Antiprogrammed death ligand 1 therapy failed to reduce the risk of developing brain metastases in patients with extensive-stage small cell lung cancer: A retrospective analysis

BACKGROUND

Immunotherapy (IO) has demonstrated promising results in treating extensive-stage small cell lung cancer (ES-SCLC), and the management of ES-SCLC brain metastases (BMs) is now receiving significant clinical attention. The objective of this study was to evaluate the role of IO in the clinical management of BMs.

METHODS

Between January 2020 and December 2021, the study included the records of 250 patients who were diagnosed with ES-SCLC. Overall survival (OS), progression-free survival, intracranial progression-free survival, and the cumulative incidence of BMs were calculated using the Kaplan-Meier method and were compared using the log-rank test. In addition, the Cox regression model was used to analyze prognostic factors.

RESULTS

In the entire group, 85 patients had baseline BMs (IO plus chemotherapy [IO + ChT], n = 38; ChT alone, n = 47), and 165 patients (IO + ChT, n = 86; ChT alone, n = 79) did not have BMs at the time of initial diagnosis. The median follow-up was 22.4 months. The OS benefit with first-line antiprogrammed death ligand 1 therapy was maintained regardless of whether patients had BMs (with BMs, 17.97 vs. 13.14 months [p = .03]; without BMs, 18.46 vs. 15.05 months [p = .047]). However, in patients without BMs, IO did not delay the median time to developing brain progression (10.84 vs. 10.74 months; p = .84), and it did not significantly reduce the risk of developing intracranial metastases (the 2-year actuarial risk of developing BMs was 57.0% vs. 50.6%, respectively).

CONCLUSIONS

Antiprogrammed death ligand 1 therapy improved OS regardless of the presence of BMs. However, IO did not delay the median time to brain progression or reduce the risk of intracranial metastasis in patients without baseline BMs. The findings of this study have important clinical implications for the future management of BMs from ES-SCLC.

The efficacy of thoracic radiotherapy in extensive stage small cell lung cancer with baseline brain metastases: a multi-institutional retrospective cohort study

Background

Thoracic radiotherapy (TRT) had been shown to improve overall survival (OS) in extensive-stage small cell lung cancer (ES-SCLC) patients. However, approximately one fourth of SCLC harbored baseline brain metastases (BMs) and were excluded from previous TRT trials. Thus, the role of TRT in this sub-cohort of ES-SCLC requires elucidation. In this study, we evaluated the efficacy of TRT in ES-SCLC patients with clinically controlled baseline BMs.

Methods

In this retrospective, multi-institutional cohort study, 49 patients fully staged as ES-SCLC with baseline BM, had their disease controlled at all sites with no BM symptoms for three months since treatment initiation were included. The patients were allocated to TRT or no-TRT groups according to whether they received consolidative TRT before progression. Their baseline characteristics were compared using the χ² test. OS was selected as the primary observational endpoint. Survival and the incidence of cumulative progression between the groups were compared using log-rank analysis, and the interaction between TRT and selected factors was assessed via Cox proportional hazard analysis. Subgroup analysis was performed in oligo-metastasis patients (defined as five or fewer metastatic lesions in two or fewer organs).

Results

Seventeen (34.7%) patients received TRT, with a median dose of 54 Gy. The failure pattern analysis revealed initial intrathoracic progression in 31.3% and 66.7% of patients in the TRT no-TRT groups, respectively. Also, the TRT group had a significantly longer OS than the no-TRT group [hazard ratio (HR) 0.426, P=0.011]. Clinical covariates including age, gender, performance status, smoking, metastatic state, response after chemotherapy, and TRT, were included in multivariate regression analysis. TRT remained significantly correlated with better OS (HR 0.430, P=0.029). Twenty-three (46.9%) patients had oligo-metastasis at baseline. Subgroup analyses showed that TRT was significantly correlated with better OS in oligo-metastatic patients but not in non-oligo metastatic patients.

Conclusions

TRT improved the prognosis of select ES-SCLC patients with baseline BMs and should be considered in this sub-cohort, which has not been covered by previous randomized trials.

The benefits of etoposide capsules as maintenance therapy for patients with extensive-stage small cell lung cancer: a prospective two-stage, two-center study

Background

Due to the high incidence and mortality of lung cancer, and etoposide is the standard first-line chemotherapy for small cell lung cancer, to evaluate the efficacy and safety of etoposide capsules at different doses as maintenance therapy for patients with extensive-stage small cell lung cancer (ES-SCLC) who show a response to etoposide plus platinum.

Methods

The study was divided into two stages: stage I, a single-center, one-arm prospective study, and stage II, a multicenter, controlled non-randomized prospective study (patients were chosen from ClinicalTrials.gov Identifier: NCT02179528). All patients received six cycles of etoposide plus platinum. Patients who were evaluated as complete remission (CR) or partial remission (PR) entered the maintenance treatment (MT) (etoposide capsule, once a day for 20 days, every 28 days as a cycle, until disease progression). In stage I, the dose of etoposide was 25 mg; in stage II, patients were non-randomized into etoposide capsule (25 mg/50 mg) and observation groups. In this study, the primary endpoints were progression-free survival (PFS) and safety; the secondary endpoint was overall survival (OS). Toxicity was graded according to the Common Terminology Criteria for Adverse Events v3.0.

Results

Ninety-two patients were enrolled. In stage I, the median PFS was 6.700 months (95% CI: 6.408–6.992). In stage II, the median PFS of the MT group was better than that in the NMT group (8.930 vs. 5.900 months, P=0.002). In the pooled analysis, the overall median PFS of the MT group was better than that of the NMT group (7.870 vs. 5.900 months, P=0.003). However, there was no significant difference in OS between the groups (15.030 vs. 14.330 months, P=0.813). Multivariate Cox regression analysis showed that maintenance therapy was an independent protective factor for PFS in patients with ES-SCLC.

Conclusions

Etoposide capsules as maintenance therapy significantly prolonged the PFS of patients with ES-SCLC who responded to etoposide plus platinum, with acceptable tolerability.

Extracranial metastatic burden in extensive-stage small cell lung cancer: implications for prophylactic cranial irradiation

Background

Patients with extensive-stage small cell lung cancer (ES-SCLC) often develop brain metastases. There is significant controversy regarding the benefit of prophylactic cranial irradiation (PCI) for patients with ES-SCLC. Our objective is to identify ES-SCLC patients who might be most likely to benefit from PCI.

Methods

We retrospectively reviewed 173 patients with ES-SCLC treated between 2010-2015. Of these, 117 patients were initially diagnosed without brain metastases and received systemic chemotherapy. Following exclusion of patients who received PCI and less than 2 cycles of platinum doublet therapy, 93 patients remained. Patient records were reviewed for clinical and radiographic features previously identified as relevant risk factors. Primary outcome was brain metastasis-free survival (BMFS). Kaplan-Meier analysis, log-rank tests and Cox multivariate models were used to compare outcomes.

Results

Median follow-up was 10.7 months (range, 3-58 months). Thirty-eight (40.9%) patients developed brain metastases. Three or more metastatic sites was associated with inferior BMFS on univariable (1-year estimate 43.8% vs. 61.3%; P=0.020) and multivariable (MVA) analysis [hazard ratio (HR) 2.33, 95% CI: 1.08-5.01; P=0.03).

Conclusions

Our results suggest that extracranial metastatic burden is associated with an increased risk for brain metastases in patients with ES-SCLC. As there is no clear standard regarding delivery of PCI in this patient population, utilizing the number of metastatic disease sites as a clinical indicator may help to improve selection of patients who benefit from PCI.