Local radiotherapy and granulocyte-macrophage colony-stimulating factor to generate abscopal responses in patients with metastatic solid tumours: a proof-of-principle trial

Efficacy and Safety of Pembrolizumab Plus Docetaxel vs Docetaxel Alone in Patients With Previously Treated Advanced Non-Small Cell Lung Cancer: The PROLUNG Phase 2 Randomized Clinical Trial

Importance

Because of socioeconomic factors, many patients with advanced non-small cell lung cancer (NSCLC) do not receive immunotherapy in the first-line setting. It is unknown if the combination of immunotherapy with chemotherapy can provide clinical benefits in immunotherapy-naive patients with disease progression after treatment with platinum-based chemotherapy.

Objective

To evaluate the safety and efficacy of the combination of pembrolizumab plus docetaxel in patients with previously treated advanced NSCLC following platinum-based chemotherapy regardless of EGFR variants or programmed cell death ligand 1 status.

Design, Setting, and Participants

The Pembrolizumab Plus Docetaxel for Advanced Non-Small Cell Lung Cancer (PROLUNG) trial randomized 78 patients with histologically confirmed advanced NSCLC in a 1:1 ratio to receive either pembrolizumab plus docetaxel or docetaxel alone from December 2016 through May 2019.

Interventions

The experimental arm received docetaxel on day 1 (75 mg/m2) plus pembrolizumab on day 8 (200 mg) every 3 weeks for up to 6 cycles followed by pembrolizumab maintenance until progression or unacceptable toxic effects. The control arm received docetaxel monotherapy.

Main Outcomes and Measures

The primary end point was overall response rate (ORR). Secondary end points included progression-free survival (PFS), overall survival, and safety.

Results

Among 78 recruited patients, 32 (41%) were men, 34 (44%) were never smokers, and 25 (32%) had an EGFR/ALK alteration. Forty patients were allocated to receive pembrolizumab plus docetaxel, and 38 were allocated to receive docetaxel. A statistically significant difference in ORR, assessed by an independent reviewer, was found in patients receiving pembrolizumab plus docetaxel vs patients receiving docetaxel (42.5% vs 15.8%; odds ratio, 3.94; 95% CI, 1.34-11.54; P = .01). Patients without EGFR variations had a considerable difference in ORR of 35.7% vs 12.0% (P = .06), whereas patients with EGFR variations had an ORR of 58.3% vs 23.1% (P = .14). Overall, PFS was longer in patients who received pembrolizumab plus docetaxel (9.5 months; 95% CI, 4.2-not reached) than in patients who received docetaxel (3.9 months; 95% CI, 3.2-5.7) (hazard ratio, 0.24; 95% CI, 0.13-0.46; P < .001). For patients without variations, PFS was 9.5 months (95% CI, 3.9-not reached) vs 4.1 months (95% CI, 3.5-5.3) (P < .001), whereas in patients with EGFR variations, PFS was 6.8 months (95% CI, 6.2-not reached) vs 3.5 months (95% CI, 2.3-6.2) (P = .04). In terms of safety, 23% (9 of 40) vs 5% (2 of 38) of patients experienced grade 1 to 2 pneumonitis in the pembrolizumab plus docetaxel and docetaxel arms, respectively (P = .03), while 28% (11 of 40) vs 3% (1 of 38) experienced any-grade hypothyroidism (P = .002). No new safety signals were identified.

Conclusions and Relevance

In this phase 2 study, the combination of pembrolizumab plus docetaxel was well tolerated and substantially improved ORR and PFS in patients with advanced NSCLC who had previous progression after platinum-based chemotherapy, including NSCLC with EGFR variations.

Trial Registration

ClinicalTrials.gov Identifier: NCT02574598.

Outcomes of Observation vs Stereotactic Ablative Radiation for Oligometastatic Prostate Cancer: The ORIOLE Phase 2 Randomized Clinical Trial

Question

How effectively does stereotactic ablative radiotherapy prevent progression of disease compared with observation in men with recurrent hormone-sensitive prostate cancer with 1 to 3 metastases?

Findings

In this phase 2 randomized clinical trial of 54 men, progression of disease at 6 months occurred in 7 of 36 participants (19%) treated with stereotactic ablative radiotherapy and in 11 of 18 participants (61%) undergoing observation, a statistically significant difference.

Meaning

Stereotactic ablative radiotherapy is a promising treatment approach for men with recurrent hormone-sensitive oligometastatic prostate cancer who wish to delay initiation of androgen deprivation therapy.

Importance

Complete metastatic ablation of oligometastatic prostate cancer may provide an alternative to early initiation of androgen deprivation therapy (ADT).

Objective

To determine if stereotactic ablative radiotherapy (SABR) improves oncologic outcomes in men with oligometastatic prostate cancer.

Design, Setting, and Participants

The Observation vs Stereotactic Ablative Radiation for Oligometastatic Prostate Cancer (ORIOLE) phase 2 randomized study accrued participants from 3 US radiation treatment facilities affiliated with a university hospital from May 2016 to March 2018 with a data cutoff date of May 20, 2019, for analysis. Of 80 men screened, 54 men with recurrent hormone-sensitive prostate cancer and 1 to 3 metastases detectable by conventional imaging who had not received ADT within 6 months of enrollment or 3 or more years total were randomized.

Interventions

Patients were randomized in a 2:1 ratio to receive SABR or observation.

Main Outcomes and Measures

The primary outcome was progression at 6 months by prostate-specific antigen level increase, progression detected by conventional imaging, symptomatic progression, ADT initiation for any reason, or death. Predefined secondary outcomes were toxic effects of SABR, local control at 6 months with SABR, progression-free survival, Brief Pain Inventory (Short Form)–measured quality of life, and concordance between conventional imaging and prostate-specific membrane antigen (PSMA)–targeted positron emission tomography in the identification of metastatic disease.

Results

In the 54 men randomized, the median (range) age was 68 (61-70) years for patients allocated to SABR and 68 (64-76) years for those allocated to observation. Progression at 6 months occurred in 7 of 36 patients (19%) receiving SABR and 11 of 18 patients (61%) undergoing observation (P = .005). Treatment with SABR improved median progression-free survival (not reached vs 5.8 months; hazard ratio, 0.30; 95% CI, 0.11-0.81; P = .002). Total consolidation of PSMA radiotracer-avid disease decreased the risk of new lesions at 6 months (16% vs 63%; P = .006). No toxic effects of grade 3 or greater were observed. T-cell receptor sequencing identified significant increased clonotypic expansion following SABR and correlation between baseline clonality and progression with SABR only (0.082085 vs 0.026051; P = .03).

Conclusions and Relevance

Treatment with SABR for oligometastatic prostate cancer improved outcomes and was enhanced by total consolidation of disease identified by PSMA-targeted positron emission tomography. SABR induced a systemic immune response, and baseline immune phenotype and tumor mutation status may predict the benefit from SABR. These results underline the importance of prospective randomized investigation of the oligometastatic state with integrated imaging and biological correlates.

Trial Registration

ClinicalTrials.gov Identifier: NCT02680587

Carbon ion triggered immunogenic necroptosis of nasopharyngeal carcinoma cells involving necroptotic inhibitor BCL-x

To explore the potential and mechanisms of necroptosis, a form of immunogenic cell death, induced by carbon ion as compared to photon beams in established photon resistant- (PR-) and sensitive nasopharyngeal carcinoma (NPC) cells. MLKL is considered a central executor of necroptosis and phosphorylation of MLKL (p-MLKL) was a critical event of necroptosis. The clonogenic survival and DNA microarray demonstrated that after repeated photon irradiation, radiosensitive NPC cells became apoptosis-resistant but could be effectively inhibited by carbon ion irradiation. The relative biologic effectiveness (RBE) at D10 and D37 were 2.15 and 2.78 for PR-NPC cells. Carbon ion induced delayed DNA damage repair, cell cycle arrest, cytogenetic damage, morphological change and cell necrosis, indicating the possibility of necroptosis in both PR- and sensitive NPC cell types. The lower expression of necroptotic inhibitors (caspase-8 and Bcl-x) and higher level of MLKL in PR-NPC cells showed it was relatively more predisposed to necroptosis compared to the sensitive cells. Subsequent experiments demonstrated the significant upregulation of p-MLKL in the PR-NPC cells treated by carbon ion (4 Gy) compared with photon irradiation at both physical (4 Gy) and RBE (10 Gy) doses (P≤0.0001). Moreover, carbon ion induced a robust (up to 28 folds) p-MLKL in the PR-NPC cells as well as sensitive cells (up to 6-fold) coupled with a lower level of BCL-x expression and increased GM-CSF implicated in resculputure of immune system. These results suggested that carbon ion could induce necroptosis of NPC cells, especially in PR-NPC cells, and its mechanisms involve BCL-x.

Synergy between early-incorporation immunotherapy and extracranial radiotherapy in metastatic non-small cell lung cancer

Background

Combining radiotherapy (RT) and immunotherapy (IT) may enhance outcomes for metastatic non-small cell lung cancer (mNSCLC). However, data on the immunomodulatory effects of extracranial RT remains limited. This retrospective database analysis examined real-world practice patterns, predictors of survival, and comparative effectiveness of extracranial radioimmunotherapy (RT + IT) versus early-incorporation immunotherapy (eIT) in patients with mNSCLC.

Methods

Patients diagnosed with mNSCLC between 2004-2016 treated with eIT or RT + IT were identified in the National Cancer Database. Practice patterns were assessed using Cochrane-Armitrage trend test. Cox proportional hazards and Kaplan-Meier method were used to analyze overall survival (OS). Propensity score matching was performed to account for baseline imbalances. Biologically effective doses (BED) were stratified based on the median (39 Gy₁₀). Stereotactic body radiotherapy (SBRT) was defined as above median BED in ≤5 fractions.

Results

eIT utilization increased from 0.3% in 2010 to 13.2% in 2016 (P<0.0001). Rates of RT + eIT increased from 38.8% in 2010 to 49.1% in 2016 among those who received eIT (P<0.0001). Compared to eIT alone, RT + eIT demonstrated worse median OS (11.2 vs. 13.2 months) while SBRT + eIT demonstrated improved median OS (25 vs. 13.2 months) (P<0.0001). There were no significant differences in OS based on sequencing of eIT relative to RT (log-rank P=0.4415) or irradiated site (log-rank P=0.1606). On multivariate analysis, factors associated with improved OS included chemotherapy (HR 0.86, P=0.0058), treatment at academic facilities (HR 0.83, P<0.0001), and SBRT (HR 0.60, P=0.0009); after propensity-score multivariate analysis, SBRT alone showed improved OS (HR 0.28, P<0.0001).

Conclusions

Utilization of RT + eIT in mNSCLC is increasing. SBRT + eIT was associated with improved OS on propensity-score matched analysis. There were no significant differences in OS based on RT + eIT sequencing or site irradiated. Whether these observations reflect patient selection or possible immunomodulatory benefits of RT is unclear and warrants further study.

Challenges and Opportunities for Pancreatic Cancer Immunotherapy

Pancreatic ductal adenocarcinoma (PDA) is among the most immune-resistant tumor types. Its unique genomic landscape shaped by oncogenic drivers promotes immune suppression from the earliest stages of tumor inception to subvert adaptive T cell immunity. Single-agent immune modulators have thus far proven clinically ineffective, and multi-modal therapies targeting mechanisms of immunotherapy resistance are likely needed. Here, we review novel immunotherapy strategies currently under investigation to (1) confer antigen specificity, (2) enhance T cell effector function, and (3) neutralize immunosuppressive elements within the tumor microenvironment that may be rationally combined to untangle the web of immune resistance in PDA and other tumors.

Generation of biological hypotheses by functional imaging links tumor hypoxia to radiation induced tissue inflammation/glucose uptake in head and neck cancer

BACKGROUND AND PURPOSE

Positron emission tomography (PET) is a functional imaging modality which is able to deliver tracer specific biological information, e.g. about glucose uptake, inflammation or hypoxia of tumors. We performed a proof-of-principle study that used different tracers and expanded the analytical scope to non-tumor structures to evaluate tumor-host interactions.

MATERIALS AND METHODS

Based on a previously reported prospective imaging study on 50 patients treated with curative intent chemoradiation (CRT) for head and neck squamous cell carcinoma, PET-based hypoxia and normal tissue inflammation measured by repeat 18F-fluoromisonidazole (FMISO) PET and 18F-fluorodesoxyglucose (FDG) PET, respectively, were correlated using the Spearman correlation coefficient R. PET parameters determined before and during CRT (week 1, 2 and 5), were associated with local tumor control and overall survival.

RESULTS

Tumor hypoxia at all measured times showed an inverse correlation with mid-treatment FDG-uptake of non-tumor affected oral (sub-)mucosa with R values between -0.35 and -0.6 (all p < 0.05). Mucosal FDG-uptake and mucosal hypoxia correlated positively but weaker (R values between 0.2 and 0.45). More tumor hypoxia in FMISO-PET (week 2) and less FDG-uptake of (sub-)mucosa in FDG-PET (week 4) were significantly associated with worse LC (FMISO TBR_peak: HR = 1.72, p = 0.030; FDG SUV_mean: HR = 0.23, p = 0.025) and OS (FMISO TBR_peak: HR = 1.71, p = 0.007; FDG SUV_mean: HR = 0.30, p = 0.003). Multivariable models including both parameters showed improved performance, suggesting that these modalities still bear distinct biological information despite their strong inter-correlation.

CONCLUSION

We report first clinical evidence that tumor hypoxia is inversely correlated with increased FDG-uptake during radiation, potentially expressing inflammation. This observation merits further research and may have important implication for future research on tumor hypoxia and radio-immunology. Our study demonstrates that functional imaging can be utilized to assess complex tumor-host interactions and generate novel biological insights in vivo vero.

IFNgamma-inducible CXCL10/CXCR3 axis alters the sensitivity of HEp-2 cells to ionizing radiation

Radiotherapy is a conventional approach for anti-cancer treatment, killing tumor cells through damaging cellular DNA. While increasing studies have demonstrated that tumors generated the tolerance to radiation and tumor immune system was found to be correlated to radiotherapy resistance. Therefore, it is critical to identify potential immune factors associated with the efficacy of radiotherapy. Here in this study, we evaluated the sensitivities of different tumor cells to radiation and determined HEp-2 cells as the radio-resistant tumor cells for further investigation. IFNgamma as a key regulator of host immune response showed the potential to sensitize tumors to ionizing radiation (IR). Besides, IFNgamma-induced CXC chemokine ligand 10 (CXCL10) was found to be necessary for effective IR-induced killing of cultured HEp-2 cells. Increased clonogenic survival was observed in CXCL10-depleted HEp-2 cells and CXCL10-KO cells. Additionally, the loss of CXCL10 in HEp-2 cells showed less progression of the G0/G1 phase to G2/M when exposed to IR (8 Gy). Local IR (20 Gy) to nude mice bearing HEp-2 tumors significantly reduced tumor burden, while fewer effects on tumor burden in mice carrying CXCL10-KO tumors were observed. We furtherly evaluated the possible roles the chemokine receptor CXCR3 plays in mediating the sensitivity of cultured HEp-2 cells to IR. Altered expression of CXCR3 in HEp-2 cells affected IR-induced killing of HEp-2 cells. Our data suggest the IFNgamma-activated CXCL10/CXCR3 axis may contribute to the effective radiation-induced killing of HEp-2 cells in vitro.

MicroRNA-200c Nanoparticles Sensitized Gastric Cancer Cells to Radiotherapy by Regulating PD-L1 Expression and EMT

Introduction

Immuno-checkpoint inhibitors (ICIs) in advanced gastric cancer either as monotherapy or in combining strategies are rapidly evolving but still in early phase. Various efforts have been made to provide insights into regulating immune checkpoint molecule programmed cell death ligand-1 (PD-L1) expression to improve ICIs efficacy. The aim of this study was to investigate the effect and potential mechanism of miR-200c nanoparticles combined with radiotherapy in gastric cancer cells.

Methods

We prepared miR-200c-loaded nanoparticles (miR-200c NPs) to achieve targeted delivery of miR-200c to AGS cells. The roles of miR-200c NPs and radiotherapy in regulating the viability of AGS cells were assessed by CCK-8 toxicity test and Annexin V-FITC/PI apoptosis kit. Flow cytometry was used to analyze expression of PD-L1 and CD44 on the surface of AGS cells treated by miR-200c NPs and/or ionizing radiation. Enzyme-linked immunosorbent assay (ELISA) was used to test the level of transforming growth factor-beta 1 (TGF-β1) secreted by AGS cells. The cooperation mechanism between miR-200c NPs and radiotherapy was also explored in vitro.

Results

Compared with naked miR-200c mimics, miR-200c NPs significantly downregulated PD-L1 expression of gastric cancer cells. The combination of miR-200c NPs and radiotherapy showed significantly synergistic inhibitory effect on gastric cancer cells by inhibiting immune escape mediated by PD-L1, reversing EMT phenotype as well as abrogating cancer stem cells (CSCs)-associated properties of tumor cells.

Conclusion

MiR-200c NPs sensitized gastric cancer cells to radiotherapy by regulating PD-L1 expression and EMT.

Radiotherapy and Immunotherapy Combinations for Lung Cancer

PURPOSE OF REVIEW

Positive results from recent immunotherapy trials of non-small cell lung cancer (NSCLC) have coincided with a greater appreciation for the impact of radiation therapy (RT) on tumor immunity. Here, we summarize key clinical findings and ongoing efforts to combine immunotherapy and RT for the treatment of NSCLC.

RECENT FINDINGS

The role of immunotherapy for NSCLC has expanded significantly following the pivotal approvals of nivolumab and pembrolizumab for metastatic NSCLC, maintenance durvalumab in unresectable stage III NSCLC, and atezolizumab for metastatic NSCLC. Several small early-phase trials have demonstrated the ability of RT to elicit clinically significant tumor immunity. These positive findings support current trial efforts combining RT with immunotherapy for NSCLC. Recently initiated trials of RT and immunotherapy hold significant promise in expanding the therapeutic options for NSCLC. Optimization of therapy will require careful patient selection to yield meaningful improvements in clinical outcomes.

Radiomics to predict outcomes and abscopal response of patients with cancer treated with immunotherapy combined with radiotherapy using a validated signature of CD8 cells

BACKGROUND

Combining radiotherapy (RT) with immuno-oncology (IO) therapy (IORT) may enhance IO-induced antitumor response. Quantitative imaging biomarkers can be used to provide prognosis, predict tumor response in a non-invasive fashion and improve patient selection for IORT. A biologically inspired CD8 T-cells-associated radiomics signature has been developed on previous cohorts. We evaluated here whether this CD8 radiomic signature is associated with lesion response, whether it may help to assess disease spatial heterogeneity for predicting outcomes of patients treated with IORT. We also evaluated differences between irradiated and non-irradiated lesions.

METHODS

Clinical data from patients with advanced solid tumors in six independent clinical studies of IORT were investigated. Immunotherapy consisted of 4 different drugs (antiprogrammed death-ligand 1 or anticytotoxic T-lymphocyte-associated protein 4 in monotherapy). Most patients received stereotactic RT to one lesion. Irradiated and non-irradiated lesions were delineated from baseline and the first evaluation CT scans. Radiomic features were extracted from contrast-enhanced CT images and the CD8 radiomics signature was applied. A responding lesion was defined by a decrease in lesion size of at least 30%. Dispersion metrices of the radiomics signature were estimated to evaluate the impact of tumor heterogeneity in patient's response.

RESULTS

A total of 94 patients involving multiple lesions (100 irradiated and 189 non-irradiated lesions) were considered for a statistical interpretation. Lesions with high CD8 radiomics score at baseline were associated with significantly higher tumor response (area under the receiving operating characteristic curve (AUC)=0.63, p=0.0020). Entropy of the radiomics scores distribution on all lesions was shown to be associated with progression-free survival (HR=1.67, p=0.040), out-of-field abscopal response (AUC=0.70, p=0.014) and overall survival (HR=2.08, p=0.023), which remained significant in a multivariate analysis including clinical and biological variables.

CONCLUSIONS

These results enhance the predictive value of the biologically inspired CD8 radiomics score and suggests that tumor heterogeneity should be systematically considered in patients treated with IORT. This CD8 radiomics signature may help select patients who are most likely to benefit from IORT.

Is there a role for locoregional treatment of the primary tumor in de novo metastatic breast cancer in the era of tailored therapies?: Evidences, unresolved questions and a practical algorithm

Improvements in systemic therapies have changed the face of de novo metastatic breast cancer (dnMBC), with a 5-year survival rate exceeding 25 %. Increasing evidence suggests that a subset of patients could benefit from a locoregional treatment (LRT) with prolonged survival, although the diversity of publications on the subject make it difficult to draw any conclusions. In this review, we summarize the available data on retrospective, prospective and current ongoing clinical trials. Since factors such as tumor biology, pattern of metastatic dissemination and the timing of the treatment are closely linked to the therapeutic strategy, we focus on papers which include these aspects. We discuss recent studies indicating that exclusive radiotherapy provides results comparable with those obtained by surgery. We will then discuss the biological rationale for LRT. Finally, we propose a decision-tree to select the optimal candidates for LRT in dnMBC patients.

Radiation and immunotherapy: emerging mechanisms of synergy

Immunotherapy (IO) has become a standard treatment in patients with metastatic and locally advanced non-small cell lung cancer (NSCLC), and is now being tested in patients with early stage disease. IO agents currently in use for lung cancer target PD-1, PD-L1, and CTLA-4. While survival and tumor control have improved with IO, many patients have limited or short responses to IO. Therefore, methods to improve the systemic response to IO are needed. Radiation therapy (RT) is an integral component of lung cancer treatment, and may improve systemic response to IO by increasing antigen presentation, increasing co-stimulatory signaling, increasing T-cells recruitment, upregulating PD-L1, increasing tumor stromal lymphocyte infiltration, and altering the microenvironment. IO after definitive chemoradiation is now standard treatment in unresectable stage III NSCLC following publication of the PACIFIC clinical trial. For early stage NSCLC, IO is being investigated in conjunction with stereotactic body radiotherapy (SBRT). The benefit of adding RT to IO in patients with metastatic disease may be especially pronounced in patients with low baseline PD-L1 expression, potentially when delivered as a short course of SBRT, as supported by the PEMBRO-RT clinical trial. Current and ongoing clinical trials are evaluating the optimal radiation dose, timing, and sequencing of RT with IO.

Immunomodulatory Effects of Radiotherapy

Radiation therapy (RT), an integral component of curative treatment for many malignancies, can be administered via an increasing array of techniques. In this review, we summarize the properties and application of different types of RT, specifically, conventional therapy with x-rays, stereotactic body RT, and proton and carbon particle therapies. We highlight how low-linear energy transfer (LET) radiation induces simple DNA lesions that are efficiently repaired by cells, whereas high-LET radiation causes complex DNA lesions that are difficult to repair and that ultimately enhance cancer cell killing. Additionally, we discuss the immunogenicity of radiation-induced tumor death, elucidate the molecular mechanisms by which radiation mounts innate and adaptive immune responses and explore strategies by which we can increase the efficacy of these mechanisms. Understanding the mechanisms by which RT modulates immune signaling and the key players involved in modulating the RT-mediated immune response will help to improve therapeutic efficacy and to identify novel immunomodulatory drugs that will benefit cancer patients undergoing targeted RT.

Combination of radiotherapy and suppression of Tregs enhances abscopal antitumor effect and inhibits metastasis in rectal cancer

Background

Distant metastasis is the major cause of mortality in patients with locally advanced rectal cancer (LARC) following neoadjuvant chemoradiotherapy. Local radiotherapy can trigger an abscopal response to metastatic tumor cells. However, the abscopal effect is a rare event. CD4+ regulatory T (Treg) cell is a highly immune-suppressive subset which impedes immune surveillance against cancer, prevents the development of effective antitumor immunity and promotes tumor progression. We assume that the exploitation of the proimmunogenic effects of radiotherapy with anti-CD25 or anti-Cytotoxic T-Lymphocyte Associated Protein 4 (anti-CTLA4) monoclonal antibodies (mAbs) may enhance the local and abscopal effects in rectal cancer and improve the therapeutic outcome.

Methods

mRNA expression profiling of 81 pretreatment biopsy samples from LARC patients who received neoadjuvant radiotherapy (nRT) was performed to analyze the correlation between gene expression and prognosis. A retrospective analysis of patients with rectal cancer with distant metastasis or synchronous extracolonic cancers was performed to evaluate the abscopal effect of radiotherapy on rectal cancer. Two different dual-tumor mouse models were established to investigate the efficacy of single dose and dose-fractionated radiotherapy combined with anti-CD25 or anti-CTLA4 and anti-Programmed cell death 1 ligand 1 (anti-PD1) mAbs on the local tumor growth and liver metastasis. The univariate Cox regression analysis, one-way analysis of variance, Dunnett’s test, a mixed-effect linear model and Kaplan-Meier survival analysis were used to calculate p values.

Results

The proportion of Tregs in pre-nRT biopsies was negatively correlated with prognosis (p=0.007). The retrospective analysis showed that regressing liver metastases were infiltrated by CD8+ T cells. In contrast, stable/progressing metastases and synchronous extracolonic cancers were characterized by PD1+ T cells and Tregs infiltration. Animal experiment results demonstrated that the combination of radiotherapy and anti-CD25/CTLA4 mAb resulted in a significant increase in CD8+ T cells and CD8+/CD4+ ratio in primary and secondary tumors compared with the irradiation alone group (all p<0.05 or p<0.01). The combined treatment was able to decrease Tregs, PD1+CD8+ and PD1+CD4+ T cells (p<0.05), suppress locally irradiated and distal unirradiated tumor growth, and improve overall survival rate. Radiotherapy in conjunction with anti-CTLA4 reduced liver metastasis (p<0.05).

Conclusions

These data indicated that radiotherapy plus depletion of Tregs was able to improve the antitumor response and generate an abscopal effect.

Low-dose radiation treatment enhances systemic antitumor immune responses by overcoming the inhibitory stroma

Background

Despite some successes with checkpoint inhibitors for treating cancer, most patients remain refractory to treatment, possibly due to the inhibitory nature of the tumor stroma that impedes the function and entry of effector cells. We devised a new technique of combining immunotherapy with radiotherapy (XRT), more specifically low-dose XRT, to overcome the stroma and maximize systemic outcomes.

Methods

We bilaterally established 344SQ lung adenocarcinoma tumors in 129Sv/Ev mice. Primary and secondary tumors were irradiated with either high-dose or low-dose of XRT with systemic anti-programmed cell death protein 1 and anti-cytotoxic T-lymphocyte associated protein 4 administration. Survival and tumor growth were monitored for the various groups, and secondary tumors were phenotyped by flow cytometry for immune populations. Tumor growth factor-beta (TGF-β) cytokine levels were assessed locally after low-dose XRT, and specific immune-cell depletion experiments were conducted to identify the major contributors to the observed systemic antitumor effect.

Results

Through our preclinical and clinical studies, we observed that when tumor burden was high, there was a necessity of combining high-dose XRT to ‘prime’ T cells at the primary tumor site, with low-dose XRT directed to secondary (metastatic) tumors to ‘modulate the stroma’. Low-dose XRT improved the antitumor outcomes of checkpoint inhibitors by favoring M1 macrophage polarization, enhancing natural killer (NK) cell infiltration, and reducing TGF-β levels. Depletion of CD4⁺ T cells and NK cells abrogated the observed antitumor effect.

Conclusion

Our data extend the benefits of low-dose XRT to reprogram the tumor environment and improve the infiltration and function of effector immune cells into secondary tumors.

Carbon Ion Radiobiology

Radiotherapy using accelerated charged particles is rapidly growing worldwide. About 85% of the cancer patients receiving particle therapy are irradiated with protons, which have physical advantages compared to X-rays but a similar biological response. In addition to the ballistic advantages, heavy ions present specific radiobiological features that can make them attractive for treating radioresistant, hypoxic tumors. An ideal heavy ion should have lower toxicity in the entrance channel (normal tissue) and be exquisitely effective in the target region (tumor). Carbon ions have been chosen because they represent the best combination in this direction. Normal tissue toxicities and second cancer risk are similar to those observed in conventional radiotherapy. In the target region, they have increased relative biological effectiveness and a reduced oxygen enhancement ratio compared to X-rays. Some radiobiological properties of densely ionizing carbon ions are so distinct from X-rays and protons that they can be considered as a different "drug" in oncology, and may elicit favorable responses such as an increased immune response and reduced angiogenesis and metastatic potential. The radiobiological properties of carbon ions should guide patient selection and treatment protocols to achieve optimal clinical results.

Anti-PD-1 Immunotherapy Combined With Stereotactic Body Radiation Therapy and GM-CSF as Salvage Therapy in a PD-L1-Negative Patient With Refractory Metastatic Esophageal Squamous Cell Carcinoma: A Case Report and Literature Review

Esophageal squamous cell carcinoma (ESCC) is a malignancy with poor prognosis, which is often diagnosed at a late stage. Effective treatment options are limited when patients fail standard systemic therapy. The application of PD-1 inhibitors have led to a paradigm shift in the treatment of ESCC, but its efficacy as monotherapy is limited. Previous studies have shown that the antitumor effects may be reinforced when a PD-1 inhibitor is combined with radiotherapy or GM-CSF. This study aimed to report a case of a patient about advanced unresectable ESCC negative expression of PD-L1, who experienced tumor progression after chemoradiotherapy and targeted therapy.A significant systemic effect was seen after PD-1 inhibitor combined with GM-CSF and stereotactic body radiotherapy (SBRT) for metastatic lesions, however, severe pneumonia occurred after the triple-combination therapy. This study also reviewed several reports about the efficacy and safety of combination therapy.

Bip inhibition in glioma stem cells promotes radiation-induced immunogenic cell death

Tumor regression in sites distant to the irradiated field are thought to be associated with emission of damage-associated molecular patterns (DAMPs) molecules and generation of immunogenic cell death (ICD). Glioma stem cells (GSCs) are resistant to high doses of radiation, and ultimately select the outgrowth of a more aggressive tumor. This study showed high-dose IR triggered fewer DAMPs molecules exposure and release in GSCs comparing to matched non-GSCs. Downregulation of binding immunoglobulin protein (Bip) promoted IR-mediated endoplasmic reticulum stress to generate DAMPs molecules by PERK and IRE1-α phosphorylation, and increased dendritic cells mature and effector T lymphocytes activation. GSCs treated with Bip knockdown and IR efficiently prevented tumor generation, and reduced post-radiotherapy tumor recurrence. These data suggest that Bip plays a critical role in inhibition of IR-induced ICD in GSCs, and Bip inhibition may be a promising strategy on adjuvant therapy by ameliorating tumor immune microenvironment.

How to improve clinical research in a department of radiation oncology

INTRODUCTION

Radiation therapy is a core modality for cancer treatment. Around 40% of cancer cures include the use of radiotherapy, either as a single strategy or combined with other treatments. In the past decade, substantial technical advances and novel insights into radiobiological properties have considerably improved patients' outcomes. This study overviewed the landscape of clinical research at our radiotherapy department.

METHODS

We surveyed our institutional database of clinical trials to collect information for completed or ongoing radiation therapy clinical trials, from 2005 to December 2017 at the Lucien Neuwirth cancer institute.

RESULTS

A total of 31 clinical trials were undertaken during the study period, of which 4 studies (12.9%) were industry-sponsored and 3 studies (9.7%) were launched by our radiotherapy unit. The vast majority of clinical trials (83.9%) were dedicated to unique organ localization, especially urological cancer (prostate or bladder) (42%). We also observed a shift towards more phase II trials during the study period as well as a special focus on elderly population. Over the last decade, the number of included patients increased by a 5.3 fold input, with 135 inclusions before 2011 and 720 inclusions after 2011.

DISCUSSION

This study provided an observational and comprehensive analysis of radiotherapy research. From a monocentric point-of-view, these results reflected the on-going progress of worldwide radiotherapy research. Based on a 13-years' experience, this study aimed at highlighting essential cues to ensure efficient and perennial research.

Advances in non and minimal-invasive transcutaneous delivery of immunotherapy for cancer treatment

Cancer research has focused on figuring out what was the difference between cancer cells and the tissues within which cancer arose and developing targeted treatments for those differences. With FDA-approved treatments for more ten different cancers and more than thousand new clinical trials, immunotherapy has recently emerged as the most promising area of cancer research by improving efficacy and controlling the adverse effects. Transcutaneous delivery drug delivery offers a number of advantages for the patient because of not only its noninvasive and convenient nature but also factors such as avoidance of first-pass metabolism and prevention of gastrointestinal degradation. The purpose of this review was to highlight technological recent approaches to non and minimal-invasive delivery of immunotherapy for cancer treatment. Finally, some practical considerations and discussions for future studies in the field of transdermal immunomodulation are also included.

Intratumoral Immunotherapy: From Trial Design to Clinical Practice

Systemic immunotherapies such as immune checkpoint blockade targeted at PD(L)1 and CTLA4 have demonstrated their ability to provide durable tumor responses and long-term overall survival benefits for some patients in several solid tumor types. However, a majority of patients remain resistant to these treatments and a significant proportion of them develop severe autoimmune and inflammatory adverse events. Preclinical studies have demonstrated that intratumoral injections of immunostimulatory products (oncolytics, pattern recognition receptor agonists,…) that are able to trigger type I IFN release and enhance tumor antigen presentation on immune cells could generate a strong antitumor immunity and overcome the resistance to systemic immune checkpoint blockade therapies. The intratumoral immunotherapy strategies that are currently in clinical development offer a unique therapeutic and exploratory setting to better understand the immune contexture across tumor lesions of patients with metastatic cancer. Also these local therapeutic products could turn cold tumors into hot and improve the response rates to cancer immunotherapies while diminishing their systemic exposure and toxicities. Intratumoral immunotherapies could prime or boost the immunity against tumors and therefore radically change the combinatorial therapeutic strategies currently pursued for metastatic and local cancers to improve their long-term survival. We aimed to review and discuss the scientific rationale for intratumoral immunotherapy, the challenges raised by this strategy in terms of drug development within clinical trials and the current state-of-the-art regarding the clinical practice of this innovative approach.

Dual blockade of CD47 and HER2 eliminates radioresistant breast cancer cells

Although the efficacy of cancer radiotherapy (RT) can be enhanced by targeted immunotherapy, the immunosuppressive factors induced by radiation on tumor cells remain to be identified. Here, we report that CD47-mediated anti-phagocytosis is concurrently upregulated with HER2 in radioresistant breast cancer (BC) cells and RT-treated mouse syngeneic BC. Co-expression of both receptors is more frequently detected in recurrent BC patients with poor prognosis. CD47 is upregulated preferentially in HER2-expressing cells, and blocking CD47 or HER2 reduces both receptors with diminished clonogenicity and augmented phagocytosis. CRISPR-mediated CD47 and HER2 dual knockouts not only inhibit clonogenicity but also enhance macrophage-mediated attack. Dual antibody of both receptors synergizes with RT in control of syngeneic mouse breast tumor. These results provide the evidence that aggressive behavior of radioresistant BC is caused by CD47-mediated anti-phagocytosis conjugated with HER2-prompted proliferation. Dual blockade of CD47 and HER2 is suggested to eliminate resistant cancer cells in BC radiotherapy.

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.

Targeting Oligometastasis with Stereotactic Ablative Radiation Therapy or Surgery in Metastatic Hormone-sensitive Prostate Cancer: A Systematic Review of Prospective Clinical Trials

CONTEXT

Metastasis-directed therapy (MDT) in the form of stereotactic ablative radiation therapy (SABR), or in combination with surgical metastasectomy, may have a role in cancer control and disease progression.

OBJECTIVE

To perform a systematic review of MDT (surgery or SABR) for oligometastatic (up to 10 metastases, recurrent or de novo) hormone-sensitive prostate cancer in addition to or following primary prostate gland treatment.

EVIDENCE ACQUISITION

Medline, Embase, Cochrane Review Database, and clinical trial Databases were systematically searched for clinical trials reporting oncological outcomes and safety. The risk of bias was assessed with the Cochrane 2.0 or ROBINS-I tool.

EVIDENCE SYNTHESIS

From 1025 articles identified, four clinical trials met the prespecified criteria. These included two randomised and two nonrandomised clinical trials (n=169). Baseline prostate-specific antigen level, age, and metastasis ranged from 2.0 to 17.0 ng/ml, 43 to 75 yr, and one to seven lesions, respectively. Nodal, bone, nodal and bone, and visceral metastases were present in 49.7% (84/169), 33.7% (57/169), 15.9% (27/169), and 0.5% (1/169) of patients, respectively. Diagnostic conventional imaging was used in 43.7% (74/169) and positron emission tomography/computerised tomography in 56.2% (95/169) of patients. SABR and surgical metastasectomy with SABR were used in 78.3% (94/120) and 21.6% (26/120) of patients, respectively. Early progression-free survival ranged from 19% to 60%. Local control was reported as 93-100%. Grade II and III SABR toxicities were reported in 8% (8/100) and 1% (1/100) of patients, respectively. Grade IIIa and IIIb surgical complications were reported in 7.69% (2/26) and 0% (0/26) of patients, respectively.

CONCLUSIONS

MDT is a promising experimental therapeutic approach in men with hormone-sensitive oligometastatic prostate cancer. Randomised comparative studies are required to ascertain its role and optimal timing in oligometastatic recurrence and efficacy in de novo synchronous disease.

PATIENT SUMMARY

We looked at the evidence regarding the use of surgery or radiotherapy at target areas of cancer spread in men with newly diagnosed or relapsed advanced (metastatic) prostate cancer. Evidence supports both treatment options as promising approaches, but further large trials are required.

Radiation therapy and the innate immune response: Clinical implications for immunotherapy approaches

Radiation therapy is an essential component of cancer care, contributing up to 40% of curative cancer treatment regimens. It creates DNA double-strand breaks causing cell death in highly replicating tumour cells. However, tumours can develop acquired resistance to therapy. The efficiency of radiation treatment has been increased by means of combining it with other approaches such as chemotherapy, molecule-targeted therapies and, in recent years, immunotherapy (IT). Cancer-cell apoptosis after radiation treatment causes an immunological reaction that contributes to eradicating the tumour via antigen presentation and subsequent T-cell activation. By contrast, radiotherapy also contributes to the formation of an immunosuppressive environment that hinders the efficacy of the therapy. Innate immune cells from myeloid and lymphoid origin show a very active role in both acquired resistance and antitumourigenic mechanisms. Therefore, many efforts are being made in order to reach a better understanding of the innate immunity reactions after radiation therapy (RT) and the design of new combinatorial IT strategies focused in these particular populations.

High versus low dose irradiation for tumor immune reprogramming

Local administration of ionizing radiation to tumors can promote anticancer immune responses that lead to the abscopal regression of distant metastases, especially in patients receiving systemic immune-checkpoint inhibitors. Growing preclinical evidence indicates that high-dose irradiation administered locally to destroy malignant lesions, can promote the release of danger-associated molecular patterns that lead to the recruitment of immune cells, thus inducing a systemic response against tumor antigens that protects against local disease relapse and also mediates distant antineoplastic effects. An accumulating body of preclinical evidence supports also the implementation of low-dose irradiation to induce tumor immune reprogramming. Here, we provide the rationale for a clinical research agenda to refine future clinical practice based on innovative combinations of radiation-immunotherapy.

The Promise of Combining Radiation Therapy With Immunotherapy

The development of immunotherapy in oncology builds upon many years of scientific investigation into the cellular mechanics underlying interactions between tumor cells and immune cell populations. The past decade has brought an accelerating pace to the clinical investigation of new immunotherapy agents, particularly in the setting of metastatic disease. The integration of immunotherapy into phase 3 clinical trial design has lagged in settings of advanced locoregional disease, where combination with radiation therapy may be critical. Yet, such may be the settings where immunotherapies have their greatest potential to affect patient survival and achieve curative outcomes. In this review, we discuss the interaction of radiation with the immune system and the potential to augment antitumor immunity through combined-modality approaches that integrate radiation and immunotherapies. The dynamics of cellular and tumor response to radiation offer unique opportunities for beneficial interplay with immunotherapy that may go unrecognized with conventional screening and monotherapy clinical testing of novel pharmaceutical agents. Using immune checkpoint blockade as a primary example, we discuss recent preclinical and clinical studies that illustrate the potential synergy of such therapies in combination with radiation, and we highlight the potential clinical value of such interactions. For various immunotherapy agents, their greatest clinical effect may rest in combination with radiation, and efforts to facilitate systematic investigation of this approach are highly warranted.

Thoracic radiotherapy plus Durvalumab in elderly and/or frail NSCLC stage III patients unfit for chemotherapy - employing optimized (hypofractionated) radiotherapy to foster durvalumab efficacy: study protocol of the TRADE-hypo trial

BACKGROUND

Non-small cell lung cancer is the most common cause of cancer death worldwide, highlighting the need for novel therapeutic concepts. In particular, there is still a lack of treatment strategies for the group of elderly and frail patients, who are frequently not capable of receiving standard therapy regimens. Despite comprising the majority of lung cancer patients, this group is underrepresented in clinical trials. This applies also to elderly and frail patients suffering from unresectable stage III NSCLC, who are unfit for chemotherapy, and, therefore, cannot receive the standard therapy comprising of radiochemotherapy and the recently approved subsequent durvalumab consolidation therapy. These patients often receive radiotherapy only, which raises the concern of undertreatment. The TRADE-hypo trial aims at optimizing treatment of this patient group by combining radiotherapy with concomitant durvalumab administration, thereby employing the immune-promoting effects of radiotherapy, and determining safety, feasibility, and efficacy of this treatment.

METHODS/ DESIGN

In this prospective phase II clinical trial, durvalumab therapy will be combined with either conventionally fractionated (CON-group) or hypofractionated (HYPO-group) thoracic radiotherapy. A safety stop-and-go lead-in phase will assess safety of hypofractionated radiotherapy with respect to severe pneumonitis in small patient cohorts before opening full enrollment. Tumor tissue, blood and stool samples will be collected before and during the study period to investigate the immunological mechanisms responsible for checkpoint inhibitor efficacy and immune-promoting effects of radiotherapy.

DISCUSSION

Preclinical data suggests that irradiation-induced immunogenicity can be further increased if applied in a hypofractionated setting, potentially boosting the expected synergistic effect with immune checkpoint inhibition in restoring the immune anti-tumor response. If proven safe and efficient, a hypofractionated radiation schedule can provide a considerably more practicable option for the patient. Taking into consideration the intend to develop a combination treatment strategy that can be made available to patients soon after proving to be efficient and the potentially elevated toxicity of a hypofractionated radiotherapy approach, this trial was designed as a two-trials-in-one design. An accompanying translational research program is planned striving to gain insights into the tumor-host biology and to identify suitable biomarkers to predict therapy response.

TRIAL REGISTRATION

Clinicaltrials.gov , NCT04351256 . Registered 17 April 2020, Eudra-CT, 2019-002192-33 . Registered 24 October 2019.

Intra-hepatic Abscopal Effect Following Radioembolization of Hepatic Metastases

Purpose

To search for abscopal effects (AE) distant to the site of radiation after sequential Yittrium-90 (Y-90) radioembolization (RE) of liver malignancies.

Methods and Materials

In this retrospective analysis, all patients treated by RE between 2007 and 2018 (n = 907) were screened for the following setting/conditions: sequential RE of left and right liver lobe in two sessions, liver-specific MRI (MRI1) acquired max. 10 days before or after first RE (RE1), liver-specific MRI (MRI2) acquired with a minimum time interval of 20 days after MRI1, but before second RE (RE2). No systemic tumor therapies between MRI1 and MRI2. No patients with liver cirrhosis. Metastases > 5 mm in untreated liver lobes were compared in MRI1 and MRI2 and rated as follows: same size or larger in MRI2 = no abscopal effect (NAE); > 30% shrinkage without Y-90 contamination in SPECT/CT = abscopal effect (AE).

Results

Ninety six of 907 patients met aforementioned criteria. Median time-frame between RE1 and MRI2 was 34 (20–64) days. These 96 cases had 765 metastases which were evaluable (median 5(1–40) metastases per patient). Four patients could be identified with at least one shrinking metastasis of the untreated site: one patient with breast cancer (3 metastases: 0 NAE; 3 AE), one patient with prostate cancer (6 metastases: 3 NAE; 3 metastases > 30% shrinkage but possible Y-90 contamination) and two patients with shrinkage of one metastasis each but less than 30%.

Conclusion

Our retrospective study documents AE after RE of liver tumors in 1 out of 96 cases, 3 other cases remain unclear.

Immune-Modulating Effects of Conventional Therapies in Colorectal Cancer

Biological heterogeneity and low inherent immunogenicity are two features that greatly impact therapeutic management and outcome in colorectal cancer. Despite high local control rates, systemic tumor dissemination remains the main cause of treatment failure and stresses the need for new developments in combined-modality approaches. While the role of adaptive immune responses in a small subgroup of colorectal tumors with inherent immunogenicity is indisputable, the challenge remains in identifying the optimal synergy between conventional treatment modalities and immune therapy for the majority of the less immunogenic cases. In this context, cytotoxic agents such as radiation and certain chemotherapeutics can be utilized to enhance the immunogenicity of an otherwise immunologically silent disease and enable responsiveness to immune therapy. In this review, we explore the immunological characteristics of colorectal cancer, the effects that standard-of-care treatments have on the immune system, and the opportunities arising from combining immune checkpoint-blocking therapy with immune-modulating conventional treatments.

Research Progress and Existing Problems for Abscopal Effect

Radiation therapy plays a vital role in the treatment of tumours. In particular, the occurrence of the “abscopal effect” brings about a favourable turn for the treatment of patients with advanced metastatic malignant tumours. Because of the abscopal effect, non-irradiated areas are also treated. However, the abscopal effect occurs by chance, not through seeking. Although the abscopal effect has been studied enthusiastically, the desired result does not appear to be achieved. Moreover, its combination with immunotherapy appears to be overwhelming. There is an opinion that abscopal effect is difficult to achieve by irradiation of a single tumour, and irradiation of multiple or total lesions is advocated to increase the possibility of obtaining clinically meaningful outcomes. Obviously, there are still questions about the mechanism, condition and possibility underlying the occurrence of the abscopal effect. Can the abscopal effect truly change the future treatment strategy as the researchers expect? What are the current problems? This article reviewed the research in recent years to explore the progress and controversy surrounding the abscopal effect of radiation therapy.

Outcomes of Hypofractional Tomotherapy in Patients with Stage III Nonsmall Cell Lung Cancer Who Are Not Eligible for Surgery or Concurrent Chemoradiation

Purpose

We assessed the clinical outcomes and toxicities following hypofractionation with helical tomographic intensity-modulated radiotherapy technology (tomotherapy) in patients with stage III non-small cell lung cancer (NSCLC) who were not candidates for surgery or concurrent chemoradiation.

Methods

Forty-three patients with stage III NSCLC who were treated between 2011 and 2017 were enrolled. The prescription doses for gross target volume and clinical target volume were 70 Gy and 60 Gy (respectively) delivered in 15–25 fractions over 3–5 weeks.

Results

The median overall survival (OS) time was 34.23 (range 11.33–99.33) months. The estimated 1-, 2-, and 3-year OS rates were 97.7%, 74.4%, and 55.9%, respectively; the corresponding progression-free survival (PFS) rates were 79.1%, 53.5%, and 36.1%, respectively. The local disease recurrence, regional disease recurrence, and distant metastasis rates at 3 years were 4.7%, 11.62%, and 55.81%, respectively. On multivariate analysis, dose regimen (<19 f vs. ≥19 f) was an independent prognostic factor affecting OS, PFS, and DM (p < 0.05). Seven patients developed grade 1-2 acute radiation pneumonia (RP), 5 patients developed grade 1-2 late RP, while 3 patients developed grade 3 late RP. None of the patients developed grade 4-5 radiation lung injury.

Conclusion

Tomotherapy may be an effective treatment option for patients with stage III NSCLC. It may be a viable alternative to surgery with lower incidence of side effects.

Prognostic role of baseline neutrophil-to-lymphocyte ratio in metastatic solid tumors

High baseline neutrophil-to-lymphocyte ratio (NLR) has been associated with poor survival in a number of solid tumors, but has not been extensively investigated in the context of radiation oncology. Developing more robust models to predict survival would inform patient care for patients with metastatic solid tumors. The present study was undertaken to evaluate the effect of baseline NLR (using 4 as a cutoff) on survival in 320 consecutive patients with metastatic cancer who were referred to a single radiation oncologist between 2012 and 2015, with a median follow-up of 20.6 months. The median NLR was 4.4 (interquartile range, 2.8-7.2). Patients with a baseline NLR ≤4 had a median survival of 9.3 months compared to 4.1 months for NLR >4 (P<0.001). The number of active tumors, Eastern Cooperative Oncology Group performance status score, baseline albumin, primary tumor site, liver metastases and baseline NLR predicted overall survival on both univariate and multivariate analysis (P<0.05 for all). After adjusting for known prognostic factors for advanced solid tumors, baseline NLR >4 independently predicted adverse survival in this cohort.

Multiple Dynamics in Tumor Microenvironment Under Radiotherapy

The tumor microenvironment (TME) is an evolutionally low-level and embryonically featured tissue comprising heterogenic populations of malignant and stromal cells as well as noncellular components. Under radiotherapy (RT), the major modality for the treatment of malignant diseases [1], TME shows an adaptive response in multiple aspects that affect the efficacy of RT. With the potential clinical benefits, interests in RT combined with immunotherapy (IT) are intensified with a large scale of clinical trials underway for an array of cancer types. A better understanding of the multiple molecular aspects, especially the cross talks of RT-mediated energy reprogramming and immunoregulation in the irradiated TME (ITME), will be necessary for further enhancing the benefit of RT-IT modality. Coming studies should further reveal more mechanistic insights of radiation-induced instant or permanent consequence in tumor and stromal cells. Results from these studies will help to identify critical molecular pathways including cancer stem cell repopulation, metabolic rewiring, and specific communication between radioresistant cancer cells and the infiltrated immune active lymphocytes. In this chapter, we will focus on the following aspects: radiation-repopulated cancer stem cells (CSCs), hypoxia and re-oxygenation, reprogramming metabolism, and radiation-induced immune regulation, in which we summarize the current literature to illustrate an integrated image of the ITME. We hope that the contents in this chapter will be informative for physicians and translational researchers in cancer radiotherapy or immunotherapy.

[Oligorecurrent prostate cancer: current management and perspectives]

Oligometastatic prostate cancer (PCa) is an intense area of research thanks to the development of novel PET tracers such as ¹⁸F-choline or ⁶⁸Ga-PSMA. Several retrospective studies in patients with hormone-sensitive oligorecurrent PCa (usually up to 5 metastases with a controlled primary tumor) showed PSA response and a low toxicity profile of metastasis-directed therapies (MDT) such as Stereotactic Body Radiation Therapy (SBRT) or salvage lymph node dissection. More recently, randomized phase 2 studies showed that SBRT can delay the introduction of androgen deprivation, decrease biochemical relapses and increase overall survival. Regarding oligoprogressive metastatic castration-resistant PCa, limited data is however available. Based on these studies the European Association of Urology and the American Society of Radiotherapy EAU now recommend using MDT instead of observation. Several studies are undergoing in France and worldwide in order to confirm the exact role of MDT.

Stereotactic ablative radiotherapy for colorectal cancer liver metastasis

Survival improvement of colorectal liver metastasis (CRLM) benefits from systemic therapy and metastasis-directed local therapy. Stereotactic ablative body radiotherapy (SABR), as a new efficient metastasis-directed local therapy with a systematic impact, plays a vital role in CRLM multidisciplinary treatment. SABR leads to a dramatic immunological change in the tumor microenvironment (TME) via differential activation of cytoprotective and cytotoxic pathways in malignant and non-malignant cells, in addition to direct tumor cell death. The synergy of SABR and immunotherapy might increase the abscopal response rate of out-field lesions by targeting different steps of the immune-mediated response, in addition to direct intratumoral cell death. The clinical treatment and efficacy of SABR, its influence on TME, and potential molecular underpinnings of which are the topic of this review.

Intratumoral Immunotherapy for Early-stage Solid Tumors

The unprecedented benefits of immunotherapy in advanced malignancies have resulted in increased interests in exploiting immune stimulatory agents in earlier-stage solid tumors in the neoadjuvant setting. However, systemic delivery of immunotherapies may cause severe immune-related side-effects and hamper the development of combination treatments. Intratumoral delivery of neoadjuvant immunotherapy provides a promising strategy in harnessing the power of immunotherapy while minimizing off-target toxicities. The direct injection of immune stimulating agents into the tumor primes the local tumor-specific immunity to generate a systemic, durable clinical response. Intratumoral immunotherapy is a highly active area of investigation resulting in a plethora of agents, for example, immune receptor agonists, non-oncolytic and oncolytic viral therapies, being tested in preclinical and clinical settings. Currently, more than 20 neoadjuvant clinical trials exploring distinct intratumoral immune stimulatory agents and their combinations are ongoing. Practical considerations, including appropriate timing and optimal local delivery of immune stimulatory agents play an important role in safety and efficacy of this approach. Here, we discuss promising approaches in drug delivery technologies and opportunity for combining intratumoral immunotherapy with other cancer treatments and summarize the recent preclinical and clinical evidences that highlighted its promise as a part of routine oncologic care.

Mitigating Coronavirus-Induced Acute Respiratory Distress Syndrome by Radiotherapy

The acute respiratory distress syndrome (ARDS) induced by SARS-CoV-2-mediated cytokine storm (CS) in lungs leads to the high mortality in COVID-19 patients. To reduce ARDS, an ideal approach is to diminish virus loading by activating immune cells for CS prevention or to suppress the overactive cytokine-releasing immune cells for CS inhibition. Here, a potential radiation-mediated CS regulation is raised by reevaluating the radiation-mediated pneumonia control in the 1920s, with the following latent advantages of lung radiotherapy (LR) in treatment of COVID-19: (1) radiation accesses poorly circulated tissue more efficiently than blood-delivered medications; (2) low-dose radiation (LDR)-mediated metabolic rewiring and immune cell activation inhibit virus loading; (3) pre-consumption of immune reserves by LDR decreases CS severity; (4) higherdose radiation (HDR) within lung-tolerable doses relieves CS by eliminating in situ overactive cytokine-releasing cells. Thus, LDR and HDR or combined with antiviral and life-supporting modalities may mitigate SARS-CoV-2 and other virus-mediated ARDS.

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.

Radiotherapy and Immunotherapy for Cancer: From "Systemic" to "Multisite"

In the era of cancer immunotherapy, there is significant interest in combining conventional cancer therapies, such as radiotherapy, with drugs that stimulate the immune system. The observation that ionizing radiation applied to murine tumors delays the growth of distant tumors ("abscopal effect") and that this effect is potentiated by immunostimulatory drugs, led to clinical trials in which often only one lesion is irradiated in combination with immunotherapy drugs. The results of these initial clinical trials combining radio therapy and immunotherapy show that a meaningful abscopal effect is still infrequent. Recent preclinical data suggest that preexistent intratumoral T cells can survive radiation and contribute to its therapeutic effect. In this review, we discuss possible mechanisms underlying the preclinical/clinical discrepancies regarding the abscopal effect, and we propose the irradiation of multiple or all tumor sites in combination with systemic immunotherapy as a possible avenue to increase the efficacy of radio-immunotherapy.

Integrating Loco-Regional Hyperthermia Into the Current Oncology Practice: SWOT and TOWS Analyses

Moderate hyperthermia at temperatures between 40 and 44°C is a multifaceted therapeutic modality. It is a potent radiosensitizer, interacts favorably with a host of chemotherapeutic agents, and, in combination with radiotherapy, enforces immunomodulation akin to “in situ tumor vaccination.” By sensitizing hypoxic tumor cells and inhibiting repair of radiotherapy-induced DNA damage, the properties of hyperthermia delivered together with photons might provide a tumor-selective therapeutic advantage analogous to high linear energy transfer (LET) neutrons, but with less normal tissue toxicity. Furthermore, the high LET attributes of hyperthermia thermoradiobiologically are likely to enhance low LET protons; thus, proton thermoradiotherapy would mimic ¹²C ion therapy. Hyperthermia with radiotherapy and/or chemotherapy substantially improves therapeutic outcomes without enhancing normal tissue morbidities, yielding level I evidence reported in several randomized clinical trials, systematic reviews, and meta-analyses for various tumor sites. Technological advancements in hyperthermia delivery, advancements in hyperthermia treatment planning, online invasive and non-invasive MR-guided thermometry, and adherence to quality assurance guidelines have ensured safe and effective delivery of hyperthermia to the target region. Novel biological modeling permits integration of hyperthermia and radiotherapy treatment plans. Further, hyperthermia along with immune checkpoint inhibitors and DNA damage repair inhibitors could further augment the therapeutic efficacy resulting in synthetic lethality. Additionally, hyperthermia induced by magnetic nanoparticles coupled to selective payloads, namely, tumor-specific radiotheranostics (for both tumor imaging and radionuclide therapy), chemotherapeutic drugs, immunotherapeutic agents, and gene silencing, could provide a comprehensive tumor-specific theranostic modality akin to “magic (nano)bullets.” To get a realistic overview of the strength (S), weakness (W), opportunities (O), and threats (T) of hyperthermia, a SWOT analysis has been undertaken. Additionally, a TOWS analysis categorizes future strategies to facilitate further integration of hyperthermia with the current treatment modalities. These could gainfully accomplish a safe, versatile, and cost-effective enhancement of the existing therapeutic armamentarium to improve outcomes in clinical oncology.

Molecular Aspects and Future Perspectives of Cytokine-Based Anti-cancer Immunotherapy

Cytokine-based immunotherapy is a promising field in the cancer treatment, since cytokines, as proteins of the immune system, are able to modulate the host immune response toward cancer cell, as well as directly induce tumor cell death. Since a low dose monotherapy with some cytokines has no significant therapeutic results and a high dose treatment leads to a number of side effects caused by the pleiotropic effect of cytokines, the problem of understanding the influence of cytokines on the immune cells involved in the pro- and anti-tumor immune response remains a pressing one. Immune system cells carry CD makers on their surface which can be used to identify various populations of cells of the immune system that play different roles in pro- and anti-tumor immune responses. This review discusses the functions and specific CD markers of various immune cell populations which are reported to participate in the regulation of the immune response against the tumor. The results of research studies and clinical trials investigating the effect of cytokine therapy on the regulation of immune cell populations and their surface markers are also discussed. Current trends in the development of cancer immunotherapy, as well as the role of cytokines in combination with other therapeutic agents, are also discussed.

Nanoparticle delivery of immunostimulatory oligonucleotides enhances response to checkpoint inhibitor therapeutics

Checkpoint inhibitor (CPI) immunotherapies have revolutionized the treatment of a wide array of cancers, but their utility remains limited to a subset of patients with favorable disease phenotypes. We show that the generation of peptide-based nanocomplexes carrying immunostimulatory oligonucleotides dramatically increases the potency of certain of these compounds to stimulate toll-like receptor signaling. The administration of immunostimulatory nanocomplexes carrying CpG oligonucleotides generates antitumor effects and enhances the efficacy of checkpoint inhibitor antibody therapy in mouse models of cancer, and the nanocomplex formulation enables drastic reductions in the dose required to generate therapeutic effects.

The recent advent of immune checkpoint inhibitor (CPI) antibodies has revolutionized many aspects of cancer therapy, but the efficacy of these breakthrough therapeutics remains limited, as many patients fail to respond for reasons that still largely evade understanding. An array of studies in human patients and animal models has demonstrated that local signaling can generate strongly immunosuppressive microenvironments within tumors, and emerging evidence suggests that delivery of immunostimulatory molecules into tumors can have therapeutic effects. Nanoparticle formulations of these cargoes offer a promising way to maximize their delivery and to enhance the efficacy of checkpoint inhibitors. We developed a modular nanoparticle system capable of encapsulating an array of immunostimulatory oligonucleotides that, in some cases, greatly increase their potency to activate inflammatory signaling within immune cells in vitro. We hypothesized that these immunostimulatory nanoparticles could suppress tumor growth by activating similar signaling in vivo, and thereby also improve responsiveness to immune checkpoint inhibitor antibody therapies. We found that our engineered nanoparticles carrying a CpG DNA ligand of TLR9 can suppress tumor growth in several animal models of various cancers, resulting in an abscopal effect on distant tumors, and improving responsiveness to anti-CTLA4 treatment with combinatorial effects after intratumoral administration. Moreover, by incorporating tumor-homing peptides, immunostimulatory nucleotide-bearing nanoparticles facilitate antitumor efficacy after systemic intravenous (i.v.) administration.

Methodological Development of Combination Drug and Radiotherapy in Basic and Clinical Research

Newer technical improvements in radiation oncology have been rapidly implemented in recent decades, allowing an improved therapeutic ratio. The development of strategies using local and systemic treatments concurrently, mainly targeted therapies, has however plateaued. Targeted molecular compounds and immunotherapy are increasingly being incorporated as the new standard of care for a wide array of cancers. A better understanding of possible prior methodology issues is therefore required and should be integrated into upcoming early clinical trials including individualized radiotherapy-drug combinations. The outcome of clinical trials is influenced by the validity of the preclinical proofs of concept, the impact on normal tissue, the robustness of biomarkers and the quality of the delivery of radiation. Herein, key methodological aspects are discussed with the aim of optimizing the design and implementation of future precision drug-radiotherapy trials.

PD-1/PD-L1 Blockers in NSCLC Brain Metastases: Challenging Paradigms and Clinical Practice

Immune checkpoint inhibitors (ICI) have revolutionized the management of advanced non-small cell lung cancer (NSCLC). However, most pivotal phase III trials systematically excluded patients with active brain metastases, precluding the generalization of the results. Although theoretically restricted from crossing the blood-brain barrier, the novel pharmacokinetic/pharmacodynamic profiles of anti-PD-1/PD-L1 drugs have prompted studies to evaluate their activity in patients with NSCLC with active central nervous system (CNS) involvement. Encouraging results have suggested that ICI could be active in the CNS in selected patients with driver-negative advanced NSCLC with high PD-L1 expression and low CNS disease burden. Single-agent CNS response rates around 30% have been reported. Beyond this particular setting, anti-PD-1/PD-L1 antibodies have been evaluated in patients receiving local therapy for brain metastases (BM), addressing concerns about potential neurologic toxicity risks associated with radiotherapy, more specifically, radionecrosis (RN). Accordingly, a variety of clinical and imaging strategies are being appropriately developed to evaluate tumor response and to rule out pseudoprogression or radionecrosis. Our purpose is to critically summarize the advances regarding the role of systemic anti-PD-1/PD-L1 antibodies for the treatment of NSCLC BM. Data were collected from the PubMed database, reference lists, and abstracts from the latest scientific meetings. Recent reports suggest anti-PD-1/PD-L1 agents are active in a subset of patients with NSCLC with BM showing acceptable toxicity. These advances are expected to change soon the management of these patients but additional research is required to address concerns regarding radionecrosis and the appropriate sequencing of local and systemic therapy combinations.