Irradiation and immunotherapy: From concept to the clinic

Tumor-intrinsic IFNα and CXCL10 are critical for immunotherapeutic efficacy by recruiting and activating T lymphocytes in tumor microenvironment

Tumor immunotherapies targeting PD-(L)1 exhibit anti-tumor efficacy in only 10-30% of patients with various cancers. Literature has demonstrated that a "hot tumor" which contains high T lymphocytes in the tumor microenvironment exhibits a better response to immunotherapies than a "cold tumor." This study aimed to investigate whether tumor-intrinsic IFNα and CXCL10 determine the recruitment and activation of CD8+ T cells to become "hot tumor." In this study, we found that CXCL10 overexpressed in a variety of tumors including lung, colon, and liver tumors with a correlation with PD-L1. High PD-L1 and CXCL10 are associated with better survival rates in tumor patients receiving immunotherapies. IFNs-downstream transcriptional factor IRF-1 and STAT1 were correlated with PD-L1 and CXCL10 expression. We demonstrated that IRF-1 and STAT1 were both bound with the promoters of PD-L1 and CXCL10, sharing the same signaling pathway and determining IFNs-mediated PD-L1 and CXCL10 expression. In addition, IFNα significantly increased activation marker IFNγ in PBMCs, promoting M1 type monocyte differentiation, CD4+ T, and CD8+ T cell activation. Particularly, we found that CD8+ T lymphocytes abundantly expressed CXCR3, a receptor of CXCL10, by flow cytometry, indicating that tumor-intrinsic CXCL10 potentially recruited CD8+ T in tumor microenvironment. To demonstrate the hypothesis, immunotherapy-sensitive CT26 and immunotherapy-resistant LL/2 were used and we found that CT26 cells exhibited higher IFNα, IFNγ, CXCL10, and PD-L1 levels compared to LL/2, leading to higher IFNγ expression in mouse splenocytes. Moreover, we found that CD8+ T cells were recruited by CXCL10 in vitro, whereas SCH546738, an inhibitor of CXCR3, inhibited T cell migration and splenocytes-mediated anti-tumor effect. We then confirmed that CT26-derived tumor was sensitive to αPD-L1 immunotherapy and LL/2-tumor was resistant, whereas αPD-L1 significantly increased T lymphocyte activation marker CD107a in CT26-derived BALB/c mice. In conclusion, this study revealed that CXCL10 expression is correlated with PD-L1 in tumors, sharing the same signaling pathway and associating with better immunotherapeutic efficacy. Further evidence in the syngeneic tumor models demonstrated that immunotherapy-sensitive CT26 intrinsically exhibited higher IFNα and CXCL10 compared to immunotherapy-resistant LL/2 to recruit and activate CD8+ T cells in the tumor microenvironment, exhibiting "hot tumor" characteristic of sensitizing αPD-L1 immunotherapies.

Molecular Changes in Breast Cancer Induced by Radiation Therapy

PURPOSE

Breast cancer treatments are based on prognostic clinicopathologic features that form the basis for therapeutic guidelines. Although the utilization of these guidelines has decreased breast cancer-associated mortality rates over the past three decades, they are not adequate for individualized therapy. Radiation therapy (RT) is the backbone of breast cancer treatment. Although a highly successful therapeutic modality clinically, from a biological perspective, preclinical studies have shown RT to have the potential to alter tumor cell phenotype, immunogenicity, and the surrounding microenvironment, potentially changing the behavior of cancer cells and resulting in a significant variation in RT response. This review presents the recent advances in revealing the complex molecular changes induced by RT in the treatment of breast cancer and highlights the complexities of translating this information into clinically relevant tools for improved prognostic insights and the revelation of novel approaches for optimizing RT.

METHODS AND MATERIALS

Current literature was reviewed with a focus on recent advances made in the elucidation of tumor-associated radiation-induced molecular changes across molecular, genetic, and proteomic bases. This review was structured with the aim of providing an up-to-date overview over the very broad and complex subject matter of radiation-induced molecular changes and radioresistance, familiarizing the reader with the broader issue at hand.

RESULTS

The subject of radiation-induced molecular changes in breast cancer has been broached from various physiological focal points including that of the immune system, immunogenicity and the abscopal effect, tumor hypoxia, breast cancer classification and subtyping, molecular heterogeneity, and molecular plasticity. It is becoming increasingly apparent that breast cancer clinical subtyping alone does not adequately account for variation in RT response or radioresistance. Multiple components of the tumor microenvironment and immune system, delivered RT dose and fractionation schedules, radiation-induced bystander effects, and intrinsic tumor physiology and heterogeneity all contribute to the resultant RT outcome.

CONCLUSIONS

Despite recent advances and improvements in anticancer therapies, tumor resistance remains a significant challenge. As new analytical techniques and technologies continue to provide crucial insight into the complex molecular mechanisms of breast cancer and its treatment responses, it is becoming more evident that personalized anticancer treatment regimens may be vital in overcoming radioresistance.

Remodeling Tumor Immune Microenvironment by Using Polymer-Lipid-Manganese Dioxide Nanoparticles with Radiation Therapy to Boost Immune Response of Castration-Resistant Prostate Cancer

Despite substantial progress in the treatment of castration-resistant prostate cancer (CRPC), including radiation therapy and immunotherapy alone or in combination, the response to treatment remains poor due to the hypoxic and immunosuppressive nature of the tumor microenvironment. Herein, we exploited the bioreactivity of novel polymer-lipid manganese dioxide nanoparticles (PLMDs) to remodel the tumor immune microenvironment (TIME) by increasing the local oxygen levels and extracellular pH and enhancing radiation-induced immunogenic cell death. This study demonstrated that PLMD treatment sensitized hypoxic human and murine CRPC cells to radiation, significantly increasing radiation-induced DNA double-strand breaks and ultimately cell death, which enhanced the secretion of damage-associated molecular patterns, attributable to the induction of autophagy and endoplasmic reticulum stress. Reoxygenation via PLMDs also polarized hypoxic murine RAW264.7 macrophages toward the M1 phenotype, enhancing tumor necrosis factor alpha release, and thus reducing the viability of murine CRPC TRAMP-C2 cells. In a syngeneic TRAMP-C2 tumor model, intravenous injection of PLMDs suppressed, while radiation alone enhanced recruitment of regulatory T cells and myeloid-derived suppressor cells. Pretreatment with PLMDs followed by radiation down-regulated programmed death-ligand 1 and promoted the infiltration of antitumor CD8+ T cells and M1 macrophages to tumor sites. Taken together, TIME modulation by PLMDs plus radiation profoundly delayed tumor growth and prolonged median survival compared with radiation alone. These results suggest that PLMDs plus radiation is a promising treatment modality for improving therapeutic efficacy in radioresistant and immunosuppressive solid tumors.

Triplet regimen as a novel modality for advanced unresectable hepatocellular carcinoma: A case report and review of literature

BACKGROUND

Portal vein tumor thrombus (PVTT) is a common complication, accounting for 44%-62.2% of Hepatocellular carcinoma (HCC), and often indicates the poor prognosis. There is no global consensus for the treatment of unresectable HCC with PVTT. In the present case, we reported a novel strategy of radiotherapy-antiangiogenesis-immune checkpoint blockade combination, which showed better response and prolonged survival.

CASE SUMMARY

A 51-year-old male diagnosed with HCC (Child-Pugh class A), chronic hepatitis B virus infection and Cheng's type III PVTT, was given radiotherapy to part of the lesion plus targeted therapy as the first-line therapy, and achieved partial remission. After radiotherapy, lenvatinib plus pembrolizumab was used as maintenance therapy, and complete remission was achieved. The patient remains alive 46 months after the diagnosis of the HCC with PVTT.

CONCLUSION

This case of unresectable HCC patient with PVTT treated by radiation-lenvatinib-pembrolizumab combination therapy shows apparent clinical efficacy, which demonstrates that local radiotherapy plus antiangiogenesis and immune checkpoint blockad could also benefit patients with advanced HCC.

Optimizing the synergy between stereotactic radiosurgery and immunotherapy for brain metastases

Solid tumors metastasizing to the brain are a frequent occurrence with an estimated incidence of approximately 30% of all cases. The longstanding conventional standard of care comprises surgical resection and whole-brain radiotherapy (WBRT); however, this approach is associated with limited long-term survival and local control outcomes. Consequently, stereotactic radiosurgery (SRS) has emerged as a potential alternative approach. The primary aim of SRS has been to improve long-term control rates. Nevertheless, rare observations of abscopal or out-of-field effects have sparked interest in the potential to elicit antitumor immunity via the administration of high-dose radiation. The blood-brain barrier (BBB) has traditionally posed a significant challenge to the efficacy of systemic therapy in managing intracranial metastasis. However, recent insights into the immune-brain interface and the development of immunotherapeutic agents have shown promise in preclinical and early-phase clinical trials. Researchers have investigated combining immunotherapy with SRS to enhance treatment outcomes in patients with brain metastasis. The combination approach aims to optimize long-term control and overall survival (OS) outcomes by leveraging the synergistic effects of both therapies. Initial findings have been encouraging in the management of various intracranial metastases, while further studies are required to determine the optimal order of administration, radiation doses, and fractionation regimens that have the potential for the best tumor response. Currently, several clinical trials are underway to assess the safety and efficacy of administering immunotherapeutic agents concurrently or consecutively with SRS. In this review, we conduct a comprehensive analysis of the advantages and drawbacks of integrating immunotherapy into conventional SRS protocols for the treatment of intracranial metastasis.

A review on lymphocyte radiosensitivity and its impact on radiotherapy

It is well known that radiation therapy causes lymphopenia in patients and that this is correlated with a negative outcome. The mechanism is not well understood because radiation can have both immunostimulatory and immunosuppressive effects. How tumor dose conformation, dose fractionation, and selective lymph node irradiation in radiation therapy does affect lymphopenia and immune response is an active area of research. In addition, understanding the impact of radiation on the immune system is important for the design and interpretation of clinical trials combining radiation with immune checkpoint inhibitors, both in terms of radiation dose and treatment schedules. Although only a few percent of the total lymphocyte population are circulating, it has been speculated that their increased radiosensitivity may contribute to, or even be the primary cause of, lymphopenia. This review summarizes published data on lymphocyte radiosensitivity based on human, small animal, and in vitro studies. The data indicate differences in radiosensitivity among lymphocyte subpopulations that affect their relative contribution and thus the dynamics of the immune response. In general, B cells appear to be more radiosensitive than T cells and NK cells appear to be the most resistant. However, the reported dose-response data suggest that in the context of lymphopenia in patients, aspects other than cell death must also be considered. Not only absolute lymphocyte counts, but also lymphocyte diversity and activity are likely to be affected by radiation. Taken together, the reviewed data suggest that it is unlikely that radiation-induced cell death in lymphocytes is the sole factor in radiation-induced lymphopenia.

Non-Small Cell Lung Cancer Treatment with Molecularly Targeted Therapy and Concurrent Radiotherapy—A Review

Lung cancer is the leading cause of death worldwide for both men and women. Surgery can be offered as a radical treatment at stages I and II and selected cases of stage III (III A). Whereas at more advanced stages, combined modalities of treatment are applied: radiochemotherapy (IIIB) and molecularly targeted treatment (small molecule tyrosine kinase inhibitors, VEGF receptor inhibitors, monoclonal antibodies, and immunological treatment with monoclonal antibodies). Combination treatment, composed of radiotherapy and molecular therapy, is increasingly employed in locally advanced and metastatic lung cancer management. Recent studies have indicated a synergistic effect of such treatment and modification of immune response. The combination of immunotherapy and radiotherapy may result in the enhancement of the abscopal effect. Anti-angiogenic therapy, in combination with RT, is associated with high toxicity and should be not recommended. In this paper, the authors discuss the role of molecular treatment and the possibility of its concurrent use with radiotherapy in non-small cell lung cancer (NSCLC).

Effectiveness and safety of radiotherapy plus programmed death-1 inhibitors and lenvatinib in patients with advanced biliary tract carcinoma: a real-world study

BACKGROUND

Radiotherapy (RT) may function synergistically with immunotherapy and targeted agents (TA). This study aimed to assess the effectiveness and safety of RT combined with programmed death-1 (PD-1) inhibitors and lenvatinib in patients with relapsed or refractory advanced biliary tract carcinoma (BTC).

METHODS

This retrospective study included patients with relapsed or refractory advanced BTC who received RT combined with PD-1 inhibitors and lenvatinib at the Peking Union Medical College Hospital (PUMCH). Overall survival (OS), progression-free survival (PFS), objective response rate (ORR), disease control rate (DCR), and safety were evaluated.

RESULTS

Thirty-one patients who received RT combined with PD-1 inhibitors and lenvatinib as a second- or later-line therapy were analyzed. RT sites were mainly distributed in the liver lesions (64.5%) and lymph nodes (58.1%). The ORR and DCR were 32.3% (10/31; 95% CI: 14.8-49.7) and 87.1% (27/31; 95% CI: 74.6-99.6), respectively. The median PFS (mPFS) and median OS (mOS) were 7.9 (95% CI: 7.1-8.7) and 11.7 (95% CI: 8.3-15.0) months, respectively. Subgroup analyses of this cohort included 12 and 19 patients who received concurrent and salvage (> 6 weeks after commencing PD-1 inhibitor therapy) RT, respectively. The salvage RT group had higher mOS (11.7 vs. 10.5; p = 0.75) and mPFS (7.9 vs. 6.9; p = 0.85) than the concurrent RT group; however, statistical significance was not reached. All patients experienced any-grade adverse events (AEs), and excessive PD-1 inhibitors or RT toxicity were not observed.

CONCLUSIONS

RT, PD-1 inhibitors, and lenvatinib may be safely combined and have antitumor effectiveness in patients with advanced BTC.

Radiotherapy enhances CXCR3highCD8+ T cell activation through inducing IFNγ-mediated CXCL10 and ICAM-1 expression in lung cancer cells

Radiotherapy (RT) not only damages tumors but also induces interferon (IFN) expression in tumors. IFNs mediate PD-L1 to exhaust CD8⁺ T cells, but which also directly impact tumor cells and potentially activate anti-tumor immune surveillance. Little is known about the contradictory mechanism of IFNs in regulating CD8⁺ T-mediated anti-tumor activity in lung cancer. This study found that RT induced IFNs and CXCL9/10 expression in the RT-treated lung cancer cells. Specifically, RT- and IFNγ-pretreated A549 significantly activated CD8⁺ T cells, resulting in significant inhibition of A549 colony formation. RNAseq and consequent qPCR results revealed that IFNγ induced PD-L1, CXCL10, and ICAM-1, whereas PD-L1 knockdown activated CD8⁺ T cells, but ICAM-1 knockdown diminished CD8⁺ T cell activation. We further demonstrated that CXCR3 and CXCL10 decreased in the CD8⁺ T cells and nonCD8⁺ PBMCs, respectively, in the patients with lung cancer that expressed lower reactivation as co-cultured with A549 cells. In addition, inhibitors targeting CXCR3 and LFA-1 in CD8⁺ T cells significantly diminished CD8⁺ T cell activation and splenocytes-mediated anti-LL/2shPdl1. In conclusion, we validated that RT suppressed lung cancer and overexpress PD-L1, CXCL10, and ICAM-1, which exhibited different roles in regulating CD8⁺ T cell activity. We propose that CXCR3^highCD8⁺ T cells stimulated by CXCL10 exhibit anti-tumor immunity, possibly by enhancing T cells-tumor cells adhesion through CXCL10/CXCR3-activated LFA-1-ICAM-1 interaction, but CXCR3^lowCD8⁺ T cells with low CXCL10 in patients with lung cancer were exhausted by PD-L1 dominantly. Therefore, RT potentially activates CD8⁺ T cells by inducing IFNs-mediated CXCL10 and ICAM-1 expression in tumors to enhance CD8⁺ T-tumor adhesion and recognition. This study clarified the possible mechanisms of RT and IFNs in regulating CD8⁺ T cell activation in lung cancer.

Long-term avelumab in advanced non-small-cell lung cancer: summaries and post hoc analyses from JAVELIN Solid Tumor

Background:

This study examined patients with advanced non-small-cell lung cancer who received long-term avelumab (anti-PD-L1) in a large phase Ib trial (JAVELIN Solid Tumor).

Methods:

Patients receiving >2 years of avelumab were reviewed and exploratory descriptive analyses were conducted.

Results:

Individuals with varying baseline characteristics who had received up to 6 years of avelumab were reviewed. Overall, 37/340 (10.9%) had received ≥2 years of treatment; in this subgroup, best response was complete response in 5.4%, partial response in 59.5% and stable disease in 29.7%; 51.4% had continued treatment beyond disease progression.

Conclusions:

In this study, 11% of patients with advanced non-small-cell lung cancer received ≥2 years of avelumab treatment and experienced prolonged response or continued clinical benefit.

Clinical Trial Registration:NCT02395172 (ClinicalTrials.gov)

Current status of immune checkpoint inhibitor therapy for advanced esophageal squamous cell carcinoma

Esophageal cancer is the seventh most common cancer, with an estimated 572,000 new cases, and the sixth most common cause of cancer-related deaths in 2018 with 509,000 annual worldwide deaths. Advanced esophageal squamous cell carcinoma (ESCC) is one of devastating tumors with a 5-year survival rate of less than 5% in patients with metastatic disease. Treatment options for patients with advanced ESCC are limited. Current guidelines recommend chemotherapy containing a platinum and a fluoropyrimidine agent as a first-line treatment. Recently, immune checkpoint inhibitors (ICIs), including nivolumab and pembrolizumab, have demonstrated antitumor activity and clinical efficacy in patients with advanced ESCC that is refractory or intolerant to first-line chemotherapy. ICIs are game-changers that not only transformed oncological strategy but also have a wide range of clinical potential in combination with conventional cytotoxic chemotherapy and radiotherapy. There is still an urgent, unmet need for reliable treatment options to conquer this intractable disease.

Dissociated Responses in Patients with Metastatic Solid Tumors Treated with Immunotherapy

BACKGROUND

Immune checkpoint inhibitors have been demonstrated to improve overall survival. Atypical patterns of response have been reported, including dissociated response (DR). We evaluated the prevalence of DR.

PATIENTS AND METHODS

Patients had to have a baseline computed tomography (CT) scan and at least one follow-up CT scan and two target lesions (TLs). Three types of DR were evaluated using RECIST1.1: DR1, defined as at least one progressive and one responding TL; DR2, defined as at least one progressive and one stable TL; and DR3, defined as at least one stable and one responding TL.

RESULTS

A total of 1244 measurements of 272 TLs were performed in 100 patients. Forty-nine out of the 272 TLs (18%) had received old or recent radiotherapy, and 42 (15%) had been biopsied. An objective response was observed in 22 patients (22%) and on 52 TLs (19%). DR1 were observed in 8% of patients. At the tumor measurement level, the response rate was lower in the case of prior radiotherapy (29% vs 34%, p = 0.01) and higher in the case of prior biopsy (40% vs 32%, p = 0.02).

CONCLUSIONS

A DR was observed in 8% of patients. Response rate was lower in the case of prior radiotherapy and higher in the case of prior biopsy.

mTOR-dependent immunometabolism as Achilles' heel of anticancer therapy

Immune cells are important constituents of the tumor microenvironment and essential in eradicating tumor cells during conventional therapies or novel immunotherapies. The mechanistic target of rapamycin (mTOR) signaling pathway senses the intra- and extracellular nutrient status, growth factor supply, and cell stress-related changes to coordinate cellular metabolism and activation dictating effector and memory functions in mainly all hematopoietic immune cells. In addition, the mTOR complex 1 (mTORC1) and mTORC2 are frequently deregulated and become activated in cancer cells to drive cell transformation, survival, neovascularization, and invasion. In this review, we provide an overview of the influence of mTOR complexes on immune and cancer cell function and metabolism. We discuss how mTOR inhibitors aiming to target cancer cells will influence immunometabolic cell functions participating either in antitumor responses or favoring tumor cell progression in individual immune cells. We suggest immunometabolism as the weak spot of anticancer therapy and propose to evaluate patients according to their predominant immune cell subtype in the cancer tissue. Advances in metabolic drug development that hold promise for more effective treatments in different types of cancer will have to consider their effects on the immune system.

Irradiation Mediates IFNα and CXCL9 Expression in Non-Small Cell Lung Cancer to Stimulate CD8+ T Cells Activity and Migration toward Tumors

Irradiation-broken DNA fragments increase type I interferon and chemokines secretion in tumor cells. Since radiotherapy may augment tumor immunotherapy, we hypothesize that the chemokines increased by irradiation could recruit CD8⁺ T cells to suppress tumor proliferation. This study intended to unveil the secreted factors activating and recruiting CD8⁺ T cells in non-small-cell lung cancer (NSCLC). EGFR-positive A549 was selected and treated by X-irradiation (IR) to identify the overexpression of chemokines associated to CD8⁺ T cell cytotoxicity and recruitment. A transwell assay with Alexa 488-labeled CD8⁺ T cells was used to evaluate CD8⁺ T cell motility in vitro. A nuclear imaging platform by In¹¹¹-labeled nivolumab was used to track CD8⁺ T cells homing to tumors in vivo. The activation markers GZMB, PRF-1, and IFNγ, migration marker CD183 (CXCR3), and inhibitory marker CD274 (PD-1), were measured and compared in CD8⁺ T cells with A549 co-cultured, chemokines treated, and patients with late-stage lung cancer. We found that IR not only suppressed A549 proliferation but also induced IFNα and CXCL9 expression (p < 0.05). IFNα majorly increased IFNγ levels in CD8⁺ T cells (p < 0.05) and synergistically with CXCL9 enhanced CD8⁺ T cell migration in vitro (p < 0.05). We found that CXCR3 and PD-1 were down-regulated and up-regulated, respectively, in the peripheral blood CD8⁺ T cells in patients with lung cancer (n = 4 vs. healthy n = 3, both p < 0.05), which exhibited reduction of cell motility (p < 0.05). The in vivo nuclear imaging data indicated highly CD8⁺ T cells migrated to A549-induced tumors. In addition, we demonstrated that healthy PBMCs significantly suppressed the parallel tumor growth (p < 0.05) and the radioresistant tumor growth in the tumor xenograft mice (p < 0.05), but PBMCs from patients with lung cancer had lost the anti-tumor capacity. We demonstrated that IR induced IFNα and CXCL9 expression in A549 cells, leading to CD8⁺ T cell migration. This study unveiled a potential mechanism for radiotherapy to activate and recruit CD8⁺ T cells to suppress lung tumors.

Irradiation Suppresses IFNγ-Mediated PD-L1 and MCL1 Expression in EGFR-Positive Lung Cancer to Augment CD8+ T Cells Cytotoxicity

Tumor cells express immune checkpoints to exhaust CD8⁺ T cells. Irradiation damages tumor cells and augments tumor immunotherapy in clinical applications. However, the radiotherapy-mediated molecular mechanism affecting CD8⁺ T cell activity remains elusive. We aimed to uncover the mechanism of radiotherapy augmenting cytotoxic CD8⁺ T cells in non-small-cell lung cancer (NSCLC). EGFR-positive NSCLC cell lines were co-cultured with CD8⁺ T cells from healthy volunteers. Tumor cell viability and apoptosis were consequently measured. IFNγ was identified secreted by CD8⁺ T cells and PBMCs. Therefore, RNAseq was used to screen the IFNγ-mediated gene expression in A549 cells. The irradiation effect to IFNγ-mediated gene expression was investigated using qPCR and western blots. We found that the co-culture of tumor cells stimulated the increase of granzyme B and IFNγ in CD8⁺ T, but A549 exhibited resistance against CD8⁺ T cytotoxicity compared to HCC827. Irradiation inhibited A549 proliferation and enhanced apoptosis, augmenting PBMCs-mediated cytotoxicity against A549. We found that IFNγ simultaneously increased phosphorylation on STAT1 and STAT3 in EGFR-positive lung cancer, resulting in overexpression of PD-L1 (p < 0.05). In RNAseq analysis, MCL1 was identified and increased by the IFNγ-STAT3 axis (p < 0.05). We demonstrated that irradiation specifically inhibited phosphorylation on STAT1 and STAT3 in IFNγ-treated A549, resulting in reductions of PD-L1 and MCL1 (both p < 0.05). Moreover, knockdowns of STAT3 and MCL1 increased the PBMCs-mediated anti-A549 effect. This study demonstrated that A549 expressed MCL1 to resist CD8⁺ T cell-mediated tumor apoptosis. In addition, we found that irradiation suppressed IFNγ-mediated STAT3 phosphorylation and PD-L1 and MCL1 expression, revealing a potential mechanism of radiotherapy augmenting immune surveillance.

Chemotherapy, targeted therapy and immunotherapy: Which drugs can be safely used in the solid organ transplant recipients?

In solid organ transplant recipients, cancer is associated with worse prognosis than in the general population. Among the causes of increased cancer‐associated mortality, are the limitations in selecting the optimal anticancer regimen in solid organ transplant recipients, because of the associated risks of graft toxicity and rejection, drug‐to‐drug interactions, reduced kidney or liver function, and patient frailty and comorbid conditions. The advent of immunotherapy has generated further challenges, mainly because checkpoint inhibitors increase the risk of rejection, which may have life‐threatening consequences in recipients of life‐saving organs. In general, there are no safe or unsafe anticancer drugs. Rather, the optimal choice of the anticancer regimen results from a careful risk/benefit assessment, from the awareness of potential pharmacokinetic and pharmacodynamic drug‐to‐drug interactions, and of the risk of drug overexposure in patients with kidney or liver dysfunction. In this review, we summarize general principles that may help the oncologists and transplant physicians in the multidisciplinary management of recipients of solid organ transplantation with cancer who are candidates for chemotherapy, targeted therapy, or immunotherapy.

Immunotherapy and Radiation Therapy in Renal Cell Carcinoma

BACKGROUND

The management of renal cell carcinoma is rapidly evolving and immunotherapy, mostly consisting of immune checkpoint inhibitors, is revolutionizing the treatment scenario of metastatic patients. Novel fractionation schedules of radiotherapy, consisting of high doses in few fractions, can overcome the radioresistance of this tumor. Localized radiotherapy is associated with a systemic effect, known as the abscopal effect. This effect mediated by the immune system can be enhanced associating radiotherapy with immunotherapy.

OBJECTIVE

In this review, we explore the role of radiotherapy and immunotherapy in RCC, the rationale of combining these strategies and the on-going clinical trials investigating combinations of these two treatment modalities.

CONCLUSION

Combining immunotherapy and radiotherapy has a strong rationale and pre-clinical studies support their association because it can overcome the immunosuppression of the tumor microenvironment and increase the anti-tumor immune response. More clinical evidence, deriving from onclinical trials, are needed to prove the efficacy and safety of these treatments combined.

Evaluation of practical experiences of German speaking radiation oncologists in combining radiation therapy with checkpoint blockade

The results of this survey reveal current clinical practice in the handling of combined radioimmunotherapy with Immune Checkpoint Inhibitors (RT + ICI). We aim to provide a basis to open a discussion for clinical application of RT + ICI by analyzation of experts’ assessment. We conducted a survey with 24 items with a focus on side effects of RT + ICI, common practice of scheduling and handling of adverse events. After pilot testing by radiation oncology experts the link to the online survey was sent to all members of the German Society of Radiation Oncology (DEGRO). In total, 51 radiation oncologists completed the questionnaire. Pulmonary toxicity under RT + ICI with ICIs was reported most frequently. Consensus was observed for bone and soft tissue RT of the limbs in favor for no interruption of ICIs. For cranial RT half of the participants do not suspend ICIs during normofractionated radiotherapy (nfRT) or stereotactic hypofractionated RT (SRT). More participants pause ICIs for central than for peripheral thoracic region. Maintenance therapy with ICIs is mostly not interrupted prior to RT. For management of RT associated pneumonitis under durvalumab the majority of 86.3% suggest corticosteroid therapy and 76.5% would postpone the next cycle of ICI therapy. The here obtained assessment and experiences by radiation oncologists reveal a large variability in practical handling of combined RT + ICI. Until scientific evidence is available a discussion for current clinical application of RT + ICI should be triggered. Interdisciplinary consensus guidelines with practical recommendations are required.

Ipilimumab and Radiation in Patients with High-risk Resected or Regionally Advanced Melanoma

PURPOSE

In this prospective trial, we sought to assess the feasibility of concurrent administration of ipilimumab and radiation as adjuvant, neoadjuvant, or definitive therapy in patients with regionally advanced melanoma.

PATIENTS AND METHODS

Twenty-four patients in two cohorts were enrolled and received ipilimumab at 3 mg/kg every 3 weeks for four doses in conjunction with radiation; median dose was 4,000 cGy (interquartile range, 3,550-4,800 cGy). Patients in cohort 1 were treated adjuvantly; patients in cohort 2 were treated either neoadjuvantly or as definitive therapy.

RESULTS

Adverse event profiles were consistent with those previously reported with checkpoint inhibition and radiation. For the neoadjuvant/definitive cohort, the objective response rate was 64% (80% confidence interval, 40%-83%), with 4 of 10 evaluable patients achieving a radiographic complete response. An additional 3 patients in this cohort had a partial response and went on to surgical resection. With 2 years of follow-up, the 6-, 12-, and 24-month relapse-free survival for the adjuvant cohort was 85%, 69%, and 62%, respectively. At 2 years, all patients in the neoadjuvant/definitive cohort and 10/13 patients in the adjuvant cohort were still alive. Correlative studies suggested that response in some patients were associated with specific CD4+ T-cell subsets.

CONCLUSIONS

Overall, concurrent administration of ipilimumab and radiation was feasible, and resulted in a high response rate, converting some patients with unresectable disease into surgical candidates. Additional studies to investigate the combination of radiation and checkpoint inhibitor therapy are warranted.

Combined Treatment of Radiotherapy and Immunotherapy for Urological Malignancies: Current Evidence and Clinical Considerations

Although it has always been believed that radiation has immunosuppressive effects, more and more preclinical and clinical trials have shown that the combination of radiotherapy and immunotherapy has a potential synergistic effect to treat cancers including urological malignancies. When radiotherapy is combined with immunotherapy, improved prognosis has been observed in different urinary tumors. However, there is no standard treatment, such as the optimal dose/fractionation and the sequence of immunotherapy and radiotherapy. In this review, we discussed the effects of radiotherapy on the cancer immune system and emphasized the synergy of radiotherapy combined with immunotherapy. Although it has significantly improved the prognosis of tumors, there are still some unresolved questions about how to best use this combination in clinical practice. Ongoing trials will provide further information on the interaction of radiotherapy combined with immunotherapy, and are expected to guide clinical practice and improve clinical outcomes.

MR-Guided Radiotherapy: The Perfect Partner for Immunotherapy?

During the last years, preclinical and clinical studies have emerged supporting the rationale to integrate radiotherapy and immunotherapy. Radiotherapy may enhance the effects of immunotherapy by improving tumor antigen release, antigen presentation, and T-cell infiltration. Recently, magnetic resonance guided radiotherapy (MRgRT) has become clinically available. Compared to conventional radiotherapy techniques, MRgRT firstly allows for daily on-table treatment adaptation, which enables both dose escalation for increasing tumor response and superior sparing of radiosensitive organs-at-risk for reducing toxicity. The current review focuses on the potential of combining MR-guided adaptive radiotherapy with immunotherapy by providing an overview on the current status of MRgRT, latest developments in preclinical and clinical radio-immunotherapy, and the unique opportunities and challenges for MR-guided radio-immunotherapy. MRgRT might especially assist in answering open questions in radio-immunotherapy regarding optimal radiation dose, fractionation, timing of immunotherapy, appropriate irradiation volumes, and response prediction.

Immunotherapy for squamous cell carcinoma of the head and neck

Squamous cell carcinoma of the head and neck is characterized by an immunosuppressive environment and evades immune responses through multiple resistance mechanisms. A breakthrough in cancer immunotherapy employing immune checkpoint inhibitors has evolved into a number of clinical trials with antibodies against programmed cell death 1 (PD-1), its ligand PD-L1 and cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) for patients with squamous cell carcinoma of the head and neck. CheckMate141 and KEYNOTE-048 were practice-changing randomized phase 3 trials for patients with platinum-refractory and platinum-sensitive recurrent or metastatic squamous cell carcinoma of the head and neck, respectively. Furthermore, many combination therapies using anti-CTLA-4 inhibitors, tyrosine kinase inhibitors and immune accelerators are currently under investigation. Thus, the treatment strategy of recurrent or metastatic squamous cell carcinoma of the head and neck is becoming more heterogeneous and complicated in the new era of individualized medicine. Ongoing trials are investigating immunotherapeutic approaches in the curative setting for locoregionally advanced disease. This review article summarizes knowledge of the role of the immune system in the development and progression of squamous cell carcinoma of the head and neck, and provides a comprehensive overview on the development of immunotherapeutic approaches in both recurrent/metastatic and locoregionally advanced diseases.

A Multimodality Image Guided Precision Radiation Research Platform: Integrating X-ray, Bioluminescence, and Fluorescence Tomography With Radiation Therapy

PURPOSE

Small animal irradiation is crucial to the investigation of radiobiological mechanisms. The paradigm of clinical radiation therapy is trending toward high-precision, stereotactic treatment. However, translating this scheme to small animal irradiation is challenging owing to the lack of high-quality image guidance. To overcome this obstacle, we developed a multimodality image guided precision radiation platform.

METHODS AND MATERIALS

The platform consists of 4 modules: x-ray computed tomography (CT), bioluminescence tomography (BLT), fluorescence molecular tomography (FMT), and radiation therapy. CT provides animal anatomy and material density for radiation dose calculation, as well as body contour for BLT and FMT reconstruction. BLT and FMT provide tumor localization to guide radiation beams and molecular activity to evaluate treatment outcome. Furthermore, we developed a Monte Carlo-based treatment planning system (TPS) for 3-dimensional dose calculation, calibrated it using radiochromic films sandwiched in a water-equivalent phantom, and validated it using in vivo dosimeters surgically implanted into euthanized mice (n = 4). Finally, we performed image guided irradiation on mice bearing orthotopic breast and prostate tumors and confirmed radiation delivery using γH2AX histology.

RESULTS

The Monte Carlo-based TPS was successfully calibrated by benchmarking simulation dose against film measurement. For in vivo dosimetry measured in the euthanized mice, the average difference between the TPS calculated dose and measured dose was 3.86% ± 1.12%. Following the TPS-generated treatment plan, we successfully delivered 20 Gy dose to an animal bearing an orthotopic prostate tumor using 4 BLT-guided radiation beams and 5 Gy dose to an animal bearing an orthotopic breast tumor using a single FMT-guided radiation beam. γH2AX histology presented significantly more DNA damage in irradiated tumors and thus validated the dose delivery accuracy.

CONCLUSIONS

Combined with Monte Carlo TPS, this multimodality CT/BLT/FMT image guided small animal radiation platform can specifically localize tumors, accurately calculate dose distribution, precisely guide radiation delivery, and molecularly evaluate treatment response. It provides an advanced toolset for radiobiology and translational cancer research.

Radiation Dose Escalation is Crucial in Anti-CTLA-4 Antibody Therapy to Enhance Local and Distant Antitumor Effect in Murine Osteosarcoma

We previously reported that a combination of 10 Gy of X-ray irradiation and dual immune checkpoint blockade with anti-CTLA-4 (C4) and anti-PD-L1 antibodies produced a significant shrinkage of irradiated and unirradiated tumors (abscopal effect) and prolonged overall survival. However, the optimal radiation delivery regimen combined with single immune checkpoint blockade of C4 for inducing a maximum systemic antitumor response still remains unclear, particularly for patients with osteosarcoma. We used syngeneic C3H mice that were subcutaneously injected with LM8 osteosarcoma cells into both legs. C4 was administered three times, and one side of the tumor was irradiated by X-ray beams. The optimal radiation dose required to induce the abscopal effect was explored with a focus on the induction of the type-I interferon pathway. Radiation delivered in a single fraction of 10 Gy, 4.5 Gy × 3 fractions (fx), and 2 Gy × 8 fx with C4 failed to produce significant inhibition of unirradiated tumor growth compared with monotherapy with C4. Dose escalation to 16 Gy in a single fraction, or the equivalent hypofractionated dose of 8 Gy × 3 fx, which significantly increased secretion of IFN-β in vitro, produced a dramatic regression of both irradiated and unirradiated tumors and prolonged overall survival in combination with C4. Furthermore, irradiation at 16 Gy in both a single fraction and 8 Gy × 3 fx diminished regulatory T cells in the unirradiated tumor microenvironment. These results suggest that total dose escalation of radiation is crucial in C4 therapy to enhance the antitumor response in both local and distant tumors and prolonged overall survival regardless of fractionation for osteosarcoma.

The Combination Options and Predictive Biomarkers of PD-1/PD-L1 Inhibitors in Esophageal Cancer

Esophageal cancer (EC) is one of the most common cancers with poor survival in the world. Nowadays, a generous number of clinical trials are underway on the use of immunotherapy in EC patients, especially the programmed death-1/programmed death-ligand 1 (PD-1/PD-L1) inhibitors. However, only a few patients could benefit from single-agent therapy. Others need combination therapies to enhance the response rate and survival. In this review, we focus on PD-1/PD-L1 inhibitors and its combination options in EC patients. We also summarized the potential predictive biomarkers for PD-1/PD-L1 inhibitors treatment.

Emerging therapeutic approaches for canine sarcomas: Pushing the boundaries beyond the conventional

Sarcomas represent a group of genomically chaotic, highly heterogenous tumours of mesenchymal origin with variable mutational load. Conventional therapy with surgery and radiation therapy is effective for managing small, low-grade sarcomas and remains the standard therapeutic approach. For advanced, high-grade, recurrent, or metastatic sarcomas, systemic chemotherapy provides minimal benefit, therefore, there is a drive to develop novel approaches. The discovery of "Coley's toxins" in the 19th century, and their use to stimulate the immune system supported the application of unconventional therapies for the treatment of sarcomas. While promising, this initial work was abandoned and treatment paradigm and disease course of sarcomas was largely unchanged for several decades. Exciting new therapies are currently changing treatment algorithms for advanced carcinomas and melanomas, and similar approaches are being applied to advance the field of sarcoma research. Recent discoveries in subtype-specific cancer biology and the identification of distinct molecular targets have led to the development of promising targeted strategies with remarkable potential to change the landscape of sarcoma therapy in dogs. The purpose of this review article is to describe the current standard of care and limitations as well as emerging approaches for sarcoma therapy that span many of the most active paradigms in oncologic research, including immunotherapies, checkpoint inhibitors, and drugs capable of cellular metabolic reprogramming.

Evolving management of positive regional lymph nodes in melanoma: Past, present and future directions

Sentinel lymph node (SLN) biopsy has become the standard of care for lymph node staging in melanoma and the most important predictor of survival in clinically node-negative disease. Previous guidelines recommend completion lymph node dissection (CLND) in cases of positive SLN; however, the lymph nodes recovered during CLND are only positive in a minority of these cases. Recent evidence suggests that conservative management (i.e. observation) has similar outcomes compared to CLND. We sought to review the most current literature regarding the management of SLN in metastatic melanoma and to discuss potential future directions.

Combination of checkpoint inhibitors with radiotherapy in esophageal squamous cell carcinoma treatment: A novel strategy

Despite the rapid development of numerous types of treatment, including radiotherapy (RT) as the main strategy, esophageal squamous cell carcinoma (ESCC) has a poor prognosis. Recent studies demonstrated that immunotherapy can improve the survival of patients with locally advanced and metastatic ESCC. Furthermore, previous studies reported that the expression of programmed death-ligand 1 is significantly associated with esophageal cancer prognosis. At present, several ongoing clinical trials have extended the use of immunotherapy from palliative and salvage treatments to neoadjuvant treatment with concurrent chemoradiation. The first- or second-line treatments were used to explore antitumor efficacy with reduced adverse events. The combination of RT and immunotherapy can exert a local therapeutic effect and improve the function of the immune system, enhancing antitumor efficacy. This review investigated the role of immunotherapy and radiotherapy in ESCC and described the potential efficacy of combining immunotherapy with radiotherapy in ESCC.

Radiotherapy activates autophagy to increase CD8+ T cell infiltration by modulating major histocompatibility complex class-I expression in non-small cell lung cancer

Objective

Radiotherapy is reported to enhance immune responses in cancer, but appropriate doses and mechanisms remain to be investigated. This study explored whether autophagy is involved in the regulation of major histocompatibility complex class I (MHC-I) expression and CD8⁺ T cell infiltration at different radiation doses.

Methods

Non-small cell lung cancer (NSCLC) cell lines A549 and H1975 were exposed to different doses of radiation. The levels of autophagy and MHC-I expression were examined 6 hours after irradiation. The effects of the autophagy inhibitor chloroquine (CQ) on MHC-I expression were also investigated, as well as the relationship between autophagy and MHC-1 expression. Pathological specimens from 69 NSCLC patients were collected, and immunohistochemistry was used to detect MHC-1 expression and CD8⁺ T cell infiltration in tumors.

Results

Irradiation induced autophagy and MHC-I expression during a single radiation dose from 2 to 20 Gy in a dose-dependent manner. CQ downregulated MHC-I expression. Immunohistochemistry indicated that MHC-I levels were positively correlated with the infiltration of CD8⁺ T cells in NSCLC cells (R² = 0.713).

Conclusions

Autophagy induced MHC-I expression and increased CD8⁺ T cell infiltration. A single radiation dose of 20 Gy induced the strongest CD8⁺ T cell infiltration.

Abscopal Effects in Radio-Immunotherapy-Response Analysis of Metastatic Cancer Patients With Progressive Disease Under Anti-PD-1 Immune Checkpoint Inhibition

Immune checkpoint inhibition (ICI) targeting the programmed death receptor 1 (PD-1) has shown promising results in the fight against cancer. Systemic anti-tumor reactions due to radiation therapy (RT) can lead to regression of non-irradiated lesions (NiLs), termed “abscopal effect” (AbE). Combination of both treatments can enhance this effect. The aim of this study was to evaluate AbEs during anti-PD-1 therapy and irradiation. We screened 168 patients receiving pembrolizumab or nivolumab at our center. Inclusion criteria were start of RT within 1 month after the first or last application of pembrolizumab (2 mg/kg every 3 weeks) or nivolumab (3 mg/kg every 2 weeks) and at least one metastasis outside the irradiation field. We estimated the total dose during ICI for each patient using the linear quadratic (LQ) model expressed as 2 Gy equivalent dose (EQD2) using α/β of 10 Gy. Radiological images were required showing progression or no change in NiLs before and regression after completion of RT(s). Images must have been acquired at least 4 weeks after the onset of ICI or RT. The surface areas of the longest diameters of the short- and long-axes of NiLs were measured. One hundred twenty-six out of 168 (75%) patients received ICI and RT. Fifty-three percent (67/126) were treated simultaneously, and 24 of these (36%) were eligible for lesion analysis. AbE was observed in 29% (7/24). One to six lesions (mean = 3 ± 2) in each AbE patient were analyzed. Patients were diagnosed with malignant melanoma (MM) (n = 3), non-small cell lung cancer (NSCLC) (n = 3), and renal cell carcinoma (RCC) (n = 1). They were irradiated once (n = 1), twice (n = 2), or three times (n = 4) with an average total EQD2 of 120.0 ± 37.7 Gy. Eighty-two percent of RTs of AbE patients were applied with high single doses. MM patients received pembrolizumab, NSCLC, and RCC patients received nivolumab for an average duration of 45 ± 35 weeks. We demonstrate that 29% of the analyzed patients showed AbE. Strict inclusion criteria were applied to distinguish the effects of AbE from the systemic effect of ICI. Our data suggest the clinical existence of systemic effects of irradiation under ICI and could contribute to the development of a broader range of cancer treatments.

Radiotherapy for Melanoma: More than DNA Damage

Despite its reputation as a radioresistant tumour, there is evidence to support a role for radiotherapy in patients with melanoma and we summarise current clinical practice. Melanoma is a highly immunogenic tumour and in this era of immunotherapy, there is renewed interest in the potential of irradiation, not only as an adjuvant and palliative treatment, but also as an immune stimulant. It has long been known that radiation causes not only DNA strand breaks, apoptosis, and necrosis, but also immunogenic modulation and cell death through the induction of dendritic cells, cell adhesion molecules, death receptors, and tumour-associated antigens, effectively transforming the tumour into an individualised vaccine. This immune response can be enhanced by the application of clinical hyperthermia as evidenced by randomised trial data in patients with melanoma. The large fraction sizes used in cranial radiosurgery and stereotactic body radiotherapy are more immunogenic than conventional fractionation, which provides additional radiobiological justification for these techniques in this disease entity. Given the immune priming effect of radiotherapy, there is a strong but complex biological rationale and an increasing body of evidence for synergy in combination with immune checkpoint inhibitors, which are now first-line therapy in patients with recurrent or metastatic melanoma. There is great potential to increase local control and abscopal effects by combining radiotherapy with both immunotherapy and hyperthermia, and a combination of all three modalities is suggested as the next important trial in this refractory disease.

Boosting Abscopal Response to Radiotherapy with Sargramostim: A Review of Data and Ongoing Studies

Drug development in oncology today routinely focuses on approaches that utilize the patients’ immune system to destroy the malignancy. Combinatorial approaches of antineoplastic agents, both new and old, are being incorporated in the armamentarium of cancer treatments. The overarching goal of therapy remains the achievement of a complete and durable response with long term remission or cure. One approach in advancing treatment is aimed at strategies that improve immunological memory to induce long lasting immunity against the tumor. Although radiation therapy has not traditionally been thought to elicit an immunological effect, an increasing number of reports document the induction of an immune response against a tumor that kills cancer cells distant to the original site of treatment after local irradiation to a tumor. This phenomenon is called an abscopal effect. Since radiation alone is rarely associated with such a response, it is being combined with immuno-oncology drugs in an attempt to enhance response. One such strategy combines sargramostim, a recombinant human granulocyte macrophage colony stimulating factor (rhu GM-CSF), with radiotherapy. GM-CSF is a cytokine secreted by multiple cells types that promotes maturation of dendritic cells and enables the presentation of tumor-associated antigens to generate a T-cell response. This review article discusses the outcomes of clinical trials and case reports examining the efficacy and safety of combining radiation therapy with this immunomodulatory agent. We will also examine future studies and challenges facing the translation of this therapeutic approach.

Stereotactic Radiation Therapy for Renal Cell Carcinoma Brain Metastases in the Tyrosine Kinase Inhibitors Era: Outcomes of 120 Patients

BACKGROUND

The objective of the study was to evaluate the outcomes in terms of efficacy and safety of a large consecutive series of 362 patients with renal cell carcinoma (RCC) brain metastases treated using stereotactic radiosurgery (SRS) in the tyrosine kinase inhibitor (TKI) era.

PATIENTS AND METHODS

From 2005 to 2015, 362 consecutive patients with brain metastases from RCC were treated using SRS in 1 fraction: 226 metastases (61 patients) using Gamma-Knife at a median of 18 Gy (50% isodose line); 136 metastases (63 patients) using linear accelerator at a median of 16 Gy (70% isodose line). The median patient age was 58 years. At the first SRS, 37 patients (31%) received a systemic treatment. Among systemic therapies, TKIs were the most common (65%).

RESULTS

The local control rates were 94% and 92% at 12 and 36 months, respectively. In multivariate analysis, a minimal dose >17 Gy and concomitant TKI treatment were associated with higher rates of local control. The overall survival rates at 12 and 36 months were 52% and 29%, respectively. In multivariate analysis, factors associated with poor survival included age ≥65 years, lower score index for SRS, concomitant lung metastases, time between RCC diagnosis and first systemic metastasis ≤4 months, occurrence during treatment with a systemic therapy, no history of neurosurgery, and persistence or occurrence of neurological symptoms at 3 months after SRS. Seventeen patients had Grade III/IV adverse effects of whom 3 patients presented a symptomatic radionecrosis.

CONCLUSION

SRS is highly effective in patients with brain metastases from RCC. Its association with TKIs does not suggest higher risk of neurologic toxicity.

Abscopal Effect of Radiotherapy in the Immunotherapy Era: Systematic Review of Reported Cases

Mounting evidence suggests that radiation stimulates the immune system and this contributes to the abscopal effect, which is defined as "response at a distance from the irradiated volume." Though identified more than 50 years ago, the abscopal effect is revisited today. One rationale is that the abscopal effect is often observed with efficient immunotherapy. Here, we give an overview of the clinical data on the abscopal effect, generated by a combination of immunotherapy and radiotherapy (RT). Only papers that included RT in combination with immunotherapy were evaluated according to four main categories including RT parameters, sequencing of therapies, the definition of the abscopal effect, and patient selection. Twenty-four cases in 15 reports were reviewed. The results varied. Patient ages ranged from 24 to 74. RT dose (median total dose 18-58 Gy) varied. Biologically effective dose (BED) 10 was calculated to be a median 49.65 Gy (28-151 Gy). The time to a documented abscopal response ranged from less than a month to 12 months. The large variation concerning fractionation and sequencing of therapies indicates that these conflicting points need to be resolved, to generate for the abscopal effect to be clinically significant.

Progression after Immunotherapy for Fibrolamellar Carcinoma

Background

Fibrolamellar carcinoma (FLC) is a rare malignancy of the liver that differs from typical hepatocellular carcinoma (HCC) in several aspects such as the absence of underlying liver disease and occurrence in younger patients. Even though the survival rates in FLC are slightly better than in typical HCC, the prognosis of metastatic FLC remains deleterious. Several reports suggest that systemic chemotherapy regimens can successfully be used to halt disease progression in FLC, while targeted tumor therapy with sorafenib seems to be of limited efficiency. However, results from controlled clinical trials investigating systemic therapies in FLC are virtually nonexistent. Therefore, the choice of treatment often relies on case series with limited numbers of patients. Immunotherapy with checkpoint inhibitors is an emerging cancer therapy in several solid malignancies including HCC. Currently, there do not exist any reports on the use of checkpoint inhibitors in FLC.

Case Report

Here, we describe a case of advanced FLC in a young man receiving immunotherapy, who progressed after 3 months of treatment - similar to 2 other patients with advanced FLC at our hospital.

Conclusion

While immunotherapy seems to be a promising treatment with limited side effects in several other tumor entities, there is currently no data supporting tumor response in FLC.

The Response of Prostate Cancer to Androgen Deprivation and Irradiation Due to Immune Modulation

This study investigated changes in the immune system and the biological consequences of androgen deprivation therapy (ADT) and radiotherapy (RT) for augmenting the treatment response in prostate cancer, particularly for castration-resistant prostate cancer (CRPC). Human and murine prostate cancer cell lines were used to examine the response to ADT and RT in vitro and in vivo. Biological changes following treatment and related immune modulation in the tumor microenvironment were examined. Our results showed that CRPC cells were demonstrated to be more resistant to the RT and ADT treatments. ADT increased tumor inhibition following irradiation. The underlying changes included increased cell death, attenuated myeloid-derived suppressor cell recruitment, and an increase in the number of tumor-infiltrating T cells (TILs). Furthermore, when high-dose fractionated RT was given to the primary CRPC tumor, a smaller size of secondary non-irradiated tumor associated with increased TILs was noted in ADT-treated mice. In conclusion, treatment resistance in CRPC was associated with a more immunosuppressive microenvironment. Enhanced antitumor immunity was responsible for the augmented RT-induced tumoricidal effect induced by ADT. Immune modulation could be a promising strategy for prostate cancer, especially for metastatic CRPC.

Theranostics in neuroendocrine tumours: somatostatin receptor imaging and therapy

Theranostics and its principles: pre-treatment selection of patients who are most likely to benefit from treatment by the use of a related, specific diagnostic test are integral to the treatment of patients with neuroendocrine tumours (NETs). This is due to NETs' important, but variable, somatostatin receptor (SSTR) expression, their heterogeneity and variation in site of primary and rate of progression. Only patients whose tumours have sufficient expression of SSTRs will benefit from SSTR-based radionuclide therapy and demonstrating this expression prior to therapy is essential. This article provides a relevant overview of NETs and the multiple facets of SSTR based theranostics, including imaging and therapy radionuclides; clinical efficacy and toxicity; patient selection and treatment and finally emerging radiopharmaceuticals and newer clinical applications.

Stereotactic radiosurgery and ipilimumab for patients with melanoma brain metastases: clinical outcomes and toxicity

INTRODUCTION

There is evidence that the combination of ipilimumab and stereotactic radiosurgery (SRS) for brain metastases improves outcomes. We investigated clinical outcomes, radiation toxicity, and impact of ipilimumab timing in patients treated with SRS for melanoma brain metastases.

METHODS

We retrospectively identified 91 patients treated with SRS at our institution for melanoma brain metastases from 2006 to 2015. Concurrent ipilimumab administration was defined as within ± 4 weeks of SRS procedure. Acute and late toxicities were graded with CTCAE v4.03. Overall survival (OS), local failure, distant brain failure, and failure-free survival were analyzed with the Kaplan-Meier method. OS was analyzed with Cox regression.

RESULTS

Twenty-three patients received ipilimumab concurrent with SRS, 28 patients non-concurrently, and 40 patients did not receive ipilimumab. The median age was 62 years and 91% had KPS ≥ 80. The median follow-up time was 7.4 months. Patients who received ipilimumab had a median OS of 15.1 months compared to 7.8 months in patients who did not (p = 0.02). In multivariate analysis, ipilimumab (p = 0.02) and diagnosis-specific graded prognostic assessment (p = 0.02) were associated with OS. There were no differences in intracranial control by ipilimumab administration or timing. The incidence of radiation necrosis was 5%, with most events occurring in patients who received ipilimumab.

CONCLUSIONS

Patients who received ipilimumab had improved OS even after adjusting for prognostic factors. Ipilimumab did not appear to increase risk for acute toxicity. The majority of radiation necrosis events, however, occurred in patients who received ipilimumab. Our results support the continued use of SRS and ipilimumab as clinically appropriate.

Inhibiting the CD8+ T cell infiltration in the tumor microenvironment after radiotherapy is an important mechanism of radioresistance

Endogenous immune response participates in tumor control, and radiotherapy has immune modulatory capacity, but the role of immune modulation in the tumor microenvironment invoked by radiotherapy in radiosensitivity is poorly defined. In the present study, a radio-resistant melanoma cell line was obtained after repeated irradiation to the parental tumor in C57BL/6 mice. Radiotherapy resulted in aggregation of CD8⁺ and CD3⁺ T cells, and decrease of myeloid-derived suppressor cells and dendritic cells in the parental tumor, but not in the resistant tumors. CD4⁺ T cells and B cells did not change significantly. The CD8⁺ T cell infiltration after radiotherapy is important for tumor response, because in the nude mice and CD8⁺ T cell-depleted C57BL/6 mice, the parental and resistant tumor has similar radiosensitivity. Patients with good radiation response had more CD8⁺ T cells aggregation after radiotherapy. Radiotherapy resulted in robust transcription of T cell chemoattractant in the parental cells, and the expression of CCL5 was much higher. These results reveal a novel mechanism of radioresistance, tumor cells inhibit the infiltration of CD8⁺ T cell after radiotherapy and become radioresistant. Increasing CD8⁺ T cell infiltration after RT may be an effective way to improve tumor radiosensitivity.

Recommendations for In Vitro and In Vivo Testing of Magnetic Nanoparticle Hyperthermia Combined with Radiation Therapy

Magnetic nanoparticle (MNP)-mediated hyperthermia (MH) coupled with radiation therapy (RT) is a novel approach that has the potential to overcome various practical difficulties encountered in cancer treatment. In this work, we present recommendations for the in vitro and in vivo testing and application of the two treatment techniques. These recommendations were developed by the members of Working Group 3 of COST Action TD 1402: Multifunctional Nanoparticles for Magnetic Hyperthermia and Indirect Radiation Therapy ("Radiomag"). The purpose of the recommendations is not to provide definitive answers and directions but, rather, to outline those tests and considerations that a researcher must address in order to perform in vitro and in vivo studies. The recommendations are divided into 5 parts: (a) in vitro evaluation of MNPs; (b) in vitro evaluation of MNP-cell interactions; (c) in vivo evaluation of the MNPs; (d) MH combined with RT; and (e) pharmacokinetic studies of MNPs. Synthesis and characterization of the MNPs, as well as RT protocols, are beyond the scope of this work.

Immunotherapy with radiotherapy in urological malignancies

PURPOSE OF REVIEW

Radiotherapy has the potential to augment the host's immune response to cancer. Urological malignancies are highly immunogenic and the combination of radiotherapy and immunotherapy shows promise. In this review, we discuss the effects of radiotherapy on the cancer immune system and highlight the rationale for using the combined approach in prostate, urothelial and renal cancers. Current clinical studies are summarized emphasising the synergistic effects of the combination and the possibility of improved clinical outcomes.

RECENT FINDINGS

Local and abscopal effects have been observed in different urological cancers when using a combined approach. Large fraction size is associated with an increased immune response. Multiple radiotherapy/immunotherapy combinations are being studied in several clinical trials although no combination has yet been introduced in to standard practice.

SUMMARY

Although our knowledge of immunomodulation by radiotherapy has improved significantly in recent times, there remain several unanswered questions regarding how to best use the combination in clinical practice. Ongoing trials will provide further insight into complex mechanisms governing radiotherapy-immunotherapy interactions, with potential to improve clinical outcomes.

Elevated serum granulocyte-macrophage colony-stimulating factor levels during radiotherapy predict favorable outcomes in lung and esophageal cancer

The combination of exogenous granulocyte-macrophage colony-stimulating factor (GM-CSF) with radiotherapy (RT) has been demonstrated to strengthen the antitumor immune response. We hypothesized that the variation of GM-CSF during RT was correlated with cancer prognosis. We measured serum levels of GM-CSF and interferon-γ (IFN-γ) before and during RT in 126 unresectable lung and esophageal cancer patients and performed survival analyses. Upregulated GM-CSF levels during RT correlated with longer overall survival (OS) and progression-free survival (PFS). On the other hand, no difference in OS or PFS was seen at different IFN-γ levels. However, the “integrated factor”, computed as the combination of high pre-RT IFN-γ levels and upregulated GM-CSF, correlated with prolonged OS and PFS. Multivariate analyses revealed that GM-CSF levels and the integrated factor were both stronger independent prognostic factors than disease stage. These data demonstrate that GM-CSF levels during RT can be used as a prognostic biomarker for lung and esophageal cancer.

Combining forces: the promise and peril of synergistic immune checkpoint blockade and targeted therapy in metastatic melanoma

Both immune checkpoint inhibitors and molecularly targeted agents have dramatically improved clinical outcomes for patients with metastatic melanoma. These two therapeutic approaches harness distinct mechanistic pathways-on the one hand, monoclonal antibodies against the immune checkpoints CTLA-4 and PD-1/PD-L1 stimulate the T cell mediated host immune response, while targeted inhibitors of the proto-oncogenes BRAF and MEK disrupt constitutive kinase activity responsible for tumor growth. The prospect of combining these two treatment modalities has been proposed as a potential way to increase overall response rate, extend durability of the anti-tumor response, and circumvent the immune-mediated resistance to targeted therapy. This review explores the preclinical rationale-building upon a wealth of in vitro and in vivo studies-for improved anti-tumor efficacy from combined immune checkpoint inhibition and targeted therapy. In the process, we detail the early clinical trials that have assessed the compatibility of combining these two therapies and the unexpected challenges faced from studies showing increased toxicity from these regimens. Ultimately, with more clinical data expected to mature and accrue in the near future, we elucidate a potentially novel and promising strategy for patients with advanced melanoma.

Pembrolizumab-Induced Encephalopathy: A Review of Neurological Toxicities with Immune Checkpoint Inhibitors

The use of immune checkpoint inhibitor (ICI) therapy in the treatment of solid organ malignancies is becoming increasingly common. This has prompted the recognition of a new class of immune-related adverse effects (irAEs) stemming from the upregulation of T-cell activity causing autoimmunity. Neurological irAEs are a rare complication of ICIs that can lead to long-term morbidity. We report a rare case of encephalopathy after treatment with pembrolizumab, to which the patient achieved durable disease response despite discontinuation of therapy. We also review the pathophysiology, incidence, clinical presentation, diagnosis, and management of neurotoxicity secondary to ICIs. Treatment requires early administration of high-dose corticosteroids, and cessation of ICI therapy is often necessary after grade 3 or 4 irAEs. However, early data suggest that neurological irAEs correlate with a favorable disease response. Consideration should also be given to the optimal duration of ICI therapy to minimize the risk of toxicity and optimize health care expenditure.

Cerebral vasculitis mimicking intracranial metastatic progression of lung cancer during PD-1 blockade

BACKGROUND

Stimulation of the immune system by targeting the PD-1/PD-L1 pathway can result in activation of anti-tumor immunity. Besides its clinical benefit immune checkpoint therapy leads to significant immune-related adverse events (irAEs). Some rare irAEs are not well described yet but are critical in patient management.

CASE PRESENTATION

Here, we describe a case of autoimmune cerebral vasculitis/encephalitis after PD-1 inhibitor treatment for metastatic adenocarcinoma of the lung. Upon PD-1 blockade, the patient developed cerebral lesions, while having disease stabilization of extracranial metastases. Imaging suggested that the patient had new progressing brain metastases. Despite stereotactic irradiation the lesions progressed further. The largest lesion became symptomatic and had to be surgically resected. On examination, cerebral vasculitis was detected but not evidence of metastatic lung cancer. Analysis of the patient's serum revealed the presence of antinuclear antibodies that were already present before starting PD-1 blockade. In addition, we also found anti-vascular endothelial antibodies in the serum.

CONCLUSION

This finding suggests that the patient had preformed autoantibodies and the checkpoint inhibitor induced a clinically relevant autoimmune disease. Taken together, encephalitic lesions in patients under PD-1/PD-L1 blockade can mimic metastatic brain lesions and this rare irAE has to be considered as a differential diagnosis in patients treated with immunotherapy.