Optimal timing and sequence of combining stereotactic radiosurgery with immune checkpoint inhibitors in treating brain metastases: clinical evidence and mechanistic basis

The Optimal Radiotherapy Strategy for Patients With Small Cell Lung Cancer and Brain Metastasis: A Retrospective Analysis

BACKGROUND

Extensive-stage small cell lung cancer (ES-SCLC) is a notoriously aggressive malignancy frequently associated with brain metastases (BMs), presenting substantial therapeutic challenges. This study delves into the effectiveness of immunotherapy combined with diverse radiotherapy, especially the influence of brain radiotherapy (BRT) on survival outcomes in the immunotherapy era.

METHODS

ES-SCLC patients treated at Xiangya Hospital and Xiangya Boai Hospital from February 2020 to June 2024 were retrospectively included. The study focused on patients receiving immune checkpoint inhibitors (ICIs). Metrics included overall survival (OS) and progression-free survival (PFS), employing univariate and multivariate Cox regression models for statistical analysis.

RESULTS

A total of 393 patients with ES-SCLC who received ICIs were included in the study. Within the entire cohort, the presence of baseline BMs did not statistically affect OS or PFS. However, thoracic radiotherapy (TRT) was identified as a favorable prognostic factor for both OS and PFS. BRT demonstrated a beneficial effect on OS across both the general cohort and the baseline_BMs subgroup. In patients from the baseline_BMs subgroup who had previously undergone TRT, ICIs plus BRT did not significantly improve OS compared to ICIs alone. Conversely, for patients who had not received prior TRT, adding BRT to ICIs significantly enhanced OS. Among the patients who underwent BRT, 71 received whole brain radiotherapy (WBRT) while 19 opted for stereotactic radiosurgery (SRS). No significant differences in OS and PFS were observed between the SRS and WBRT modalities. The sequence of ICIs relative to BRT was found to influence PFS adversely. Administering BRT before ICIs (RT-ICI) was associated with worse PFS compared to administering ICIs followed by BRT (ICI-RT). Additionally, no significant differences in OS and PFS were noted among the three subgroups defined by varying intervals between ICIs and BRT. For patients without baseline BMs, TRT and prophylactic cranial irradiation were associated with delayed onset of brain metastases.

CONCLUSIONS

Our study underscores the importance of optimizing treatment strategies and considering the timing and integration of radiotherapy and immunotherapy to improve outcomes for patients with ES-SCLC, particularly those at risk of or presenting with BMs.

Efficacy and safety of personalized optimal PD-(L)1 combinations in advanced NSCLC: a network meta-analysis

INTRODUCTION

Programmed death 1 (PD-1)/programmed death 1 ligand 1 (PD-L1)-directed immunotherapy has revolutionized the treatments for advanced non-small cell lung cancer (NSCLC), whereas the optimal therapeutic combinations remain uncertain.

METHODS

Our study encompassed phase II/III randomized controlled trials (RCTs) that involved anti-PD-(L)1-based therapies for stage-IV NSCLC. The primary outcomes included overall survival (OS), progression-free survival (PFS), objective response rate (ORR), and incidences of adverse events. Subgroup analyses were conducted by treatment lines, PD-L1 expression levels, histological types, and metastatic sites.

RESULTS

Our analysis incorporated 38 publications, covering 14 therapeutic combinations and involving 18 048 participants. PD-(L)1+chemotherapy (CT), PD-(L)1+ cytotoxic T lymphocyte-associated antigen-4 (CTLA4) +CT, and PD-(L)1+ T-cell immunoglobulin and ITIM domain were notably effective in prolonging OS. Overall, PD-(L)1+CT and PD-(L)1+CT+ vascular endothelial growth factor (VEGF) were significantly beneficial for PFS and ORR. As for the subsequent-line treatments, incorporating radiotherapy can enhance PFS and ORR (ranked fourth among enrolled treatments). For patients with PD-L1 <1%, PD-(L)1+CT+VEGF and PD-(L)1+CTLA4+CT were favorable approaches. Conversely, in patients with PD-L1 ≥50%, PD-(L)1+CT represented an effective treatment. Patients with nonsquamous cell carcinoma or liver metastases might benefit from the addition of VEGF. In cases of squamous cell carcinoma or brain metastases, the combination of PD-(L)1+CTLA4+CT yielded superior benefits.

CONCLUSIONS

This study underscores the enhanced efficacy of combination immunotherapies over monotherapy. It highlights the necessity for personalized treatment, considering individual factors. These insights are vital for clinical decision making in the management of advanced NSCLC.

Immunotherapy and Radiation Therapy Sequencing in Breast Cancer: A Systematic Review

PURPOSE

In the past decade, immune checkpoint inhibitors (ICIs) have emerged as a treatment option for metastatic breast cancer (BC). More recently, ICIs have been approved in the perioperative setting. This has led to clinical scenarios where radiation therapy (RT) is given concurrently with ICIs. On the other hand, moderate and ultrahypofractionated schedules of RT are being widely adopted in the adjuvant setting, in addition to an increased use of metastasis-directed therapy. Furthermore, RT can modulate the tumor microenvironment and induce a systemic response at nonirradiated sites, an "abscopal effect." The amplification of antitumor immune response is used as the rationale behind the concomitant use of ICIs and RT. To date, there is a lack of literature on the optimal sequence, timing, dose/fractionation schema, and treated RT volumes with ICIs in patients with BC, especially in the era of ultrahypofractionation.

METHODS AND MATERIALS

We conducted a systematic review to delineate the reported treatment details, safety, and efficacy of combining ICI and RT in patients with BC. PubMed, Embase, and Cochrane CENTRAL were searched between 2014 and 2023. Data were extracted to assess the details of ICIs/RT delivery, safety, and efficacy.

RESULTS

Of the 12 eligible studies, 9 involved patients with metastatic BC. Most studies were phase 1/2, had a small sample size (range, 8-28), and were heterogenous in patient population and reported outcomes. The combination was reported to be safe. We identified 1 study in the perioperative setting, which did a posthoc analysis of safety/efficacy of ICIs in the adjuvant setting with receipt and pattern of RT.

CONCLUSIONS

In conclusion, there are limited data on the dose, timing, fractionation, and volumes of RT in both the adjuvant and metastatic setting in BC. Ongoing/future trials should collect and report such data on RT details, whenever RT is used in combination with ICIs.

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.

The Role of Radiotherapy in the Management of Vaginal Melanoma: A Literature Review with a Focus on the Potential Synergistic Role of Immunotherapy

Among the mucosal melanomas, vaginal melanomas are very rare tumors, accounting for less than 20% of melanomas arising from the female genital tract. They occur most frequently in women in post-menopausal age, but younger patients may also experience this neoplasm, mainly located in the lower third of the vagina or the anterior wall. The optimal management of this tumor remains controversial, with surgery reported as the most frequently adopted approach. However, a clear benefit of surgical treatment in terms of survival has not yet been demonstrated. Conversely, radiotherapy may represent an attractive non-invasive alternative, and there are several favorable reports of the role of radiation therapy, either delivered with photons, brachytherapy, or hadrontherapy. A wide range of techniques and fractionation regimens are reported with substantially good tolerance to the treatment, and acute G3 or higher toxicities are reported only in the case of concurrent immunotherapy. Of note, due to the rarity of the disease, there is a lack of high-level evidence for the optimal therapeutic option. In this scenario, recent studies theorize the possibility of developing combinatorial approaches of radiotherapy with immunotherapy based on cutaneous melanomas reports. In this review, we aim to summarize the evidence available in the literature supporting the role of definitive radiotherapy for vaginal melanomas, with a focus on the combination of RT with immunotherapy, in terms of optimal timing and biological rationale.