Immune microenvironment remodeling after radiation of a progressing brain metastasis

First-Line Immune-Combination Therapy for Driver Gene-Negative NSCLC With Brain Metastases: Real-World Outcomes

BACKGROUND

Optimal treatment for driver gene-negative non-small cell lung cancer (NSCLC) with brain metastases (BM) remains unclear, particularly regarding immune checkpoint inhibitor (ICI)-based combinations and local BM therapy. Predictive biomarkers for intracranial efficacy are also undefined.

METHODS

This retrospective study analyzed driver gene-negative NSCLC patients with BM treated with first-line ICI-based systemic therapy (ICI plus chemotherapy [ICI + CT] or ICI + CT plus bevacizumab [ICI + CT + Bev]) from June 2019 to June 2024. The intracranial progression-free survival (icPFS), progression-free survival (PFS), and overall survival (OS) were compared between treatment groups and by BM local therapy. The PD-L1 tumor proportion score (TPS) expression was evaluated for correlation with intracranial efficacy.

RESULTS

A total of 36 patients were enrolled in the study. The intracranial objective response rate (icORR) was 70.6% (ICI + CT) versus 78.6% (ICI + CT + Bev) (p = 0.689), with no significant differences in icPFS, PFS, or OS between the two different first-line systemic regimens (all p > 0.05). Local BM therapy (n = 18) did not improve icPFS and OS (all p > 0.05). Extracranial PD-L1 (TPS ≥ 50%, n = 13) correlated with superior icPFS, PFS, and OS (all p < 0.05) versus PD-L1 TPS < 50%. Multivariate analysis confirmed PD-L1 ≥ 50% as an independent prognostic factor (HR = 0.155; 95% CI, 0.025-0.939; p = 0.042).

CONCLUSIONS

Adding bevacizumab to first-line ICI-chemotherapy did not enhance survival outcomes. Local treatment for BM did not provide additional survival advantages when combined with first-line ICI-based systemic therapy. Extracranial PD-L1 TPS ≥ 50% predicted improved intracranial efficacy.

Efficacy and toxicity of stereotactic radiotherapy combined with third-generation EGFR-TKIs and immunotherapy in patients with brain metastases from non-small cell lung cancer

OBJECTIVE

Stereotactic radiotherapy (SRT) is fast gaining attention as a preferred treatment alternative for patients with brain metastases (BM) from non-small cell lung cancer (NSCLC). In this study, we examined the efficacy and safety of combining SRT with immunotherapy (IT) and targeted therapy (TT), either separately or concurrently with the aim to formulate an optimal therapeutic regimen for patients with NSCLC BM.

METHODS

The combination therapy were comprised of IT and TT agents. For the SRT-combined TT agents group, TT was limited to third-generation EGFR-TKIs. The administration of these drugs within 30 days before or after SRT was defined as combination therapy. The primary endpoint was 1-year progression-free survival (PFS), which was evaluated by a blinded independent review committee and categorized into local recurrence at the radiation site and the emergence of new distant intracranial metastases. Secondary endpoints included confirmed intracranial objective response rate (IORR) and intracranial disease control rate in the overall population. Post-treatment grading was performed according to CTCAE, and the levels of radiation necrosis were differentiated.

RESULTS

The 266 patients with NSCLC BM were categorized into the following four groups based on their treatment methods: SRT alone, SRT combined with IT, SRT combined with third-generation EGFR-TKIs, and SRT combined with both IT and TT. For the local radiation range, the 1‑year PFS of these four groups were 77.89% (P = 0.239), 88.75% (P = 0.266), 88.01% (P = 0.210), and 91.97% (P = 0.057), respectively. For new intracranial metastases outside of the radiotherapy site, the corresponding values were 63.96% (P = 0.039), 74.17% (P = 0.258), 88.70% (P = 0.024), and 87.81% (P = 0.015), respectively. By the end of the study period, the IORR increased from 32% with SRT alone to 46% in the IT group, 58% in the TT group, and 61% in the SRT combined with both the IT and TT groups. However, the group that received SRT in combination with IT and TT exhibited a higher occurrence rate of grade 3 adverse events, and a statistically significant difference was observed in grade 3 radiation necrosis.

CONCLUSION

For NSCLC BM, IT, TT, or both together with SRT increased the distant intracranial tumor control. Nonetheless, combining SRT with both IT and TT increased the occurrence rate of acute adverse events. Thus, while SRT provided good local control independently, the incidence of symptomatic RN was low.

Immunotherapy in lung cancer brain metastases

Brain metastases (BM) occur frequently in lung cancer, particularly in non-small cell lung cancer (NSCLC) patients and remain a significant cause of morbidity and mortality. Standard therapies have limited efficacy due to poor crossing of the blood-brain barrier and the distinct features between BM and the primary tumor. This review explores the immune landscape of brain metastatic disease, emerging immunotherapeutic strategies, and promising biomarkers in NSCLC patients.

Stereotactic radiosurgery for patients with brain metastases: current principles, expanding indications and opportunities for multidisciplinary care

The management of brain metastases is challenging and should ideally be coordinated through a multidisciplinary approach. Stereotactic radiosurgery (SRS) has been the cornerstone of management for most patients with oligometastatic central nervous system involvement (one to four brain metastases), and several technological and therapeutic advances over the past decade have broadened the indications for SRS to include polymetastatic central nervous system involvement (>4 brain metastases), preoperative application and fractionated SRS, as well as combinatorial approaches with targeted therapy and immune-checkpoint inhibitors. For example, improved imaging and frameless head-immobilization technologies have facilitated fractionated SRS for large brain metastases or postsurgical cavities, or lesions in proximity to organs at risk. However, these opportunities come with new challenges and questions, including the implications of tumour histology as well as the role and sequencing of concurrent systemic treatments. In this Review, we discuss these advances and associated challenges in the context of ongoing clinical trials, with insights from a global group of experts, including recommendations for current clinical practice and future investigations. The updates provided herein are meaningful for all practitioners in clinical oncology.

Tobacco smoke exposure is a driver of altered oxidative stress response and immunity in head and neck cancer

BACKGROUND

Exposomes are critical drivers of carcinogenesis. However, how they modulate tumor behavior remains unclear. Extensive clinical data show cigarette smoke to be a key exposome that promotes aggressive tumors, higher rates of metastasis, reduced response to chemoradiotherapy, and suppressed anti-tumor immunity. We sought to determine whether smoke itself can modulate aggressive tumor behavior in head and neck squamous cell carcinoma (HNSCC) through reprogramming of the cellular reductive state.

METHODS

Using established human and murine HNSCC cell lines and syngeneic mouse models, we utilized conventional western blotting, steady state and flux metabolomics, RNA sequencing, quantitative proteomics and flow cytometry to analyze the impact of smoke exposure on HNSCC tumor biology and anti-tumor immunity.

RESULTS

Cigarette smoke persistently activated Nrf2 target genes essential for maintenance of the cellular reductive state and survival under conditions of increased oxidative stress in HNSCC regardless of human papillomavirus (HPV) association. In contrast to e-cigarette vapor, conventional cigarette smoke mobilizes cellular metabolism toward oxidative stress adaptation, resulting in development of cross-resistance to cisplatin. In parallel, smoke exposure modulates expression of PDL1 and the secretory phenotype of HNSCC cells resulting in an altered tumor immune microenvironment (TIME) in syngeneic mouse models and downregulated expression of antigen presentation and costimulatory genes in myeloid cells.

CONCLUSION

The cigarette smoke exposome is a potent activator of the Nrf2 pathway and appears to be the primary trigger for a tripartite phenotype of aggressive HNSCC consisting of: (1) reduced chemotherapy sensitivity, (2) enhanced metastatic potential and (3) suppressed anti-tumor immunity.

Is modulation of immune checkpoints on glioblastoma-infiltrating myeloid cells a viable therapeutic strategy?

The field of immunology has traditionally focused on immune checkpoint modulation of adaptive immune cells. However, many malignancies such as glioblastoma are mostly devoid of T cells and rather are enriched with immunosuppressive myeloid cells of the innate immune system. While some immune checkpoint targets are shared between adaptive and innate immunity, myeloid-specific checkpoints could also serve as potential therapeutics. To better understand the impact of immune checkpoint blockade on myeloid cells, we systematically summarize the current literature focusing on the direct immunological effects of PD-L1/PD-1, CD24/Siglec-10, collagen/LAIR-1, CX3CL1/CX3CR1, and CXCL10/CXCR3. By synthesizing the molecular mechanisms and the translational implications, we aim to prioritize agents in this category of therapeutics for glioblastoma.

Dynamic single-cell sequencing unveils the tumor microenvironment evolution of gastric cancer abdominal wall metastases during radiotherapy

Although the combination of immunotherapy and radiotherapy (RT) for the treatment of malignant tumors has shown rapid development, the insight of how RT remodels the tumor microenvironment to prime antitumor immunity involves a complex interplay of cell types and signaling pathways, much of which remains to be elucidated. Four tumor samples were collected from the same abdominal wall metastasis site of the patient with gastric cancer at baseline and during fractionated RT for single-cell RNA and T-cell receptor sequencing. The Seurat analysis pipeline and immune receptor analysis were used to characterize the gastric cancer metastasis ecosystem and investigated its dynamic changes of cell proportion, cell functional profiles and cell-to-cell communication during RT. Immunohistochemical and immunofluorescent staining and bulk RNA sequencing were applied to validate the key results. We found tumor cells upregulated immune checkpoint genes in response to RT. The infiltration and clonal expansion of T lymphocytes declined within tumors undergoing irradiation. Moreover, RT led to the accumulation of proinflammatory macrophages and natural killer T cells with enhanced cytotoxic gene expression signature. In addition, subclusters of dendritic cells and endothelial cells showed decrease in the expression of antigen present features in post-RT samples. More ECM component secreted by myofibroblasts during RT. These findings indicate that RT induced the dynamics of the immune response that should be taken into consideration when designing and clinically implementing innovative multimodal cancer treatment regimens of different RT and immunotherapy approaches.

Tobacco smoke exposure is a driver of altered oxidative stress response and immunity in head and neck cancer

Purpose

Exposomes are critical drivers of carcinogenesis. However, how they modulate tumor behavior remains unclear. Extensive clinical data link cigarette smoke as a key exposome that promotes aggressive tumors, higher rates of metastasis, reduced response to chemoradiotherapy, and suppressed anti-tumor immunity. We sought to determine whether smoke itself can modulate aggressive tumor behavior in head and neck squamous cell carcinoma (HNSCC) through reprogramming the cellular reductive state.

Experimental design

Using established human and murine HNSCC cell lines and syngeneic mouse models, we utilized conventional western blotting, steady state and flux metabolomics, RNA sequencing, quantitative proteomics and flow cytometry to analyze the impact of smoke exposure on HNSCC tumor biology.

Results

Cigarette smoke persistently activated Nrf2 target genes essential for maintenance of the cellular reductive state and survival under conditions of increased oxidative stress in HNSCC regardless of HPV status. In contrast to e-cigarette vapor, conventional cigarette smoke mobilizes cellular metabolism toward oxidative stress adaptation, resulting in development of cross-resistance to cisplatin. In parallel, smoke exposure modulates both expression of PDL1 and the secretory phenotype of HNSCC cells through activation of NF-κB resulting in an altered tumor immune microenvironment (TIME) in syngeneic mouse models and altered PBMC differentiation that includes downregulated expression of antigen presentation and costimulatory genes in myeloid cells.

Conclusion

Cigarette smoke exposome is a potent activator of the Nrf2 pathway and is a likely primary trigger for the tripartite phenotype of aggressive HNSCC consisting of: 1) reduced chemotherapy sensitivity, 2) enhanced metastatic potential and 3) suppressed anti-tumor immunity.

Statement of significance

The smoke exposome drives aggressive tumor behavior, treatment resistance and suppressed immunity through coordinated metabolic reprogramming. Successfully targeting this adaptation is critical to improving survival in smokers with head and neck cancer.

A single dose of radiation elicits comparable acute salivary gland injury to fractionated radiation

The salivary glands are often damaged during head and neck cancer radiotherapy. This results in chronic dry mouth, which adversely affects quality of life and for which there is no long-term cure. Mouse models of salivary gland injury are routinely used in regenerative research. However, there is no clear consensus on the radiation regime required to cause injury. Here, we analysed three regimes of γ-irradiation of the submandibular salivary gland. Transcriptional analysis, immunofluorescence and flow cytometry was used to profile DNA damage, gland architecture and immune cell changes 3 days after single doses of 10 or 15 Gy or three doses of 5 Gy. Irrespective of the regime, radiation induced comparable levels of DNA damage, cell cycle arrest, loss of glandular architecture, increased pro-inflammatory cytokines and a reduction in tissue-resident macrophages, relative to those observed in non-irradiated submandibular glands. Given these data, coupled with the fact that repeated anaesthetic can negatively affect animal welfare and interfere with saliva secretion, we conclude that a single dose of 10 Gy irradiation is the most refined method of inducing acute salivary gland injury in a mouse model.

Combination of radiosurgery and immunotherapy in brain metastases: balance between efficacy and toxicities

PURPOSE OF REVIEW

The incidence of brain metastasis is high and still increasing. Among local therapies, stereotactic radiosurgery (SRS) is an effective treatment option, optimally sparing normal brain, even for multiple brain metastases. Immune checkpoint inhibitors (ICIs) become the new standard of care in an increasing number of cancers, and the combination SRS and ICI is often proposed to patients, but few data have been published on the efficacy and the toxicity of this association.

RECENT FINDINGS

Explaining this lack of consensus: retrospective studies with different primary cancers, various treatment lines and unknown levels of steroid exposure. Concerning the toxicity, the independent association of radionecrosis with brain-PTV volume was confirmed, and a decreased dose of SRS is now tested in a randomized study. Finally, a 'concurrent' delivery of SRS and ICI (within a 4 weeks' interval) seems the optimal schedule; fractionated radiosurgery for large brain metastasis should be favored. Radio-sensitizing nanoparticles and devices aiming to increase the permeability of the blood brain barrier should be considered in future combinations.

SUMMARY

The efficacy/toxicity balance of SRS-ICI combination should be regularly re-evaluated, anticipating continued progress in ICI and SRS delivery, with more long-survivors potentially exposed to long-term toxicities. Patients should be included in clinical trials and clearly informed to participate more closely in the final choice.

Targeting tumor-associated macrophage: an adjuvant strategy for lung cancer therapy

The emergence of immunotherapy has revolutionized the treatment landscape for various types of cancer. Nevertheless, lung cancer remains one of the leading causes of cancer-related mortality worldwide due to the development of resistance in most patients. As one of the most abundant groups of immune cells in the tumor microenvironment (TME), tumor-associated macrophages (TAMs) play crucial and complex roles in the development of lung cancer, including the regulation of immunosuppressive TME remodeling, metabolic reprogramming, neoangiogenesis, metastasis, and promotion of tumoral neurogenesis. Hence, relevant strategies for lung cancer therapy, such as inhibition of macrophage recruitment, TAM reprograming, depletion of TAMs, and engineering of TAMs for drug delivery, have been developed. Based on the satisfactory treatment effect of TAM-targeted therapy, recent studies also investigated its synergistic effect with current therapies for lung cancer, including immunotherapy, radiotherapy, chemotherapy, anti-epidermal growth factor receptor (anti-EGFR) treatment, or photodynamic therapy. Thus, in this article, we summarized the key mechanisms of TAMs contributing to lung cancer progression and elaborated on the novel therapeutic strategies against TAMs. We also discussed the therapeutic potential of TAM targeting as adjuvant therapy in the current treatment of lung cancer, particularly highlighting the TAM-centered strategies for improving the efficacy of anti-programmed cell death-1/programmed cell death-ligand 1 (anti-PD-1/PD-L1) treatment.