Avelumab plus standard-of-care chemoradiotherapy versus chemoradiotherapy alone in patients with locally advanced squamous cell carcinoma of the head and neck: a randomised, double-blind, placebo-controlled, multicentre, phase 3 trial

FLT3L Release by Natural Killer Cells Enhances Response to Radioimmunotherapy in Preclinical Models of HNSCC

PURPOSE

Natural killer (NK) cells are type I innate lymphoid cells that are known for their role in killing virally infected cells or cancer cells through direct cytotoxicity. In addition to direct tumor cell killing, NK cells are known to play fundamental roles in the tumor microenvironment through secretion of key cytokines, such as FMS-like tyrosine kinase 3 ligand (FLT3L). Although radiotherapy is the mainstay treatment in most cancers, the role of radiotherapy on NK cells is not well characterized.

EXPERIMENTAL DESIGN

This study combines radiation, immunotherapies, genetic mouse models, and antibody depletion experiments to identify the role of NK cells in overcoming resistance to radiotherapy in orthotopic models of head and neck squamous cell carcinoma.

RESULTS

We have found that NK cells are a crucial component in the development of an antitumor response, as depleting them removes efficacy of the previously successful combination treatment of radiotherapy, anti-CD25, and anti-CD137. However, in the absence of NK cells, the effect can be rescued through treatment with FLT3L. But neither radiotherapy with FLT3L therapy alone nor radiotherapy with anti-NKG2A yields any meaningful tumor growth delay. We also identify a role for IL2 in activating NK cells to secrete FLT3L. This activity, we show, is mediated through CD122, the intermediate affinity IL2 receptor, and can be targeted with anti-CD25 therapy.

CONCLUSIONS

These findings highlight the complexity of using radio-immunotherapies to activate NK cells within the tumor microenvironment, and the importance of NK cells in activating dendritic cells for increased tumor surveillance.

Radiotherapy and immunotherapy: open questions and future strategies

Immune checkpoint blockade (ICB) improves outcomes for some patients with advanced or metastatic cancers. Despite demonstrable progress, many patients do not respond to ICB. Recently, clinical trials have focused on combinations of ICB with radiation therapy. Although two recent Phase III randomized trials demonstrated improved survival with adjuvant ICB following chemoradiation, other Phase I/II/III trials are either negative or inconclusive, but do yield suggestive results and promising insights into future therapeutic strategies. We provide a selective review of a subset of these trials and attempt to integrate with basic laboratory findings where relevant to define issues pertaining to the combination of radiotherapy and immunotherapy.

Therapeutic strategies for systemic therapies of human papillomavirus-related oropharyngeal cancer

Our understanding of human papillomavirus (HPV)-related oropharyngeal cancer (OPC) and its molecular basis continues to evolve and produce important insights into customized therapeutic strategies. Novel therapeutics exploiting HPV-related targets are being evaluated in the incurable setting, while the favorable prognosis of locoregionally advanced disease has stimulated investigation into de-escalation strategies. There is much opportunity for better personalization of standard therapy according to HPV status. This review discusses both current and investigational therapeutic strategies for HPV-related OPC.

Combination of radiation therapy-immunotherapy for head and neck cancers: Promises kept?

Chemoradiotherapy with concurrent cisplatin has been the standard treatment for locally advanced head and neck squamous cell carcinoma (HNSCC) for over 20 years. Recently, immunotherapy, a new therapeutic class, has emerged for patients with recurrent or metastatic HNSCC and has significantly extended their survival. Will it bring the same benefit to patients with localized tumors? There is a strong rationale for combining radiation therapy and checkpoint inhibitors for HNSCC. Indeed, radiation therapy can have both immunostimulatory and immunomodulatory effects. This is what explains the famous abscopal effect. The aim of this review is to present the data available on the combination of radiation therapy and immunotherapy for HNSCC.

Radiotherapy driven immunomodulation of the tumor microenvironment and its impact on clinical outcomes: a promising new treatment paradigm

Traditional treatment approaches for advanced malignancies have been associated with limited clinical outcomes necessitating the development of novel therapies. However, the ability of radiotherapy to induce pro-immunogenic changes in tumor immune microenvironment can be leveraged when combined with systemic agents. Radio-immunotherapeutic initiatives employing the use of monoclonal antibodies, genetically engineered T cells, cytokines and virus-vector mediated gene therapies have demonstrated promising potential for the management of various solid malignancies. Future studies incorporating biomarker enrichment strategies and radiobiological variables could pave the way for immune-oncology based personalized medicine approaches to be integrated in standard of care practices for the treatment of challenging clinical populations.

A Rational Approach to Unilateral Neck RT for Head and Neck Cancers in the Era of Immunotherapy

Radiotherapy plays an important role in the definitive and adjuvant treatment of head and neck squamous cell carcinoma (HNSCC). However, standard courses of radiation therapy may contribute to the depletion of circulating lymphocytes and potentially attenuate optimal tumor antigen presentation that may be detrimental to the efficacy of novel immunotherapeutic agents. This review explores the advantages of restricting radiation to the primary tumor/tumor bed and ipsilateral elective neck as it pertains to the evolving field of immunotherapy.

Avelumab for platinum-ineligible/refractory recurrent and/or metastatic squamous cell carcinoma of the head and neck: phase Ib results from the JAVELIN Solid Tumor trial

Background

Recurrent and/or metastatic (R/M) disease develops in approximately 65% of patients with squamous cell carcinoma of the head and neck (SCCHN) and is associated with a poor prognosis. Immune checkpoint inhibitors have proven effective in multiple tumor types, including R/M SCCHN. We report the efficacy and safety of avelumab (antiprogrammed death ligand 1 antibody) in an expansion cohort of patients with platinum-refractory/ineligible R/M SCCHN enrolled in the phase I JAVELIN Solid Tumor trial (NCT01772004).

Methods

Eligible patients with R/M SCCHN were aged ≥18 years and had received ≥1 line of platinum-based chemotherapy with disease progression or recurrence within 6 months of the last dose or were ineligible for platinum-based chemotherapy. All patients received avelumab 10 mg/kg every 2 weeks. Tumor assessments were carried out by a blinded independent review committee (IRC) and investigators according to Response Evaluation Criteria in Solid Tumors V.1.1 (RECIST 1.1). Key endpoints included best overall response, duration of response (DOR) and progression-free survival (PFS) assessed by IRC and investigator per RECIST 1.1, overall survival (OS), and safety.

Results

Between April 24, 2015, and November 13, 2015, 153 patients were enrolled. Patients had a median of two prior lines of therapy for metastatic or locally advanced disease (range 0–6); 12 patients (7.8%) were not eligible for platinum-based chemotherapy. At data cut-off (December 31, 2017), the confirmed objective response rate was 9.2% (95% CI 5.1% to 14.9%) assessed by IRC and 13.1% (95% CI 8.2% to 19.5%) assessed by investigator. Median DOR was not reached (95% CI 4.2 to not estimable) based on IRC assessment. Median PFS was 1.4 months (95% CI 1.4 to 2.6) assessed by IRC and 1.8 months (95% CI 1.4 to 2.7) assessed by investigator; median OS was 8.0 months (95% CI 6.5 to 10.2). Any-grade treatment-related adverse events (TRAEs) occurred in 83 patients (54.2%) and were grade ≥3 in 10 patients (6.5%). The most common TRAEs were fatigue (n=19, 12.4%), fever (n=14, 9.2%), pruritus (n=12, 7.8%), and chills (n=11, 7.2%), and there were no treatment-related deaths.

Conclusion

Avelumab showed clinical activity and was associated with a low rate of grade ≥3 TRAEs in heavily pretreated patients with platinum-refractory/ineligible R/M SCCHN.

Kickstarting Immunity in Cold Tumours: Localised Tumour Therapy Combinations With Immune Checkpoint Blockade

Cancer patients with low or absent pre-existing anti-tumour immunity ("cold" tumours) respond poorly to treatment with immune checkpoint inhibitors (ICPI). In order to render these patients susceptible to ICPI, initiation of de novo tumour-targeted immune responses is required. This involves triggering of inflammatory signalling, innate immune activation including recruitment and stimulation of dendritic cells (DCs), and ultimately priming of tumour-specific T cells. The ability of tumour localised therapies to trigger these pathways and act as in situ tumour vaccines is being increasingly explored, with the aspiration of developing combination strategies with ICPI that could generate long-lasting responses. In this effort, it is crucial to consider how therapy-induced changes in the tumour microenvironment (TME) act both as immune stimulants but also, in some cases, exacerbate immune resistance mechanisms. Increasingly refined immune monitoring in pre-clinical studies and analysis of on-treatment biopsies from clinical trials have provided insight into therapy-induced biomarkers of response, as well as actionable targets for optimal synergy between localised therapies and ICB. Here, we review studies on the immunomodulatory effects of novel and experimental localised therapies, as well as the re-evaluation of established therapies, such as radiotherapy, as immune adjuvants with a focus on ICPI combinations.

The Key Differences between Human Papillomavirus-Positive and -Negative Head and Neck Cancers: Biological and Clinical Implications

Head and neck squamous cell carcinoma (HNSCC) is a unique malignancy associated with two distinct risk factors: exposure to typical carcinogens and infection of human papillomavirus (HPV). HPV encodes the potent oncoproteins E6 and E7, which bypass many important oncogenic processes and result in cancer development. In contrast, HPV-negative HNSCC is developed through multiple mutations in diverse oncogenic driver genes. While the risk factors associated with HPV-positive and HPV-negative HNSCCs are discrete, HNSCC patients still show highly complex molecular signatures, immune infiltrations, and treatment responses even within the same anatomical subtypes. Here, we summarize the current understanding of biological mechanisms, treatment approaches, and clinical outcomes in comparison between HPV-positive and -negative HNSCCs.

The Abscopal Effect: A Review of Pre-Clinical and Clinical Advances

Radiotherapy has been used for more than a hundred years to cure or locally control tumors. Regression of tumors outside of the irradiated field was occasionally observed and is known as the abscopal effect. However, the occurrence of systemic anti-tumor effects was deemed too rare and unpredictable to be a therapeutic goal. Recent studies suggest that immunotherapy and radiation in combination may enhance the abscopal response. Increasing numbers of cases are being reported since the routine implementation of immune checkpoint inhibitors, showing that combined radiotherapy with immunotherapy has a synergistic effect on both local and distant (i.e., unirradiated) tumors. In this review, we summarize pre-clinical and clinical reports, with a specific focus on the mechanisms behind the immunostimulatory effects of radiation and how this is enhanced by immunotherapy.

Combining immune checkpoint inhibitors with chemotherapy in advanced solid tumours: A review

The use of immune checkpoint inhibitors (ICIs), especially anti-programmed cell death 1 (PD1) and anti-programmed cell death ligand 1 (PD-L1), has changed practices in oncology, becoming a new standard of care in first or subsequent lines for several cancer subtypes. Recent data have highlighted the ability of standard chemotherapy to enhance immunogenicity and/or to break immunoresistance of the tumour and its microenvironment, leading to a rationale for the use of ICIs in combination with the standard chemotherapy regimen to improve efficacy of cancer treatment. Here, we propose to review randomised clinical trials evaluating concomitant administration of ICIs and chemotherapy, to assess clinical efficacy and safety profiles in advanced solid tumours. Association of these two modes of action on treatments has shown improved overall survival and better objective response rates than standard chemotherapy, especially in first-line treatment of non-small cell lung cancer (NSCLC) and for PD1/PD-L1 enriched tumours, highlighting a potential synergistic effect of this treatment combination in certain tumour types. However, improved survival results with the use of anti-PD-L1 avelumab as a maintenance schedule for bladder cancer raises the question of the most appropriate approach between sequential and concomitant administration of chemoimmunotherapy. To date, no trials have compared in a head-to-head protocol the administration of concomitant chemoimmunotherapy with chemotherapy, used for tumour debulking, followed by administration of ICIs. Regarding the tolerance profile, no new safety signals were found with the combination tested to date. Interestingly, recent results have shown an improved Progression Free survival 2 (PFS2) (defined as the progression after the next line of therapy) in head-and-neck cancers or NSCLC after a first-line pembrolizumab-chemotherapy combination, suggesting a potential long-lasting effect of ICIs when used in combination in the first-line setting.

Reduction of Elective Radiotherapy Treatment Volume in Definitive Treatment of Locally Advanced Head and Neck Cancer-Comparison of a Prospective Trial with a Revised Simulated Contouring Approach

Definitive radiochemotherapy of locally advanced head and neck squamous cell cancer (HNSCC) achieves high locoregional tumor control rates; but is frequently associated with long-term toxicity. A future direction could be a de-escalation strategy focusing on treated volume rather than radiotherapy dose. This analysis evaluates radiotherapy dose and volume parameters of patients treated with a standard contouring approach in a clinical trial context compared with a revised volume-reduced contouring approach. In this case, 30 consecutive patients from the CheckRad-CD8 trial treated at a single study center were included in this analysis. Treatment toxicity and quality of life were assessed at the end of radiotherapy. Standard treatment plans (ST) following state of the art contouring guidelines that were used for patient treatment and volume reduced treatment plans (VRT) according to a revised simulated approach were calculated for each patient. Planning target volumes (PTV) and mean doses to 38 organs-at-risk structures were compared. At the end of radiotherapy patients reported high rates of mucositis; dysphagia and xerostomia. In addition; patient reported quality of life as assessed by the EORTC QLQ-HN35 questionnaire deteriorated. Comparing the two contouring approaches; the elective PTV_56 Gy and the high risk PTV_63 Gy (shrinking field) were significantly smaller in the VRT group. Significant reduction of mean dose to structures of the oral cavity; the larynx as well as part of the swallowing muscles and the submandibular glands was achieved in the simulated VRT-plan. Treatment de-intensification by reduction of the irradiated volume could potentially reduce treatment volume and mean doses to organs at risk. The proposed contouring approach should be studied further in the context of a clinical trial.

PD-L1 evaluation in head and neck squamous cell carcinoma: Insights regarding specimens, heterogeneity and therapy

Immunohistochemical assessment with combined positive score (CPS) of programmed death-ligand 1 (PD-L1) is the prerequisite for administration of checkpoint inhibitor therapy in head and neck squamous cell carcinoma (HNSCC). Practicing pathologists are required to assess PD-L1 in routinary work and can be faced up with practical issues not always addressed in clinical trials or guidelines, such as choice of specimen to test, the intrinsic heterogeneity in PD-L1 expression in tumors and the potential impact of already administered therapy, given that patients' material can be procured at several times of cancer natural history. In the present work, we review and discuss the recent literature regarding the assessment of PD-L1 in HNSCC from the perspective of the practicing pathologist, providing some evidence on the single issues. It emerges a general trend to an underestimation of PD-L1 expression in biopsies compared to resection specimens and to a higher degree of positivity in metastatic lymph nodes in respect to primary tumors. Moreover, therapy shows to have contrasting effect on PD-L1 expression. Although further studies are needed, taking into account the intrinsic heterogeneity in PD-L1 expression and the conflicting evidences, it may be speculated that the most recent material of patients in respect to the natural history of tumor can be the most reliable to evaluate PD-L1 expression.

Defining the Role of Immunotherapy in the Curative Treatment of Locoregionally Advanced Head and Neck Cancer: Promises, Challenges, and Opportunities

Recent advancements in the development of immunotherapies have raised the hope for patients with locally-advanced HNSCC (LA-HNSCC) to achieve improved oncologic outcomes without the heavy burden of treatment-related morbidity. While there are several ongoing late phase clinical trials that seek to determine whether immunotherapy can be effectively employed in the definitive setting, initial results from concurrent immuno-radiotherapy therapy trials have not shown strong evidence of benefit. Encouragingly, evidence from preclinical studies and early-phase neoadjuvant studies have begun to show potential pathways forward, with therapeutic combinations and sequences that intentionally spare tumor draining lymphatics in order to maximize the synergy between definitive local therapy and immunotherapy. The intent of this review is to summarize the scientific rationale and current clinical evidence for employing immunotherapy for LA-HNSCC as well as the ongoing efforts and challenges to determine how to optimally deliver and sequence immunotherapy alongside traditional therapeutics. In both the preclinical and clinical settings, we will discuss the application of immunotherapies to both surgical and radiotherapeutic management of HNSCC.

Repurposing Radiation Therapy for Immuno-oncology

Radiation therapy is traditionally used for the local control of tumour growth, but recent studies suggest that radiation therapy can have immunomodulatory properties that can be applied in combination therapy with immunotherapeutic agents. The paradigm of using radiation therapy for immunomodulation in cancer treatment is a rapidly progressing field, with multiple ongoing clinical trials exploring its use in combination with immune checkpoint blockades to induce an abscopal effect. Permutations of radiation therapy regimens, including variations in radiation dosing, radiation planning parameters and radiation modality, are being tested with varying degrees of success. The relative biological effectiveness was a concept introduced in the early days of radiation biology that allows the comparison of local tumour control across various radiation modalities and energies. Similarly, there remains a need for a new concept of comparing the immunological effectiveness of various radiation modalities. In this review, we will provide an overview of immunobiological models for preclinical and clinical monitoring of radiation therapy regimens and introduce the concept of relative immunological effectiveness to compare and screen for immune-activating functions of these regimens.

Treatment of Cancer with Radio-Immunotherapy: What We Currently Know and What the Future May Hold

Radiotherapy and immunotherapy are most effective as cancer therapies in the setting of low-volume disease. Although initial studies of radio-immunotherapy in patients with metastatic cancer have not confirmed the efficacy of this approach, the role of radio-immunotherapy in patients with limited metastatic burden is unclear. We propose that further investigation of radio-immunotherapy in metastatic patients should focus upon patients with oligometastatic disease.

[A decade of checkpoint inhibitors: current standard of care and future trends]

Therapy with checkpoint inhibitors still revolutionizes the therapeutical landscape in oncology. Since the first approval of a checkpoint inhibitor for the therapy of malignant melanoma 2011, many other approvals in the field of hematology and oncology followed. Besides monotherapy, a rapidly increasing number of trials is investigating checkpoint inhibitors in different combination therapies for advanced disease. Cumulating evidence suggests checkpoint blockade also as promising option for (neo)-adjuvant treatment. Here we review the different treatment strategies of mono- and combination-therapies. Additionally, important biomarkers for the treatment with checkpoint inhibitors are discussed.

Targeted Therapy as a Potential De-Escalation Strategy in Locally Advanced HPV-Associated Oropharyngeal Cancer: A Literature Review

The treatment landscape of locally advanced HPV-oropharyngeal squamous cell carcinoma (OPSCC) is undergoing transformation. This is because the high cures rates observed in OPSCC are paired with severe treatment-related, long-term toxicities. These significant adverse effects have led some to conclude that the current standard of care is over-treating patients, and that de-intensifying the regimens may achieve comparable survival outcomes with lower toxicities. Consequently, several de-escalation approaches involving locally advanced OPSCC are underway. These include the reduction of dosage and volume of intensive cytotoxic regimens, as well as elimination of invasive surgical procedures. Such de-intensifying treatments have the potential to achieve efficacy and concurrently alleviate morbidity. Targeted therapies, given their overall safer toxicity profiles, also make excellent candidates for de-escalation, either alone or alongside standard treatments. However, their role in these endeavors is currently limited, because few targeted therapies are currently in clinical use for head and neck cancers. Unfortunately, cetuximab, the only FDA-approved targeted therapy, has shown inferior outcomes when paired with radiation as compared to cisplatin, the standard radio-sensitizer, in recent de-escalation trials. These findings indicate the need for a better understanding of OPSCC biology in the design of rational therapeutic strategies and the development of novel, OPSCC-targeted therapies that are safe and can improve the therapeutic index of standard therapies. In this review, we summarize ongoing research on mechanism-based inhibitors in OPSCC, beginning with the salient molecular features that modulate tumorigenic processes and response, then exploring pharmacological inhibition and pre-clinical validation studies of candidate targeted agents, and finally, summarizing the progression of those candidates in the clinic.

Tumor Immunity and Immunotherapy for HPV-Related Cancers

Human papillomavirus (HPV) infection drives tumorigenesis in the majority of cervical, oropharyngeal, anal, and vulvar cancers. Genetic and epidemiologic evidence has highlighted the role of immunosuppression in the oncogenesis of HPV-related malignancies. Here we review how HPV modulates the immune microenvironment and subsequent therapeutic implications. We describe the landscape of immunotherapies for these cancers with a focus on findings from early-phase studies exploring antigen-specific treatments, and discuss future directions. Although responses across these studies have been modest to date, a deeper understanding of HPV-related tumor biology and immunology may prove instrumental for the development of more efficacious immunotherapeutic approaches. SIGNIFICANCE: HPV modulates the microenvironment to create a protumorigenic state of immune suppression and evasion. Our understanding of these mechanisms has led to the development of immunomodulatory treatments that have shown early clinical promise in patients with HPV-related malignancies. This review summarizes our current understanding of the interactions of HPV and its microenvironment and provides insight into the progress and challenges of developing immunotherapies for HPV-related malignancies.

Post treatment NLR is a predictor of response to immune checkpoint inhibitor therapy in patients with esophageal squamous cell carcinoma

BACKGROUND

In view of the fact that peripheral blood parameters have been reported as predictors of immunotherapy to various cancers, this study aimed to determine the predictors of response to anti-programmed death-1 (anti-PD-1) therapy in patients with esophageal squamous cell carcinoma (ESCC) from peripheral blood parameters.

METHODS

A retrospective analysis was conducted to investigate the predictive value of peripheral blood parameters including neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), monocyte-to-lymphocyte ratio (MLR) and systemic immune-inflammation index (SII) in the response to anti-PD-1 antibody treatment. 119 ESCC patients receiving combined treatment including anti-PD-1 antibody were enrolled in this study.

RESULTS

The median progression-free survival (PFS) of all ESCC patients was 3.73 months. PFS rate in ESCC patients with low NLR at 6 weeks post treatment was higher than patients with high NLR (HR = 2.097, 95% CI 0.996-4.417, P = 0.027). However, PFS rate in ESCC patients with low NLR at baseline (HR = 1.060, 95% CI 0.524-2.146, P = 0.869) or 3 weeks post treatment (HR = 1.293, 95% CI 0.628-2.663, P = 0.459) was comparable with high NLR. And no statistically different was found in PFS rate between low PLR and high PLR at baseline (HR = 0.786, 95% CI 0.389-1.589, P = 0.469), 3 weeks post treatment (HR = 0.767, 95% CI 0.379-1.552, P = 0.452) or 6 weeks post treatment (HR = 1.272, 95% CI 0.624-2.594, P = 0.488) in ESCC patients. PFS rate was also comparable between low MLR and high MLR at baseline (HR = 0.826, 95% CI 0.408-1.670, P = 0.587), 3 weeks post treatment (HR = 1.209, 95% CI 0.590-2.475, P = 0.580) or 6 weeks post treatment (HR = 1.199, 95% CI 0.586-2.454, P = 0.596). PFS rate was similar between patients with low SII and high SII at baseline (HR = 1.120, 95% CI 0.554-2.264, P = 0.749), 3 weeks post treatment (HR = 1.022, 95% CI 0.500-2.089, P = 0.951) and 6 weeks post treatment (HR = 1.759, 95% CI 0.851-3.635, P = 0.097).

CONCLUSIONS

NLR at 6 weeks post treatment is a predictor of the response to anti-PD-1 treatment in patients with ESCC.

Radiotherapy and Immunotherapy Combinations in the Treatment of Patients with Metastatic Disease: Current Status and Future Focus

Radiotherapy and immunotherapy benefit subsets of patients with metastatic cancer. Here, we review selected laboratory and clinical studies investigating the utility of combining radiotherapy and immunotherapy in metastatic patients. We examine potential approaches to increase the therapeutic ratio of radioimmunotherapy in the treatment of metastatic cancers moving forward.

Neoadjuvant immunotherapy is reshaping cancer management across multiple tumour types: The future is now!

The Italian Network for Tumor Biotherapy (Network Italiano per la Bioterapia dei Tumori [NIBIT]) Foundation hosted its annual 2020 Think Tank meeting virtually, at which representatives from academic, clinical, industry, philanthropic, and regulatory organisations discussed the role of neoadjuvant immunotherapy for the treatment of cancer. Although the number of neoadjuvant immunotherapeutic trials is increasing across all malignancies, the Think Tank focused its discussion on the status of neoadjuvant trials in cutaneous melanoma (CM), muscle-invasive urothelial bladder cancer (MIBC), head and neck squamous cell carcinoma (HNSCC), and pancreatic adenocarcinoma (PDAC). Neoadjuvant developments in CM are nothing short of trailblazing. Pathologic Complete Response (pCR), pathologic near Complete Response, and partial Pathologic Responses reduce 90-100% of recurrences. This is in sharp contrast to targeted therapies in neoadjuvant CM trials, where only a pCR seems to reduce recurrence. The pCR rate after neoadjuvant immunotherapy varies among the different malignancies of CM, MIBC, HNSCC, and PDAC and may be associated with different reductions of recurrence rates. In CM, emerging evidence suggests that neoadjuvant immunotherapy with anti-CTLA-4 plus anti-PD1 is a game changer in patients with palpable nodal Stage III or resectable Stage IV disease by curing more patients, reducing recurrences and the need for surgical interventions, such as lymph node dissections and metastasectomies. The Think Tank panel discussed future approaches on how to optimise results across different tumour types. Future approaches should include reducing monocyte-mediated (tumour-associated macrophages) and fibroblast-mediated (cancer-associated fibroblasts) barriers in the tumour microenvironment to facilitate the recruitment of immune cells to the tumour site, to reduce immune-suppressive mediators, and to increase antigen presentation at the site of the tumour.

De-Escalation Strategies of (Chemo)Radiation for Head-and-Neck Squamous Cell Cancers-HPV and Beyond

Oncological outcomes for head-and-neck squamous cell carcinoma (HNSCC) patients are still unsatisfactory, especially for advanced tumor stages. Besides the moderate survival rates, the prevalence of severe treatment-induced normal tissue toxicities is high after multimodal cancer treatments, both causing significant morbidity and decreasing quality of life of surviving patients. Therefore, risk-adapted and individualized treatment approaches are urgently needed for HNSCC patients to optimize the therapeutic gain. It has been a well-known fact that especially HPV-positive oropharyngeal squamous cell carcinoma (OSCC) patients exhibit an excellent prognosis and may therefore be subject to overtreatment, resulting in long-term treatment-related toxicities. Regarding the superior prognosis of HPV-positive OSCC patients, treatment de-escalation strategies are currently investigated in several clinical trials, and HPV-positive OSCC may potentially serve as a model for treatment de-escalation also for other types of HNSCC. We performed a literature search for both published and ongoing clinical trials and critically discussed the presented concepts and results. Radiotherapy dose or volume reduction, omission or modification of concomitant chemotherapy, and usage of induction chemotherapy are common treatment de-escalation strategies that are pursued in clinical trials for biologically selected subgroups of HNSCC patients. While promising data have been reported from various Phase II trials, evidence from Phase III de-escalation trials is either lacking or has failed to demonstrate comparable outcomes for de-escalated treatments. Therefore, further data and a refinement of biological HNSCC stratification are required before deescalated radiation treatments can be recommended outside of clinical trials.