Radiation therapy and the abscopal effect: a concept comes of age

A Review of Immunotherapy in Non-Small-Cell Lung Cancer

Cancer immunotherapy in the form of immune checkpoint inhibitors has led to a dramatic increase in the survival of patients with lung cancer across all stages. Over the past decade, the field has experienced rapid maturation; however, several challenges continue to complicate patient management. This review aims to highlight the data that led to this dramatic shift in practice as well as to focus on key challenges. These include determining the optimal therapy duration, managing frail patients or those with brain metastases, addressing the challenges posed by immune-related adverse events, and defining the various patterns of clinical and radiological responses to immunotherapy.

Non-targeted effects of radiation therapy for glioblastoma

Radiotherapy is recommended for the treatment of brain tumors such as glioblastoma (GBM) and brain metastases. Various curative and palliative scenarios suggest improved local-regional control. Although the underlying mechanisms are not yet clear, additional therapeutic effects have been described, including proximity and abscopal reactions at the treatment site. Clinical and preclinical data suggest that the immune system plays an essential role in regulating the non-targeted effects of radiotherapy for GBM. This article reviews current biological mechanisms for regulating the non-targeted effects caused by external and internal radiotherapy, and how they might be applied in a clinical context. Optimization of therapeutic regimens requires assessment of the complexity of the host immune system on the activity of immunosuppressive or immunostimulatory cells, such as glioma-associated macrophages and microglia. This article also discusses recent preclinical models adapted to post-radiotherapy responses. This narrative review explores and discusses the current status of immune responses both locally via the "bystander effect" and remotely via the "abscopal effect". Preclinical and clinical observations demonstrate that unirradiated cells, near or far from the irradiation site, can control the tumor response. Nevertheless, previous studies do not address the problem in its global context, and present gaps regarding the link between the role of the immune system in the control of non-targeted effects for different types of radiotherapy and different fractionation schemes applied to GBM. This narrative synthesis of the scientific literature should help to update and critique available preclinical and medical knowledge. Indirectly, it will help formulate new research projects based on the synthesis and interpretation of results from a non-systematic selection of published studies.

Mathematical modeling of the synergistic interplay of radiotherapy and immunotherapy in anti-cancer treatments

Introduction

While radiotherapy has long been recognized for its ability to directly ablate cancer cells through necrosis or apoptosis, radiotherapy-induced abscopal effect suggests that its impact extends beyond local tumor destruction thanks to immune response. Cellular proliferation and necrosis have been extensively studied using mathematical models that simulate tumor growth, such as Gompertz law, and the radiation effects, such as the linear-quadratic model. However, the effectiveness of radiotherapy-induced immune responses may vary among patients due to individual differences in radiation sensitivity and other factors.

Methods

We present a novel macroscopic approach designed to quantitatively analyze the intricate dynamics governing the interactions among the immune system, radiotherapy, and tumor progression. Building upon previous research demonstrating the synergistic effects of radiotherapy and immunotherapy in cancer treatment, we provide a comprehensive mathematical framework for understanding the underlying mechanisms driving these interactions.

Results

Our method leverages macroscopic observations and mathematical modeling to capture the overarching dynamics of this interplay, offering valuable insights for optimizing cancer treatment strategies. One shows that Gompertz law can describe therapy effects with two effective parameters. This result permits quantitative data analyses, which give useful indications for the disease progression and clinical decisions.

Discussion

Through validation against diverse data sets from the literature, we demonstrate the reliability and versatility of our approach in predicting the time evolution of the disease and assessing the potential efficacy of radiotherapy-immunotherapy combinations. This further supports the promising potential of the abscopal effect, suggesting that in select cases, depending on tumor size, it may confer full efficacy to radiotherapy.

Immunotherapy Plus Chemoradiation Improves Overall Survival in Stage IV Esophageal Cancer: A Cohort Study

Background and Aims

The association of immunotherapy in combination with radiation therapy (RT) or chemoradiation with the overall survival (OS) of patients diagnosed with stage IV esophageal cancer (EC) is unknown. The aim of the current study is to explore the association of immunotherapy with OS in patients with advanced stage EC who received chemotherapy, RT, or chemoradiation.

Methods

We conducted a cohort study using the National Cancer Database and included patients diagnosed between 2013 and 2020 with stage IV esophageal adenocarcinoma or squamous cell carcinoma. The association of immunotherapy with OS was assessed with Cox proportional hazards regression, adjusted for age at diagnosis, race, sex, stage, histology, Charlson score, education, income, insurance, hospital type, place of living, region, distance to facility, year of diagnosis, and treatment modality.

Results

Of 18,260 patients, 2946 (17%) received immunotherapy. In the multivariable COX analysis, patients who received immunotherapy had significantly improved OS compared with no immunotherapy (hazard ratio [HR]: 0.71; 95% confidence interval [CI]: 0.67-0.75; P < .001). Chemotherapy plus immunotherapy was associated with improved OS compared to chemotherapy alone (HR: 0.69; 95% CI: 0.64-0.75; P < .001). RT plus immunotherapy was associated with improved OS compared to RT alone (HR: 0.60; 95% CI: 0.46-0.78; P < .001). Treatment with chemoradiation plus immunotherapy was associated with significantly improved OS compared with chemoradiation alone (HR 0.78; 95% CI: 0.71-0.86; P < .001).

Conclusion

The addition of immunotherapy to chemotherapy, RT, and chemoradiation was associated with improved OS compared with chemotherapy alone, RT alone, or chemoradiation alone in patients with stage IV EC.

Dynamic changes of phenotype and function of natural killer cells in peripheral blood before and after thermal ablation of hepatitis B associated hepatocellular carcinoma and their correlation with tumor recurrence

BACKGROUND

Thermal therapy induces an immune response in patients with hepatocellular carcinoma (HCC), but the dynamic characteristics of the natural killer (NK) cell immune response post-thermal ablation remain unclear. We conducted a prospective longitudinal cohort study to observe the dynamic changes of phenotype and function of NK cells in peripheral blood before and after thermal ablation of hepatitis B-associated HCC and their correlation with tumor recurrence.

METHODS

Fifty-six patients clinically and pathologically confirmed with hepatitis B-associated HCC were selected for thermal ablation. Peripheral blood was collected on day 0, day 7, and month 1. NK cell subsets, receptors, and killing function were detected by flow cytometry, and the LDH levels were examined. Overall recurrence and associated variables were estimated using Kaplan-Meier, log-rank, and Cox proportional-hazards analyses.

RESULTS

The frequency of CD3^-CD56⁺ cells was increased on day 7 (P < 0.01) without significant differences between D0 and M1. NKG2D, NKp44, NKp30, CD159a, and CD158a expression was increased on M1 (all P < 0.05). The granzyme B and IFN-γ expression in NK cells were higher on M1 vs. D0 (P < 0.05). On day 7, the NK cell lysis activity of the target K562 cells was increased (P < 0.01) but decreased on M1 (P < 0.05). Survival analysis showed that CD158a expression and IFN-γ and perforin release on day 0 were associated with the risk of HCC recurrence. Cox regression analysis showed that the expression changes in CD56, NKp46, granzyme B, and perforin (D7-D0) induced by thermal ablation were associated with recurrence-free survival (RFS) of patients with HCC.

CONCLUSION

Thermal ablation increased the frequency and function of CD3^-CD56⁺ NK cells in the peripheral blood of patients with HCC. These cells tended to be more differentiated and activated. Notably, expression levels of NK cell receptors NKp46, perforin, and granzyme B were associated with RFS.

MR Imaging-Based In Vivo Macrophage Imaging to Monitor Immune Response after Radiofrequency Ablation of the Liver

PURPOSE

To establish molecular magnetic resonance (MR) imaging instruments for in vivo characterization of the immune response to hepatic radiofrequency (RF) ablation using cell-specific immunoprobes.

MATERIALS AND METHODS

Seventy-two C57BL/6 wild-type mice underwent standardized hepatic RF ablation (70 °C for 5 minutes) to generate a coagulation area measuring 6-7 mm in diameter. CD68+ macrophage periablational infiltration was characterized with immunohistochemistry 24 hours, 72 hours, 7 days, and 14 days after ablation (n = 24). Twenty-one mice were subjected to a dose-escalation study with either 10, 15, 30, or 60 mg/kg of rhodamine-labeled superparamagnetic iron oxide nanoparticles (SPIONs) or 2.4, 1.2, or 0.6 mg/kg of gadolinium-160 (160Gd)-labeled CD68 antibody for assessment of the optimal in vivo dose of contrast agent. MR imaging experiments included 9 mice, each receiving 10-mg/kg SPIONs to visualize phagocytes using T2∗-weighted imaging in a horizontal-bore 9.4-T MR imaging scanner, 160Gd-CD68 for T1-weighted MR imaging of macrophages, or 0.1-mmol/kg intravenous gadoterate (control group). Radiological-pathological correlation included Prussian blue staining, rhodamine immunofluorescence, imaging mass cytometry, and immunohistochemistry.

RESULTS

RF ablation-induced periablational infiltration (206.92 μm ± 12.2) of CD68+ macrophages peaked at 7 days after ablation (P < .01) compared with the untreated lobe. T2∗-weighted MR imaging with SPION contrast demonstrated curvilinear T2∗ signal in the transitional zone (TZ) (186 μm ± 16.9), corresponsing to Iron Prussian blue staining. T1-weighted MR imaging with 160Gd-CD68 antibody showed curvilinear signal in the TZ (164 μm ± 3.6) corresponding to imaging mass cytometry.

CONCLUSIONS

Both SPION-enhanced T2∗-weighted and 160Gd-enhanced T1-weighted MR imaging allow for in vivo monitoring of macrophages after RF ablation, demonstrating the feasibility of this model to investigate local immune responses.

Comparison of NK cell subsets, receptors and functions induced by radiofrequency ablation and microwave ablation in HBV-associated primary hepatocellular carcinoma

Background

Topical therapy has been shown to induce an immune response in patients with hepatocellular carcinoma (HCC). In this study, a prospective parallel group control experiment was conducted to compare the differences between radiofrequency ablation and microwave ablation in inducing the immune regulation of NK cells.

Methods

Sixty patients with clinically and pathologically confirmed hepatitis B-associated hepatocellular carcinoma (HCC) were selected for thermal ablation. Patients were randomly assigned into the MWA group (n = 30) and the RFA group (n = 30). Patient's peripheral blood was isolated on days D0, D7, and month M1. NK cell subsets, receptors, and killing function were detected by flow cytometry and LDH. Student t test and rank sum test were used to compare the statistical differences between the RFA (radio frequency) and MWA (microwave) groups. The Kaplan-Meier curve and log-rank test were used to calculate the difference between the two survival curves.

Results

Comparison of the frequency of CD3-CD56+ and CD3-CD56+CD16+ in NK cells between the RFA and WMA groups showed that there was no difference in the D0, D7, M1, D7-D0, M1-D0, and M1-D7 groups. The changes of the inhibitory NK cell receptor CD159A were significantly different at D7 (P<0.05). CD107a were compared between the RFA and WMA groups, indicating that CD107a changes induced by NK cells were significantly different at D7-D0 (P<0.05). Comparison of NK cell lysis activity of target K562 cells between the RFA and WMA groups showed that there was no difference at D0, D7, D7-D0. There was no difference in recurrence-free survival (RFS) between the RFA and WMA groups (P=0.11).

Conclusions

The difference between MWA and RFA-induced NK cell changes was mainly manifested in the inhibitory receptors CD159a and CD107a 1 week after surgery, with microwave-induced changes being more severe. Comparison of the NK cell lysis activity of the target K562 cells between the RFA and WMA groups showed that there was no difference in D0, D7, D7- D0. Survival analysis showed that these differences did not affect the recurrence-free survival (RFS) in the two groups.

Neoadjuvant immunotherapy for resectable esophageal cancer: A review

Esophageal cancer (EC) is one of the most common cancers worldwide, especially in China. Despite therapeutic advances, the 5-year survival rate of EC is still dismal. For patients with resectable disease, neoadjuvant chemoradiotherapy (nCRT) in combination with esophagectomy is the mainstay of treatment. However, the pathological complete response (pCR) rate to nCRT of 29.2% to 43.2% is not satisfactory, and approximately half of the patients will develop either a locoregional recurrence or distant metastasis. It is, therefore, necessary to explore novel and effective treatment strategies to improve the clinical efficacy of treatment. Immunotherapy utilizing immune checkpoint inhibitors (ICIs) has significantly changed the treatment paradigm for a wide variety of advanced cancers, including EC. More recently, increasing clinical evidence has demonstrated that neoadjuvant immunotherapy can potentially improve the survival of patients with resectable cancers. Furthermore, accumulating findings support the idea that chemotherapy and/or radiotherapy can activate the immune system through a variety of mechanisms, so a combination of chemotherapy and/or radiotherapy with immunotherapy can have a synergistic antitumor effect. Therefore, it is reasonable to evaluate the role of neoadjuvant immunotherapy for patients with surgically resectable EC. In this review, we discuss the rationale for neoadjuvant immunotherapy in patients with EC, summarize the current results of utilizing this strategy, review the planned and ongoing studies, and highlight the challenges and future research needs.

The ADAM17-directed Inhibitory Antibody MEDI3622 Antagonizes Radiotherapy-induced VEGF Release and Sensitizes Non-Small Cell Lung Cancer for Radiotherapy

The cellular response to ionizing radiation (IR) depends on tumor cell and microenvironmental factors. Here, we investigated the role of IR-induced ADAM17 matrix metalloproteinase activity for the intercellular communication between tumor cells and the tumor vasculature in non-small cell lung cancer (NSCLC) tumor models. Factors shed by ADAM17 from NSCLC tumor cells (A549, H358) and relevant for endothelial cell migration were investigated using transwell migration assays, ELISA, and flow cytometry. Tumor angiogenesis-related endpoints were analyzed with the chorio-allantoic membrane assay and in murine NSCLC tumor models. Efficacy-oriented experiments were performed in a murine orthotopic NSCLC tumor model using irradiation with an image-guided small-animal radiotherapy platform alone and in combination with the novel ADAM17-directed antibody MEDI3622. In vitro, VEGF was identified as the major factor responsible for IR-induced and ADAM17-dependent endothelial cell migration toward attracting tumor cells. IR strongly enhanced tumor cell-associated ADAM17 activity, released VEGF in an ADAM17-dependent manner, and thereby coordinated the communication between tumor and endothelial cells. In vivo, tumor growth and microvessel size and density were strongly decreased in response to the combined treatment modality of IR and MEDI3622 but not by either treatment modality alone and thus suggest that the supra-additive effect of the combined treatment modality is in part due to abrogation of the ADAM17-mediated IR-induced protective effect on the tumor vasculature. Furthermore, we demonstrate that the novel ADAM17-inhibitory antibody MEDI3622 potently improves the radiotherapy response of NSCLC.

Significance

The tumor response to radiotherapy is influenced by several factors of the tumor microenvironment. We demonstrate that inhibition of the sheddase ADAM17 by the novel antibody MEDI3622 reduces IR-induced VEGF release from tumor cells relevant for endothelial cell migration and vasculature protection, thereby enhancing radiotherapy treatment outcome of NSCLC.

New challenges in the combination of radiotherapy and immunotherapy in non-small cell lung cancer

Immunotherapy has represented one of the main medical revolutions of recent decades, and is currently a consolidated treatment for different types of tumors at different stages and scenarios, and is present in a multitude of clinical trials. One of the diseases in which it is most developed is non-small cell lung cancer. The combination of radiotherapy and immunotherapy in cancer in general and lung cancer in particular currently represents one of the main focuses of basic and clinical research in oncology, due to the synergy of this interaction, which can improve tumor response, resulting in improved survival and disease control. In this review we present the biochemical and molecular basis of the interaction between radiotherapy and immunotherapy. We also present the current clinical status of this interaction in each of the stages and cases of non-small cell lung cancer, with the main results obtained in the different studies both in terms of tumor response and survival as well as toxicity. Finally, we mention the main studies underway and the challenges of this interaction in the coming years, including how these treatments should be combined to achieve the greatest efficacy with the fewest possible side effects (dose, type of radiotherapy and drugs, sequence of treatments).

Interventional Radiology Image-Guided Locoregional Therapies (LRTs) and Immunotherapy for the Treatment of HCC

Image-guided locoregional therapies (LRTs) are a crucial asset in the treatment of hepatocellular carcinoma (HCC), which has proven to be characterized by an impaired antitumor immune status. LRTs not only directly destroy tumor cells but also have an immunomodulating role, altering the tumor microenvironment with potential systemic effects. Nevertheless, the immune activation against HCC induced by LRTs is not strong enough on its own to generate a systemic significant antitumor response, and it is incapable of preventing tumor recurrence. Currently, there is great interest in the possibility of combining LRTs with immunotherapy for HCC, as this combination may result in a mutually beneficial and synergistic relationship. On the one hand, immunotherapy could amplify and prolong the antitumoral immune response of LRTs, reducing recurrence cases and improving outcome. On the other hand, LTRs counteract the typical immunosuppressive HCC microenvironment and status and could therefore enhance the efficacy of immunotherapy. Here, after reviewing the current therapeutic options for HCC, we focus on LRTs, describing for each of them the technique and data on its effect on the immune system. Then, we describe the current status of immunotherapy and finally report the recently published and ongoing clinical studies testing this combination.

Risk of corticosteroid treatment and hospitalization after checkpoint inhibitor and radiation therapy in patients with cancer

BACKGROUND

Immune checkpoint inhibitors (ICIs) are potent new cancer therapies but can cause serious immune-related adverse events. ICIs have contributed significantly to improved survival and thereby provide more opportunity for the development of local disease symptomatology requiring palliative radiation. Radiation therapy (RT) has also recently shown benefit in the oligometastatic setting. Data on the interaction and safety of concurrent ICIs and RT are limited.

METHODS

In this retrospective cohort study using a large medical claims database from 2010 to 2017, the need for corticosteroid therapy and the risk of hospitalization within 180 days of treatment with an ICI were determined for patients with a diagnosis of malignant melanoma or lung cancer. Patients were stratified by the use of RT within the 30 days before and after ICI therapy.

RESULTS

In all, 2020 patients (218 with RT and 1802 without RT) met the inclusion criteria for prednisone analysis, whereas 3519 patients (361 with RT and 3158 without RT) met the inclusion criteria for all other analyses. In a univariable analysis, RT was not associated with the need for prednisone (relative risk [RR], 1.2; 95% confidence interval [CI], 0.8-1.9) or methylprednisolone (RR, 1.1; 95% CI, 0.7-2.0). When the end point was hospitalization, RT was significantly associated with hospitalization after ICI therapy for certain cancer/drug combinations (RR for lung cancer/programmed death 1 receptor inhibitors, 1.4; 95% CI, 1.2-1.6; P < .001; RR for melanoma/ipilimumab, 2.0; 95% CI, 1.0-3.5; P = .03).

CONCLUSIONS

In patients treated with ICIs, receiving RT was not associated with a higher risk of requiring corticosteroid therapy in comparison with not receiving RT. However, RT was associated with a higher risk of hospitalization, although this finding may be a result of differences in the underlying patient illness severity or oncologic disease burden at the baseline.

LAY SUMMARY

Data on the interaction of immunotherapy (immune checkpoint inhibitors) and radiation therapy and the safety of combining them are limited. Using a large database, this study has found that patients treated concurrently with immune checkpoint inhibitors and radiation therapy are not at increased risk for requiring corticosteroid therapy (which is used as a proxy for immune-related adverse events). However, concurrent therapy is associated with a higher risk of hospitalization, although this finding may be due to differences in the underlying patient illness severity (sicker patients may require both immunotherapy and radiation therapy).

Targeted radioimmunotherapy with the iodine-131-labeled caerin 1.1 peptide for human anaplastic thyroid cancer in nude mice

OBJECTIVE

The combination of two or more drugs with different mechanisms is a promising strategy for cancer treatment, and radioimmunotherapy (RIT) is a trending antitumor strategy. Radiotherapy (RT) can promote and activate antitumor immune effects, and immunotherapy can strengthen the effects of selective internal radiotherapy (SIRT); the RIT combination is synergistic and can overcome the adverse side effects of monotherapy. In this study, we developed a radioimmunoconjugate (RIC)-the iodine-131 (131I)-labeled caerin 1.1 peptide-to treat human anaplastic thyroid cancer (ATC).

METHODS

Antitumor activity of caerin 1.1 peptide was determined by MTT assay, plate colony formation and cell wound scratch assays, and the mechanism of the inhibition of carein 1.1 peptide on the growth of CAL-62 cells was identified by cell cycle and western blot. Then, we investigated the efficacy of the caerin 1.1 peptide as a single drug and the 131I-labeled caerin 1.1 peptide for ATC. H&E and TUNEL staining was performed to detect dead cells in the tumor tissue sections.

RESULTS

We found that caerin 1.1 arrested cells in the S phase to induce apoptosis and inhibited tumor growth to inhibit phosphorylation of Akt. In vivo, the iodine-131 (131I)-labeled caerin 1.1 peptide achieved better antitumor efficacy than radiotherapy alone and showed a good biosafety profile.

CONCLUSIONS

Our study demonstrates for the first time that the iodine-131 (131I)-labeled caerin 1.1 peptide can inhibit CAL-62 tumor growth and migration. The iodine-131 (131I)-labeled caerin 1.1 peptide, which represents a radioimmunotherapy strategy based on the combination of SIRT with a peptide-drug conjugate, could provide a treatment means for the radical cure of ATC.

Role of gamma knife radiosurgery in the management of intracranial gliomas

Gamma knife for gliomas is a relatively obscure treatment modality with few reports and small series available on the same. An extensive search of English Language literature yields no comprehensive reviews of the same. We here, attempt to review the available literature on gamma knife for all types of gliomas: Low grade, High grade, recurrent, and also for pediatric populations. We used keywords such as "Gamma Knife Glioma," "Stereotactic Radiosurgery Glioma," "Gamma Knife," "Adjuvant therapy Glioma" "Recurrent Glioma" on PubMed search engine, and articles were selected with respect to their use of gamma Knife for Gliomas and outcome for the same. These were then analyzed and salient findings were elucidated. This was combined with National Comprehensive Cancer Network guidelines for the same and also included our own initial experience with these tumors. Gamma-knife improved long term survival and quality of life in patients with low grade gliomas. In pediatric low grade gliomas, it may be considered as a treatment modality with a marginal dose of 12-14 Gy, especially in eloquent structures such as brain stem glioma, anterior optic pathway hypothalamic glioma. However, in newly diagnosed high-grade glioma gamma knife radiosurgery (GKRS) is not recommended because of a lack of definitive evidence in tumor control and quality of life. GKRS may find its role in palliative care of recurrent gliomas irrespective of type and grade. Inspite of growing experience with GKRS for gliomas, there is no Level I evidence in support of GKRS, hence better designed randomized controlled trials with long term outcomes are warranted. Although this modality is not a "one size fits all' therapy, it has its moments when chosen correctly and applied wisely. Gliomas being the most common tumors operated in any neurosurgical setting, knowledge about this modality and its application is essential and useful.

Percutaneous microwave ablation applications for liver tumors: recommendations for COVID-19 patients

Microwave ablation (MWA) is an alternative locoregional therapy to surgical resection of solid tumors in the treatment of malignancies, and is widely used for hepatic tumors. It has a slightly higher overall survival (OS) rate compared to external beam radiation therapy (EBRT), and proton beam therapy (PBT), and better long-term recurrence-free OS rate compared to radiofrequency ablation (RFA). In this paper, current commercial devices, most recent noncommercial designs, and the principles behind them alongside the recently reported developments and issues of MWA are reviewed. The paper also provides microscopic insights on effects of microwave irradiation in the body. Our review shows that MWA is a safe and effective, minimally invasive method with high ablation completion rates. However, for large tumors, the completion rates slightly decrease, and recurrences increase. Thus, for large tumors we suggest using a cooled shaft antenna or multiple antenna placements. Comparisons of the two common ablation frequencies 915 MHz and 2.45 GHz have shown inconsistent results due to non-identical conditions. This review suggests that 915 MHz devices are more effective for ablating large tumors and the theory behind MWA effects corroborates this proposition. However, for small tumors or tumors adjacent to vital organs, 2.45 GHz is suggested due to its more localized ablation zone. Among the antenna designs, the double-slot antenna with a metallic choke seems to be more effective by localizing the radiation around the tip of the antenna, while also preventing backward radiation towards the skin. The review also pertains to the use of MWA in COVID-19 patients and risk factors associated with the disease. MWA should be considered for COVID-19 patients with hepatic tumors as a fast treatment with a short recovery time. As liver injury is also a risk due to COVID-19, it is recommended to apply liver function tests to monitor abnormal levels in alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bilirubin, and other liver function indicators.

Synergies Radiotherapy-Immunotherapy in Head and Neck Cancers. A New Concept for Radiotherapy Target Volumes-"Immunological Dose Painting"

The combination of immune checkpoint inhibitors and definitive radiotherapy is investigated for the multimodal treatment of cisplatin non-eligible locally advanced head and neck cancers (HNC). In the case of recurrent and metastatic HNC, immunotherapy has shown benefit over the EXTREME protocol, being already considered the standard treatment. One of the biggest challenges of multimodal treatment is to establish the optimal therapy sequence so that the synergistic effect is maximal. Thus, superior results were obtained for the administration of anti-CTLA4 immunotherapy followed by hypofractionated radiotherapy, but the anti-PD-L1 therapy demonstrates the maximum potential of radio-sensitization of the tumor in case of concurrent administration. The synergistic effect of radiotherapy–immunotherapy (RT–IT) has been demonstrated in clinical practice, with an overall response rate of about 18% for HNC. Given the demonstrated potential of radiotherapy to activate the immune system through already known mechanisms, it is necessary to identify biomarkers that direct the “nonresponders” of immunotherapy towards a synergistic RT–IT stimulation strategy. Stimulation of the immune system by irradiation can convert “nonresponder” to “responder”. With the development of modern techniques, re-irradiation is becoming an increasingly common option for patients who have previously been treated with higher doses of radiation. In this context, radiotherapy in combination with immunotherapy, both in the advanced local stage and in recurrent/metastatic of HNC radiotherapy, could evolve from the “first level” of knowledge (i.e., ballistic precision, dose conformity and homogeneity) to “level two” of “biological dose painting” (in which the concept of tumor heterogeneity and radio-resistance supports the need for doses escalation based on biological criteria), and finally to the “third level“ ofthe new concept of “immunological dose painting”. The peculiarity of this concept is that the radiotherapy target volumes and tumoricidal dose can be completely reevaluated, taking into account the immune-modulatory effect of irradiation. In this case, the tumor target volume can include even the tumor microenvironment or a partial volume of the primary tumor or metastasis, not all the gross and microscopic disease. Tumoricidal biologically equivalent dose (BED) may be completely different from the currently estimated values, radiotherapy treating the tumor in this case indirectly by boosting the immune response. Thus, the clinical target volume (CTV) can be replaced with a new immunological-clinical target volume (ICTV) for patients who benefit from the RT–IT association (Image 1).

Premetastasis

Sterile inflammation within primary tumor tissues can spread to distant organs that are devoid of tumor cells. This happens in a manner dependent on tumor-led secretome, before the actual metastasis occurs. The premetastatic microenvironment is established in this way and is at least partly regulated by hijacking the host innate immune system. The biological manifestation of premetastasis include increased vascular permeability, cell mobilization via the blood stream, degradation of the extracellular matrix, immunosuppression, and host antineoplastic activities.

Current locoregional therapies and treatment strategies in hepatocellular carcinoma

Locoregional therapies (lrts) play an important role in the treatment of hepatocellular carcinoma (hcc), with the aim of increasing overall survival while preserving liver function. Various forms of lrt are available, and choosing the best one depends on technical aspects, liver morphology, tumour biology, and the patient's symptoms. The purpose of the present review article is to provide an overview of the current evidence relating to the use of percutaneous ablation, transarterial chemoembolization, and transarterial radioembolization for the curative or palliative treatment of hcc. Special situations are also reviewed, including the combined use of systemic therapy and lrt, indications and techniques for bridging to transplant and downstaging, and the use of lrt to treat patients with hcc and macrovascular invasion.

CAR T Cell Therapy for Solid Tumors: Bright Future or Dark Reality?

Chimeric antigen receptor (CAR) T cell therapy has garnered significant excitement due to its success for hematological malignancies in clinical studies leading to the US Food and Drug Administration (FDA) approval of three CD19-targeted CAR T cell products. In contrast, the clinical experience with CAR T cell therapy for solid tumors and brain tumors has been less encouraging, with only a few patients achieving complete responses. Clinical and preclinical studies have identified multiple "roadblocks," including (1) a limited array of targetable antigens and heterogeneous antigen expression, (2) limited T cell fitness and survival before reaching tumor sites, (3) an inability of T cells to efficiently traffic to tumor sites and penetrate physical barriers, and (4) an immunosuppressive tumor microenvironment. Herein, we review these challenges and discuss strategies that investigators have taken to improve the effector function of CAR T cells for the adoptive immunotherapy of solid tumors.

A review of radiation induced abscopal effect: combining radiotherapy and immunotherapy to treat the untreated distant metastatic tumours

Background:

Radiotherapy is an effective and significant mode of definitive cancer treatment with well-established local tumour control success, especially in the treatment of localised tumours. Although, for metastatic disease, the role of radiotherapy has generally been limited to palliation of symptoms. In the treatment of metastatic diseases settings, the radiation therapy technique has always been confronted with the challenge of the simultaneous treatment of all of the various distant metastatic tumour sites, however, some recent evidence suggests that radiotherapy can potentially induce anticancer immune responses whose effectors potentially migrate to distant metastatic tumours to provoke their regression in cancer patients. Thus, unirradiated distant metastatic tumour sites can exhibit a delayed therapeutic response termed the abscopal effect.

Materials and methods:

This paper reports on a review of the abscopal effect, including its biological mechanism, the effect of radiation dose and fractionation regime and the timing of immunotherapy administration on radiotherapy-induced abscopal effect, the enhancement of radiotherapy-induced abscopal effects with immunotherapy, the effect of the location of the irradiated tumour and the radiotherapy of multiple tumour sites on the likelihood and effectiveness of inducing abscopal responses in the preclinical and clinical settings and also reports on some evidence of clinical observations in patients.

Conclusions:

Although abscopal effects of radiotherapy are still relatively rare in patients, it has gained a lot of interest due to recent development and use of immunotherapy strategies incorporating combinations of targeted immunomodulators and immune checkpoint blockade with radiation therapy. The enhancement of cancer immunotherapy could potentially enable the translation of the concept of abscopal effect into the clinics as a new strategy to induce therapeutically effective anti-tumour immune responses in cancer patients. The combination of radiotherapy and immunotherapy has the potential to expand the role of radiotherapy from a purely local tumour control treatment to play a significant role in advanced and metastatic tumour control and this could likely lead to a paradigm shift in the treatment of patients with metastatic cancer.

Surgical therapy for breast cancer liver metastases

Breast cancer is the most commonly diagnosed cancer in females worldwide. If diagnosed early, patients generally have good outcomes. However, approximately 20% to 30% of all women diagnosed with breast cancer develop metastatic disease. Metastatic breast cancer is incurable, but there is growing evidence that resection or other local therapy for breast cancer liver metastases (BCLM) may improve survival. We aimed to review indications for and outcomes of perioperative liver resection and other local therapies for BCLM. In this series, we reviewed 11 articles (605 patients) focusing on surgical resection and 7 articles (266 patients) describing radiofrequency ablation (RFA) for BCLM. Median disease-free survival (DFS) after surgical resection was 23 months (range, 14–29 months) and median overall survival (OS) was 39.5 months (range, 26–82 months). One, 3- and 5-year survivals were 89.5%, 70%, and 38%, respectively. The factors favoring better outcomes are hormone receptor positive primary breast cancer status, R0 resection, no extrahepatic metastases (EHM), small BCLM, and solitary liver metastases. On the other hand, the median DFS with RFA was 11 months, median OS was 32 months, and the 3- and 5-year OS were 43% and 27%, respectively. The clinical features that are indications for RFA are smaller tumor and higher EHM rate than those favoring surgical resection (2.4 vs. 4.0 cm and 46% vs. 27%). The merits of RFA are its high technical success rate, low morbidity, short hospital stay, and that it can be repeated. Although results are as yet limited, in carefully selected patients, resection or other local therapies such as RFA, render BCLM potentially provide prognostic improvement.

Chemoradioimmunotherapy of inoperable stage III non-small cell lung cancer: immunological rationale and current clinical trials establishing a novel multimodal strategy

Immune-checkpoint inhibitors (ICI) have dramatically changed the landscape of lung cancer treatment. Preclinical studies investigating combination of ICI with radiation show a synergistic improvement of tumor control probability and have resulted in the development of novel therapeutic strategies. For advanced non-small cell lung cancer (NSCLC), targeting immune checkpoint pathways has proven to be less toxic with more durable treatment response than conventional chemotherapy. In inoperable Stage III NSCLC, consolidation immune checkpoint inhibition with the PD-L1 inhibitor durvalumab after completion of concurrent platinum-based chemoradiotherapy resulted in remarkable improvement of progression-free and overall survival. This new tri-modal therapy has become a new treatment standard. Development of predictive biomarkers and improvement of patient selection and monitoring is the next step in order to identify patients most likely to derive maximal benefit from this new multimodal approach. In this review, we discuss the immunological rationale and current trials investigating chemoradioimmunotherapy for inoperable stage III NSCLC.

Radiation-induced bystander and abscopal effects: important lessons from preclinical models

Radiotherapy is a pivotal component in the curative treatment of patients with localised cancer and isolated metastasis, as well as being used as a palliative strategy for patients with disseminated disease. The clinical efficacy of radiotherapy has traditionally been attributed to the local effects of ionising radiation, which induces cell death by directly and indirectly inducing DNA damage, but substantial work has uncovered an unexpected and dual relationship between tumour irradiation and the host immune system. In clinical practice, it is, therefore, tempting to tailor immunotherapies with radiotherapy in order to synergise innate and adaptive immunity against cancer cells, as well as to bypass immune tolerance and exhaustion, with the aim of facilitating tumour regression. However, our understanding of how radiation impacts on immune system activation is still in its early stages, and concerns and challenges regarding therapeutic applications still need to be overcome. With the increasing use of immunotherapy and its common combination with ionising radiation, this review briefly delineates current knowledge about the non-targeted effects of radiotherapy, and aims to provide insights, at the preclinical level, into the mechanisms that are involved with the potential to yield clinically relevant combinatorial approaches of radiotherapy and immunotherapy.

Percutaneous Ablation-Induced Immunomodulation in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the most common causes of cancer-related deaths worldwide and its incidence is rising. Percutaneous locoregional therapies, such as radiofrequency ablation and microwave ablation, are widely used as curative treatment options for patients with small HCC, but their effectiveness remains restricted because of the associated high rate of recurrence, occurring in about 70% of patients at five years. These thermal ablation techniques have the particularity to induce immunomodulation by destroying tumours, although this is not sufficient to raise an effective antitumour immune response. Ablative therapies combined with immunotherapies could act synergistically to enhance antitumour immunity. This review aims to understand the different immune changes triggered by radiofrequency ablation and microwave ablation as well as the interest in using immunotherapies in combination with thermal ablation techniques as a tool for complementary immunomodulation.

Abscopal effect in lung cancer: three case reports and a concise review

The abscopal effect describes the ability of locally administered radiotherapy to induce systemic antitumor effects. Over the past 40 years, reports on the abscopal effect following conventional radiation have been relatively rare, especially in less immunogenic tumors such as lung cancer. However, with the continued development and use of immunotherapy, reports on the abscopal effect have become increasingly frequent during the last decade. Here, we present three illustrative case reports from our own institution and previous published cases of the abscopal effect in patients with non-small cell lung cancer, treated with immune checkpoint inhibitors and radiotherapy. We also present a concise review of the clinical and experimental literature on the abscopal effect in non-small cell lung cancer.

Recent Advances: The Imbalance of Immune Cells and Cytokines in the Pathogenesis of Hepatocellular Carcinoma

Recent advancement in the immunological understanding of genesis of hepatocellular carcinoma (HCC) has implicated a decline in anti-tumour immunity on the background of chronic inflammatory state of liver parenchyma. The development of HCC involves a network of immunological activity in the tumour microenvironment involving continuous interaction between tumour and stromal cells. The reduction in anti-tumour immunity is secondary to changes in various immune cells and cytokines, and the tumour microenvironment plays a critical role in modulating the process of liver fibrosis, hepatocarcinogenesis, epithelial-mesenchymal transition (EMT), tumor invasion and metastasis. Thus, it is considered as one of primary factor behind the despicable tumour behavior and observed poor survival; along with increased risk of recurrence following treatment in HCC. The primary intent of the present review is to facilitate the understanding of the complex network of immunological interactions of various immune cells, cytokines and tumour cells associated with the development and progression of HCC.

Potent immunomodulatory effects of an anti-CEA-IL-2 immunocytokine on tumor therapy and effects of stereotactic radiation

While anti-CEA antibodies have no direct effect on CEA-positive tumors, they can be used to direct potent anti-tumor effects as an antibody-IL-2 fusion protein (immunocytokine, ICK), and at the same time reduce the toxicity of IL-2 as a single agent. Using a fusion protein of humanized anti-CEA with human IL-2 (M5A-IL-2) in a transgenic murine model expressing human CEA, we show high tumor uptake of the ICK to CEA-positive tumors with additional lymph node targeting. ICK treated CEA-positive tumors exhibit significant tumor eradication. Analysis of tumor-infiltrating lymphocytes shows a high frequency of both CD8⁺ and CD4⁺ T cells along with CD11b positive myeloid cells in ICK treated mice. The frequency of tumor-infiltrating FoxP3⁺ CD4⁺ T cells (Tregs) is significantly reduced vs anti-CEA antibody-treated controls, indicating that ICK did not preferentially stimulate migration or proliferation of Tregs to the tumor. Combination therapy with anti-PD-1 antibody did not improve tumor reduction over ICK therapy alone. Since stereotactic tumor irradiation (SRT), commonly used in cancer therapy has immunomodulatory effects, we tested combination SRT+ICK therapy in two tumor model systems. Use of fractionated vs single high dose SRT in combination with ICK resulted in greater tumor inhibition and immunity to tumor rechallenge. In particular, tumor microenvironment and myeloid cell composition appear to play a significant role in the response rate to ICK+SRT combination therapy.

Current status and progress of concurrent chemoradiotherapy in patients with locally advanced non-small cell lung cancer prior to the approval of durvalumab

Background

The standard treatment for patients with unresectable locally advanced (LA) non‐small cell lung cancer (NSCLC) is chemoradiotherapy (CRT). Consolidation therapy with durvalumab after CRT demonstrated survival benefits and was approved in Japan in July 2018. The use of immune checkpoint inhibitors (ICIs) is entering routine oncological practice, and here we investigate the feasibility of concurrent CRT for LA‐NSCLC patients based on the PACIFIC criteria.

Methods

We performed a retrospective study to evaluate the feasibility and efficacy of concurrent CRT prior to the approval of durvalumab. We assessed consecutive patients with LA‐NSCLC treated with CRT between January 2012 and June 2018.

Results

We analyzed a total of 108 consecutive patients who received radical thoracic radiotherapy and concurrent platinum‐based chemotherapy. Of those patients, 105 (97%) completed the planned radiotherapy. Radiation pneumonitis was observed in 93 patients (85%), with a median of 130 days (range: 41–317 days) from the initiation of radiation to the onset of the complication. Among the patients, 74 (69%) were considered eligible for consolidation therapy with durvalumab. The overall response rate was 64%, and the two‐year survival rate was 63%. Patients who received an ICI after relapse were associated with significantly better survival than those who did not receive an ICI (two‐year survival rate: 87% vs. 41%, respectively; P = 0.001).

Conclusions

Prior to the approval of durvalumab, the clinical application of ICIs improved the outcome of patients with relapsed NSCLC after CRT for LA‐NSCLC. The management of radiation pneumonitis remains a challenge following the approval of durvalumab.

Expression of lymphocyte immunoregulatory biomarkers in bone and soft-tissue sarcomas

Despite advances in our understanding of the underlying molecular drivers of sarcomas, few treatments are available with proven benefit for advanced metastatic sarcomas. Immunotherapy has value in this setting for some types of cancers, but sarcomas, with their multiplicity of rare types, have not been characterized in detail for their expression of targetable immune biomarkers. This study provides the most systematic evaluation to date of tumor-infiltrating lymphocytes and immune checkpoint biomarker expression in sarcomas. We examined by morphology and immunohistochemistry 1072 sarcoma specimens representing 22 types, in addition to 236 benign bone and soft-tissue tumors. Genomically-complex sarcoma types-those driven by mutations and/or copy-number alterations-had much higher numbers of tumor-infiltrating lymphocytes than translocation-associated sarcomas. Prior exposure to radiotherapy was associated with increased immune infiltrates. Higher lymphocytic infiltration was associated with better overall survival among the non-translocation-associated sarcomas. Expression of PD-1 and CD56 were associated with worse overall survival. LAG-3 and TIM-3, two emerging immune checkpoints, were frequently expressed in most sarcoma types. Indeed, most cases positive for PD-(L)1 coexpressed one or both of these novel biomarkers, providing a potential rationale in support for trials targeting LAG-3 and/or TIM-3 in conjunction with PD-1 inhibition.

Cullin Ring Ubiquitin Ligases (CRLs) in Cancer: Responses to Ionizing Radiation (IR) Treatment

Treatment with ionizing radiation (IR) remains the cornerstone of therapy for multiple cancer types, including disseminated and aggressive diseases in the palliative setting. Radiotherapy efficacy could be improved in combination with drugs that regulate the ubiquitin-proteasome system (UPS), many of which are currently being tested in clinical trials. The UPS operates through the covalent attachment of ATP-activated ubiquitin molecules onto substrates following the transfer of ubiquitin from an E1, to an E2, and then to the substrate via an E3 enzyme. The specificity of ubiquitin ligation is dictated by E3 ligases, which select substrates to be ubiquitylated. Among the E3s, cullin ring ubiquitin ligases (CRLs) represent prototypical multi-subunit E3s, which use the cullin subunit as a central assembling scaffold. CRLs have crucial roles in controlling the cell cycle, hypoxia signaling, reactive oxygen species clearance and DNA repair; pivotal factors regulating the cancer and normal tissue response to IR. Here, we summarize the findings on the involvement of CRLs in the response of cancer cells to IR, and we discuss the therapeutic approaches to target the CRLs which could be exploited in the clinic.

Emerging Therapeutic Targets in Oncologic Photodynamic Therapy

Background:

Reactive oxygen species sustain tumorigenesis and cancer progression through deregulated redox signalling which also sensitizes cancer cells to therapy. Photodynamic therapy (PDT) is a promising anti-cancer therapy based on a provoked singlet oxygen burst, exhibiting a better toxicological profile than chemo- and radiotherapy. Important gaps in the knowledge on underlining molecular mechanisms impede on its translation towards clinical applications.

Aims and Methods:

The main objective of this review is to critically analyse the knowledge lately gained on therapeutic targets related to redox and inflammatory networks underlining PDT and its outcome in terms of cell death and resistance to therapy. Emerging therapeutic targets and pharmaceutical tools will be documented based on the identified molecular background of PDT.

Results:

Cellular responses and molecular networks in cancer cells exposed to the PDT-triggered singlet oxygen burst and the associated stresses are analysed using a systems medicine approach, addressing both cell death and repair mechanisms. In the context of immunogenic cell death, therapeutic tools for boosting anti-tumor immunity will be outlined. Finally, the transcription factor NRF2, which is a major coordinator of cytoprotective responses, is presented as a promising pharmacologic target for developing co-therapies designed to increase PDT efficacy.

Conclusion:

There is an urgent need to perform in-depth molecular investigations in the field of PDT and to correlate them with clinical data through a systems medicine approach for highlighting the complex biological signature of PDT. This will definitely guide translation of PDT to clinic and the development of new therapeutic strategies aimed at improving PDT.

Positive Immuno-Modulation Following Radiofrequency Assisted Liver Resection in Hepatocellular Carcinoma

Introduction: Hepatocellular carcinoma (HCC) often develops on a background of chronic inflammation and a complex immunosuppressive network with increased regulatory T cells, impaired CD8⁺ T cells and the secretion of immunosuppressive cytokines. Previous clinical studies have reported a superior disease-free survival (DFS) following a radiofrequency-based ablation or resection in HCC tumours compared to conventional liver resection techniques. The aim of this study was to investigate whether there is any correlation with the use of a radiofrequency-assisted liver resection and clinical outcome. Material and Methods: Patients’ peripheral blood was collected prior and 7 days following surgery from patients undergoing a liver resection for HCC. There were 5 liver resections performed using CUSA and 6 liver resections with the RF-based device, Habib^TM 4X. The primary endpoint of the study was to assess the immunological parameters of circulating immune cell populations as well as serum cytokines. The Student’s t-test, chi-square or Fisher’s Exact test were applied for statistical comparisons, as appropriate. Results: Patients undergoing an RF-assisted liver resection with Habib^TM 4X had a significant decrease in the inhibitory Treg cells (p = 0.002) and a significant increase in CD8⁺ T lymphocytes (p = 0.050) and CD4⁺CD45RO⁺/CD4⁺ memory T cells (p = 0.002) compared to those patients undergoing a liver resection with CUSA. It was also noted that the RF-assisted liver resection group had a significant decrease in circulating TGF-ß (p = 0.000), IL10 (p = 0.000) and a significant increase in IFN-gamma (p = 0. 027) and IL-17 compared to the CUSA group. Conclusion: A liver resection with RF-based device Habib^TM 4X was associated with positive immunomodulatory changes in circulating immune cells and circulating cytokines which could explain the significant improvement in DFS.

Reduced Number of Lymphocytes by X-ray Irradiation: A Problem in a Combination Therapy Trial that Elicits the Abscopal Effect in Preclinical Studies Using Electron Beam Irradiation

In preclinical studies with model animals, intravenous administration of a derivative of chemokine CCL3, named eMIP, after local electron-beam irradiation, not only enhanced tumor growth inhibition at a target site but also induced tumor killing beyond the treated site (a phenomenon known as the abscopal effect). eMIP works with alarmins such as high mobility group box 1 (HMGB1) and heat shock protein 70 (HSP70) released from overexpressed tumor cells by irradiation. These alarmins at the irradiated tumor bed trap injected eMIP and, by forming complexes with eMIP, play a key role to recruit and activate tumor inhibitory natural killer (NK) cells and CD4⁺ and CD8⁺ T cells. Tumor type-specific secretion of gamma interferon from splenocytes was also demonstrated, which may also activate NK cells. During Phase 1 clinical studies using X-rays, however, no apparent abscopal effect was observed. Instead, we saw frequent reduction in numbers of lymphocytes in the peripheral blood of irradiated patients. The reduced number of lymphocytes recovered poorly once depleted, in contrast to neutrophils, and persisted for months after the treatment. This might have affected outcome after combination treatment of irradiation and eMIP. To enhance host defense mechanisms during and after photon-beam (X-ray) radiotherapy of a deep-seated tumor, it seems essential to keep lymphocytes undamaged by eliminating reactive oxygen species that are formed in the peripheral blood during irradiation.

Future of IR: Emerging Techniques, Looking to the Future…and Learning from the Past

Innovation has been the cornerstone of interventional radiology since the early years of the founders, with a multitude of new therapeutic approaches developed over the last 50 years. What is the future holding for us? This article presents an overview of the in-coming developments that are catching on at this moment, particularly focusing on three items: the new applications of existing techniques, particularly embolotherapy and interventional oncology; the cutting-edge devices; the imaging technologies at the forefront of the image-guidance. Besides this, clinical vision and patient relation remain crucial for the future of the discipline.

Previous Radiotherapy Increases the Efficacy of IL-2 in Malignant Pleural Effusion: Potential Evidence of a Radio-Memory Effect?

Preclinical and clinical studies have shown that prior receipt of radiotherapy enhances antitumor immune responses, a phenomenon we call the “radio-memory effect.” However, all of the evidence regarding this effect to date comes from work with PD1/PDL1 inhibitors. Here we explored whether this effect also occurs with other forms of immune therapy, specifically interleukin-2 (IL-2). We retrospectively assessed outcomes in patients with malignant pleural effusion (MPE) who had previously received radiotherapy for non-small-cell lung cancer (NSCLC) within 18 months before the intrapleural infusion of IL-2 or cisplatin. Radiotherapy sites included lungs, thoracic lymph nodes, and intracranial. All patients received intrapleural infusion of IL-2 or cisplatin, and most had had several cycles of standard chemotherapy for NSCLC. We identified 3,747 patients with MPE (median age 64 years [range 29–88)) treated at one of several institutions from August 2009 through February 2015; 642 patients had been treated with IL-2 and 1102 with cisplatin and had survived for at least 6 months afterward. Among those who received IL-2, 288 had no radiotherapy, 324 had extracranial (i.e., thoracic) radiotherapy, and 36 had intracranial radiotherapy. The median follow-up time for surviving patients was 38 months. Patients who had received extracranial radiotherapy followed by IL-2 had significantly longer PFS than patients who had not received extracranial radiotherapy (i.e., either no radiotherapy or intracranial radiotherapy). Patients who had received intracranial or extracranial radiotherapy followed by IL-2 had significantly longer OS than did other patients. No survival advantage was noted for prior radiotherapy among patients who received intrapleural cisplatin. We speculate that previous radiotherapy could enhance the efficacy of subsequent intrapleural infusion of IL-2, a “radio-memory” effect that could be beneficial in future studies.

Multidisciplinary approach for post-liver transplant recurrence of hepatocellular carcinoma: A proposed management algorithm

A large number of liver transplants have been performed for hepatocellular carcinoma (HCC), and recurrence is increasingly encountered. The recurrence of HCC after liver transplantation is notoriously difficult to manage. We hereby propose multi-disciplinary management with a systematic approach. The patient is jointly managed by the transplant surgeon, physician, oncologist and radiologist. Immunosuppressants should be tapered to the lowest effective dose to protect against rejection. The combination of a mammalian target of rapamycin inhibitor with a reduced calcineurin inhibitor could be considered with close monitoring of graft function and toxicity. Comprehensive staging can be performed by dual-tracer positron emission tomography-computed tomography or the combination of contrast computed tomography and a bone scan. In patients with disseminated recurrence, sorafenib confers survival benefits but is associated with significant drug toxicity. Oligo-recurrence encompasses recurrent disease that is limited in number and location so that loco-regional treatments convey disease control and survival benefits. Intra-hepatic recurrence can be managed with graft resection, but significant operative morbidity is expected. Radiofrequency ablation and stereotactic body radiation therapy (SBRT) are effective alternative strategies. In patients with more advanced hepatic disease, regional treatment with trans-arterial chemoembolization or intra-arterial Yttrium-90 can be considered. For patients with extra-hepatic oligo-recurrence, loco-regional treatment can be considered if practical. Patients with more than one site of recurrence are not always contraindicated for curative treatments. Surgical resection is effective for patients with pulmonary oligo-recurrence, but adequate lung function is a pre-requisite. SBRT is a non-invasive and effective modality that conveys local control to pulmonary and skeletal oligo-recurrences.

TGF-beta 1 levels are associated with lymphocyte percentages in patients with lung cancer treated with radiation therapy

Purpose

Plasma TGF-β1 protein levels reportedly may predict the treatment outcomes of lung cancer. We hypothesized that in patients with lung cancer treated with radiation therapy (RT), TGF-β1 levels may correlate with the percentages of CD4⁺ T cells, CD8⁺ T cells, and the CD4⁺/CD8⁺ T cell ratio in peripheral blood.

Patients and methods

Eighty-two lung cancer patients satisfied the inclusion criteria. Platelet-poor plasma was obtained before RT, at the second and fourth weeks during RT, and at the end of RT (pre-, during-, and post-RT, respectively). TGF-β1 was measured via ELISA, while recording the percentages of lymphocyte subsets in peripheral blood. Short-term efficacy was categorized as complete response, partial response, stable disease, or progressive disease.

Results

Patients who had significantly lower TGF-β1 protein levels after RT than pre-RT seemed to have a better short-term effect (P<0.05) than those who had higher TGF-β1 levels. There was a significant association between the TGF-β1 levels and percentages of CD4⁺ T cells, CD8⁺ T cells, or CD4⁺/CD8⁺ T cell ratio during and at the end of RT. Changes in CD3⁺ T cells, B cells, or natural killer cells were not statistically related to the changes in TGF-β1 levels.

Conclusion

Lung cancer patients with TGF-β1 levels in plasma after RT that are below pre-RT levels may experience better short-term efficacy. The underlying mechanism may be related to the influence of TGF-β1 on antitumor immunity.

Combining Heavy-Ion Therapy with Immunotherapy: An Update on Recent Developments

Clinical trials and case reports of cancer therapies combining radiation therapy with immunotherapy have at times demonstrated total reduction or elimination of metastatic disease. While virtually all trials focus on the use of immunotherapy combined with conventional photon irradiation, the dose-distributive benefits of particles, in particular the distinct biological effects of heavy ions, have unknown potential vis-a-vis systemic disease response. Here, we review recent developments and evidence with a focus on the potential for heavy-ion combination therapy.

Radiation, inflammation and the immune response in cancer

Radiation is an important component of cancer treatment with more than half of all patients receive radiotherapy during their cancer experience. While the impact of radiation on tumour morphology is routinely examined in the pre-clinical and clinical setting, the impact of radiation on the tumour microenvironment and more specifically the inflammatory/immune response is less well characterised. Inflammation is a key contributor to short- and long-term cancer eradication, with significant tumour and normal tissue consequences. Therefore, the role of radiation in modulating the inflammatory response is highly topical given the current wave of targeted and immuno-therapeutic treatments for cancer. This review provides a general overview of how radiation modulates the inflammatory and immune response—(i) how radiation induces the inflammatory/immune system, (ii) the cellular changes that take place, (iii) how radiation dose delivery affects the immune response, and (iv) a discussion on research directions to improve patient survival, reduce side effects, improve quality of life, and reduce financial costs in the immediate future. Harnessing the benefits of radiation on the immune response will enhance its maximal therapeutic benefit and reduce radiation-induced toxicity.

The Integration of Radiotherapy with Immunotherapy for the Treatment of Non-Small Cell Lung Cancer

Five-year survival rates for non-small cell lung cancer (NSCLC) range from 14% to 49% for stage I to stage IIIA disease, and are <5% for stage IIIB/IV disease. Improvements have been made in the outcomes of patients with NSCLC due to advancements in radiotherapy (RT) techniques, the use of concurrent chemotherapy with RT, and the emergence of immunotherapy as first- and second-line treatment in the metastatic setting. RT remains the mainstay treatment in patients with inoperable early-stage NSCLC and is given concurrently or sequentially with chemotherapy in patients with locally advanced unresectable disease. There is emerging evidence that RT not only provides local tumor control but also may influence systemic control. Multiple preclinical studies have demonstrated that RT induces immunomodulatory effects in the local tumor microenvironment, supporting a synergistic combination approach with immunotherapy to improve systemic control. Immunotherapy options that could be combined with RT include programmed cell death-1/programmed cell death ligand-1 blockers, as well as investigational agents such as OX-40 agonists, toll-like receptor agonists, indoleamine 2,3-dioxygenase-1 inhibitors, and cytokines. Here, we describe the rationale for the integration of RT and immunotherapy in patients with NSCLC, present safety and efficacy data that support this combination strategy, review planned and ongoing studies, and highlight unanswered questions and future research needs.

Concomitant Radioembolization and Immune Checkpoint Inhibition in Metastatic Renal Cell Carcinoma

This case represents the challenge and creativity necessary when treating patients with metastatic renal cell carcinoma who have been exposed to multiple lines of therapy. At present, treatment with immune checkpoint inhibition has stabilized and improved the metastatic disease of this patient with the exception of hepatic lesions. This isolated progression within the liver led the employment of radioembolization, which successfully treated those metastases. This is the first documented case of metastatic renal cell carcinoma controlled with concurrent use of immune checkpoint inhibition and radioembolization for both extrahepatic and hepatic metastases, respectively. This case can be construed as a potential example of the abscopal effect and may provide the basis for understanding this type of response in select patients.

Molecular mechanism of bystander effects and related abscopal/cohort effects in cancer therapy

Cancer cells subjected to ionizing radiation may release signals which can influence nearby non-irradiated cells, termed bystander effects. The transmission of bystander effects among cancer cells involves the activation of inflammatory cytokines, death ligands, and reactive oxygen/nitrogen species. In addition to bystander effects, two other forms of non-target effects (NTEs) have been identified in radiotherapy, as one is called cohort effects and the other is called abscopal effects. Cohort effects represent the phenomenon where irradiated cells can produce signals that reduce the survival of neighboring cells within an irradiated volume. The effects suggest the importance of cellular communication under irradiation with non-uniform dose distribution. In contrast, abscopal effects describe the NTEs that typically occur in non-irradiated cells distant from an irradiated target. These effects can be mediated primarily by immune cells such as T cells. Clinical trials have shown that application of radiation along with immunotherapy may enhance abscopal effects and improve therapeutic efficacy on non-target lesions outside an irradiated field. According to NTEs, cell viability is reduced not only by direct irradiation effects, but also due to signals emitted from nearby irradiated cells. A clinical consideration of NTEs could have a revolutionary impact on current radiotherapy via the establishment of more efficient and less toxic radiobiological models for treatment planning compared to conventional models. Thus, we will review the most updated findings about these effects and outline their mechanisms and potential applications in cancer treatment with a special focus on the brain, lung, and breast cancers.

Immunotherapy in pancreatic adenocarcinoma-overcoming barriers to response

Pancreatic adenocarcinoma (PAC) remains one of the leading causes of cancer-related death. Despite multiple advances in targeted and immune therapies, the 5-year survival in advanced PAC remains poor. In this review, we discuss some of the unique aspects of the tumor microenvironment (TME) in PAC that may contribute to its resistance to immune therapies, as well as opportunities to potentially overcome some of these inherent barriers. Furthermore, we discuss strategies to enable immune therapies in PAC such as cytotoxic chemotherapy and radiation therapy, cancer vaccines, cytokine based therapy, oncolytic viruses, and adoptive T-cell therapy. Finally, we address a variety of targeted therapies as a strategy to further amplify immune responses in PAC.

Abscopal effect of radiation on bone metastases of breast cancer: A case report

The abscopal effect is defined as the clearance of distant tumors after applying localized irradiation to a particular tumor site. It has been proposed that a mechanism for the abscopal effect might be the activation of the immune system, which leads to immunogenic tumor cell death. Here, we describe a woman with advanced breast cancer that received modified ablative radiation therapy that targeted her primary breast tumor. She experienced an apparent regression of metastatic mass in the thoracic spine. This case supported the hypothesis that the abscopal effect might be attributable to an activation of the systemic immune response.

Effect of Gamma Knife Radiosurgery and Programmed Cell Death 1 Receptor Antagonists on Metastatic Melanoma

Learning objectives

To evaluate radiation-induced changes in patients with brain metastasis secondary to malignant melanoma who received treatment with Gamma Knife radiosurgery (GKRS) and programmed cell death 1 (PD-1) receptor antagonists.

Introduction 

Stereotactic radiosurgery and chemotherapeutics are used together for treatment of metastatic melanoma and have been linked to delayed radiation-induced vasculitic leukoencephalopathy (DRIVL). There have been reports of more intense interactions with new immunotherapeutics targeting PD-1 receptors, but their interactions have not been well described and may result in an accelerated response to GKRS. Here we present data on subjects treated with this combination from a single institution.

Methods

Records from patients who underwent treatment for metastatic melanoma to the brain with GKRS from 2011 to 2016 were reviewed. Demographics, date of brain metastasis diagnosis, cause of death when applicable, immunotherapeutics, and imaging findings were recorded. The timing of radiation therapy and medications were also documented. 

Results

A total of 79 subjects were treated with GKRS, and 66 underwent treatment with both GKRS and immunotherapy. Regarding the 30 patients treated with anti-PD-1 immunotherapy, 21 patients received pembrolizumab, seven patients received nivolumab, and two patients received pembrolizumab and nivolumab. Serial imaging was available for interpretation in 25 patients, with 13 subjects who received GKRS and anti-PD-1 immunotherapy less than six weeks of each other. While four subjects had indeterminate/mixed findings on subsequent magnetic resonance imaging (MRI), nine subjects were noted to have progression. Two of these patients showed progression but subsequent imaging revealed a decrease in progression or improvement on MRI to previously targeted lesions by GKRS. None of the 13 subjects had surgery following their combined therapies.

Conclusions

This data suggests that there is need for further investigation of the role for concurrent treatment with PD-1 inhibitors and GKRS to enhance the treatment of metastatic melanoma. We present data on 13 patients who appear to have some radiologic benefit to this treatment combination, two of whom had radiographic pseudoprogression.

Immuno-thermal ablations - boosting the anticancer immune response

The use of immunomodulation to treat malignancies has seen a recent explosion in interest. The therapeutic appeal of these treatments is far reaching, and many new applications continue to evolve. In particular, immune modulating drugs have the potential to enhance the systemic anticancer immune effects induced by locoregional thermal ablation. The immune responses induced by ablation monotherapy are well documented, but independently they tend to be incapable of evoking a robust antitumor response. By adding immunomodulators to traditional ablative techniques, several researchers have sought to amplify the induced immune response and trigger systemic antitumor activity. This paper summarizes the work done in animal models to investigate the immune effects induced by the combination of ablative therapy and immunomodulation. Combination therapy with radiofrequency ablation, cryoablation, and microwave ablation are all reviewed, and special attention has been paid to the addition of checkpoint blockades.