Hypofractionated radiotherapy with immunochemotherapy for extensive-stage small-cell lung cancer

Interactions between radiotherapy resistance mechanisms and the tumor microenvironment

BACKGROUND

Resistance to radiotherapy (RT) presents a significant clinical challenge in management of cancer. Recent evidence points to specific mechanisms of resistance within the tumor microenvironment (TME), which we aim to discuss, with the aim of overcoming the clinical challenge.

METHODS

We performed the narrative review using PubMed and Web of Science databases to identify studies that reported the regulative network and treatments of RT resistance from TME perspectives.

RESULTS

RT significantly changes the immune TME of cancers, which is closely appearing to play a key role in RT resistance (RTR) by modulating immune cell infiltration and function. Various phenotypes are involved in the development of RTR, such as autophagy, senescence, oxidative stress, cell polarization, ceramide metabolism, and angiogenesis in the TME. Key genes and pathways are also implicated in RTR, including immune and inflammatory cytokines, TGF-β, P53, the NF-κB pathway, the cGAS/STING pathway, the ERK and AKT pathway, and the STAT pathway. Based on the mechanism of RTR in the TME, many proposed routes to overcome RTR, several specifically target the TME including targeting fibroblast activation protein, exosomes management, nanomedicine, and immunotherapy. Many challenges in RT resistance still need to be further explored with emerging investigative methods, such as artificial intelligence, genetic technologies, and bioengineering.

CONCLUSIONS

The complex interactions between RT and TME significantly affect the efficiency of RT. Novel approaches to overcome this clinical difficulty are promising, which needs future work to further explore and identify better treatment strategies.

The effect and toxicity profile of consolidative or salvage thoracic radiotherapy following chemoimmunotherapy in patients with extensive stage small cell lung cancer

This study evaluated the efficacy and safety of thoracic radiotherapy (TRT) after first-line chemotherapy or chemoimmunotherapy in patients with extensive-stage small cell lung cancer (ES-SCLC), focusing on the impact of different TRT timing strategies (consolidative vs. salvage) on survival. A total of 54 ES-SCLC patients treated between January 2019 and July 2022 were retrospectively analyzed. Patients receiving consolidative TRT (cTRT) within 3 months after first-line treatment completion were compared to those receiving salvage TRT (sTRT) following disease progression. Primary endpoints included overall survival (OS), progression-free survival (PFS), locoregional-free survival (LRFS), and distant metastasis-free survival (DMFS); safety was a secondary endpoint. The cTRT group (n=41) showed significantly longer median OS (26.6 vs. 14.8 months, P=0.048), PFS (12.9 vs. 3.5 months, P< 0.0001), and DMFS (10.7 vs. 3.4 months, P= 0.0044) than the sTRT group (n=13). Multivariate analysis identified cTRT as an independent favorable prognostic factor. No significant differences in OS or LRFS were found between high-dose (≥50 Gy) and low-dose (<50 Gy) TRT. Hematologic and respiratory toxicities were the most common adverse events, with acceptable tolerability. In conclusion, consolidative TRT after chemoimmunotherapy significantly improves survival outcomes in ES-SCLC patients, and low-dose TRT may be a suitable option.

Efficacy Analysis of Hypofractionated Radiotherapy for Oligometastatic Tumors: A Retrospective Study

INTRODUCTION

Metastasis remains a major cause of death among patients with malignant tumors. Radiotherapy is one of the main modalities of cancer treatment. The rapid development of radiotherapy technology has enabled the widespread application of hypofractionated radiotherapy (HFRT) in clinical practice. This study aimed to evaluate the effect of HFRT on the survival and safety of patients with oligometastatic tumors.

METHODS

We conducted a retrospective study that involved 65 patients with well-controlled primary tumors and 1-5 metastatic foci treated at the study site between January 2020 and December 2022. Patients were aged >18 years and had a ≥ 6-month life expectancy. The patients received standard treatments plus HFRT for all metastatic foci. The dose fractionation regimen was adjusted according to the location and size of the patient's metastatic foci. The planning gross tumor volume of HFRT was 82.93 cm3 (range: 10.12-562.80 cm3), and the radiation dose range was 20 Gy/5 F-60 Gy/15 F. Progression-free survival (PFS), overall survival (OS), local control rates, and incidence of adverse events of the patients were observed.

RESULTS

Among the 65 patients, the median follow-up time, PFS, and OS were 26 months (95% CI: 0.80-37.50), 15 months (95% CI: 9.36-20.64), and 28 months (95% CI: 16.71-39.29), respectively. The 1- and 2-year PFS were 53.8% and 40.0%, respectively, while the 1- and 2-year OS rates were 73.8% and 56.9%, respectively. In total, 13.8%, 55.4%, 20.0%, and 13.8% of patients showed complete response, partial response, stable disease, and progressive disease, respectively. Four patients developed grade 3 or worse adverse events, and no treatment-related deaths occurred.

CONCLUSIONS

HFRT showed favorable clinical efficacy and safety in patients with oligometastatic tumors, generally achieving a good OS rate. Further randomized trials should be conducted.

Long-term survival after combination therapy with atezolizumab in a patient with small-cell lung cancer: a case report

Background

Small-cell lung cancer (SCLC) is highly malignant. Despite being highly sensitive to initial chemotherapy and radiotherapy, the recurrence rate is high. Atezolizumab is the first immune checkpoint inhibitor (ICI) that has been proven to provide an overall survival (OS) benefit for extensive-stage SCLC (ES-SCLC), making ICIs in combination with chemotherapy the standard first-line treatment for ES-SCLC. However, the real-world treatment of SCLC is more complex, and multimodal therapy may be needed to achieve long-term patient survival. Few reports on later-line chemotherapy combined with immunotherapy have been published thus far. Moreover, there is limited data on the efficacy and safety of thoracic radiotherapy and radiotherapy for metastatic lesions after multiple lines of treatment have failed in ES-SCLC, and the value of small-molecule antiangiogenesis combined with immunotherapy also needs further exploration.

Case Description

A patient was diagnosed with mediastinal limited-stage SCLC (LS-SCLC) and experienced local progression following standard chemoradiotherapy and prophylactic cranial irradiation. Subsequently, the patient underwent second-line irinotecan chemotherapy, which resulted in severe hematological toxicity. Upon initiation of third-line therapy with anlotinib, the disease remained stable for 9 months. Unfortunately, imaging revealed the presence of a new lesion at the right lung apex. Nevertheless, there was renewed hope for survival when atezolizumab was introduced as part of the treatment regimen. Despite the later development of brain metastases and metastasis adjacent to the aortic arch, long-term survival was achieved through combination therapy involving immunotherapy, antiangiogenic therapy, and radiotherapy targeting the metastatic lesions. By March 2024, the OS had reached 70 months, with a duration of treatment with atezolizumab of 48 months, and only grade II hypothyroidism occurred during treatment, with no other immunotherapy-related adverse events being observed.

Conclusions

This case report suggests the potential efficacy and safety of integrating chemotherapy, immunotherapy, radiotherapy, and antiangiogenic therapy for the treatment of SCLC. Further clinical trials are warranted to validate the value of combining chemotherapy, immunotherapy, radiotherapy, and antiangiogenic therapy.

Local radiotherapy in extensive-stage small-cell lung cancer sustainably boosts the clinical benefit of first-line immunotherapy: a case report

Background

Extensive-stage small-cell lung cancer (ES-SCLC) has a dismal prognosis owing to its high aggressiveness, rapid drug resistance, and early metastasis. ES-SCLC responds well to first-line chemotherapy, and chemotherapy coupled with immunotherapy can further improve overall survival. However, the long-term survival of patients remains unsatisfactory because of its high recurrence rate and the poor efficacy of second-line treatment. Although local radiotherapy is an important component of the overall treatment for ES-SCLC, its value in the age of immunotherapy remains controversial.

Case description

A 54-year-old male with ES-SCLC achieved a complete response (CR), as determined using enhanced computed tomography (CT) after four cycles of immunochemotherapy (serplulimab, carboplatin, and etoposide). Whole-body positron emission tomography-CT was performed during maintenance treatment with serplulimab, which showed primary lung, liver, and bone metastatic lesions with CR. However, several mediastinal lymph nodes exhibited glucose metabolism uptake, and new lesions appeared on the head. The patient underwent palliative radiotherapy of the head and consolidative thoracic radiotherapy of the chest and continued maintenance treatment with serplulimab. Subsequent magnetic resonance imaging of the head suggested good control of metastatic lesions (CR). The patient received first-line immunotherapy for approximately 20 months.

Conclusions

This report presents a patient with ES-SCLC who underwent local radiotherapy in addition to serplulimab as maintenance therapy. Although the programmed death-ligand 1 (PD-L1) expression level was negative and a PD-1 inhibitor instead of a PD-L1 inhibitor was used, the patient did not experience significant pneumonia during treatment, and the efficacy of the current treatment was evident. This treatment model warrants further clinical investigation.

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.

Real-world evaluation of first-line treatment of extensive-stage small-cell lung cancer with atezolizumab plus platinum/etoposide: a focus on patients with brain metastasis

PURPOSE

A previous real-world study conducted in China confirmed that first-line atezolizumab, in combination with etoposide/platinum (EP), leads to significantly longer progression-free survival (PFS) compared to EP alone in patients with extensive-stage small-cell lung cancer (ES-SCLC). The present study aimed to provide updated survival outcome data and evaluate the clinical efficacy of atezolizumab plus chemotherapy in ES-SCLC patients with brain metastasis (BM).

METHODS

This retrospective study included 225 patients with ES-SCLC who were treated with EP alone (EP group) or a combination of EP + atezolizumab (atezolizumab group). Survival outcomes for the total study sample and patients in the BM subgroup were estimated using the Kaplan-Meier method.

RESULTS

The atezolizumab group continued to demonstrate significantly longer PFS than the EP group (hazard ratio [HR], 0.68). The median overall survival (OS) was 26.2 months in the atezolizumab group vs. 14.8 months in the EP group (HR, 0.63). Additionally, among the BM patients in our study, the median PFS was found to be longer in the atezolizumab group (7.0 months) than in the EP group (4.1 months) (HR, 0.46). The OS of the BM patients did not differ significantly between the two treatment groups.

CONCLUSIONS

The addition of atezolizumab to EP as a first-line treatment for ES-SCLC was found to improve survival outcomes. This treatment combination may also prolong PFS in patients with BM, regardless of the administration of cranial irradiation. However, among the BM patients in our study, there was no significant difference in OS between the two treatment groups.