Outcomes of prophylactic cranial irradiation in patients with small cell lung cancer in the modern era of baseline magnetic resonance imaging of the brain

Efficacy evaluation of prophylactic cranial irradiation for limited stage small‑cell lung cancer in the magnetic resonance imaging era: A meta‑analysis

The role of prophylactic cranial irradiation (PCI) in patients with limited-stage small-cell lung cancer (LS-SCLC) remains controversial in the era of magnetic resonance imaging (MRI). The present study aimed to evaluate the effectiveness of PCI in the treatment of LS-SCLC in the era of MRI. The PubMed, EMBASE and Cochrane Library databases were searched from the time of database creation until May 24, 2023, to identify clinical studies that evaluated the effectiveness of PCI in patients with LS-SCLC in the MRI era. The references of the obtained studies were also reviewed to identify clinical studies that were not discovered in the initial search. All studies were screened in accordance with the inclusion criteria, and the data were extracted and subjected to meta-analysis using STATA17.0. In total, 21 studies were included in the analysis. Notably, 10 studies only used brain MRI at baseline to confirm the absence of brain metastases (BMs; pre-chemoradiotherapy MRI group), 7 studies used brain MRI prior to PCI to confirm the absence of BMs (pre-PCI MRI group) and 4 studies used active surveillance in the form of brain MRI following PCI (MRI surveillance group). The results of the meta-analysis demonstrated that for all included patients, PCI was associated with a significant improvement in overall survival time [OS; hazard ratio (HR), 0.61; confidence interval (CI), 0.53-0.70] and progression-free survival (HR, 0.69; CI, 0.61-0.79), as well as a significant decrease in the rate of BM (HR, 0.59; CI, 0.50-0.70). Subgroup analyses revealed that PCI remained effective in improving OS and reducing the rate of BM in patients with LS-SCLC who did not have BMs confirmed via brain MRI performed at baseline or prior to PCI. However, in the MRI surveillance group, PCI failed to significantly improve the OS (HR, 0.65; CI, 0.41-1.05), despite significantly reducing the BM rate (HR, 0.6; CI, 0.45-0.8) of LS-SCLC. Collectively, the results of the present study demonstrated that PCI remained effective in improving OS and reducing the rate of BM in patients with LS-SCLC who had the absence of BM confirmed via brain MRI at baseline or prior to PCI. Additionally, in patients with LS-SCLC who had undergone active surveillance using brain MRI following PCI, the incidence of BM was reduced, while the OS was not significantly improved. However, additional randomized controlled clinical studies are required to verify these findings.

The impact of Prophylactic cranial irradiation on the prognosis of patients with limited-stage small cell lung cancer in the MRI era

PURPOSES

To evaluate the impact of prophylactic cranial irradiation (PCI) on the prognosis of patients with limited-stage small cell lung cancer (SCLC) in the era of MRI surveillance.

METHODS

Limited-stage SCLC patients with complete remission (CR) or partial remission (PR) of tumor after definitive chemo-radiotherapy (CRT) were retrospectively analyzed. Survival data were calculated by Kaplan-Meier methods, Cox proportional hazards model was applied for multivariate prognostic analysis.

RESULTS

Between June 2002 and January 2017, 620 patients with limited-stage SCLC were accrued in our study. After CRT, 228 (36.8%) patients achieved CR, of whom, 29 patients did not receive PCI, among the rest 199 patients, 172 (86.4%) received brain MRI to exclude brain metastasis (BM) before PCI. With a median follow-up time of 25.6 months, the cumulative BM rate was 17.1% and 37.9% in patients who received or did not receive PCI (P = 0.011). The median survival time was 30.2 months and 30.5 months, respectively and the 1 -, 3 -, 5-year survival rates were 93.7%, 42.9%, 35.8% and 83.4%, 46.5%, 41.9%, respectively (P = 0.98). Multivariate analysis indicated that baseline KPS ≥ 90 was a favorable independent prognostic factor for OS in CR patients (HR: 0.33, 95% CI: 0.23-0.46, P = 0.000). After CRT, 392 (63.2%) patients achieved PR, 53 cases did not receive PCI and 310 (91.4%) of the remaining 339 patients received brain MRI before PCI. With a median follow-up time of 15.5 months, the cumulative brain metastasis rate was 12.7% and 46.2% respectively (P = 0.000). The median survival time was 25.7 months and 18.6 months, respectively. The 1 -, 3 -, and 5-year survival rates were 87.6%, 40.2%, 29.2% and 75.7%, 16.7%, 10.3% (P = 0.000). Baseline KPS ≥ 90 (HR: 0.32, 95% CI: 0.25-0.41, P = 0.000) and PCI (HR: 0.57, 95% CI: 0.41-0.79, P = 0.001) were favorable prognostic factors for OS in PR patients.

CONCLUSIONS

In this study, PCI significantly reduced the incidence of BM in patients with limited-stage SCLC who were evaluated as CR and PR after CRT, but it has no significantly positive impact on overall survival in CR patients. Further prospective randomized studies were warranted.

Analysis of high‑risk factors for brain metastasis and prognosis after prophylactic cranial irradiation in limited‑stage small cell lung cancer

Small cell lung cancer (SCLC) is an aggressive malignancy with a high propensity for brain metastases (BM). Limited-stage SCLC (LS-SCLC) can be effectively treated with chemoradiotherapy and prophylactic cranial irradiation (PCI) to enhance patient outcomes. The aim of the present study was to assess the risk factors and prognostic significance of brain metastases (BM) in patients with limited-stage small cell lung cancer (LS-SCLC) who attained complete remission (CR) or partial remission (PR) following combined chemoradiotherapy and subsequent prophylactic cranial irradiation (PCI). Data for 290 patients diagnosed with LS-SCLC and treated at Chengde Central Hospital and Hebei Cangzhou Hospital of Integrated Traditional Chinese and Western Medicine (Chengde, China), who achieved CR or PR and underwent PCI between 2015 and 2023, were retrospectively analyzed. BM rates and overall survival (OS) were estimated using the Kaplan-Meier method, whilst differences were assessed using the log-rank test. Risk factors affecting BM and OS were assessed using univariate and multivariate Cox regression analyses. The overall incidence of BM after PCI was 16.6% (48/290), with annual rates of 1.4, 6.6 and 12.8% at 1, 2 and 3 years, respectively. Multivariate Cox regression analysis identified an initial tumor size of >5 cm [hazard ratio (HR)=15.031; 95% confidence interval (CI): 5.610-40.270; P<0.001] as a significant independent risk factor for BM following PCI. The median OS was 28.8 months and the 5-year OS rate was 27.9%. The median OS for patients with and without BM at 27.55 and 32.5 months, respectively, and the corresponding 5-year OS rates were 8.3 and 31.8%, respectively (P=0.001). Median OS rates for stages I, II and III were 61.15, 48.5 and 28.4 months, respectively, with 5-year OS rates of 62.5, 47.1 and 21.6%, respectively (P<0.001). Further multivariate Cox regression analysis indicated that BM (HR=1.934; 95% CI: 1.358-2.764; P<0.001) and clinical stage (HR=1.741; 95% CI: 1.102-2.750; P=0.018; P=0.022) were significant independent risk factors associated with patient OS. In conclusion, a tumor size of >5 cm is a significant risk factor for BM following PCI in patients with LS-SCLS achieving CR or PR through radiotherapy and chemotherapy. Furthermore, BM and clinical staging independently influence OS.

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.

Efficacy of Prophylactic Cranial Irradiation According to the Risk of Extracranial Recurrence in Limited-Stage Small Cell Lung Cancer

PURPOSE

We aimed to evaluate the effectiveness of prophylactic cranial irradiation (PCI) for "early brain metastasis", which occurs before extracranial recurrence (ECR), and "late brain metastasis", which occurs after ECR, in limited-stage small cell lung cancer (LS-SCLC).

Materials and Methods

We retrospectively analyzed 271 LS-SCLC patients who underwent definitive chemoradiation. All patients were initially staged with brain magnetic resonance imaging and positron emission tomography. Intracranial recurrence (ICR), ECR, progression-free rate (PFR), and overall survival (OS) were analyzed as clinical endpoints. The competing risk of the first recurrence with ICR (ICRfirst) was evaluated. Significantly associated variables in multivariate analysis of ECR were considered as ECR risk factors. Patients were stratified according to the number of ECR risk factors.

RESULTS

The application of PCI was associated with higher PFR (p=0.008) and OS (p=0.045). However, PCI was not associated with any of the clinical endpoints in multivariate analysis. The competing risk of ICRfirst was significantly decreased with the application of PCI (hazard ratio, 0.476; 95% confidence interval, 0.243 to 0.931; p=0.030). Stage III disease, sequential, and stable disease after thoracic radiation were selected as ECR risk factors. For patients without these risk factors, the application of PCI was significantly associated with increased OS (p=0.048) and a decreased risk of ICRfirst (p=0.026).

CONCLUSION

PCI may play a role in preventing early brain metastasis rather than late brain metastasis after ECR, suggesting that only patients with a low risk of ECR may currently benefit from PCI.

Rare thoracic cancers: a comprehensive overview of diagnosis and management of small cell lung cancer, malignant pleural mesothelioma and thymic epithelial tumours

Despite the progress in outcomes seen with immunotherapy in various malignancies, including nonsmall cell lung cancer, the benefits are less in small cell lung cancer, malignant pleural mesothelioma and thymic epithelial tumours. New effective treatment options are needed, guided via more in-depth insights into the pathophysiology of these rare malignancies. This review comprehensively presents an overview of the clinical presentation, diagnostic tools, staging systems, pathophysiology and treatment options for these rare thoracic cancers. In addition, opportunities for further improvement of therapies are discussed.

Serum lactate dehydrogenase predicts brain metastasis and survival in limited-stage small cell lung cancer patients treated with thoracic radiotherapy and prophylactic cranial irradiation

BACKGROUND

Small cell lung cancer (SCLC) is characterized by a high risk of brain metastasis and poor survival. This study aims to assess the prognostic role of lactate dehydrogenase (LDH) in limited-stage small cell lung cancer (LS-SCLC) treated with thoracic radiotherapy (TRT) and prophylactic cranial irradiation (PCI).

METHODS

This study retrospectively evaluated 197 consecutive patients who underwent TRT and PCI for LS-SCLC between November 2005 and October 2017. Both pretreatment and maximal serum LDH levels (mLDH) during treatment were checked, and an increased LDH level was defined as more than 240 IU/ml. Clinical factors were tested for associations with intracranial progression-free survival (IPFS) and overall survival (OS) after PCI. The Kaplan-Meier method was used to calculate survival rates, and multivariate Cox regression analyses were carried out to identify variables associated with survival.

RESULTS

Of the total patients, 28 had higher pretreatment LDH levels and mLDH levels were increased in 95 patients during treatment. In patients in the normal and elevated mLDH groups, the 1‑, 2‑, and 5‑year IPFS rates were 96.7% vs. 90.1%, 91.7% vs. 73.8%, and 87.8% vs. 61.0% (P < 0.01), respectively. Compared to those with normal LDH levels, patients with increased mLDH levels had a higher cumulative risk of intracranial metastasis (hazard ratio [HR] 3.87; 95% confidence interval [CI] 1.73-8.63; P < 0.01) and worse overall survival (HR 2.59; 95% CI 1.67-4.04; P < 0.01). The factors LDH level at baseline or changes between pretreatment level and maximum level during treatment failed to predict brain metastases or OS with statistical significance. In the multivariate analyses, both mLDH during treatment (HR 3.53; 95% CI 1.57-7.92; P = 0.002) and patient age ≥ 60 (HR 2.46; 95% CI 1.22-4.94; P = 0.012) were independently associated with worse IPFS. Factors significantly associated with worse OS included mLDH during treatment (HR 2.45; 95% CI 1.56-3.86; P < 0.001), IIIB stage (HR 1.75; 95% CI 1.06-2.88; P = 0.029), and conventional radiotherapy applied in TRT (HR 1.66; 95% CI 1.04-2.65; P = 0.034).

CONCLUSION

The mLDH level during treatment predicts brain metastasis and survival in LS-SCLC patients treated with TRT and PCI, which may provide valuable information for identifying patients with poor survival outcomes and possible candidates for treatment intensification.

The overall survival impact of prophylactic cranial irradiation in limited-stage small-cell lung cancer: a systematic review and meta-analysis

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PCI for LS-SCLC patients has become more controversial.

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Literature search on PCI impact on overall survival in LS-SCLC yielded 28 studies.

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Meta-analysis of adjusted HRs revealed pooled HR of 0.62 (95% CI: 0.57–0.69).

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Findings support PCI in current practice while awaiting prospective trial results.

Background

Prophylactic cranial irradiation (PCI) for limited-stage small-cell lung cancer (LS-SCLC) patients has become more controversial. Since the publication of the systematic review by Aupérin et al. in 1999, no randomized controlled trials regarding PCI in LS-SCLC have been completed. The aim of this study was to systematically review and meta-analyze the effect of PCI on overall survival (OS) in patients with LS-SCLC.

Methods

A systematic search was conducted in the databases of MEDLINE (PubMed), Embase and the Cochrane library. Only studies that reported an adjusted hazard ratio (aHR), indicating the effect of PCI versus no PCI on OS (adjusted for confounders) in patients with LS-SCLC were included for critical appraisal and meta-analysis. A pooled aHR estimate was calculated using a random-effects model.

Results

Pooling of 28 retrospective studies including a total of 18,575 patients demonstrated a significant beneficial effect of PCI versus no PCI on OS with a pooled aHR of 0.62 (95% CI: 0.57–0.69). Substantial heterogeneity of reported aHRs among studies was observed (I² = 65.9%). Subgroup analyses revealed that this heterogeneity could partly be explained by study sample size. The pooled aHR among 7 versus 21 studies with a sample size of > 300 versus ≤ 300 patients was 0.79 (95% CI: 0.64–0.97) versus 0.56 (95% CI: 0.46–0.69; p < 0.001), respectively.

Conclusions

This meta-analysis demonstrates a significant beneficial effect of PCI on OS in patients with LS-SCLC. Larger studies reported a milder beneficial effect, possibly due to a decreased risk of model overfitting. Serious risk of selection and confounding bias were of concern due to the lack of prospective trials. These results support the role of PCI in standard clinical practice in patients with LS-SCLC while awaiting results of prospective trials on alternative strategies.