Vernon K. Sondak

Final Version of 2009 AJCC Melanoma Staging and Classification

PURPOSE To revise the staging system for cutaneous melanoma on the basis of data from an expanded American Joint Committee on Cancer (AJCC) Melanoma Staging Database. METHODS The melanoma staging recommendations were made on the basis of a multivariate analysis of 30,946 patients with stages I, II, and III melanoma and 7,972 patients with stage IV melanoma to revise and clarify TNM classifications and stage grouping criteria. RESULTS Findings and new definitions include the following: (1) in patients with localized melanoma, tumor thickness, mitotic rate (histologically defined as mitoses/mm(2)), and ulceration were the most dominant prognostic factors. (2) Mitotic rate replaces level of invasion as a primary criterion for defining T1b melanomas. (3) Among the 3,307 patients with regional metastases, components that defined the N category were the number of metastatic nodes, tumor burden, and ulceration of the primary melanoma. (4) For staging purposes, all patients with microscopic nodal metastases, regardless of extent of tumor burden, are classified as stage III. Micrometastases detected by immunohistochemistry are specifically included. (5) On the basis of a multivariate analysis of patients with distant metastases, the two dominant components in defining the M category continue to be the site of distant metastases (nonvisceral v lung v all other visceral metastatic sites) and an elevated serum lactate dehydrogenase level. CONCLUSION Using an evidence-based approach, revisions to the AJCC melanoma staging system have been made that reflect our improved understanding of this disease. These revisions will be formally incorporated into the seventh edition (2009) of the AJCC Cancer Staging Manual and implemented by early 2010.

High-Dose Interferon Alfa-2b Significantly Prolongs Relapse-Free and Overall Survival Compared With the GM2-KLH/QS-21 Vaccine in Patients With Resected Stage IIB-III Melanoma: Results of Intergroup Trial E1694/S9512/C509801

PURPOSE Vaccine alternatives to high-dose interferon alfa-2b therapy (HDI), the current standard adjuvant therapy for high-risk melanoma, are of interest because of toxicity associated with HDI. The GM2 ganglioside is a well-defined melanoma antigen, and anti-GM2 antibodies have been associated with improved prognosis. We conducted a prospective, randomized, intergroup trial to evaluate the efficacy of HDI for 1 year versus vaccination with GM2 conjugated to keyhole limpet hemocyanin and administered with QS-21 (GMK) for 96 weeks (weekly x 4 then every 12 weeks x 8). PATIENTS AND METHODS Eligible patients had resected stage IIB/III melanoma. Patients were stratified by sex and number of positive nodes. Primary end points were relapse-free survival (RFS) and overall survival (OS). RESULTS Eight hundred eighty patients were randomized (440 per treatment group); 774 patients were eligible for efficacy analysis. The trial was closed after interim analysis indicated inferiority of GMK compared with HDI. For eligible patients, HDI provided a statistically significant RFS benefit (hazard ratio [HR] = 1.47, P = .0015) and OS benefit (HR = 1.52, P = .009) for GMK versus HDI. Similar benefit was observed in the intent-to-treat analysis (RFS HR = 1.49; OS HR = 1.38). HDI was associated with a treatment benefit in all subsets of patients with zero to > or = four positive nodes, but the greatest benefit was observed in the node-negative subset (RFS HR = 2.07; OS HR = 2.71 [eligible population]). Antibody responses to GM2 (ie, titers > or = 1:80) at days 29, 85, 365, and 720 were associated with a trend toward improved RFS and OS (P2 = .068 at day 29). CONCLUSION This trial demonstrated a significant treatment benefit of HDI versus GMK in terms of RFS and OS in melanoma patients at high risk of recurrence.

Meta-Analysis of Phase II Cooperative Group Trials in Metastatic Stage IV Melanoma to Determine Progression-Free and Overall Survival Benchmarks for Future Phase II Trials

PURPOSE Objective tumor response rates observed in phase II trials for metastatic melanoma have historically not provided a reliable indicator of meaningful survival benefits. To facilitate using overall survival (OS) or progression-free survival (PFS) as an endpoint for future phase II trials, we evaluated historical data from cooperative group phase II trials to attempt to develop benchmarks for OS and PFS as reference points for future phase II trials. PATIENTS AND METHODS Individual-level and trial-level data were obtained for patients enrolled onto 42 phase II trials (70 trial arms) that completed accrual in the years 1975 through 2005 and conducted by Southwest Oncology Group, Eastern Cooperative Oncology Group, Cancer and Leukemia Group B, North Central Cancer Treatment Group, and the Clinical Trials Group of the National Cancer Institute of Canada. Univariate and multivariate analyses were performed to identify prognostic variables, and between-trial(-arm) variability in 1-year OS rates and 6-month PFS rates were examined. RESULTS Statistically significant individual-level and trial-level prognostic factors found in a multivariate survival analysis for OS were performance status, presence of visceral disease, sex, and whether the trial excluded patients with brain metastases. Performance status, sex, and age were statistically significant prognostic factors for PFS. Controlling for these prognostic variables essentially eliminated between-trial variability in 1-year OS rates but not in 6-month PFS rates. CONCLUSION Benchmarks are provided for 1-year OS or OS curves that make use of the distribution of prognostic factors of the patients in the phase II trial. A similar benchmark for 6-month PFS is provided, but its use is more problematic because of residual between-trial variation in this endpoint.

Phase I Trial of Interleukin-12 Plasmid Electroporation in Patients With Metastatic Melanoma

PURPOSE Gene-based immunotherapy for cancer is limited by the lack of safe, efficient, reproducible, and titratable delivery methods. Direct injection of DNA into tissue, although safer than viral vectors, suffers from low gene transfer efficiency. In vivo electroporation, in preclinical models, significantly enhances gene transfer efficiency while retaining the safety advantages of plasmid DNA. PATIENTS AND METHODS A phase I dose escalation trial of plasmid interleukin (IL)-12 electroporation was carried out in patients with metastatic melanoma. Patients received electroporation on days 1, 5, and 8 during a single 39-day cycle, into metastatic melanoma lesions with six 100-mus pulses at a 1,300-V/cm electric field through a penetrating six-electrode array immediately after DNA injection. Pre- and post-treatment biopsies were obtained at defined time points for detailed histologic evaluation and determination of IL-12 protein levels. RESULTS Twenty-four patients were treated at seven dose levels, with minimal systemic toxicity. Transient pain after electroporation was the major adverse effect. Post-treatment biopsies showed plasmid dose proportional increases in IL-12 protein levels as well as marked tumor necrosis and lymphocytic infiltrate. Two (10%) of 19 patients with nonelectroporated distant lesions and no other systemic therapy showed complete regression of all metastases, whereas eight additional patients (42%) showed disease stabilization or partial response. CONCLUSION This report describes the first human trial, to our knowledge, of gene transfer utilizing in vivo DNA electroporation. The results indicated this modality to be safe, effective, reproducible, and titratable.

A Pooled Analysis of Eastern Cooperative Oncology Group and Intergroup Trials of Adjuvant High-Dose Interferon for Melanoma

Purpose: Nearly 2000 patients with stage IIB and III melanoma have participated in four multicenter, randomized trials, conducted by the Eastern Cooperative Oncology Group and the Intergroup, investigating adjuvant high-dose IFN-α 2b therapy. The objectives of this study were to update the analyses of each individual trial and to analyze prognostic factors and treatment effects based on pooled data. Experimental Design: Survival and disease status were updated to April 2001. Analysis of prognostic factors using optimized statistical models was based on data from patients in E1684, E1690, E1694, and E2696. Analysis of treatment effects versus observation (Obs) was based on data from 713 patients randomized to high-dose IFN-α 2b (HDI) or Obs in Trials E1684 and E1690. Results: Updated analysis of E1684, E1690, and E1694 confirmed their original conclusions, now at median follow-up intervals of 2.1–12.6 years. Based on two-sided univariate log-rank analysis of pooled data from E1684 and E1690 (median follow-up, 7.2 years), relapse-free survival (RFS)—but not overall survival (OS)—was significantly prolonged (two-sided log-rank P value = 0.006) for patients treated with HDI versus Obs. Among all patients, prognostic factors that significantly negatively impacted RFS and OS included ulceration, recurrent disease at entry, enrollment in E1684, and age > 49 years. Multivariate statistical models adjusting for these factors confirmed the statistically significant RFS benefit of HDI versus Obs but did not demonstrate a significant OS benefit in the pooled populations. Conclusions: In patients with high-risk resected melanoma, HDI is effective adjuvant therapy with strong evidence for improved RFS and evidence for moderate improvement in OS based on two prospective randomized studies but not the pooled analysis. Analyses of predictors of relapse and response are now needed to improve the therapeutic value of this modality.

PTEN loss confers BRAF inhibitor resistance to melanoma cells through the suppression of BIM expression

This study addresses the role of PTEN loss in intrinsic resistance to the BRAF inhibitor PLX4720. Immunohistochemical staining of a tissue array covering all stages of melanocytic neoplasia (n = 192) revealed PTEN expression to be lost in >10% of all melanoma cases. Although PTEN expression status did not predict for sensitivity to the growth inhibitory effects of PLX4720, it was predictive for apoptosis, with only limited cell death observed in melanomas lacking PTEN expression (PTEN-). Mechanistically, PLX4720 was found to stimulate AKT signaling in the PTEN- but not the PTEN+ cell lines. Liquid chromatography multiple reaction monitoring mass spectrometry (LC-MRM) was performed to identify differences in apoptosis signaling between the two cell line groups. PLX4720 treatment significantly increased BIM expression in the PTEN+ (>14-fold) compared with the PTEN- cell lines (four-fold). A role for PTEN in the regulation of PLX4720-mediated BIM expression was confirmed by siRNA knockdown of PTEN and through reintroduction of PTEN into cells that were PTEN-. Further studies showed that siRNA knockdown of BIM significantly blunted the apoptotic response in PTEN+ melanoma cells. Dual treatment of PTEN- cells with PLX4720 and a PI3K inhibitor enhanced BIM expression at both the mRNA and protein level and increased the level of apoptosis through a mechanism involving AKT3 and the activation of FOXO3a. In conclusion, we have shown for the first time that loss of PTEN contributes to intrinsic BRAF inhibitor resistance via the suppression of BIM-mediated apoptosis.

Multivariate Analysis of Prognostic Factors Among 2,313 Patients With Stage III Melanoma: Comparison of Nodal Micrometastases Versus Macrometastases

PURPOSE To determine the survival rates and independent predictors of survival using a contemporary international cohort of patients with stage III melanoma. PATIENTS AND METHODS Complete clinicopathologic and follow-up data were available for 2,313 patients with stage III disease in an updated and expanded American Joint Committee on Cancer (AJCC) melanoma staging database. Kaplan-Meier and Cox multivariate survival analyses were performed. RESULTS Among all 2,313 patients with stage III disease, 81% had micrometastases, and 19% had clinically detectable macrometastases. The 5-year overall survival was 63%; it was 67% for patients with nodal micrometastases, and it was 43% for those with nodal macrometastases (P < .001). Tremendous heterogeneity in survival was observed, particularly in the microscopically detected nodal metastasis subset (from 23% to 87% for 5-year survival). Multivariate analysis demonstrated that in patients with nodal micrometastases, number of tumor-containing lymph nodes, primary tumor thickness, patient age, ulceration, and anatomic site of the primary independently predicted survival (all P < .01). When added to the model, primary tumor mitotic rate was the second-most powerful predictor of survival after the number of tumor-containing nodes. In contrast, for patients with nodal macrometastases, the number of tumor-containing nodes, primary ulceration, and patient age independently predicted survival (P < .01). CONCLUSION In this multi-institutional analysis, we demonstrated remarkable heterogeneity of prognosis among patients with stage III melanoma, especially among those with nodal micrometastases. These results should be incorporated into the design and interpretation of future clinical trials involving patients with stage III melanoma.

Mitotic Rate and Younger Age Are Predictors of Sentinel Lymph Node Positivity: Lessons Learned From the Generation of a Probabilistic Model

Background: Sentinel lymph node (SLN) biopsy allows surgeons to identify patients with subclinical nodal involvement who may benefit from lymphadenectomy and, possibly, adjuvant therapy. Several factors have been variably, and sometimes discordantly, reported to have predictive value for SLN metastasis to best select which patients require SLN biopsy.Methods: We reviewed 419 patients who underwent SLN biopsy for melanoma from a prospectively collected melanoma database. To derive a probabilistic model for the occurrence of a positive SLN, a multivariate logistic model was fit by using a stepwise variable selection method. The accuracy of each model was evaluated by using receiver operator characteristic curves.Results: On univariate analysis, the number of mitoses per square millimeter, increasing Breslow depth, decreasing age, ulceration, and melanoma on the trunk showed a significant relationship to a positive SLN. Multivariate analysis revealed that once age, mitotic rate, and Breslow thickness were included, no other factor, including ulceration, was significantly associated with a positive SLN. The data suggest that younger patients with tumors <1 mm may still have a substantial risk for a positive SLN, especially if the mitotic rate is high.Conclusions: In addition to Breslow depth, mitoses per square millimeter and younger age were factors identified as independent predictors of a positive SLN. This model may identify patients with thin melanoma at sufficient risk for metastases to justify SLN biopsy.

Phase III Trial Comparing Concurrent Biochemotherapy With Cisplatin, Vinblastine, Dacarbazine, Interleukin-2, and Interferon Alfa-2b With Cisplatin, Vinblastine, and Dacarbazine Alone in Patients With Metastatic Malignant Melanoma (E3695): A Trial Coordinated by the Eastern Cooperative Oncology Group

PURPOSE Phase II trials with biochemotherapy (BCT) have shown encouraging response rates in metastatic melanoma, and meta-analyses and one phase III trial have suggested a survival benefit. In an effort to determine the relative efficacy of BCT compared with chemotherapy alone, a phase III trial was performed within the United States Intergroup. PATIENTS AND METHODS Patients were randomly assigned to receive cisplatin, vinblastine, and dacarbazine (CVD) either alone or concurrent with interleukin-2 and interferon alfa-2b (BCT). Treatment cycles were repeated at 21-day intervals for a maximum of four cycles. Tumor response was assessed after cycles 2 and 4, then every 3 months. RESULTS Four hundred fifteen patients were enrolled, and 395 patients (CVD, n = 195; BCT, n = 200) were deemed eligible and assessable. The two study arms were well balanced for stratification factors and other prognostic factors. Response rate was 19.5% for BCT and 13.8% for CVD (P = .140). Median progression-free survival was significantly longer for BCT than for CVD (4.8 v 2.9 months; P = .015), although this did not translate into an advantage in either median overall survival (9.0 v 8.7 months) or the percentage of patients alive at 1 year (41% v 36.9%). More patients experienced grade 3 or worse toxic events with BCT than CVD (95% v 73%; P = .001). CONCLUSION Although BCT produced slightly higher response rates and longer median progression-free survival than CVD alone, this was not associated with either improved overall survival or durable responses. Considering the extra toxicity and complexity, this concurrent BCT regimen cannot be recommended for patients with metastatic melanoma.

Recovery of phospho-ERK activity allows melanoma cells to escape from BRAF inhibitor therapy

Background:Resistance to BRAF inhibitors is an emerging problem in the melanoma field. Strategies to prevent and overcome resistance are urgently required.Methods:The dynamics of cell signalling, BrdU incorporation and cell-cycle entry after BRAF inhibition was measured using flow cytometry and western blot. The ability of combined BRAF/MEK inhibition to prevent the emergence of resistance was demonstrated by apoptosis and colony formation assays and in 3D organotypic cell culture.Results:BRAF inhibition led to a rapid recovery of phospho-ERK (pERK) signalling. Although most of the cells remained growth arrested in the presence of drug, a minor population of cells retained their proliferative potential and escaped from BRAF inhibitor therapy. A function for the rebound pERK signalling in therapy escape was demonstrated by the ability of combined BRAF/MEK inhibition to enhance the levels of apoptosis and abrogate the onset of resistance.Conclusion:Combined BRAF/MEK inhibition may be one strategy to prevent the emergence of drug resistance in BRAF-V600E-mutated melanomas.