (p < 0.0001), and specific melanoma survival (p = 0.023).

Study limitation

Unicentric study.

Conclusion

The mitotic index was shown to be a very important prognostic factor in the present study, but it was not observed in patients classified as T1. The mitotic index should no longer be used as the only reason to refer sentinel lymph node biopsy in patients with thin melanoma.

Sentinel Node Status is the Most Important Prognostic Information for Clinical Stage IIB and IIC Melanoma Patients

BACKGROUND

Sentinel node biopsy (SNB) for melanoma patients has been questioned. We aimed to study high-risk stage II melanoma patients who underwent SNB to determine what the prognostic factors regarding recurrence and mortality were, and evaluate how relevant SNB status is in this scenario.

METHODS

This was a retrospective analysis of clinical stage IIB/IIC melanoma patients who underwent SNB from 2000 to 2015 in a single institution. Prognostic factors related to distant recurrence-free survival (DRFS) and melanoma-specific survival (MSS) were assessed from multiple Cox regression. Relevant variables were used to create risk predictor nomograms for DRFS and MSS.

RESULTS

From 1213 SNB, 259 were performed for clinical stage IIB/IIC melanoma patients. SNB status was the most important variable for both endpoints. Patients with positive SNB presented median DRFS of 35.73 months (95% CI 21.38-50.08, SE 7.32) and median MSS of 66.4 months (95% CI 29.76-103.03, SE 18.69), meanwhile both median DRFS and MSS were not achieved for those with negative SNB (logrank < 0.0001). Both nomograms have been internally validated and presented adequate calibration (C-index was 0.734 for DRFS and 0.718 for MSS).

CONCLUSIONS

SNB status was the most important risk factor in our cohort of clinical stage IIB and IIC patients and, in conjunction with well-established primary tumor characteristics, should not be abandoned. Their use in prognosis for these patients remains extremely useful for daily practice.

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.

An evidence-based approach to positive sentinel node disease: should we ever do a completion node dissection?

Management of later stage melanoma has undergone significant changes. Sentinel node biopsy has long been an accepted method of staging, but two recent randomized-controlled trials have provided an evidence base for decision making about completion lymphadenectomy. They showed no survival advantage in further surgery for patients with positive sentinel node biopsies. There is now no evidence to support completion lymphadenectomy in the majority of patients, and this is reflected in international practice guidelines.