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BACKGROUND: Vaginal melanoma (VM) is a rare cancer and has a poor response to immune checkpoint blockade (ICB). CD8+Tissue Resident Memory (TRM) T cells proliferate in response to ICB and correlate with longer survival in metastatic cutaneous melanoma. However, their capacity to respond to VM and their neoantigens is not known. METHODS: Using longitudinal samples, we explored the evolution of VM mutations by whole-exome sequencing and RNAseq, we also defined the immune context using multiplex immunohistochemistry and nanostring pan cancer immune profile. Then using fresh single cell suspensions of the metastatic samples, we explored VM T cells via mass cytometry and single cell RNAseq and T cell receptor sequencing (TCRseq). Finally, we investigated TRM, pre-TRM and exhausted T cell function against melanoma neo-antigens and melanoma differentiation antigens in vitro. RESULTS: Primary VM was non-inflamed and devoid of CD8+ TRM cells. In contrast, both metastases showed proliferating CD8+ TRM were clustered at the tumor margin, with increased numbers in the second ICB-refractory metastasis. The first metastasis showed dense infiltration of CD8+ T cells, the second showed immune exclusion with loss of melanoma cell Major histocompatibility complex (MHC)-I expression associated with downregulation of antigen presentation pathway gene expression. CD8+ TRM from both metastases responded to autologous melanoma cells more robustly than all other CD8+ T cell subsets. In addition, CD8+ TRM shared TCR clones across metastases, suggesting a response to common antigens, which was supported by recognition of the same neoantigen by expanded tumor infiltrating lymphocytes. CONCLUSIONS: In this study, we identified TRM clusters in VM metastases from a patient, but not primary disease. We showed TRM location at the tumor margin, and their superior functional response to autologous tumor cells, predicted neoantigens and melanoma differentiation antigens. These CD8+ TRM exhibited the

BACKGROUND: Patients with BRAF-mutant and wild-type melanoma have different response rates to immune checkpoint blockade therapy. However, the reasons for this remain unknown. To address this issue, we investigated the precise immune composition resulting from BRAF mutation in treatment-naive melanoma to determine whether this may be a driver for different response to immunotherapy. METHODS: In this study, we characterized the treatment-naive immune context in patients with BRAF-mutant and BRAF wild-type (BRAF-wt) melanoma using data from single-cell RNA sequencing, bulk RNA sequencing, flow cytometry and immunohistochemistry (IHC). RESULTS: In single-cell data, BRAF-mutant melanoma displayed a significantly reduced infiltration of CD8+ T cells and macrophages but also increased B cells, natural killer (NK) cells and NKT cells. We then validated this finding using bulk RNA-seq data from the skin cutaneous melanoma cohort in The Cancer Genome Atlas and deconvoluted the data using seven different algorithms. Interestingly, BRAF-mutant tumors had more CD4+ T cells than BRAF-wt samples in both primary and metastatic cohorts. In the metastatic cohort, BRAF-mutant melanoma demonstrated more B cells but less CD8+ T cell infiltration when compared with BRAF-wt samples. In addition, we further investigated the immune cell infiltrate using flow cytometry and multiplex IHC techniques. We confirmed that BRAF-mutant melanoma metastases were enriched for CD4+ T cells and B cells and had a co-existing decrease in CD8+ T cells. Furthermore, we then identified B cells were associated with a trend for improved survival (p=0.078) in the BRAF-mutant samples and Th2 cells were associated with prolonged survival in the BRAF-wt samples. CONCLUSIONS: In conclusion, treatment-naive BRAF-mutant melanoma has a distinct immune context compared with BRAF-wt melanoma, with significantly decreased CD8+ T cells and increased B cells and CD4+ T cells in the tumor microenvironment. These findings in

BACKGROUND: Understanding of factors that contribute to implementation of effective cancer multidisciplinary team meetings (MDMs) is still limited. Published literature on the effect of teamwork function, leadership roles, decision-making processes and structural components on the quality of MDMs was reviewed and synthesised. METHODS: In this paper, a MEDLINE review (September 2020) was performed to assess clinical decision-making in the context of MDM discussions. RESULTS: Twenty-nine eligible studies were included. Six studies addressed the infrastructural aspects of MDMs. Nine studies used either qualitative or mixed method approach to develop and validate observational tools to assess the quality of MDMs. Seven studies used qualitative approaches to explore the opinions of MDM members on factors that impact on the effectiveness of MDMs. Five studies used validated observational tools to observe and assess the effectiveness of MDMs. One prospective study explored the relationship between quality of information presented at MDMs and ability of MDM members to make clinical decisions. The final study prospectively tested the ability of a multicomponent intervention to improve decision-making processes within MDMs. CONCLUSIONS: A broad range of factors including teamwork, leadership, case complexity, decision-making processes and availability of patient information were identified to impact the quality of MDMs. Evidence currently available largely focuses on the development of tools to identify factors in need of improvement to optimise MDMs. Robust research is required to identify the factors that are demonstrated to enhance MDM quality which can then aid the standardisation of how MDMs are conducted.

PURPOSE: Guidelines addressing melanoma in-transit metastasis (ITM) recommend immune checkpoint inhibitors (ICI) as a first-line treatment option, despite the fact that there are no efficacy data available from prospective trials for exclusively ITM disease. The study aims to analyze the outcome of patients with ITM treated with ICI based on data from a large cohort of patients treated at international referral clinics. METHODS: A multicenter retrospective cohort study of patients treated between January 2015 and December 2020 from Australia, Europe, and the USA, evaluating treatment with ICI for ITM with or without nodal involvement (AJCC8 N1c, N2c, and N3c) and without distant disease (M0). Treatment was with PD-1 inhibitor (nivolumab or pembrolizumab) and/or CTLA-4 inhibitor (ipilimumab). The response was evaluated according to the RECIST criteria modified for cutaneous lesions. RESULTS: A total of 287 patients from 21 institutions in eight countries were included. Immunotherapy was first-line treatment in 64 (22%) patients. PD-1 or CTLA-4 inhibitor monotherapy was given in 233 (81%) and 23 (8%) patients, respectively, while 31 (11%) received both in combination. The overall response rate was 56%, complete response (CR) rate was 36%, and progressive disease (PD) rate was 32%. Median PFS was ten months (95% CI 7.4-12.6 months) with a one-, two-, and five-year PFS rate of 48%, 33%, and 18%, respectively. Median MSS was not reached, and the one-, two-, and five-year MSS rates were 95%, 83%, and 71%, respectively. CONCLUSION: Systemic immunotherapy is an effective treatment for melanoma ITM. Future studies should evaluate the role of systemic immunotherapy in the context of multimodality therapy, including locoregional treatments such as surgery, intralesional therapy, and regional therapies.

Until recently, most patients with sentinel lymph node-positive (SLN+) melanoma underwent a completion lymph node dissection (CLND), as mandated in published trials of adjuvant systemic therapies. Following multicenter selective lymphadenectomy trial-II, most patients with SLN+ melanoma no longer undergo a CLND prior to adjuvant systemic therapy. A retrospective analysis of clinical outcomes in SLN+ melanoma patients treated with adjuvant systemic therapy after July 2017 was performed in 21 international cancer centers. Of 462 patients who received systemic adjuvant therapy, 326 patients received adjuvant anti-PD-1 without prior immediate (IM) CLND, while 60 underwent IM CLND. With median follow-up of 21 months, 24-month relapse-free survival (RFS) was 67% (95% CI 62% to 73%) in the 326 patients. When the patient subgroups who would have been eligible for the two adjuvant anti-PD-1 clinical trials mandating IM CLND were analyzed separately, 24-month RFS rates were 64%, very similar to the RFS rates from those studies. Of these no-CLND patients, those with SLN tumor deposit >1 mm, stage IIIC/D and ulcerated primary had worse RFS. Of the patients who relapsed on adjuvant anti-PD-1, those without IM CLND had a higher rate of relapse in the regional nodal basin than those with IM CLND (46% vs 11%). Therefore, 55% of patients who relapsed without prior CLND underwent surgery including therapeutic lymph node dissection (TLND), with 30% relapsing a second time; there was no difference in subsequent relapse between patients who received observation vs secondary adjuvant therapy. Despite the increased frequency of nodal relapses, adjuvant anti-PD-1 therapy may be as effective in SLN+ pts who forego IM CLND and salvage surgery with TLND at relapse may be a viable option for these patients.

BACKGROUND: Clinical quality registries aim to identify significant variations in care and provide anonymised feedback to institutions to improve patient outcomes. Thirty-six Australian organisations with an interest in melanoma, raised funds through three consecutive Melanoma Marches, organised by Melanoma Institute Australia, to create a national Melanoma Clinical Outcomes Registry (MelCOR). This study aimed to formally develop valid clinical quality indicators for the diagnosis and early management of cutaneous melanoma as an important step in creating the registry. METHODS: Potential clinical quality indicators were identified by examining the literature, including Australian and international melanoma guidelines, and by consulting with key melanoma and registry opinion leaders. A modified two-round Delphi survey method was used, with participants invited from relevant health professions routinely managing melanoma as well as relevant consumer organisations. RESULTS: Nineteen participants completed at least one round of the Delphi process. 12 of 13 proposed clinical quality indictors met the validity criteria. The clinical quality indicators included acceptable biopsy method, appropriate excision margins, standardised pathology reporting, indications for sentinel lymph node biopsy, and involvement of multidisciplinary care and referrals. CONCLUSION: This study provides a multi-stakeholder consensus for important clinical quality indicators that define optimal practice that will now be used in the Australian Melanoma Clinical Outcomes Registry (MelCOR).

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.

Desmoplastic melanomas are uncommon. Their behaviour differs from that of other melanoma subtypes; therefore, management guidelines for non-desmoplastic melanomas may not be applicable. This review sought to examine all available evidence relating to the behaviour and management of desmoplastic melanomas, based on review of all relevant English-language publications, and to critically assess the recommendations for their management in current published melanoma management guidelines. Compared with other melanoma subtypes, patients with 'pure' desmoplastic melanomas (where ≥90% of the invasive melanoma is of desmoplastic melanoma subtype) have much lower rates of sentinel node positivity and distant metastasis. Local recurrence rates are higher for desmoplastic melanomas, but resection margins wider than those recommended for non-desmoplastic melanomas have not been shown to be of benefit. Adjuvant radiotherapy reduces the risk of local recurrence when a satisfactory histological clearance (≥8 mm) cannot be achieved. Of 29 published melanoma management guidelines identified, only 11 specified management for desmoplastic melanomas, while seven simply stated that the feature should be reported. Desmoplastic melanoma is a unique melanoma subtype with biology that differs from that of other melanoma subtypes. It requires specific management strategies but few current guidelines address these.

BACKGROUND: For patients with sentinel lymph node (SLN)-positive cutaneous melanoma, the Second Multicenter Selective Lymphadenectomy trial demonstrated equivalent disease-specific survival (DSS) with active surveillance using nodal ultrasound versus completion lymph node dissection (CLND). Adoption and outcomes of active surveillance in clinical practice and in adjuvant therapy recipients are unknown. METHODS: In a retrospective cohort of SLN-positive adults treated at 21 institutions in Australia, Europe, and the United States from June 2017 to November 2019, the authors evaluated the impact of active surveillance and adjuvant therapy on all-site recurrence-free survival (RFS), isolated nodal RFS, distant metastasis-free survival (DMFS), and DSS using Kaplan-Meier curves and Cox proportional hazard models. RESULTS: Among 6347 SLN biopsies, 1154 (18%) were positive and had initial negative distant staging. In total, 965 patients (84%) received active surveillance, 189 (16%) underwent CLND. Four hundred thirty-nine patients received adjuvant therapy (surveillance, 38%; CLND, 39%), with the majority (83%) receiving anti-PD-1 immunotherapy. After a median follow-up of 11 months, 220 patients developed recurrent disease (surveillance, 19%; CLND, 22%), and 24 died of melanoma (surveillance, 2%; CLND, 4%). Sixty-eight patients had an isolated nodal recurrence (surveillance, 6%; CLND, 4%). In patients who received adjuvant treatment without undergoing prior CLND, all isolated nodal recurrences were resectable. On risk-adjusted multivariable analyses, CLND was associated with improved isolated nodal RFS (hazard ratio [HR], 0.36; 95% CI, 0.15-0.88), but not all-site RFS (HR, 0.68; 95% CI, 0.45-1.02). Adjuvant therapy improved all-site RFS (HR, 0.52; 95% CI, 0.47-0.57). DSS and DMFS did not differ by nodal management or adjuvant treatment. CONCLUSIONS: Active surveillance has been adopted for most SLN-positive patients. At initial assessment, real-world outcomes align with r

A recent study by Oliveira et al. provides, in unprecedented detail, novel insights into the relationship between tumorreactivity and functional states of CD8 T cells in metastatic melanoma.

Australia and New Zealand have the highest incidence and mortality rates for melanoma in the world. Local surgery is still the standard treatment of primary cutaneous melanoma, and it is therefore important that surgeons understand the optimal care pathways for patients with melanoma. Accurate staging is critical to ensure a reliable assessment of prognosis and to guide treatment selection. Sentinel node biopsy (SNB) plays an important role in staging and the provision of reliable prognostic estimates for patients with cutaneous melanoma. Patients with stage III melanoma have a substantial risk of disease recurrence following surgery, leading to poor long-term outcomes. Systemic immunotherapies and targeted therapies, known to be effective for stage IV melanoma, have now also been shown to be effective as adjuvant post-surgical treatments for resected stage III melanoma. These patients should be made aware of this and preferably managed in an integrated multidisciplinary model of care, involving the surgeon, medical oncologists and radiation oncologists. This review considers the impact of a recent update to the American Joint Committee on Cancer (AJCC) staging system, the role of SNB for patients with high-risk primary melanoma and recent advances in adjuvant systemic therapies for high-risk patients.

BACKGROUND: The evidence-based management of melanoma patients with a positive sentinel lymph node biopsy (SLNB) has undergone a dramatic shift following publication of practice-changing surgical trials demonstrating no melanoma-specific survival advantage for completion lymph node dissection (CLND) in this scenario. We aimed to survey how surgeons' clinical practice had shifted in response to new evidence from these trials, and at a time when there was starting to become available systemic adjuvant treatments for AJCC Stage III melanoma patients. METHODS: A web-based survey consisting of practice-based questions and hypothetical clinical scenarios about current melanoma practice with regard to positive sentinel node biopsy was developed and sent to the surgical members of a Melanoma and Skin Cancer (MASC) Trials group in December 2018. Responses were analysed using descriptive statistics. RESULTS: There were 212 invitations sent and 65 respondents (31%). Respondents were from 17 countries, 94% of whom practice in specialist melanoma centres or at referral centres. Of these 97% were familiar with the MSLT2 and DeCOG-SLT clinical trials. At survey, 5% of respondents reported routinely recommending CLND and 55% recommend CLND in selected cases. Respondents were most likely to recommend CLND when multiple SLNs were positive. Important factors for surgical decision-making mentioned included size of SLN deposit, number of positive SLNs and likely compliance with the recommended surveillance regimen. CONCLUSION: In line with rapid adoption of published evidence, surgical management of Stage III melanoma has altered significantly, with few surgeons within the cohort now performing routine CLNDs after positive SLNB.

PURPOSE: This study examined the clinical outcomes and prognostic factors of patients with metastatic cutaneous SCC metastatic to the axilla and groin when managed with curative-intent lymphadenectomy and received (neo)adjuvant treatment. METHODS AND MATERIALS: We conducted a single institution retrospective review. Patients who had nodal disease without distant spread were 18 years or older with no non-cutaneous primary identified. RESULTS: From January 2000 to July 2015, 78 patients were treated for axilla (64, 82%) or inguinal (14, 18%) involvement with cSCC. The median age was 75.5 years (range: 29-95), and 8 patients (11%) were immunosuppressed. The median size of the largest node was 45 mm (range: 8-135), and extracapsular extension was found in 63 (81%) cases. A majority of patients were treated with surgery alone (21, 26.9%) and surgery with adjuvant radiation therapy (54, 69%). The 2-year OS and PFS were 50% (95% CI: 40%-63%) and 43% (95% CI: 33%-56%), and 5-year OS and PFS were 33% (95% CI:23%-47%) and 32% (95% CI:22%-46%) respectively in the entire cohort. On univariable analysis, factors associated with longer OS were as follows: younger age (HR 1.1, 95% CI: 0.9-1.3 P = 0.021), improved performance status (HR 1.5, 95% CI:1.0-2.3 P = 0.026), lack of immunosuppression (HR 3.3, 95% CI: 1.5-7.3 P = 0.001), lower lymph node ratio (HR 1.2, 95% CI:1.0-1.3 P = 0.007), lower number of positive nodes (HR 1.1, 95% CI:1.0-1.2 P = 0.004) and the use of radiation therapy (HR 0.5, 95% CI:0.3-0.9 P = 0.012). CONCLUSION: Metastasis to the axilla and groin with cSCC has poor outcomes with standard treatment. The addition of immunotherapy warrants investigation.

Background: Tumor-infiltrating lymphocytes (TILs) and chimeric antigen receptor (CAR) T-cell therapies have demonstrated promising, though limited, efficacy against melanoma. Methods: We designed a model system to explore the efficacy of dual specific T cells derived from melanoma patient TILs by transduction with a Her2-specific CAR. Results: Metastatic melanoma cells in our biobank constitutively expressed Her2 antigen. CAR-TIL produced greater amounts of IFN compared with parental TIL, when co-cultured with Her2 expressing tumor lines, including autologous melanoma tumor lines, although no consistent increase in cytotoxicity by TIL was afforded by expression of a CAR. Results of an in vivo study in NSG mice demonstrated tumor shrinkage when CAR-TILs were used in an adoptive cell therapy protocol. Conclusion: Potential limitations of transduced TIL in our study included limited proliferative potential and a terminally differentiated phenotype, which would need addressing in further work before consideration of clinical translation.

BACKGROUND: The role of 18 F-fluorodeoxyglucose positron emission tomography/computed tomography (18 F-FDG PET/CT) in the evaluation of retroperitoneal sarcomas is poorly defined. We evaluated the correlation of maximum standardized uptake value (SUVmax) with pathologic tumor grade in the surgical specimen of primary retroperitoneal dedifferentiated liposarcoma (DDLPS) and leiomyosarcoma (LMS). METHODS: Patients with the above histological subtypes in three participating institutions with preoperative 18 F-FDG PET/CT scan and histopathological specimen available for review were included. The association between SUVmax and pathological grade was assessed. Correlation between SUVmax and relapse-free survival (RFS) and overall survival (OS) were also studied. RESULTS: Of the total 58 patients, final pathological subtype was DDLPS in 44 (75.9%) patients and LMS in 14 (24.1%) patients. The mean SUVmax was 8.7 with a median 7.1 (range, 2.2-33.9). The tumors were graded I, II, III in 6 (10.3%), 35 (60.3%), and 17 (29.3%) patients, respectively. There was an association of higher histological grade with higher SUVmax (rs = 0.40, p = .002). Increasing SUVmax was associated with worse RFS (p = .003) and OS (p = .003). CONCLUSION: There is a correlation between SUVmax and pathologic tumor grade; increasing SUVmax was associated with worse OS and RFS, providing a preoperative noninvasive surrogate marker of tumor grade and biological behavior.

Tissue-resident memory T cells (TRM cells) are key elements of tissue immunity. Here, we investigated the role of the regulator of T cell receptor and cytokine signaling, Ptpn2, in the formation and function of TRM cells in skin. Ptpn2-deficient CD8+ T cells displayed a marked defect in generating CD69+ CD103+ TRM cells in response to herpes simplex virus type 1 (HSV-1) skin infection. This was accompanied by a reduction in the proportion of KLRG1- memory precursor cells and a transcriptional bias toward terminal differentiation. Of note, forced expression of KLRG1 was sufficient to impede TRM cell formation. Normalizing memory precursor frequencies by transferring equal numbers of KLRG1- cells restored TRM generation, demonstrating that Ptpn2 impacted skin seeding with precursors rather than downstream TRM cell differentiation. Importantly, Ptpn2-deficient TRM cells augmented skin autoimmunity but also afforded superior protection from HSV-1 infection. Our results emphasize that KLRG1 repression is required for optimal TRM cell formation in skin and reveal an important role of Ptpn2 in regulating TRM cell functionality.

INTRODUCTION: Sentinel lymph node biopsy (SLNB) is a diagnostic procedure developed in the 1990s. It is currently used to stage patients with primary cutaneous melanoma, provide prognostic information and guide management. The Australian Clinical Practice Guidelines state that SLNB should be considered for patients with cutaneous melanoma >1 mm in thickness (or >0.8 mm with high-risk pathology features). Until recently, sentinel lymph node (SLN) status was used to identify patients who might benefit from a completion lymph node dissection, a procedure that is no longer routinely recommended. SLN status is now also being used to identify patients who might benefit from systemic adjuvant therapies such as anti-programmed cell death 1 (PD1) checkpoint inhibitor immunotherapy or BRAF-directed molecular targeted therapy, treatments that have significantly improved relapse-free survival for patients with resected stage III melanoma and improved overall survival of patients with unresectable stage III and stage IV melanoma. Australian and international data indicate that approximately half of eligible patients receive an SLNB. METHODS AND ANALYSIS: This mixed-methods study seeks to understand the structural, contextual and cultural factors affecting implementation of the SLNB guidelines. Data collection will include: (1) cross-sectional questionnaires and semistructured interviews with general practitioners and dermatologists; (2) semistructured interviews with other healthcare professionals involved in the diagnosis and early definitive care of melanoma patients and key stakeholders including researchers, representatives of professional colleges, training organisations and consumer melanoma groups; and (3) documentary analysis of documents from government, health services and non-government organisations. Descriptive analyses and multivariable regression models will be used to examine factors related to SLNB practices and attitudes. Qualitative data will be analysed using

BACKGROUND: The efficacy of immune checkpoint inhibitors (ICI) in metastatic melanoma is well established. However, there are limited data regarding their efficacy in in-transit melanoma (ITM). This study assessed the efficacy of ICI in patients with ITM. METHODS: A retrospective review of patients with ITM commenced on an ICI between March 2013 and February 2018 at three tertiary centers in Australia. Patients were excluded if they had previous or synchronous distant metastases. Overall response rate (ORR), progression-free survival (PFS) and overall survival (OS) were based on a composite of radiological and clinical assessments. RESULTS: Fifty-four patients were included: 27 (50%) female; median age 75 (range 26-94); 12 (22%) stage IIIB, 40 (74%) stage IIIC and 2 (4%) stage IIID; 10 (19%) BRAF mutant. Forty (74%) received single-agent anti-PD-1 (pembrolizumab or nivolumab), 8 (15%) single agent anti-CTLA-4 (ipilimumab), 5 (9%) combination anti-PD-1/anti-CTLA-4 (ipilimumab and nivolumab or pembrolizumab) and 1 (2%) combination anti-PD-L1 (atezolizumab) and MEK inhibitor (cobimetinib). The median follow-up was 15 months (2-46).ORR to ICI was 54%: 14 (26%) complete responses; 15 (28%) partial responses; 9 (17%) stable disease; 16 (30%) progressive disease. Thirteen (46%) responders had only one ITM lesion. ORR was 58% for single-agent anti-PD-1, 38% for single-agent anti-CTLA4 and 40% for anti-PD-1/anti-CTLA-4. The median PFS was 11.7 months (6.6-not reached). 1-year and 2-year PFS were 48% and 39%, respectively,. Fourteen progressed locoregionally and 11 progressed distantly. The median OS was not reached. 1-year and 2-year OS were 85% and 63%, respectively. No clinicopathological features were associated with ORR. CONCLUSIONS AND RELEVANCE: ICI produce objective responses in ITM and should be considered in patients with unresectable ITM or disease recurrence.

Serous carcinomas of the testis or para-testis are extremely rare tumors of Mullerian type. We report a case of high-grade serous papillary carcinoma of the tunica vaginalis, treated with radical orchiectomy and hemi-scrotectomy after being referred for a rapidly growing painless scrotal mass. In addition to negative testicular tumor markers, scrotal ultrasound, and conventional computerized tomography (CT) scanning, this patient's workup included a positron emission tomography (PET) scan using F-18-fluoro-deoxyglucose (FDG), demonstrating metabolically avid uptake of the disease. This patient is completing ongoing close follow up and is currently disease free at nine months post definitive treatment.

OBJECTIVE: The immune system can halt cancer progression by suppressing outgrowth of clinically occult micrometastases in a state of cancer-immune equilibrium. Cutaneous melanoma provides a unique opportunity to study the immune contexture of such lesions, as miniscule skin metastases are accessible to clinical inspection and diagnostic biopsy. METHODS: Here, we analysed by multiplex immunofluorescence microscopy samples from a melanoma patient presenting with an overt and an occult in-transit metastasis (ITM), the latter of which appeared as a small erythematous papule. RESULTS: Microarchitecture and immune composition in the two lesions were vastly different. CD4+ and CD8+ T cells accumulated around the margin of the overt SOX10+ Melan A+ ITM but were largely excluded from the tumor centre. By contrast, the occult micrometastasis contained only few SOX10+ Melan A- melanoma cells which were scattered within a dense infiltrate of T cells, including a prominent population of CD103+ CD8+ T cells resembling tissue-resident memory T (TRM) cells. Notably, almost every single melanoma cell in the micrometastasis was in close proximity to these TRM-like cells. CONCLUSION: Such results support the emerging concept that CD103+ CD8+ TRM cells are key mediators of cancer surveillance and imply an important function of these cells in controlling clinically occult micrometastases in humans.

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.

In-transit metastases (ITM) of cutaneous melanoma are locoregional recurrences confined to the superficial lymphatics that occur in 3.4-6.2% of patients diagnosed with melanoma. ITM are a heterogeneous disease that poses a therapeutic dilemma. Patients may have a prolonged disease trajectory involving multiple or repeat treatment modalities for frequent recurrences. The management of ITM has evolved without the development of a standardized protocol. Owing to the variability of the disease course there are few dedicated clinical trials, with a number of key trials in stage III melanoma excluding ITM patients. Thus, there is a paucity of quality data on the efficacy of the treatment modalities available for ITM and even fewer studies directly comparing modalities. At present the mainstay of ITM treatment is surgical resection, with intralesional therapies, isolated limb infusion and radiotherapy utilized as second-line measures. The developing role of targeted therapies and immunotherapy has yet to be explored completely in these patients. This review addresses the evidence base of the efficacy of the various treatment modalities available and those factors that have impacted their clinical uptake.

Immune checkpoint inhibitors and BRAF-MEK inhibitors have revolutionized the management and prognosis of patients with metastatic melanoma. However, there is minimal evidence to guide their incorporation into current treatment paradigms for unresectable stage III disease. The era of effective systemic therapies has prompted a discussion about what constitutes unresectable disease. Patients with unresectable stage III disease can experience significant morbidity from their disease and locoregional therapies, and may progress with distant metastases. Despite increasing use of systemic therapies in unresectable stage III disease, further evidence is needed to establish their degree of benefit in this population.

BACKGROUND: Several unanswered questions surround the management of retroperitoneal sarcoma (RPS). Guidelines recommend treatment by a multidisciplinary team at a specialized referral centre. The objective of this study was to describe the management of RPS at an Australian specialist sarcoma centre, comparing outcomes to international standards and analysing for predictors of local failure. METHODS: A retrospective review of a prospectively maintained database was performed on patients with RPS treated between 2008 and 2016. A 5-year outcome analyses focussed on patients undergoing curative-intent surgery for primary, non-metastatic RPS. RESULTS: Eighty-eight patients underwent surgery for primary RPS. Five-year overall survival was 66%, 5-year freedom from local recurrence was 65% and 5-year freedom from distant metastasis was 71%. Overall survival was associated with tumour grade (hazard ratio (HR) 6.1, P < 0.001) and histologic organ invasion (HR 5.7, P < 0.001). Variables associated with improved freedom from local recurrence were macroscopically complete resection (HR 0.14, P < 0.001) and neoadjuvant radiotherapy (HR 0.33, P = 0.014). Treatment at a specialist sarcoma centre was associated with a higher rate of preoperative biopsy and neoadjuvant radiotherapy (both with P < 0.001). There was a trend towards improved local control for patients undergoing surgery at a specialist centre (P = 0.055). CONCLUSION: This is the largest Australian series of RPS and outcomes are comparable to major international sarcoma centres. Patients treated at a specialist centre had higher rates of preoperative diagnosis and tailored therapy which was associated with improved outcomes. Patients with suspected RPS should be referred to a specialist centre for optimal preoperative evaluation and multidisciplinary management.

Soft tissue sarcoma is an umbrella term which encompasses over 60 histological tumour types. Approximately 15% of soft tissue sarcomas arise in the retroperitoneum. This complex group of tumours poses unique management challenges due to their often large size, histological heterogeneity and complexity of anatomical relationships. This review discusses the management of retroperitoneal tumours including the need for preoperative diagnosis, the evidence for neoadjuvant radiotherapy, the role of multivisceral resection and the importance of a multidisciplinary team approach.

BACKGROUND AND OBJECTIVES: The aim of this study was to perform a retrospective analysis of survival rates and determine prognostic indicators for patients who underwent definitive surgical resection of stage IV melanoma. METHODS: Patients included were those who underwent complete resection of metastatic melanoma. Data was analyzed using IBM SPSS 2.0. Survival estimates were derived from Kaplan-Meier, log-rank, and Breslow tests. RESULTS: The study population (n = 95) consisted of 60 males and 35 females. Median overall survival (OS) from the first metastasectomy was 49 months (95% confidence interval, 31-67 months). OS at 1, 2, and 5 years was 92%, 87%, and 50% respectively. Predictors of survival included clear surgical margins compared to patients with positive margins (median OS 53 vs 20 months, P = .026). A preoperative neutrophil to lymphocyte ratio less than 5 experienced a median OS of 65 months compared to 15 months ( P = .006; multivariable analysis for OS: hazard ratio 3.590, P = .009). CONCLUSION: This study's results are consistent with previous findings demonstrating favourable long-term outcomes following selective resection of metastatic melanoma. In addition to achieving clear surgical margins, a low preoperative neutrophil to lymphocyte ratio was associated with improved outcomes. These factors may help identify surgical candidates.

A prospective study explored the heterogeneous nature of metastatic melanoma using Multiplex immunohistochemistry (IHC) and flow cytometry (FACS). Multiplex IHC data quantitated immune subset number present intra-tumoral (IT) vs the tumor stroma, plus distance of immune subsets from the tumor margin (TM). In addition, mIHC showed a close association between the presence of IT CD8+ T cells and PDL1 expression in melanoma, which was more prevalent on macrophages than on melanoma cells. In contrast, FACS provided more detailed information regarding the T cell subset differentiation, their activation status and expression of immune checkpoint molecules. Interestingly, mIHC detected significantly higher Treg numbers than FACS and showed preferential CD4+ T cell distribution in the tumor stroma. Based on the mIHC and FACS data, we provide a model which defines metastatic melanoma immune context into four categories using the presence or absence of PDL1+ melanoma cells and/or macrophages, and their location within the tumor or on the periphery, combined with the presence or absence of IT CD8+ T cells. This model interprets melanoma immune context as a spectrum of tumor escape from immune control, and provides a snapshot upon which interpretation of checkpoint blockade inhibitor (CBI) therapy responses can be built.

A sentinel lymph node biopsy is a surgical staging procedure performed for patients with primary cutaneous melanoma who are clinically lymph-node negative to determine whether there is low volume nodal metastasis in the draining lymph node field. A systematic review was recently performed to update the Australian clinical practice guidelines for the diagnosis and management of melanoma, addressing the question, 'When is a sentinel lymph node biopsy indicated?' This article discusses the findings of the systematic review and the evidence base for the updated guidelines.

The strategy of immune modulation for the treatment of cancer is being refined with the introduction of multiple new therapeutic agents into the clinic. Melanoma is a disease where many of these agents have demonstrated efficacy. The mechanisms of action of these agents exploit the counter-regulatory mechanisms of the immune response. However, these agents are also associated with immune-related adverse events (IRAEs), which represent tissue-specific inflammatory responses. These IRAEs highlight the delicate balance of immunologic homeostasis and, with some interventions, may occur more frequently in patients who sustain a therapeutic response. This review will discuss melanoma immunogenicity and immunotherapy. Furthermore, the spectrum and distinction between a reversible immune adverse event and autoimmunity will be highlighted.

INTRODUCTION: Macrophages in the mammary gland are essential for morphogenesis of the ductal epithelial tree and have been implicated in promoting breast tumor metastasis. Although it is well established that macrophages influence normal mammopoiesis, the mammary cell types that these accessory cells influence have not been determined. Here we have explored a role for macrophages in regulating mammary stem cell (MaSC) activity, by assessing the ability of MaSCs to reconstitute a mammary gland in a macrophage-depleted fat pad. METHODS: Two different in vivo models were used to deplete macrophages from the mouse mammary fat pad, allowing us to examine the effect of macrophage deficiency on the mammary repopulating activity of MaSCs. Both the Csf1op/op mice and clodronate liposome-mediated ablation models entailed transplantation studies using the MaSC-enriched population. RESULTS: We show that mammary repopulating ability is severely compromised when the wild-type MaSC-enriched subpopulation is transplanted into Csf1op/op fat pads. In reciprocal experiments, the MaSC-enriched subpopulation from Csf1op/op glands had reduced regenerative capacity in a wild-type environment. Utilizing an alternative strategy for selective depletion of macrophages from the mammary gland, we demonstrate that co-implantation of the MaSC-enriched subpopulation with clodronate-liposomes leads to a marked decrease in repopulating frequency and outgrowth potential. CONCLUSIONS: Our data reveal a key role for mammary gland macrophages in supporting stem/progenitor cell function and suggest that MaSCs require macrophage-derived factors to be fully functional. Macrophages may therefore constitute part of the mammary stem cell niche.