Association of Twice-Daily Radiotherapy With Subsequent Brain Metastases in Adults With Small Cell Lung Cancer

Efficacy of Prophylactic Cranial Irradiation in Early to Mid-stage Small Cell Lung Cancer Patients in the Era of Magnetic Resonance Imaging

BACKGROUND

Recent advancements in magnetic resonance imaging (MRI) for staging have highlighted the critical question of the need for prophylactic cranial irradiation (PCI) in managing early to mid-stage small cell lung cancer (SCLC). This study assesses the impact of PCI on overall survival (OS) and intracranial control among patients with stage I-IIB SCLC.

METHODS

Data from 148 stage I-IIB SCLC patients treated with thoracic radiation therapy (TRT) at two centers were examined. Patients were categorized based on PCI administration: 63 received PCI, while 85 did not. All underwent pretreatment MRI, achieving at least a partial response to therapy. A 1:1 propensity score matching analysis corrected for potential biases.

RESULTS

Propensity scores were generated to 116 patients, considering patient demographics, disease progression, and treatment methods. Death was included as a competing risk. The 3-year brain metastases (BM) occurrence rate was significantly higher in patients who did not receive PCI (30.0%) compared to those who did (14.8%), however, the difference was not statistically significant (No PCI vs. PCI, hazard ratio [HR]: 2.08, 95% CI [0.93-4.55], P = .07). No significant effect of PCI on OS was observed [PCI vs. No PCI, HR: 0.80, 95% CI (0.45-1.43), P = .45]. A subgroup analysis of stage IIB patients showed a significant increase in BM risk and mortality for those not receiving PCI (No PCI vs. PCI, BM risk HR: 5.85, 95% CI: 1.83-18.87, P = .003; mortality HR: 2.78, 95% CI: 1.14-6.67, P = .02), with less pronounced effects in stages I-IIA.

CONCLUSION

With modern MRI-based screening, PCI may markedly benefit stage IIB SCLC patients by reducing BM and improving OS after initial sensitive treatment. This benefit does not appear to extend to stage I-IIA patients.

Construction of brain metastasis prediction model in limited stage small cell lung cancer patients without prophylactic cranial irradiation

INTRODUCTION

Small cell lung cancer (SCLC) is a highly aggressive lung cancer variant known for its elevated risk of brain metastases (BM). While earlier meta-analyses supported the use of prophylactic cranial irradiation (PCI) to reduce BM incidence and enhance overall survival, modern MRI capabilities raise questions about PCI's universal benefit for limited-stage SCLC (LS-SCLC) patients. As a response, we have created a predictive model for BM, aiming to identify low-risk individuals who may not require PCI.

METHODS

A total of 194 LS-SCLC patients without PCI treated between 2009 and 2021 were included. We conducted both univariate and multivariate analyses to pinpoint the factors associated with the development of BM. A nomogram for predicting the 2- and 3-year probabilities of BM was then constructed.

RESULTS

Univariate and multivariate analyses revealed several significant independent risk factors for the development of BM. These factors include TNM stage, the number of chemotherapy (ChT) cycles, Ki-67 expression level, pretreatment serum lactate dehydrogenase (LDH) levels, and haemoglobin (HGB) levels. These findings underscore their respective roles as independent predictors of BM. Based on the results of the final multivariable analysis, a nomogram model was created. In the training cohort, the nomogram yielded an area under the receiver operating characteristic curve (AUC) of 0.870 at 2 years and 0.828 at 3 years. In the validation cohort, the AUC values were 0.897 at 2 years and 0.789 at 3 years. The calibration curve demonstrated good agreement between the predicted and observed probabilities of BM.

CONCLUSIONS

A novel nomogram has been developed to forecast the likelihood of BM in patients diagnosed with LS-SCLC. This tool holds the potential to assist healthcare professionals in formulating more informed and tailored treatment plans.

Reshaping the systemic tumor immune environment (STIE) and tumor immune microenvironment (TIME) to enhance immunotherapy efficacy in solid tumors

The development of combination immunotherapy based on the mediation of regulatory mechanisms of the tumor immune microenvironment (TIME) is promising. However, a deep understanding of tumor immunology must involve the systemic tumor immune environment (STIE) which was merely illustrated previously. Here, we aim to review recent advances in single-cell transcriptomics and spatial transcriptomics for the studies of STIE, TIME, and their interactions, which may reveal heterogeneity in immunotherapy responses as well as the dynamic changes essential for the treatment effect. We review the evidence from preclinical and clinical studies related to TIME, STIE, and their significance on overall survival, through different immunomodulatory pathways, such as metabolic and neuro-immunological pathways. We also evaluate the significance of the STIE, TIME, and their interactions as well as changes after local radiotherapy and systemic immunotherapy or combined immunotherapy. We focus our review on the evidence of lung cancer, hepatocellular carcinoma, and nasopharyngeal carcinoma, aiming to reshape STIE and TIME to enhance immunotherapy efficacy.

Risk Factors for Brain Metastases in Patients With Small Cell Lung Cancer: A Systematic Review and Meta-Analysis

The use of prophylactic cranial irradiation (PCI) for small cell lung cancer (SCLC) patients is controversial. Risk factors for brain metastasis (BM) development are largely lacking, hampering personalized treatment strategies. This study aimed to identify the possible risk factors for BM in SCLC.We systematically searched the Pubmed database (1 January 1995 to 18 January 2021) according to the PRISMA guidelines. Eligibility criteria: studies reporting detailed BM data with an adequate sample size (randomized clinical trials [RCTs]: N ≥50; non-RCTs: N ≥100) in patients with SCLC. We summarized the reported risk factors and performed meta-analysis to estimate the pooled hazard ratios (HR) if enough qualified data (i.e., two or more studies; the same study type; the same analysis method; and HRs retrievable) were available. In total, 61/536 records were eligible (18 RCTs and 39 non-RCTs comprising 13,188 patients), in which 57 factors were reported. Ten factors qualified BM data for meta-analysis: Limited stage disease (LD) (HR = 0.34, 95% CI: 0.17-0.67; P = 0.002) and older age (≥65) (HR = 0.70, 95% CI: 0.54-0.92; P = 0.01) were associated with less BM; A higher T stage (≥T3) (HR = 1.72, 95% CI: 1.16-2.56; P = 0.007) was a significant risk factor for BM. Male sex (HR = 1.24, 95% CI: 0.99-1.54; P = 0.06) tended to be a risk factor, and better PS (0-1) (HR = 0.66, 95% CI: 0.42-1.02; P = 0.06) tended to have less BM. Smoking, thoracic radiotherapy dose were not significant (P >0.05). PCI significantly decreased BM (P <0.001), but did not improve OS in ED-SCLC (P = 0.81). A higher PCI dose did not improve OS (P = 0.11). The impact on BM was conflicting between Cox regression data (HR = 0.59, 95% CI: 0.26-1.31; P = 0.20) and competing risk regression data (HR = 0.74, 95% CI: 0.55-0.99; P = 0.04). Compared to M0-M1a, M1b was a risk factor for OS (P = 0.01) in ED-SCLC, but not for BM (P = 0.19). As regular brain imaging is rarely performed, high-quality data is lacking. Other factors such as N-stage and blood biomarkers had no qualified data to perform meta-analysis. In conclusion, younger age, higher T stage, and ED are risk factors for BM, suggesting that PCI should be especially discussed in such cases. Individual patient data (IPD) meta-analysis and well-designed RCTs are needed to better identify more risk factors and further confirm our findings. Systematic Review Registration: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021228391, identifier CRD42021228391.

Factors Affecting the Risk of Brain Metastasis in Limited-Stage Small Cell Lung Cancer After Prophylactic Cranial Irradiation

Background

Prophylactic cranial irradiation (PCI) can reduce the risk of brain metastases (BM) and improve overall survival (OS) in patients with limited-stage small cell lung cancer (LS-SCLC) after partial or complete response to primary therapy. However, some SCLC patients still develop BM after PCI. This study aimed to evaluate the risk factors of BM in patients with LS-SCLC after PCI and identify characteristics of patients who may not benefit from PCI.

Methods and Materials

We identified 550 patients with LS-SCLC who received chemoradiotherapy at Zhejiang Cancer Hospital between 2002 and 2017. All patients received PCI. Kaplan–Meier analyses and Cox regression analyses were used to identify factors affecting OS and brain metastasis-free survival (BMFS).

Results

For this patient population, the median survival time was 27.9 months, and the 5-year OS rate was 31%. The median survival time was 24.9 months (95% CI: 22.6–27.2 months), and 30.2 months (95% CI: 24.2–36.3 months) in patients with or without BM (P = 0.000). The overall BM rate was 15.6% (86/550). The frequency of BM in patients with pathologic stages I, II, and III were 9.3% (4/43), 13.4% (7/52), and 16.5% (75/455). The patients with tumors ≥5 cm had an increased risk of BM (HR: 1.781, 95% CI: 1.044–3.039, P = 0.034) but not death (HR: 1.126, 95% CI: 0.925–1.663, P = 0.182). The median survival time among patients <60 years was significantly longer than patients ≥60 years (34.9 months vs 24.6 months, P = 0.001); however, the difference in the BM risk between the two groups was not statistically significant.

Conclusion

PCI remains the standard of care for LS-SCLC patients who achieve complete or partial response after completion of chemoradiotherapy. However, patients with tumors ≥5 cm may have a higher risk of developing BM after PCI.

Risk factors for neurocognitive decline in lung cancer patients treated with prophylactic cranial irradiation: A systematic review

BACKGROUND

Prophylactic cranial irradiation (PCI) reduces brain metastasis incidence in lung cancer, however with risk of neurocognitive decline. Nevertheless, risk factors for neurocognitive decline after PCI remain unclear.

METHODS

We systematically reviewed the PubMed database according to the PRISMA guideline. Inclusion criteria were: randomized clinical trials (RCTs) and observational/single arm trials evaluating PCI, including ≥20 patients, reporting neurocognitive test results for lung cancer. Primary aim: evaluate risk factors associated with neurocognitive decline after PCI.

RESULTS

Twenty records were eligible (8 different RCTs, 8 observational studies), including 3553 patients in total (858 NSCLC, 2695 SCLC) of which 73.6% received PCI. Incidence of mild/moderate cognitive decline after PCI varied from 8 to 89% (grading not always provided); for those without PCI, this was 3.4-42%. Interestingly, 23-95% had baseline cognitive impairment. Risk factors were often not reported. In one trial, both age (>60 years) and higher PCI dose (36 Gy) including twice-daily PCI were associated with a higher risk of cognitive decline. In one trial, white matter abnormalities were more frequent in the concurrent or sandwiched PCI arm, but without significant neuropsychological differences. One trial identified hippocampal sparing PCI to limit the neurocognitive toxicities of PCI and another reported an association between hippocampal dose volume effects and memory decline. As neurocognition was a secondary endpoint in most RCTs, and was assessed by various instruments with often poor/moderate compliance, high-quality data is lacking.

CONCLUSIONS

Age, PCI dose, regimen and timing might be associated with cognitive impairment after PCI in lung cancer patients, but high-quality data is lacking. Future PCI trials should collect and evaluate possible risk factors systematically.

A Meta-Analysis of the Efficacy and Toxicity of Twice-Daily vs. Once-Daily Concurrent Chemoradiotherapy for Limited-Stage Small Cell Lung Cancer Based on Randomized Controlled Trials

Background: Currently, the accepted standard management of limited-stage small cell lung cancer (SCLC) is concurrent chemoradiotherapy (CCRT), but the frequency of radiotherapy is controversial. Therefore, this meta-analysis, which compared the efficacy and toxicity between twice-daily (BID) and once-daily (OD) CCRT, was performed to help clinicians make better decisions. Methods: Relevant randomized controlled trials (RCTs) were collected by searching the PubMed, Ovid MEDLINE, Embase, ScienceDirect, Web of Science, the Cochrane Library, Scopus and Google Scholar databases to assess antitumor effects (overall survival, OS; progression-free survival, PFS; overall response rate, ORR) and toxicity (adverse effects, AEs). Results: We screened 1499 articles and included 5 RCTs including 1421 patients. We found that BID CCRT improved OS (hazard ratio, HR = 0.88, 95% confidence interval, CI 0.78-0.99, p = 0.03), the 1-year OS rate (OSR-1y, risk ratio, RR = 1.07, 95%CI 1.01-1.13, p = 0.03), and OSR-4y (RR = 1.22, 95%CI 1.03-1.43, p = 0.02), with better trends in OSR-2y, OSR-3y, and OSR-5y, compared to OD CCRT. In addition, BID CCRT had a higher complete response (CR, RR = 1.31, 95%CI 1.01-1.70, p = 0.04) than OD CCRT. PFS (HR = 0.92, 95%CI 0.79-1.07, p = 0.29), annual PFS rate, ORR (RR = 0.99, 95%CI 0.93-1.05, p = 0.72), and AEs for all grades (RR = 1.00, 95%CI 0.98-1.01, p = 0.57), and grades 3-5 (RR = 1.02, 95%CI 0.95-1.09, p = 0.60) were similar between the two arms. Conclusions: BID CCRT appears to be better than OD CCRT for limited-stage SCLC, with better antitumor effects (OS, OSR, and CR) and similar AEs. However, the high levels of AEs in both arms should be taken as a sign of caution. More large sample and high-quality RCTs need to be conducted to confirm our conclusions.