The Role of Radiation Oncology in Immuno-Oncology

PC4 Potentially Predicts Chemoradiation-Induced Antitumor Immunity in Esophageal Squamous Cell Carcinoma

Chemoradiotherapy (CRT) induces an antitumor immune response in esophageal squamous cell carcinoma (ESCC), and thereby has enormous potential by itself and in combination with immune checkpoint inhibitors (ICI). Our previous studies indicated that human positive cofactor 4 (PC4) was an independent predictor of poor survival in patients with ESCC or lung cancer who were treated with definitive chemoradiation, with a mechanism involving the enhancement of nonhomologous end joining (NHEJ)-mediated DNA repair. Due to the important role of double-strand DNA (dsDNA) in the antitumor immune response, the present study aims to investigate PC4 as a predictor of pathological response and antitumor immune response in ESCC patients who underwent neoadjuvant CRT. In ESCC, low PC4 expression levels have significant power to predict pCR. In particular, pCR is 61.2% in patients with low PC4 expression, but only 23.4% in patients with high PC4. Both disease-free survival (DFS) and overall survival (OS) are significantly longer for patients with low PC4 than for those with high PC4. In agreement with our previous finding that PC4 participates in NHEJ-mediated DNA repair, our further analysis indicates that the expression of PC4 is not only significantly negatively correlated with cyto-free dsDNA in postoperative specimens, but also with tumor-infiltrating CD8+T lymphocytes (CD8+TILs) and GZMB+CD8+TILs, suggesting a possible mechanism that high PC4 negatively regulates the antitumor response and therefore results in poor prognosis. Together, our findings demonstrate that low expression of PC4 is a potential biomarker for predicting the antitumor immune response to chemoradiation in patients with operable locally advanced ESCC.

The impact of EGFR mutation and PD-L1 status on the efficacy of postoperative radiotherapy in stage III-pN2 NSCLC

BACKGROUND

The role of postoperative radiotherapy (PORT) for patients with completely resected stage III-pN2 non-small-cell lung cancer (NSCLC) remains controversial. PORT is not routinely recommended for patients with completely resected stage III-pN2 NSCLC. Therefore, identifying the population that could benefit from PORT is urgently needed.

METHODS

We retrospectively enrolled 251 patients with completely resected stage III-pN2 NSCLC at our institution between 2018 and 2023. The Kaplan-Meier curves and log-rank tests were used to analyze disease-free survival (DFS) and overall survival (OS). Risk factors were identified using univariate and multivariate Cox regression analyses. The cumulative incidence rates of locoregional recurrence (LRR) were calculated via competing risk analyses and compared using the Gray test.

RESULTS

A total of 251 patients were enrolled in the study, with the median follow-up of 24.9 months. Among overall patients, 61 patients underwent PORT, and 190 patients did not. Although patients in the PORT group exhibited a trend toward longer DFS, the difference was not statistically significant (median DFS: 39.1 vs. 35.5 months; HR 0.58, 95% CI 0.35-0.97; p = 0.072). Subgroup analyses revealed that PORT significantly prolonged DFS both in EGFR wild-type patients (median DFS: 35.3 vs. 18.3 months; HR 0.33, 95% CI 0.17-0.62; p = 0.002) and in PD-L1 positive patients (median DFS: 35.3 vs.16.4 months; HR 0.35, 95% CI 0.16-0.74; p = 0.029). In contrast, no significant DFS or OS benefits were observed in EGFR mutant patients or PD-L1 negative patients. Furthermore, PORT was associated with the significantly lower risk of LRR in overall patients (HR 0.39, 95% CI 0.16-0.97; p = 0.043), EGFR wild-type patients (HR 0.25, 95% CI 0.09-0.68; p = 0.007), and PD-L1 positive patients (HR 0.15, 95% CI 0.03-0.70; p = 0.016). PORT did not confer a locoregional control benefit in EGFR mutant patients (HR 0.58, 95% CI 0.07-4.58; p = 0.61) or PD-L1 negative patients (HR 1.02, 95% CI 0.27-3.82; p = 0.98).

CONCLUSION

For patients with completely resected stage III-pN2 NSCLC, PORT significantly improves DFS and reduces the risk of LRR in EGFR wild-type patients or PD-L1 positive patients. The EGFR and PD-L1 status may serve as biomarkers to identify the population that could benefit from PORT.

Tislelizumab plus concurrent chemoradiotherapy versus concurrent chemoradiotherapy for elderly patients with inoperable locally advanced esophageal squamous cell carcinoma: a multicenter, randomized, parallel-controlled, phase II clinical trial

BACKGROUND

The standard treatment for elderly patients with unresectable locally advanced esophageal squamous cell carcinoma (ESCC) is definitive chemoradiotherapy with S-1. However, the 3-year overall survival (OS) is limited to approximately 40%. Tislelizumab is the first- and second-line standard treatment for advanced ESCC with tolerable toxicity. In this study, we aimed to explore a new curative strategy for locally advanced unresectable ESCC in the elderly by combining tislelizumab with chemoradiotherapy.

METHODS

This study is an open-label, multicenter, investigator-initiated phase II clinical trial in older patients with inoperable locally advanced ESCC evaluating tislelizumab plus concurrent chemoradiotherapy compared with concurrent chemoradiotherapy. The main inclusion criteria were pathological confirmation of locally advanced inoperable ESCC at clinical cT1N2-3M0 or cT2-4bN0-3M0 (stage II-IVA), age ≥ 70 years, absence of previous systemic anti-tumor therapy, and adequate organ function. A total of 136 patients will be recruited from approximately seven centers (in Tianjin, Chengdu, Taiyuan, Zhengzhou, Shijiazhuang, Changsha, Nanjing) over a period of 18 months and randomized in a 1:1 ratio to receive tislelizumab in combination with concurrent chemoradiotherapy (tislelizumab + S-1 + radiotherapy) or concurrent chemoradiotherapy (S-1 + radiotherapy). The efficacy and safety of the treatment will be evaluated during the therapy and follow-up period until disease progression, death, or the end of the trial. The primary study endpoint was investigator-assessed progression-free survival (PFS), and secondary study endpoints were OS, objective response rate (ORR), duration of remission (DOR), and safety. Fresh or archival tumor tissues and peripheral blood samples will be used in exploratory studies.

DISCUSSION

This study is the first "programmed death-1 (PD-1) inhibitor combined with concurrent chemoradiotherapy" for elderly patients with inoperable locally advanced ESCC (NCT06061146). The synergistic efficacy of combined definitive concurrent chemoradiotherapy with tislelizumab is expected to result in survival benefits for elderly patients with inoperable locally advanced ESCC. Because S-1 plus concurrent radiotherapy is the standard treatment option for locally advanced ESCC in older patients, the combination of definitive concurrent chemoradiotherapy and tislelizumab has the potential to change the standard ESCC therapeutic strategy with comparable safety.

TRIAL REGISTRATION

ClinicalTrials.gov NCT06061146.Registered 9/10/2023.

Immunotherapy in the Battle Against Bone Metastases: Mechanisms and Emerging Treatments

Bone metastases are a prevalent complication in advanced cancers, particularly in breast, prostate, and lung cancers, and are associated with severe skeletal-related events (SREs), including fractures, spinal cord compression, and debilitating pain. Conventional bone-targeted treatments like bisphosphonates and RANKL inhibitors (denosumab) reduce osteoclast-mediated bone resorption but do not directly impact tumor progression within the bone. This review focuses on examining the growing potential of immunotherapy in targeting the unique challenges posed by bone metastases. Even though immune checkpoint inhibitors (ICIs) have significantly changed cancer treatment, their impact on bone metastases appears limited because of the bone microenvironment's immunosuppressive traits, which include high levels of transforming growth factor-beta (TGFβ) and the immune-suppressing cells, such as regulatory T cells (Tregs) and myeloid-derived suppressor cells (MDSCs). This review underscores the investigation of combined therapeutic approaches that might ease these difficulties, such as the synergy of immune checkpoint inhibitors with agents aimed at bones (denosumab, bisphosphonates), chemotherapy, and radiotherapy, as well as the combination of immune checkpoint inhibitors with different immunotherapeutic methods, including CAR T-cell therapy. This review provides a comprehensive analysis of preclinical studies and clinical trials that show the synergistic potential of these combination approaches, which aim to both enhance immune responses and mitigate bone destruction. By offering an in-depth exploration of how these strategies can be tailored to the bone microenvironment, this review underscores the need for personalized treatment approaches. The findings emphasize the urgent need for further research into overcoming immune evasion in bone metastases, with the goal of improving patient survival and quality of life.

The efficacy of postoperative radiotherapy in resected pⅢA-N2 EGFR mutant and wild-type lung adenocarcinoma

The resected pⅢA-N2 non-small-cell lung cancer (NSCLC) patients who could benefit from postoperative radiotherapy (PORT) are not well-defined. The study explored the role of PORT on EGFR mutant and wild-type NSCLC patients. We retrospectively searched for resected pIIIA-N2 lung adenocarcinoma patients who underwent EGFR mutation testing. 80 patients with EGFR wild-type and 85 patients with EGFR mutation were included. 62 patients received PORT. In overall population, the median disease-free survival (DFS) was improved in PORT arm compared to non-PORT arm (22.9 vs. 16.1 months; p = 0.036), along with higher 2-year locoregional recurrence-free survival (LRFS) rate (88.3% vs. 69.3%; p = 0.004). In EGFR wild-type patients, PORT was associated with a longer median DFS (23.3 vs. 17.2 months; p = 0.044), and a higher 2-year LRFS rate (86.8% vs. 61.9%; p = 0.012). In EGFR mutant patients, PORT was not significantly correlated with improved survival outcomes. EGFR wild-type may a biomarker to identify the cohort that benefits from PORT.

Ionizing Radiation Reduces Head and Neck Squamous Cell Carcinoma Cell Viability and Is Associated with Predictive Tumor-Specific T Cell Responses

Head and neck squamous cell carcinoma (HNSCC) is common and deadly, and there is a need for improved strategies to predict treatment responses. Ionizing radiation (IR) has been demonstrated to improve HNSCC outcomes, but its effects on immune responses are not well characterized. We determined the impact of IR on T cell immune responses ex vivo. Human and mouse HNSCC cells were exposed to IR ranging from 20 to 200 Gy to determine cell viability and the ability to stimulate T-cell-specific responses. Lymph node cells of LY2 and MOC2 tumor-bearing or non-tumor-bearing mice were re-stimulated with a tumor antigen derived from LY2 or MOC2 cells treated with 200 Gy IR, ultraviolet (UV) exposure, or freeze/thaw cycle treatments. T cell proliferation and cytokine production were compared to T cells restimulated with plate-bound CD3 and CD28 antibodies. Human and mouse HNSCC cells showed reduced viability in response to ionizing radiation in a dose-dependent manner, and induced expression of T cell chemotactic cytokines. Tumor antigens derived from IR-treated LY2 and MOC2 cells induced greater proliferation of lymph node cells from tumor-bearing mice and induced unique T cell cytokine expression profiles. Our results demonstrate that IR induces potent tumoral immune responses, and IR-generated tumor antigens can potentially serve as an indicator of antitumor immune responses to HNSCC in ex vivo T cell restimulation assays.

Stereotactic Ablative Radiation for Systemic Therapy-naïve Oligometastatic Kidney Cancer

BACKGROUND

Evidence-based guidelines for the management of systemic therapy-naïve oligometastatic renal cell carcinoma (RCC) are lacking.

OBJECTIVE

To evaluate the potential of stereotactic ablative radiotherapy (SAbR) to provide longitudinal disease control while preserving quality of life (QOL) in patients with systemic therapy-naïve oligometastatic RCC.

DESIGN, SETTING, AND PARTICIPANTS

RCC patients with three or fewer extracranial metastases were eligible. SAbR was administered longitudinally to all upfront and, as applicable, subsequent metastases.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

This prospective phase II single-arm trial was powered to achieve a primary objective of freedom from systemic therapy for >1 yr in >60% of patients (using the Clopper and Pearson methodology). Secondary endpoints included progression-free survival (PFS), defined as the time from first SAbR to progression not amenable to SAbR (local failure at SAbR-treated sites, new metastases not amenable to SAbR, more than three new metastases, or brain metastases); patient-reported QOL metrics; local control (LC) rates; toxicity; cancer-specific survival (CSS); and overall survival (OS).

RESULTS AND LIMITATIONS

Twenty-three patients received SAbR to 33 initial and 57 total sites. The median follow-up was 21.7 mo (interquartile range 16.3-30.3). Exceeding the prespecified 60% benchmark, freedom from systemic therapy at 1 yr was 91.3% (95% confidence interval [CI]: 69.5, 97.8). One-year PFS was 82.6% (95% CI: 60.1, 93.1). QOL was largely unaffected. LC was 100%. There were no grade 3/4 toxicities, but there was one death due to immune-related colitis 3 mo after SAbR while on subsequent checkpoint inhibitor therapy, where a SAbR contribution could not be excluded. One-year OS was 95.7% (95% CI: 72.9, 99.4); one-year CSS was 100%.

CONCLUSIONS

SAbR for oligometastatic RCC was associated with meaningful longitudinal disease control while preserving QOL. These data support further evaluation of SAbR for systemic therapy-naïve oligometastatic RCC.

PATIENT SUMMARY

Sequential stereotactic radiation therapy can safely and effectively control metastatic kidney cancer with limited spread for over a year without compromising patients' quality of life.

The Emerging Role of Radiation Therapy in Renal Cell Carcinoma

Advancements in radiation delivery technology have made it feasible to treat tumors with ablative radiation doses via stereotactic ablative radiation therapy (SAbR) at locations that were previously not possible. Renal cell cancer (RCC) was initially thought to be radioresistant, even considered toxic, in the era of conventional protracted course radiation. However, SAbR has been demonstrated to be safe and effective in providing local control to both primary and metastatic RCC by using ablative radiation doses. SAbR can be integrated with other local and systemic therapies to provide optimal management of RCC patients. We will discuss the rationale and available evidence for the integration and sequencing of SAbR with local and systemic therapies for RCC.

Phase II Trial of Stereotactic Ablative Radiation for Oligoprogressive Metastatic Kidney Cancer

BACKGROUND

Patients with metastatic renal cell carcinoma (mRCC) treated with systemic therapy sometimes progress at limited sites.The best treatment approach for patients with oligoprogression remains unclear.

OBJECTIVE

To determine the ability of stereotactic ablative radiation (SAbR) to extend ongoing systemic therapy in mRCC patients with oligoprogression.

DESIGN, SETTING, AND PARTICIPANTS

A single-arm phase II clinical trial was conducted at a university medical center and county hospital, including 20 patients with mRCC on first- to fourth-line systemic therapy with three or fewer sites of progression (including new sites) involving ≤30% of all sites.

INTERVENTION

SAbR to oligoprogressing metastases at outset and longitudinally, while radiated sites remain controlled and overall disease oligoprogressive.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The primary objective was to extend ongoing systemic therapy by >6 mo in >40% of patients. Secondary endpoints included overall survival, toxicity, and patient-reported quality of life.

RESULTS AND LIMITATIONS

Twenty patients were enrolled. Upfront and sequential SAbR was administered to a total of 37 sites. The local control rate was 100%. At a median follow-up of 10.4 mo (interquartile range: 5.8-16.4), SAbR extended the duration of the ongoing systemic therapy by >6 mo in 14 patients (70%, 95% confidence interval [CI]: 49.9-90.1). The median time from SAbR to the onset of new systemic therapy or death was 11.1 mo (95% CI: 4.5-19.3). The median duration of SAbR-aided systemic therapy was 24.4 mo (95% CI: 15.3-42.2). Median overall survival was not reached. One patient developed grade 3 gastrointestinal toxicity possibly related to treatment. There was no significant decline in quality of life. Limitations include nonrandomized design and a small patient cohort.

CONCLUSIONS

SAbR extended the duration of the ongoing systemic therapy for patients with oligoprogressive mRCC without undermining quality of life. These data support the evaluation of SAbR for oligoprogressive mRCC in a prospective randomized clinical trial.

PATIENT SUMMARY

Patients with metastatic kidney cancer on systemic therapy but progressing at limited sites may benefit from focused radiation to progressive sites. Focused radiation was safe and effective, and extended the duration of the ongoing systemic therapy.

Introduction to novel developments in radio-imaging and radiotherapy

Radiation therapy has long been known to be a very effective form of therapy in relieving symptoms and prolonging the life of patients with brain metastases. Novel developments in this field have allowed oncologists to improve on older forms of radiation therapy; these recent advances in radiotherapeutic techniques (stereotactic radiosurgery and hippocampal-avoidant whole brain radiation therapy) allow sparing of the healthy brain from receiving unnecessary radiation while delivering effective treatment to the metastases, thus improving the quality of life for surviving patients. Furthermore, multiple clinical trials have documented the increased loco-regional control in the brain when radiosurgery is interdigitated with immune check point inhibitors for treatment of melanoma brain metastases. Mild hyperthermia has been used for decades as an adjuvant to radiotherapy in the treatment of radiation resistant cancers; lately, however, thermal therapies, such as hyperthermia, cryoablation, radiofrequency ablation and high intensity focused ultrasound are being investigated to provide a new ablative approach to cancer while thermoacoustic imaging and thermometry have recently been proposed as new techniques for monitoring tissue temperature in the breast during ablation treatment. In addition, other hybrid techniques have emerged that combine ultrasounds with other forms of energy such as light to provide a more accurate diagnosis and enhance the efficacy of therapy for early and late stage cancers.

Immunotherapy combined with high- and low-dose radiation to all sites leads to complete clearance of disease in a patient with metastatic vaginal melanoma

A 73-year-old woman with metastatic vaginal mucosal melanoma that had progressed on ipilimumab and nivolumab experienced clinical and radiographic complete response to dual checkpoint inhibitor immunotherapy given in combination with high-dose plus low-dose radiation. General characteristics and treatment options in this disease are highlighted.

Combination of Immune Checkpoint Inhibitors and Radiotherapy for Advanced Non-Small-Cell Lung Cancer and Prostate Cancer: A Meta-Analysis

Objectives

Immune checkpoint inhibitors (ICI) combined with radiotherapy (RT) have emerged as a breakthrough therapy in the treatment of various cancers. The combination has a strong rationale, but data on their efficacy and safety are still limited. Hence, we comprehensively searched the database and performed this study to elucidate the clinical manifestations of this combined strategy.

Methods

We performed a meta-analysis of randomized trials that compared ICI plus RT with placebo plus RT or ICI alone for the treatment of advanced nonsmall-cell lung cancer (NSCLC) and prostate cancer. The outcomes included overall survival (OS), progression-free survival (PFS), disease control rate (DCR), and treatment-related adverse events. A fixed-effects or random-effects model was adopted depending on between-study heterogeneity.

Results

Three trials involving 1584 patients were included. ICI plus RT was significantly associated with improvement of OS (hazard ratio [HR] = 0.81, 95% confidence interval [CI] = 0.70–0.94, P=0.004), PFS (HR = 0.64; 95% CI 0.56–0.72, P < 0.00001), and DCR (relative risk [RR] = 1.38; 95% CI 1.03–1.84, P=0.03). A significant predictor for PFS with the combination of ICI and RT was age, as a significant improvement in PFS (HR = 0.49; 95% CI 0.37–0.64, P < 0.00001) was observed in NSCLC patients aged under 65 years. In safety analyses, patients receiving ICI plus RT had a significantly higher incidence of dyspnea (RR = 2.43; 95% CI 1.16–5.08, P=0.02) and pneumonitis of grade 3 or higher (RR = 2.78; 95% CI 1.32–5.85, P=0.007).

Conclusion

The combination of ICI and RT was associated with improved OS, PFS, and DCR. Patients under 65 years will be the dominant beneficiaries. However, the incidence of dyspnea and pneumonia of grade 3 or higher also increased, which deserves our vigilance.

Clinical significance of BIM deletion polymorphism in chemoradiotherapy for non-small cell lung cancer

The standard treatment for locally advanced non‐small cell lung cancer (NSCLC) is chemoradiotherapy (CRT) followed by anti‐programmed cell death‐ligand 1 (anti‐PD‐L1) treatment. BIM deletion polymorphism induces the suppression of apoptosis resulting from epidermal growth factor (EGFR)‐tyrosine kinase inhibitors in EGFR‐mutated NSCLC patients. We aimed to examine the effects of BIM polymorphism on CRT and anti‐PD‐L1/PD‐1 treatment in NSCLC patients. In this retrospective study of 1312 patients with unresectable NSCLC treated at Higashi‐Hiroshima Medical Center and Hiroshima University Hospital between April 1994 and October 2019, we enrolled those who underwent CRT or chemotherapy using carboplatin + paclitaxel or cisplatin + vinorelbine, or anti‐PD‐L1/PD‐1 treatment. Of 1312 patients, 88, 80, and 74 underwent CRT, chemotherapy, and anti‐PD‐L1/PD‐1 treatment, respectively, and 17.0%, 15.2% and 17.6% of these patients showed BIM polymorphism. Among patients receiving CRT, the progression‐free survival was significantly shorter in those with BIM deletion than in those without. In the multivariate analyses, BIM polymorphism was an independent factor of poor anti‐tumor effects. These results were not observed in the chemotherapy and anti‐PD‐L1/PD‐1 treatment groups. In in vitro experiments, BIM expression suppression using small interfering RNA in NSCLC cell lines showed a significantly suppressed anti‐tumor effect and apoptosis after irradiation but not chemotherapy. In conclusion, we showed that BIM polymorphism was a poor‐predictive factor for anti‐tumor effects in NSCLC patients who underwent CRT, specifically radiotherapy. In the implementation of CRT in patients with BIM polymorphism, we should consider subsequent treatment, keeping in mind that CRT may be insufficient.

Radiotherapy for non-small cell lung cancer in the immunotherapy era: the opportunity and challenge-a narrative review

Immunotherapy has radically changed the clinical management of patients with cancer in recent years. Immune checkpoint inhibitors (ICIs) reversing the immunosuppressive effects of the tumor microenvironment are one type of immunotherapy, several of which are approved by the US Food and Drug Administration (FDA) as first-line treatments for patients with non-small cell lung cancer (NSCLC). However, response rates to ICIs are around 19-47% among patients with advanced NSCLC. As a result, the development of combined ICI and radiotherapy has begun with the aim of strengthening patients' antitumor immunity. Radiotherapy with substantial technological improvements not only achieves local tumor control through the induction of deoxyribonucleic acid (DNA) damage in irradiated regions, but also has the potential to mediate immunostimulatory effects that could result in tumor regression beyond irradiated regions. At present, numerous preclinical and clinical research are investigating the efficiency and safety of combining ICI with radiotherapy. The PACIFIC trial showed that combining chemoradiotherapy with ICI could improve clinical outcomes. In this review, we summarize the rationale for combining radiotherapy with immunotherapy. We also discuss the opportunities and challenges of combination therapy, including the timing of radiotherapy, optimal dose and fractionations, radiotherapy target and target volume, acquired resistance, patient selection, and radioimmunotherapy toxicity.

The Association of the Sequence of Immunotherapy With the Survival of Unresectable Pancreatic Adenocarcinoma Patients: A Retrospective Analysis of the National Cancer Database

Background: Immunotherapy has shown great success in various malignancies. However, its efficacy in pancreatic ductal adenocarcinoma (PDAC) remains a challenge, and the lack of understanding about the appropriate timing of immunotherapy with other standard-of-care cancer treatments may be one of the causes. The objective of the current study is to investigate the impact of the timing of immunotherapy with chemotherapy and radiation therapy (RT) on the overall survival (OS) of PDAC patients who did not receive surgical resection of the pancreatic tumor.

Materials and Methods: Patients with pancreatic adenocarcinoma who did not receive surgical resection of the pancreatic tumor were identified from the National Cancer Database (NCDB). Cox proportional hazard models were employed to compare the OS between patients who received immunotherapy with chemotherapy or RT with a different sequence of treatment. The multivariable analysis was adjusted for age of diagnosis, race, sex, place of living, income, education, treatment facility type, insurance status, and year of diagnosis.

Results: In total, 705 patients received chemotherapy and immunotherapy, while 226 received radiation therapy and immunotherapy. In the multivariable analysis, there was no significant difference in the OS of patients who started immunotherapy 31–90 days before the start of chemotherapy with a hazard ratio (HR) of [HR:1.057 (CI: 0.716–1.56; p < 0.781)] and patients who started immunotherapy 91–180 days before the start of chemotherapy [HR: 0.900 (CI: 0.584–1.388; p < 0.635)] compared to patients who started chemotherapy and immunotherapy within 30 days of each other. There was also no significant difference in the OS of patients who started RT> 30 days before the start of immunotherapy [HR: 0.636 (CI: 0.346–1.171; p < 0.146)] and patients who started immunotherapy > 30 days before the start of RT [HR: 0.660 (CI: 0.328–1.329; p < 0.246)] compared to patients who started RT and immunotherapy within 30 days of each other.

Conclusion: The sequence of immunotherapy with chemotherapy or RT was not associated with improved OS. Future studies with a larger subgroup sample size investigating the impact of the timing of immunotherapy with chemotherapy and RT on the OS of PDAC patients who do not receive surgical resection of the pancreatic tumor are needed.

Combining PD-1 Inhibitor Nivolumab with Radiotherapy Successfully Treated a Patient with Refractory Primary Mediastinal Large B-Cell Lymphoma: A Case Report and Literature Review

Primary mediastinal large B-cell lymphoma (PMBCL) is relatively infrequent and generally has a good prognosis with standard immunochemotherapy. However, treatment options are limited for patients with relapsed/refractory PMBCL who are ineligible for stem cell transplantation. In this report, we treated a refractory PMBCL patient, who did not respond to salvage chemotherapy, with combined nivolumab and radiotherapy. The patient achieved a complete remission with mild adverse reactions and has survived without relapse 2 years after treatment.

The future of cancer immunotherapy: microenvironment-targeting combinations

Immunotherapy holds the potential to induce durable responses, but only a minority of patients currently respond. The etiologies of primary and secondary resistance to immunotherapy are multifaceted, deriving not only from tumor intrinsic factors, but also from the complex interplay between cancer and its microenvironment. In addressing frontiers in clinical immunotherapy, we describe two categories of approaches to the design of novel drugs and combination therapies: the first involves direct modification of the tumor, while the second indirectly enhances immunogenicity through alteration of the microenvironment. By systematically addressing the factors that mediate resistance, we are able to identify mechanistically-driven novel approaches to improve immunotherapy outcomes.

Single Radiotherapy Fraction with Local Anti-CD40 Therapy Generates Effective Abscopal Responses in Mouse Models of Cervical Cancer

Current treatment options for advanced cervical cancer are limited, especially for patients in poor-resource settings, with a 17% 5-year overall survival rate. Here, we report results in animal models of advanced cervical cancer, showing that anti-CD40 therapy can effectively boost the abscopal effect, whereby radiotherapy of a tumor at one site can engender therapeutically significant responses in tumors at distant untreated sites. In this study, two subcutaneous cervical cancer tumors representing one primary and one metastatic tumor were generated in each animal. Only the primary tumor was treated and the responses of both tumors were monitored. The study was repeated as a function of different treatment parameters, including radiotherapy dose and dosing schedule of immunoadjuvant anti-CD40. The results consistently suggest that one fraction dose of radiotherapy with a single dose of agonistic anti-CD40 can generate highly effective abscopal responses, with a significant increase in animal survival (p = 0.0004). Overall, 60% of the mice treated with this combination showed long term survival with complete tumor regression, where tumors of mice in other cohorts continued to grow. Moreover, re-challenged responders to the treatment developed vitiligo, suggesting developed immune memory for this cancer. The findings offer a potential new therapy approach, which could be further investigated and developed for the treatment of advanced cervical cancer, with major potential impact, especially in resource-poor settings.

Sublethal Radiation Affects Antigen Processing and Presentation Genes to Enhance Immunogenicity of Cancer Cells

While immunotherapy in cancer is designed to stimulate effector T cell response, tumor-associated antigens have to be presented on malignant cells at a sufficient level for recognition of cancer by T cells. Recent studies suggest that radiotherapy enhances the anti-cancer immune response and also improves the efficacy of immunotherapy. To understand the molecular basis of such observations, we examined the effect of ionizing X-rays on tumor antigens and their presentation in a set of nine human cell lines representing cancers of the esophagus, lung, and head and neck. A single dose of 7.5 or 15 Gy radiation enhanced the New York esophageal squamous cell carcinoma 1 (NY-ESO-1) tumor-antigen-mediated recognition of cancer cells by NY-ESO-1-specific CD8+ T cells. Irradiation led to significant enlargement of live cells after four days, and microscopy and flow cytometry revealed multinucleation and polyploidy in the cells because of dysregulated mitosis, which was also revealed in RNA-sequencing-based transcriptome profiles of cells. Transcriptome analyses also showed that while radiation had no universal effect on genes encoding tumor antigens, it upregulated the expression of numerous genes involved in antigen processing and presentation pathways in all cell lines. This effect may explain the immunostimulatory role of cancer radiotherapy.

Abscopal effect of high-dose-rate brachytherapy on pelvic bone metastases from renal cell carcinoma: a case report

Radiation therapy is considered an optimal partner for immunotherapies. Several pre-clinical studies have demonstrated that regression of distant metastases, at remote non-irradiated sites of the body, termed the “abscopal effect”, can be achieved by an appropriate timing and combination of radiation with immunotherapy. However, nearly all pre-clinical and clinical studies evaluating a combination of radiation and immunotherapies have used external beam radiation therapy. We present in this case report, the abscopal effect observed in a 30-year-old Japanese woman with metastatic renal cell carcinoma after the treatment with high-dose-rate interstitial brachytherapy combined with nivolumab. This is the first published report demonstrating an abscopal effect following brachytherapy for human malignancy. Our case indicates that immuno-oncology effects are not limited to external beam irradiation regimens as they can also be attained by brachytherapy.

Targeted Radionuclide Therapy for Patients with Metastatic Pheochromocytoma and Paraganglioma: From Low-Specific-Activity to High-Specific-Activity Iodine-131 Metaiodobenzylguanidine

Low-specific-activity iodine-131–radiolabeled metaiodobenzylguanidine (I-131-MIBG) was introduced last century as a potential systemic therapy for patients with malignant pheochromocytomas and paragangliomas. Collective information derived from mainly retrospective studies has suggested that 30–40% of patients with these tumors benefit from this treatment. A low index of radioactivity, lack of therapeutic standardization, and toxicity associated with intermediate to high activities (absorbed radiation doses) has prevented the implementation of I-131-MIBG’s in clinical practice. High-specific-activity, carrier-free I-131-MIBG has been developed over the past two decades as a novel therapy for patients with metastatic pheochromocytomas and paragangliomas that express the norepinephrine transporter. This drug allows for a high level of radioactivity, and as yet is not associated with cardiovascular toxicity. In a pivotal phase two clinical trial, more than 90% of patients achieved partial responses and disease stabilization with the improvement of hypertension. Furthermore, many patients exhibited long-term persistent antineoplastic effects. Currently, the high-specific-activity I-131-MIBG is the only approved therapy in the US for patients with metastatic pheochromocytomas and paragangliomas. This review will discuss the historical development of high-specific-activity I-131-MIBG, its benefits and adverse events, and future directions for clinical practice applicability and trial development.

Strategies to Improve Cancer Immune Checkpoint Inhibitors Efficacy, Other Than Abscopal Effect: A Systematic Review

Despite that the impact of immune checkpoint inhibitors on malignancies treatment is unprecedented, a lack of response to these molecules is observed in several cases. Differently from melanoma and non-small cell lung cancer, where the use of immune checkpoint inhibitors results in a high efficacy, the response rate in other tumors, such as gastrointestinal cancers, breast cancer, sarcomas, and part of genitourinary cancers remains low. The first strategy evaluated to improve the response rate to immune checkpoint inhibitors is the use of predictive factors for the response such as PD-L1 expression, tumor mutational burden, and clinical features. In addition to the identification of the patients with a higher expression of immune checkpoint molecules, another approach currently under intensive investigation is the use of therapeutics in a combinatory manner with immune checkpoint inhibitors in order to obtain an enhancement of efficacy through the modification of the tumor immune microenvironment. In addition to the abscopal effect induced by radiotherapy, a lot of studies are evaluating several drugs able to improve the response rate to immune checkpoint inhibitors, including microbiota modifiers, drugs targeting co-inhibitory receptors, anti-angiogenic therapeutics, small molecules, and oncolytic viruses. In view of the rapid and extensive development of this research field, we conducted a systematic review of the literature identifying which of these drugs are closer to achieving validation in the clinical practice.