Can immunostimulatory agents enhance the abscopal effect of radiotherapy?

Efficacy of innovative systemic treatments in combination with radiotherapy for bone metastases: a GEMO (the European Study Group of Bone Metastases) state of the art

The management of bone metastases (BoM) requires a multidisciplinary approach to prevent complications, necessitating updated knowledge in light of the rapid advancements in systemic treatments and surgical, interventional radiology or radiation techniques. This review aims to discuss efficacy of new systemic treatments on BoM, the benefits of radiotherapy adjunction, and the optimal methods for combining them. Preliminary evidence suggesting reduced efficacy of immune checkpoint inhibitors (ICI), and several multi-kinase inhibitors regarding BoM may encourage early use of radiotherapy (RT). Systemic treatment efficacy modulation by RT and ablative RT strategies are explored. Concerns for increased side effects for several kinase inhibitors and double ICI in combination with RT imply suspending those systemic treatments during RT. Various timing strategies to combine prostate hormone therapies and RT are developed. Emerging internal vectorized radiotherapy molecules necessitate developing new combination strategies with RT. Further prospective data collection and comparative trials should be encouraged.

Current status of neoadjuvant immunotherapy for the treatment of gastric cancer

Gastric cancer is one of the most prevalent malignant tumors worldwide, characterized by high incidence and mortality rates. At present, comprehensive surgical treatment has enhanced the prognosis of locally advanced gastric cancer patients significantly. However, the postoperative recurrence rate remains high, and the long-term survival for patients is sub-optimal. In recent years, immunotherapy has garnered extensive attention as an innovative approach to the treatment of gastric cancer. Indeed, multiple studies have validated its therapeutic effects in advanced gastric cancer patients, leading to its incorporation into treatment guidelines. Currently, researchers are exploring the application of immunotherapy in the neoadjuvant setting globally in order to further adjust and refine neoadjuvant immunotherapy regimens for gastric cancer. This article summarizes the research progress and controversies associated with neoadjuvant immunotherapy in gastric cancer, aiming to optimize clinical benefits for gastric cancer patients undergoing this treatment approach. The retrieval methods of this study encompassed databases such as PubMed, Google Scholar, Web of Science, clinicaltrials.gov, etc. The retrieved articles included guidelines, consensus, meta-analyses, clinical trials, and reviews related to locally advanced gastric cancer published up to January 2024.

A comprehensive overview of radiation therapy impacts of various cancer treatments and pivotal role in the immune system

The cancer treatment landscape is significantly evolving, focusing on advanced radiation therapy methods to maximize effectiveness and minimize the adverse effects. Recognized as a pivotal component in cancer and disease treatment, radiation therapy (RT) has drawn attention in recent research that delves into its intricate interplay with inflammation and the immune response. This exploration unveils the underlying processes that significantly influence treatment outcomes. In this context, the potential advantages of combining bronchoscopy with RT across diverse clinical scenarios, alongside the targeted impact of brachytherapy, are explored. Concurrently, radiation treatments serve multifaceted roles such as DNA repair, cell elimination, and generating immune stress signaling molecules known as damage-associated molecular patterns, elucidating their effectiveness in treating various diseases. External beam RT introduces versatility by utilizing particles such as photons, electrons, protons, or carbon ions, each offering distinct advantages. Advanced RT techniques contribute to the evolving landscape, with emerging technologies like FLASH, spatially fractionated RT, and others poised to revolutionize the field. The comprehension of RT, striving for improved treatment outcomes, reduced side effects, and facilitating personalized and innovative treatments for cancer and noncancer patients. After navigating these advancements, the goal is fixed to usher in a new era in which RT is a cornerstone of precision and effectiveness in medical interventions. In summarizing the myriad findings, the review underscores the significance of understanding the differential impacts of radiation approaches on inflammation and immune modulation, offering valuable insights for developing innovative therapeutic interventions that harness the immune system in conjunction with RT.

TLR3 activation enhances abscopal effect of radiotherapy in HCC by promoting tumor ferroptosis

Radiotherapy (RT) has been reported to induce abscopal effect in advanced hepatocellular carcinoma (HCC), but such phenomenon was only observed in sporadic cases. Here, we demonstrated that subcutaneous administration of Toll-like receptor 3 (TLR3) agonist poly(I:C) could strengthen the abscopal effect during RT through activating tumor cell ferroptosis signals in bilateral HCC subcutaneous tumor mouse models, which could be significantly abolished by TLR3 knock-out or ferroptosis inhibitor ferrostatin-1. Moreover, poly(I:C) could promote the presentation of tumor neoantigens by dendritic cells to enhance the recruitment of activated CD8+ T cells into distant tumor tissues for inducing tumor cell ferroptosis during RT treatment. Finally, the safety and feasibility of combining poly(I:C) with RT for treating advanced HCC patients were further verified in a prospective clinical trial. Thus, enhancing TLR3 signaling activation during RT could provide a novel strategy for strengthening abscopal effect to improve the clinical benefits of advanced HCC patients.

The potential role of precision medicine to alleviate racial disparities in prostate, bladder and renal urological cancer care

Background

Racial disparities in oncological outcomes resulting from differences in social determinants of health (SDOH) and tumour biology are well described in prostate cancer (PCa) but similar inequities exist in bladder (BCa) and renal cancers (RCCs). Precision medicine (PM) aims to provide personalized treatment based on individual patient characteristics and has the potential to reduce these inequities in GU cancers.

Objective

This article aims to review the current evidence outlining racial disparities in GU cancers and explore studies demonstrating improved oncological outcomes when PM is applied to racially diverse patient populations.

Evidence acquisition

Evidence was obtained from Pubmed and Web of Science using keywords prostate, bladder and renal cancer, racial disparity and precision medicine. Because limited studies were found, preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines were not applied but rather related articles were studied to explore existing debates, identify the current status and speculate on future applications.

Results

Evidence suggests addressing SDOH for PCa can reverse racial inequities in oncological outcomes but differences in incidence remain. Similar disparities in BCa and RCC are seen, and it would be reasonable to suggest achieving parity in SDOH for all races would do the same. Research applying a PM approach to different ethnicities is lacking although in African Americans (AAs) with metastatic castrate-resistant prostate cancer (mCRPCa) better outcomes have been shown with androgen receptor inhibitors, radium-223 and sipuleucel. Exploiting the abscopal effect with targeted radiation therapy (RT) and immunotherapy has promise but requires further study, as does defining actionable mutations in specific patient groups to tailor treatments as appropriate.

Conclusion

For all GU cancers, the historical underrepresentation of ethnic minorities in clinical trials still exists and there is an urgent need for recruitment strategies to address this. PM is a promising development with the potential to reduce inequities in GU cancers, however, both improved understanding of race-specific tumour biology, and enhanced recruitment of minority populations into clinical trials are required. Without this, the benefits of PM will be limited.

Association of Radiochemotherapy to Immunotherapy in unresectable locally advanced Oesophageal carciNoma-randomized phase 2 trial ARION UCGI 33/PRODIGE 67: the study protocol

BACKGROUND

In case of locally advanced and/or non-metastatic unresectable esophageal cancer, definitive chemoradiotherapy (CRT) delivering 50 Gy in 25 daily fractions in combination with platinum-based regimen remains the standard of care resulting in a 2-year disease-free survival of 25% which deserves to be associated with new systemic strategies. In recent years, several immune checkpoint inhibitors (anti-PD1/anti-PD-L1, anti-Program-Death 1/anti-Program-Death ligand 1) have been approved for the treatment of various solid malignancies including metastatic esophageal cancer. As such, we hypothesized that the addition of an anti-PD-L1 to CRT would provide clinical benefit for patients with locally advanced oesophageal cancer. To assess the efficacy of the anti-PD-L1 durvalumab in combination with CRT and then as maintenance therapy we designed the randomized phase II ARION (Association of Radiochemotherapy with Immunotherapy in unresectable Oesophageal carciNoma- UCGI 33/PRODIGE 67).

METHODS

ARION is a multicenter, open-label, randomized, comparative phase II trial. Patients are randomly assigned in a 1:1 ratio in each arm with a stratification according to tumor stage, histology and centre. Experimental arm relies on CRT with 50 Gy in 25 daily fractions in combination with FOLFOX regimen administrated during and after radiotherapy every two weeks for a total of 6 cycles and durvalumab starting with CRT for a total of 12 infusions. Standard arm is CRT alone. Use of Intensity Modulated radiotherapy is mandatory. The primary endpoint is to increase progression-free survival at 12 months from 50 to 68% (HR = 0.55) (power 90%; one-sided alpha-risk, 10%). Progression will be defined with central external review of imaging.

ANCILLARY STUDIES ARE PLANNED

PD-L1 Combined Positivity Score on carcinoma cells and stromal immune cells of diagnostic biopsy specimen will be correlated to disease free survival. The study of gut microbiota will aim to determine if baseline intestinal bacteria correlates with tumor response. Proteomic analysis on blood samples will compare long-term responder after CRT with durvalumab to non-responder to identify biomarkers.

CONCLUSION

Results of the present study will be of great importance to evaluate the impact of immunotherapy in combination with CRT and decipher immune response in this unmet need clinical situation.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT: 03777813.Trial registration date: 5th December 2018.

Non-cellular immunotherapies in pediatric central nervous system tumors

Central nervous system (CNS) tumors are the second most common type of cancer and the most common cause of cancer death in pediatric patients. New therapies are desperately needed for some of the most malignant of all cancers. Immunotherapy has emerged in the past two decades as an additional avenue to augment/replace traditional therapies (such as chemotherapy, surgery, and radiation therapy). This article first discusses the unique nature of the pediatric CNS immune system and how it interacts with the systemic immune system. It then goes on to review three important and widely studied types of immune therapies: checkpoint inhibitors, vaccines, and radiation therapy, and touches on early studies of antibody-mediated immunogenic therapies, Finally, the article discusses the importance of combination immunotherapy for pediatric CNS tumors, and addresses the neurologic toxicities associated with immunotherapies.

Effect of external beam radiation therapy versus transcatheter arterial chemoembolization for non-diffuse hepatocellular carcinoma (≥ 5 cm): a multicenter experience over a ten-year period

BACKGROUND

The optimal local treatment for HCC with tumor diameter ≥ 5 cm is not well established. This research evaluated the effectiveness of external beam radiation therapy (EBRT) versus transcatheter arterial chemoembolization (TACE) for HCC with tumor diameter ≥ 5 cm.

METHODS

A total of 1210 HCC patients were enrolled in this study, including 302 and 908 patients that received EBRT and TACE, respectively. Propensity score matching (PSM) was used to identify patient pairs with similar baseline characteristics. Overall survival (OS) was the primary study endpoint.

RESULTS

We identified 428 patients using 1:1 PSM for survival comparison. Compared with the TACE group, the EBRT group had a significantly longer median OS (mOS) before (14.9 vs. 12.3 months, p = 0.0085) and after (16.8 vs. 11.4 months, p = 0.0026) matching. In the subgroup analysis, compared with the TACE group, the EBRT group had a significantly longer mOS for HCC with tumor diameters of 5-7 cm (34.1 vs. 14.3 months, p = 0.04) and 7-10 cm (34.4 vs. 10 months, p = 0.00065), whereas for HCC with tumor diameters ≥ 10 cm, no significant difference in mOS was observed (11.2 vs. 11.2 months, p = 0.83). In addition, the multivariable Cox analysis showed that Child-A, alkaline phosphatase < 125 U/L, and EBRT were independent prognostic indicators for longer survival.

CONCLUSION

EBRT is more effective than TACE as the primary local treatment for HCC with tumor diameter ≥ 5 cm, especially for HCC with tumor diameter of 5-10 cm.

Mechanisms of radiotherapy resistance and radiosensitization strategies for esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (ESCC) is the sixth most common cause of cancer-related mortality worldwide, with more than half of them occurred in China. Radiotherapy (RT) has been widely used for treating ESCC. However, radiation-induced DNA damage response (DDR) can promote the release of cytokines and chemokines, and triggers inflammatory reactions and changes in the tumor microenvironment (TME), thereby inhibiting the immune function and causing the invasion and metastasis of ESCC. Radioresistance is the major cause of disease progression and mortality in cancer, and it is associated with heterogeneity. Therefore, a better understanding of the radioresistance mechanisms may generate more reversal strategies to improve the cure rates and survival periods of ESCC patients. We mainly summarized the possible mechanisms of radioresistance in order to reveal new targets for ESCC therapy. Then we summarized and compared the current strategies to reverse radioresistance.

Implications of the Organ-Specific Immune Environment for Immune Priming Effect of Radiotherapy in Metastatic Setting

With the development of immune checkpoint inhibitors (ICIs), the tumour immune microenvironment (TIME) has been increasingly considered to improve cancer management. The TIME of metastatic lesions is strongly influenced by the underlying immune contexture of the organ in which they are located. The metastatic location itself appears to be an important prognostic factor in predicting outcomes after ICI treatment in cancer patients. Patients with liver metastases are less likely to respond to ICIs than patients with metastases in other organs, likely due to variations in the metastatic TIME. Combining additional treatment modalities is an option to overcome this resistance. Radiotherapy (RT) and ICIs have been investigated together as an option to treat various metastatic cancers. RT can induce a local and systemic immune reaction, which can promote the patient's response to ICIs. Here, we review the differential impact of the TIME according to metastatic location. We also explore how RT-induced TIME modifications could be modulated to improve outcomes of RT-ICI combinations.

Pembrolizumab versus cetuximab concurrent with radiotherapy in patients with locally advanced squamous cell carcinoma of head and neck unfit for cisplatin (GORTEC 2015-01 PembroRad): a multicenter, randomized, phase II trial

BACKGROUND

To evaluate potential synergistic effect of pembrolizumab with radiotherapy (RT) compared with a standard-of-care (SOC) cetuximab-RT in patients with locally advanced-squamous cell carcinoma of head and neck (LA-SCCHN).

PATIENTS AND METHODS

Patients with nonoperated stage III-IV SCC of oral cavity, oropharynx, hypopharynx, and larynx and unfit for receiving high-dose cisplatin were enrolled. Patients received once-daily RT up to 69.96 Gy in 33 fractions with weekly cetuximab (cetuximab-RT arm) or 200 mg Q3W pembrolizumab during RT (pembrolizumab-RT arm). The primary endpoint was locoregional control (LRC) rate 15 months after RT. To detect a difference between arms of 60%-80% in 15-month LRC, inclusion of 66 patients per arm was required to achieve a power of at least 0.85 at two-sided significance level of 0.20.

RESULTS

Between May 2016 and October 2017, 133 patients were randomized to cetuximab-RT (n = 66) and pembrolizumab-RT (n = 67). Two patients (one in each arm) were not included in the analysis (a consent withdrawal and a progression before treatment start). The median age was 65 years (interquartile range 60-70 years), 92% were smokers, 60% were oropharynx (46% of oropharynx with p16+) and 75% were stage IV. Median follow-up was 25 months in both arms. The 15-month LRC rate was 59% with cetuximab-RT and 60% with pembrolizumab-RT ]odds ratio 1.05, 95% confidence interval (CI) 0.43-2.59; P = 0.91]. There was no significant difference between arms for progression-free survival (hazard ratio 0.85, 95% CI 0.55-1.32; P = 0.47) and for overall survival (hazard ratio 0.83, 95% CI 0.49-1.40; P = 0.49). Toxicity was lower in the pembrolizumab-RT arm than in the cetuximab-RT arm: 74% versus 92% patients with at least one grade ≥3 adverse events (P = 0.006), mainly due to mucositis, radiodermatitis, and rash.

CONCLUSION

Compared with the SOC cetuximab-RT, pembrolizumab concomitant with RT did not improve the tumor control and survival but appeared less toxic in unfit patients with LA-SCCHN.

PD-1 inhibitors plus anti-angiogenic therapy with or without intensity-modulated radiotherapy for advanced hepatocellular carcinoma: A propensity score matching study

BACKGROUND

Whether intensity-modulated radiotherapy (IMRT) can enhance the efficacy of the programmed death (PD)-1 inhibitors combined with anti-angiogenic therapy for hepatocellular carcinoma (HCC) is unclear. Therefore, we conducted this multicenter retrospective study to investigate the efficacy of the combination of PD-1 inhibitors with anti-angiogenic therapy and IMRT.

METHODS

From April 2019 to March 2022, a total of 197 patients with HCC [combination of PD-1 inhibitors with anti-angiogenic therapy and IMRT (triple therapy group), 54; PD-1 inhibitors plus anti-angiogenic therapy (control group), 143] were included in our study. Propensity score matching (PSM) was applied to identify two groups with similar baselines. The objective response rate (ORR), overall survival (OS), and progression-free survival (PFS) of the two groups were compared before and after matching.

RESULTS

Prior to PSM, the triple therapy group had higher ORR (42.6% vs 24.5%, P = 0.013) and more superior median OS (mOS) (20.1 vs 13.3 months, P = 0.009) and median PFS (mPFS) (8.7 vs 5.4 months, P = 0.001) than the control group. Following PSM, the triple therapy group still exhibited better mPFS (8.7 vs 5.4 months, P = 0.013) and mOS (18.5 vs 12.6 months, P = 0.043) than the control group. However, the ORR of the two groups was similar (40% vs 25%, P = 0.152). No significant difference was observed in the treatment-related adverse events between the two groups (P < 0.05 for all).

CONCLUSIONS

The combination of PD-1 inhibitors with anti-angiogenic therapy and IMRT for HCC is a promising regimen.

Tumor-infiltrating lymphocytes predict improved overall survival after post-mastectomy radiotherapy: a study of the randomized DBCG82bc cohort

BACKGROUND

The predictive value of tumor-infiltrating lymphocytes (TILs) on the benefit from radiotherapy (RT) remains unclear. Our aim was to investigate the association between TILs and post-mastectomy RT (PMRT) regarding the risk of recurrence and survival in a randomized cohort.

MATERIAL AND METHODS

Stromal TILs were histologically estimated in 1011 tumors from high-risk breast cancer (BC) patients from the DBCG82bc trial. Patients were diagnosed between 1982 and 90, treated with total mastectomy and partial axillary lymph node dissection, randomized to ± PMRT followed by adjuvant systemic treatment. A competing risk model, Kaplan-Meier analysis and multivariate Cox regression analysis were used for correlating TILs and clinical outcome.

RESULTS

106 of 1011 patients (10.5%) showed high TILs using a 30% cut-off. In multivariate regression analysis, a high level of TILs was an independent factor associated with lower risk of distant metastasis (DM) and improved overall survival (OS), but without association with loco-regional control. High TILs were associated with a significantly greater OS after PMRT at 20 years compared to low TILs (8% improvement for low TILs (23% to 31%) vs. 22% for high TILs (26% to 48%), interaction-test: p = 0.028). The association between TILs and PMRT was more pronounced among estrogen-receptor negative (ER-) tumors, and patients having ER-/low TILs tumors showed no OS benefit from PMRT at 20 years (-4% improvement for low TILs (28% to 24%) vs. 23% for high TILs (20% to 43%). A similar trend in the association between high TILs and reduced risk of DM after PMRT was seen.

CONCLUSION

High TILs predict improved OS from PMRT in BC patients, and the association appeared especially strong for ER- tumors. A trend in the association between high TILs and reduced risk of DM after PMRT was seen. These findings may indicate that RT triggers an immune response inducing a systemic effect outside the treatment field.

Impact of radiation therapy on healthy tissues

Radiation therapy has a fundamental role in the management of cancers. However, despite a constant improvement in radiotherapy techniques, the issue of radiation-induced side effects remains clinically relevant. Mechanisms of acute toxicity and late fibrosis are therefore important topics for translational research to improve the quality of life of patients treated with ionizing radiations. Tissue changes observed after radiotherapy are consequences of complex pathophysiology, involving macrophage activation, cytokine cascade, fibrotic changes, vascularization disorders, hypoxia, tissue destruction and subsequent chronic wound healing. Moreover, numerous data show the impact of these changes in the irradiated stroma on the oncogenic process, with interplays between tumor radiation response and pathways involved in the fibrotic process. The mechanisms of radiation-induced normal tissue inflammation are reviewed, with a focus on the impact of the inflammatory process on the onset of treatment-related toxicities and the oncogenic process. Possible targets for pharmacomodulation are also discussed.

Effectiveness and safety of immune checkpoint inhibitors in combination with palliative radiotherapy in advanced melanoma: A systematic review

BACKGROUND

Radiotherapy is frequently added to immune checkpoint inhibitors (ICI) when treating melanoma. We sought to describe the efficacy of combination ICI and palliative radiotherapy (pRT) and assess safety, focusing on immune related adverse events (irAE).

METHODS

A systematic search for studies investigating the combination of pRT and ICI was conducted.

RESULTS

Five hundred-two articles were identified; nine met inclusion criteria. Improvements in objective response rate (p = 0.02), complete response (p = 0.04), and one-year local control (p < 0.005) were demonstrated when pRT was added to ICI. While some studies revealed improved overall and progression free survival, findings were mixed. No significant increases in adverse events or irAE were seen with the combined treatment compared with ICI alone.

CONCLUSION

The included studies revealed that the addition of pRT to ICI is effective and safe in patients with advanced melanoma. Measures of survival varied. More studies are warranted to identify optimal conditions for combination treatment.

PD-1 iNhibitor and chemotherapy with concurrent IRradiation at VAried tumor sites in advanced Non-small cell lung cAncer: the Prospective Randomized Phase 3 NIRVANA-Lung Trial

Advanced non-small cell lung cancer (NSCLC) remains a high unmet medical need. The first line standard-of-care therapy comprises concurrent chemotherapy-immunotherapy with pembrolizumab. Concurrent irradiation with pembrolizumab has been shown to significantly improve survival benefit compared with immunotherapy alone in a pooled analysis of 2 randomized phase 2 trials. We present the rationale and study design of the "PD-1 iNhibitor and chemotherapy with concurrent IRradiation at VAried tumor sites in advanced Non-small cell lung cAncer" (NIRVANA-Lung) trial (ClinicalTrials.gov identifier, NCT03774732). This study is a national multicenter 1:1 randomized phase III trial testing in 460 patients, the addition of multisite radiotherapy in advanced NSCLC treated with standard immune checkpoint inhibitors (pembrolizumab)-chemotherapy in first line. The primary objective of the trial is to compare the overall survival between the 2 arms at year 1 of the study. The secondary objective is to compare the progression-free survival and cancer-specific survival at year 1 and 2, as well as to determine quality of life, local and distant control in irradiated and nonirradiated sites at 6 months and year 1.

Stereotactic body radiotherapy and checkpoint inhibitor for locally recurrent unresectable nasopharyngeal carcinoma

The treatment of local recurrence of nasopharyngeal carcinoma (NPC) is challenging, and the role of reirradiation is controversial regarding the high risk for severe toxicity. Stereotactic body radiotherapy (SBRT) is a high-precision radiation technique that can spare surrounding normal tissues. Studies have demonstrated the high activity and low toxicity of both SBRT and anti-programmed-cell-death-1 immune checkpoint inhibitors for head and neck cancers. There has been preclinical and clinical evidence suggesting synergy between radiotherapy and checkpoint inhibitors. We report two patients with locally recurrent unresectable rT4 NPC both involving the retro-orbital areas. They received the same treatment with low-dose SBRT (28 Gy in 5 fractions) and pembrolizumab, and showed a remarkable tumour response without untoward radiation toxicity. SBRT plus an immune checkpoint inhibitor may provide a new treatment option for locally recurrent NPC. We propose further investigation with a formal clinical trial.

Survival in Patients With Metastatic Prostate Cancer Undergoing Radiotherapy: The Importance of Prostate-Specific Antigen-Based Stratification

OBJECTIVES

To explore the effectiveness of radiotherapy in mPCa patients with different PSA stratifications based on the cancer database of a large population.

BACKGROUND

Screening criteria for patients with metastatic prostate cancer, who are candidates for radiotherapy, are rarely reported.

PATIENTS AND METHODS

We identified 22,604 patients with metastatic prostate cancer in the Surveillance, Epidemiology, and End Results database and divided them into a radiotherapy group and a control group. Patients with metastatic prostate cancer were divided into subgroups according to their levels of prostate-specific antigen to evaluate the efficacy of radiotherapy. They were also divided into six subgroups according to their prostate-specific antigen levels. We used multivariate Cox analysis to evaluate overall survival and cancer-specific survival. After 1:1 propensity score matching, Kaplan-Meier analysis was used to explore the difference in overall survival and cancer-specific survival in the radiotherapy and control group.

RESULTS

In all, 5,505 patients received radiotherapy, compared to 17,099 in the control group. In the multivariate Cox analysis, radiotherapy improved overall survival (hazard ratio [HR]: 0.730, 95% confidence interval [CI]: 0.636-0.838; P<0.001) and cancer-specific survival (HR: 0.764, 95% CI: 0.647-0.903; P=0.002) in patients with a PSA level of 4-10 ng/mL. Similar results were obtained by Kaplan-Meier analysis after 1:1 propensity score matching. In patients with prostate-specific antigen levels between 4-10 ng/mL, the overall survival (P<0.001) and cancer-specific survival (P<0.05) in the radiotherapy group was significantly better than those in the control group.

CONCLUSION

The result of this large population-based study shows that rigorous selection of appropriate metastatic prostate cancer patients for radiotherapy can benefit prognosis significantly. This can be the basis for future prospective trials.

Immune Response: A Missed Opportunity Between Vitamin D and Radiotherapy

Radiotherapy (RT) is a mainstay treatment in several types of cancer and acts by mediating various forms of cancer cell death, although it is still a large challenge to enhance therapy efficacy. Radiation resistance represents the main cause of cancer progression, therefore, overcoming treatment resistance is now the greatest challenge for clinicians. Increasing evidence indicates that immune response plays a role in reprogramming the radiation-induced tumor microenvironment (TME). Intriguingly, radiation-induced immunosuppression possibly overwhelms the ability of immune system to ablate tumor cells. This induces an immune equilibrium, which, we hypothesize, is an opportunity for radiosensitizers to make actions. Vitamin D has been reported to act in synergistic with RT by potentiating antiproliferative effect induced by therapeutics. Additionally, vitamin D can also regulate the TME and may even lead to immunostimulation by blocking immunosuppression following radiation. Previous reviews have focused on vitamin D metabolism and epidemiological trials, however, the synergistic effect of vitamin D and existing therapies remains unknown. This review summarizes vitamin D mediated radiosensitization, radiation immunity, and vitamin D-regulated TME, which may contribute to more successful vitamin D-adjuvant radiotherapy.

Sequence of αPD-1 relative to local tumor irradiation determines the induction of abscopal antitumor immune responses

Although radiotherapy has been used for over a century to locally control tumor growth, alone it rarely induces an abscopal response or systemic antitumor immunity capable of inhibiting distal tumors outside of the irradiation field. Results from recent studies suggest that combining immune checkpoint blockades to radiotherapy may enhance abscopal activity. However, the treatment conditions and underlying immune mechanisms that consistently drive an abscopal response during radiation therapy combinations remain unknown. Here, we analyzed the antitumor responses at primary and distal tumor sites, demonstrating that the timing of αPD-1 antibody administration relative to radiotherapy determined the potency of the induced abscopal response. Blockade of the PD-1 pathway after local tumor irradiation resulted in the expansion of polyfunctional intratumoral CD8⁺ T cells, a decrease in intratumoral dysfunctional CD8⁺ T cells, expansion of reprogrammable CD8⁺ T cells, and induction of potent abscopal responses. However, administration of αPD-1 before irradiation almost completely abrogated systemic immunity, which associated with increased radiosensitivity and death of CD8⁺ T cells. The subsequent reduction of polyfunctional effector CD8⁺ T cells at the irradiated tumor site generated a suboptimal systemic antitumor response and the loss of abscopal responses. Therefore, this report maximizes the potential synergy between radiotherapy and αPD-1 immunotherapy, information that will benefit clinical combinations of radiotherapy and immune checkpoint blockade.

Overview of checkpoint inhibitor pneumonitis: incidence and associated risk factors

Introduction: The development of immune checkpoint inhibitors (ICIs) has been a breakthrough in the treatment of several types of cancer. With the widespread use of ICIs in clinical practice, checkpoint inhibitor pneumonitis (CIP) is expected to increase and its management will pose a challenge for clinicians.Areas covered: In this article, we review the incidence, associated risk factors, radiological patterns, clinical features, and management of CIP.Expert opinion: Several clinical trials assessing the efficacy and safety of combination treatments with various drugs and ICIs have been conducted. From the results of these trials, CIP is thought to be an acceptable side effect because the frequency of its development was slightly higher during combination therapies than during ICI monotherapies. However, the risk of developing CIP associated with combinations of chemotherapy and ICIs may be higher in the real world than in clinical trials. Because combinations of chemotherapy and ICIs are associated with increased toxicity, the proper management of immune-related adverse events is necessary to maximize the efficacy of the treatment.

Radiotherapy-Mediated Immunomodulation and Anti-Tumor Abscopal Effect Combining Immune Checkpoint Blockade

Radiotherapy (RT) is a conventional method for clinical treatment of local tumors, which can induce tumor-specific immune response and cause the shrinkage of primary tumor and distal metastases via mediating tumor infiltration of CD8+ T cells. Ionizing radiation (IR) induced tumor regression outside the radiation field is termed as abscopal effect. However, due to the mobilization of immunosuppressive signals by IR, the activated CD8+T cells are not sufficient to maintain a long-term positive feedback to make the tumors regress completely. Eventually, the "hot" tumors gradually turn to "cold". With the advent of emerging immunotherapy, the combination of immune checkpoint blockade (ICB) and local RT has produced welcome changes in stubborn metastases, especially anti-PD-1/PD-L1 and anti-CTLA-4 which have been approved in clinical cancer treatment. However, the detailed mechanism of the abscopal effect induced by combined therapy is still unclear. Therefore, how to formulate a therapeutic schedule to maximize the efficacy should be took into consideration according to specific circumstance. This paper reviewed the recent research progresses in immunomodulatory effects of local radiotherapy on the tumor microenvironment, as well as the unique advantage for abscopal effect when combined with ICB, with a view to exploring the potential application value of radioimmunotherapy in clinic.

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.

[Treatment of primary disease for synchronous metastatic prostate cancer]

The management of early metastatic prostate cancer is based on systemic treatment by androgen deprivation therapy with or without chemotherapy or next-generation anti-androgen therapies. Local treatment of the prostate was initially used only to alleviate local symptoms. However, local radiotherapy of the prostate has been the subject of retrospective and prospective studies in patients with better prognostic factors, particularly in oligometastatic status. The results of these studies support that prostate radiotherapy can prolong the survival of patients with a low metastatic burden. This article states the biological bases, the main published and future published studies aimed to embed this strategy to optimize therapeutic management.

The mechanism and risk factors for immune checkpoint inhibitor pneumonitis in non-small cell lung cancer patients

Immune checkpoint inhibitors (ICIs) are new and promising therapeutic agents for non-small cell lung cancer (NSCLC). However, along with demonstrating remarkable efficacy, ICIs can also trigger immune-related adverse events. Checkpoint inhibitor pneumonitis (CIP) has been reported to have a morbidity rate of 3% to 5% and a mortality rate of 10% to 17%. Moreover, the incidence of CIP in NSCLC is higher than that in other tumor types, reaching 7% to 13%. With the increased use of ICIs in NSCLC, CIP has drawn extensive attention from oncologists and cancer researchers. Identifying high risk factors for CIP and the potential mechanism of CIP are key points in preventing and monitoring serious adverse events. In this review, the results of our analysis and summary of previous studies suggested that the risk factors for CIP may include previous lung disease, prior thoracic irradiation, and combinations with other drugs. Our review also explored potential mechanisms closely related to CIP, including increased T cell activity against associated antigens in tumor and normal tissues, preexisting autoantibodies, and inflammatory cytokines.

Dose escalation phase 1 study of radiotherapy in combination with anti-cytotoxic-T-lymphocyte-associated antigen 4 monoclonal antibody ipilimumab in patients with metastatic melanoma

BACKGROUND

A synergy between radiotherapy and anti-cytotoxic-T-lymphocyte-associated antigen 4 (anti-CTLA-4) monoclonal antibody has been demonstrated preclinically. The Mel-Ipi-Rx phase 1 study aimed to determine the maximum tolerated dose (MTD) and safety profile of radiotherapy combined with ipilimumab in patients with metastatic melanoma.

PATIENTS AND METHODS

A 3+3 dose escalation design was used with 9, 15, 18 and 24 Gy dose of radiotherapy at week 4 combined with 10 mg/kg ipilimumab every 3 weeks for four doses. Patients with evidence of clinical benefit at week 12 were eligible for maintenance with ipilimumab 10 mg/kg every 12 weeks starting at week 24 until severe toxicity or disease progression. The database lock occurred on April 30, 2019. Tumor growth rate of irradiated lesions and non-irradiated lesions were analyzed to assess the systemic immunologic antitumor response. Blood immune monitoring was performed before and during treatment to determine if radiotherapy could modify ipilimumab pharmacodynamics.

RESULTS

19 patients received ipilimumab between August 2011 and July 2015. Nine patients received the four doses of ipilimumab. All patients received the combined radiotherapy. Grade 3 adverse events occurred in nine patients, the most common being colitis and hepatitis. No drug-related death occurred. Dose limiting toxicity occurred in two of six patients in the cohort receiving 15 Gy. The MTD was 9 Gy. Two patients had complete response, three had partial response response and seven had stable disease, giving an objective response rate of 31% and a clinical benefit rate of 75% at week 24. The median duration of follow-up was 5.8 years (Q1=4.5; Q3=6.8). The median overall survival (95% CI) was estimated at 0.9 years (0.5-2). The median progression-free survival (PFS) (95% CI) was 0.4 (0.2-1.4). Radiotherapy combined with ipilimumab was associated with increased CD4+ and CD8+ICOS+ T cells. Increased CD8+ was significantly associated with PFS.

CONCLUSION

When combined with ipilimumab at 10 mg/kg, the MTD of radiotherapy was 9 Gy. This combination of ipilimumab and radiotherapy appears to be associated with antitumor activity. Increased CD8+ was significantly associated with PFS. Thus, immune biomarkers may be useful for early response evaluation.

TRIAL REGISTRATION NUMBER

NCT01557114.

Abscopal effect of radiation therapy after nivolumab monotherapy in a patient with oral mucosal melanoma: A case report

The Abscopal effect is a rare phenomenon whereby tumors outside of the irradiated field regress due to systemic antitumor effects of localized radiotherapy. In patients with oral mucosal melanoma, only one instance of the abscopal effect has been described in the English-language literature [1]. Herein, we describe an instance of the abscopal effect following whole-brain radiation therapy after nivolumab monotherapy in a patient with oral mucosal melanoma.

Abscopal effect in radioimmunotherapy

Abscopal effect is an interesting phenomenon in radiobiology that causes activation of immune system against cancer cells. Traditionally, this phenomenon was known as a suppressor of non-irradiated tumors or metastasis. However, it can be used as a stimulator of the immune system against primary tumor during radiotherapy. Immunotherapy, a novel tumor therapy modality, also triggers immune system against cancer. To date, some immunotherapy types have been developed. However, immune checkpoint blockade is a more common modality and some drugs have been approved by the FDA. Studies have shown that radiotherapy or immunotherapy administered alone have low efficiency for tumor control. However, their combination has a more potent anti-tumor immunity. For this aim, it is important to induce abscopal effect in primary tumors, and also use appropriate drugs to target the mechanisms involved in the exhaustion of cytotoxic CD8+T lymphocytes (CTLs) and natural killer (NK) cells. Among the different radiotherapy techniques, stereotactic body radiation therapy (SBRT) with some few fractionations is the best choice for inducing abscopal effect. On the other hand, programmed cell death 1 (PD-1) is known as one of the best targets for triggering anti-tumor immunity. This combination is known as the best choice among various strategies for radioimmunotherapy. However, there is the need for other strategies to improve the duration of immune system's activity within tumor microenvironment (TME). In this review, we explain the cellular and molecular mechanisms behind abscopal effect by radiotherapy and evaluate the molecular targets which induce potent anti-tumor immunity.

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.

Pure abscopal effect of radiotherapy in a salivary gland carcinoma: Case report, literature review, and a search for new approaches

We report the case of an 84-year-old woman with poorly differentiated non-small cell carcinoma of the right parotid who presented with headache, was found to have a primary right parotid gland cancer as well as metastatic disease, and underwent palliative radiotherapy to the primary site. The patient received no chemotherapy or immunotherapy, but both the primary site and several non-irradiated foci in the lungs regressed or completely resolved. The patient remained free of disease for about one year before progression. The case is a rare instance of abscopal regression of metastatic disease in the absence of pharmacologic immunomodulation. A literature review surveys the history of the abscopal effect of radiation therapy, attempts to understand the mechanisms of its successes and failures, and points to new approaches that can inform and improve the outcomes of radioimmunotherapy.

[Role of immunotherapy in locally advanced non-small cell lung cancer]

Concomitant radiochemotherapy has been the standard of care for unresectable stage III non-small cell lung cancer (NSCLC), irrespective of histological sub-type or molecular characteristics. Currently, only 15-30 % of patients are alive five years after radiochemotherapy, and this figure remains largely unchanged despite multiple phase III randomised trials. In recent years, immune-checkpoint blockades with anti-PD-(L)1 have revolutionised the care of metastatic NSCLC, becoming the standard front- and second-line strategy. Several preclinical studies reported an increased tumour antigen release, improved antigen presentation, and T-cell infiltration in irradiated tumours. Immunotherapy has therefore recently been evaluated for patients with locally advanced stage III NSCLC. Following the PACIFIC trial, the anti-PD-L1 durvalumab antibody has emerged as a new standard consolidative treatment for patients with unresectable stage III NSCLC whose disease has not progressed following concomitant platinum-based chemoradiotherapy. Immunoradiotherapy therefore appears to be a promising association in patients with localised NSCLC. Many trials are currently evaluating the value of concomitant immunotherapy and chemoradiotherapy and/or consolidative chemotherapy with immunotherapy in patients with locally advanced unresectable NSCLC.

The role of radiation therapy and systemic therapies in elderly with breast cancer

The focus of this review deals with the management of elderly patients with early stage breast cancer, discussing the role of systemic therapies [endocrine therapy (ET), chemotherapy, novel agents] and radiation therapy (RT). Several studies have evaluated in elderly low risk patients the possibility of omitting the RT but, at the same time, higher locoregional relapse (LR) rates without significant impact on overall survival (OS) were observed in all studies when RT was excluded. Technological improvements [intensity-modulated RT (IMRT), volumetric modulated arc therapy (VMAT), high dose brachy therapy (HDBT)] are very useful in order to reduce cosmetic outcome and improve quality of life of frail patients. The optimal sequence of ET, concomitant or sequential to RT, is currently under investigation, and specifically in the elderly it is questioned the possible choice of prolonged therapy after standard 5 years. Data regarding chemotherapy suggesting no benefit of OS in endocrine responsive diseases, whereas endocrine non-responsive breast cancer still showed a better outcome. Cyclophosphamide, methotrexate and 5-fluorouracil (CMF) regimen is recognized as the standard protocol, although age-dependent increase in therapy related mortality was reported. Neoadjuvant chemotherapy in elderly showed a lower ratio of pathological complete response in comparison to younger patients, but triple negative breast cancer patients showed a good prognosis regarding OS, comparable to younger patients. The risk of cardiotoxicity seems to increase with age, so the use trastuzumab in this setting is much debated. Currently, other anti-HER2 agents (pertuzumab, lapatinib) are used in neoadjuvant setting, but the data on elderly are still premature. Novel molecules are rapidly changing the clinical management of breast cancer patients but are tested especially in locally advanced and metastatic setting. Among these, particularly interesting are inhibitors of CDK4 and 6, alpelisib (PI3K enzymes mutations), immune checkpoint (PD1, PDL1, CTLA4) inhibitors, atezolizumab. Elderly patients are under-represented in clinical trials, although ageing can be frequently correlated with a decrease in the effectiveness of the immune system. For elderly women, treatment decisions should be individually decided, taking into account the geriatric assessment and limited life expectancy and tumor characteristics.

Relationship between immune-related adverse events and the long-term outcomes in recurrent/metastatic head and neck squamous cell carcinoma treated with nivolumab

OBJECTIVES

Immune-related adverse events (irAEs) have been shown to be associated with higher antitumor responses and a clinical benefit in non-small cell lung carcinoma, renal cell carcinoma, and melanoma patients. However, little is known regarding the association between irAEs and the clinical effect of nivolumab for recurrent/metastatic head and neck squamous cell carcinoma (R/MHNSCC).

MATERIALS AND METHODS

We evaluated 108 patients treated with nivolumab for R/MHNSCC at 2 participating institutions. IrAEs were identified and profiled. We analyzed the association of each immune-related adverse effect with the clinical outcome of the patients.

RESULTS

Among 108 patients, the objective response rate (ORR) was 29.6% (32/108 patients), and the disease control rate (DCR) was 50.0% (54/108 patients). IrAEs were observed in 41 patients (38.0%). Patients with irAEs had a significantly higher ORR and DCR than those without irAEs (46.3% vs. 19.4%, P = 0.004 and 75.6% vs. 34.3%, P < 0.001, respectively). The median progression-free and overall survival rates in patients with irAEs were significantly longer than in those without irAEs.

CONCLUSIONS

There was a significant relationship between irAEs and efficacy in R/MHNSCC patients treated with nivolumab. Our results indicate that the development of irAEs may aid in the earlier prediction of anticancer effects in patients with recurrent or metastatic HNSCC during nivolumab monotherapy.

[Stereotactic body radiotherapy: Passing fad or revolution?]

Stereotactic body radiotherapy (SBRT) is a young technology that can deliver a high dose of radiation to the target, utilizing either a single dose or a small number of fractions with a high degree of precision within the body. Various technical solutions co-exist nowadays, with particular features, possibilities and limitations. Health care authorities have currently validated SBRT in a very limited number of locations, but many indications are still under investigation. It is therefore challenging to accurately appreciate the SBRT therapeutic index, its place and its role within the anticancer therapeutic arsenal. The aim of the present review is to provide SBRT definitions, current indications, and summarize the future ways of research. There are three validated indications for SBRT: un-resecable T1-T2 non small cell lung cancer, <3 slow-growing pulmonary metastases secondary to a stabilized primary, and the tumours located close to the medulla. In other situations, the benefit of SBRT is still to be demonstrated. One of the most promising way of research is the ablative treatment of oligo metastatic cancers, with recent studies suggesting a survival benefit. Furthermore, the most recent data suggest that SBRT is safe. Finally, the SBRT combined with immune therapies is promising, since it could theoretically trigger the adaptative anticancer response.

IDO inhibitor synergized with radiotherapy to delay tumor growth by reversing T cell exhaustion

Previous studies suggest that radiotherapy (RT) can induce immune activation, which not only reduces the progression of tumors, but also causes the release of tumor antigens. The combination of RT and immune checkpoint blockade, such as the inhibition of programmed cell death 1 (PD‑1) and programmed cell death ligand 1 (PD‑L1), has been demonstrated to yield impressive response rates. However, a substantial proportion of patients develop resistance such therapies. Previous studies have shown that indoleamine 2,3‑dioxygenase (IDO) causes T cell exhaustion and increased formation of regulatory T cells (Tregs), upregulating the expression of inhibitory receptors and ligands. Therefore, the application of IDO inhibitors combined with RT may have a synergistic effect by relieving immunosuppression. Lewis lung cancer cell‑bearing mice were treated with the IDO inhibitor 1‑methyl‑tryptophan (1MT) and/or 10 Gy RT. Tumor size was measured every day, flow cytometry was performed to measure the expression of dendritic cell (DC) maturation markers, inhibitory receptors, ligands, cytotoxic T cells and Treg phenotypic markers. Reverse transcription‑quantitative PCR was used to evaluate the mRNA expression levels of IDO, PD‑L1, PD‑1, T cell immunoglobulin domain and mucin domain 3 (TIM‑3), B‑ and T‑lymphocyte attenuator (BTLA) and galectin‑9. Compared with the control group, treatment with 1MT or RT reduced tumor growth, however, the combination therapy was more effective than either treatment alone. Flow cytometry showed the upregulation of CD80, CD86 and the major histocompatibility complex II in spleen DCs and the concurrent downregulation of CD4, CD25 and forkhead box protein P3 in lymphocytes in the treatment groups. Compared with the control group, inhibitory receptors and ligands that affect DCs and T cells were observed, expression levels of PD‑L1, PD‑1, TIM‑3, BTLA and galectin‑9 are decreased in treatment group compared with control. IDO inhibition synergized with RT to downregulate Tregs, inhibitory receptors and ligands to prevent T cell exhaustion. By activating DCs and T cells, this combination therapy may strongly enhance antitumor immunity and inhibit tumor progression.

Cytoreductive treatment strategies for de novo metastatic prostate cancer

In the past decade, a revolution in the treatment of metastatic prostate cancer has occurred with the advent of novel hormonal agents and life-prolonging chemotherapy regimens in combination with standard androgen-deprivation therapy. Notwithstanding, the use of systemic therapy alone can result in a castrate-resistant state; therefore, increasing focus is being placed on the additional survival benefits that could potentially be achieved with local cytoreductive and/or metastasis-directed therapies. Local treatment of the primary tumour with the established modalities of radiotherapy and radical prostatectomy has been explored in this context, and the use of novel minimally invasive ablative therapies has been proposed. In addition, evidence of the potential clinical benefits of metastasis-directed therapy with ionizing radiation (primarily stereotactic ablative radiotherapy) is accumulating. Herein, we summarize the pathobiological rationale for local cytoreduction and the potentially systemic immunological responses to radiotherapy and ablative therapies in patients with metastatic prostate cancer. We also discuss the current evidence base for a cytoreductive strategy, including metastasis-directed therapy, in the current era of sequential multimodal therapy incorporating novel treatments. Finally, we outline further research questions relating to this complex and evolving treatment landscape.

Possible Abscopal Effect Observed in Frontal Meningioma After Localized IMRT on Posterior Meningioma Resection Cavity Without Adjuvant Immunotherapy

Background: Localized radiation therapy (RT) is known to infrequently cause off-target or “abscopal” effects at distant metastatic lesions. The mechanism through which abscopal effects occur remains unknown, but is thought to be caused by a humoral immune response to tumor-specific antigens generated by RT. Combination treatment regimens involving RT and immunotherapy to boost the humoral immune response have demonstrated synergistic effects in promoting and accelerating abscopal effects in metastatic cancer. Nevertheless, abscopal effects, particularly after RT alone, remain exceedingly rare.

Case Presentation: We report the case of an 84-year-old man with an atypical meningioma, who demonstrated a radiographically significant response to an untreated second intracranial lesion, likely also a meningioma, after intensity-modulated radiation therapy (IMRT) to a separate, detatched resection cavity. Serial annual MRI imaging starting at 2- to 3.5-year (most recent) post-IMRT follow-up demonstrated a persistent decrease in both tumor size and surrounding edema in the untreated second lesion, suggestive of a possible abscopal effect.

Conclusions: We describe here the first report of a potential abscopal effect in meningioma, summarize the limited literature on the topic of abscopal effects in cancer, and detail the existing hypothesis on how this phenomenon may occur and possibly relate to the development of future treatments for patients with metastatic disease.

[Definitive or neo-adjuvant chemoradiation in esophageal carcinoma?]

Management of resectable esophageal carcinoma is based on a multimodal treatment associating neo-adjuvant chemoradiation before surgery. This therapeutic sequence allows a disease-free survival rate at 2 years around 45% but remains associated with a high post-operative morbidity. In case of definitive chemoradiotherapy, the dose delivered to the macroscopic disease is a controversial topic since decades and the prognosis of patients treated in this setting at the dose of 50Gy remains poor. This article proposes a review of the main published data and the ongoing studies related to the management of these patients.

The potential combinational immunotherapiesfor treatment of hepatocellular carcinoma

The treatment choices available for hepatocellular carcinoma (HCC) are limited and unsatisfactory. Recent improvements in our understanding of the mechanism involving immune checkpoints, including programmed cell death protein 1 (PD1), programmed death-ligand 1 (PD-L1), and cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), and also progress in the development of medicines make immunotherapy a promising approach to the treatment of numerous cancers, especially HCC. However, around 40% of patients still suffer from a progressive disease when treated with a monotherapy. Several clinical trials applying a combination therapy including immune checkpoint inhibitors have demonstrated the durable antitumor activity of these approaches in HCC patients. These clinical trials were done with the intent of evaluating the safety of these combination therapies, as well as whether they help improve the overall survival of patients. This study reviewed the recent progress in the use of combination therapies including immunotherapy in treating patients with HCC.

Increased bone marrow SUVmax on 18F-FDG PET is associated with higher pelvic treatment failure in patients with cervical cancer treated by chemoradiotherapy and brachytherapy

The aim of this study was to evaluate if bone marrow (BM) SUVmax measured on pre-treatment 18F-FDG PET/CT predicts the clinical outcome of locally advanced cervical cancer (LACC). We recruited retrospectively patients with LACC who underwent staging 18F-FDG PET/CT and had baseline blood tests, then treated by chemoradiation therapy (CRT), followed by image-guided adaptive brachytherapy (IGABT). BM SUVmax was calculated and correlated to inflammatory blood markers. Tumor size and pelvic lymph node involvement were evaluated on baseline MRI. Prognostic value of SUV uptake and blood markers regarding overall survival (OS), pelvic and extra-pelvic recurrence-free survival (PRFS and EPRFS respectively) was assessed using Cox models with adjusted p-values. 116 patients with FIGO stage Ib-IVa cervical cancer, treated between 2005 and 2014, were analyzed. The median follow-up was 75.5 months. BM SUVmax was significantly correlated to tumor SUVmax. In multivariate analysis, PRFS was significantly poorer in patients with high BM SUVmax (>2.8) and neutrophilia (p < .05). Tumor size (>5 vs ≤5 cm) could predict PRFS, EPRFS and OS (p < .05). In our cohort, FIGO stage (I-II vs III-IV), pelvic lymph node involvement and tumor SUVmax (>12 vs ≤12) were not prognostic for OS or pelvic and extra-pelvic relapses. Patients with LACC and high BM SUVmax on 18F-FDG PET have worse PFRS following CRT plus IGABT. These results can be potentially explained by the pro-inflammatory role of the tumor microenvironment and G-CSF expressed by tumor cells. These data support the role of PET as a potential indicator of disease aggressiveness beyond tumor staging.

Rationale for combination of radiation therapy and immune checkpoint blockers to improve cancer treatment

Radiation therapy for cancer is considered to be immunosuppressive. However, the cellular response after radiation therapy may stimulate or suppress an immune response. The effect may vary with the tumor type and occasionally tumor regressions have been observed outside the irradiated volume, both in animal studies and in the clinic. A renewed interest in the role of immunity for the observed effect of radiation came with the current recognized role of immune checkpoint blockers (ICBs) for control of selected cancer types. We therefore here review preclinical studies and clinical reports on the interaction of ICBs and radiation as a basis for further clinical trials. Some tumor types where the combination of these modalities seems especially promising are also proposed.