Prophylactic cranial irradiation is associated with improved survival following resection for limited stage small cell lung cancer

Prophylactic cranial irradiation in resected early stage small cell lung cancer: an updated systematic review and meta-analysis

BACKGROUND

The use of prophylactic cranial irradiation (PCI) in early stage small cell lung cancer (SCLC) patients post-surgery remains controversial. This meta-analysis aimed to evaluate the efficacy of PCI in resected early stage SCLC patients.

METHODS

Relevant literature was reviewed through PubMed, Cochrane, and Embase databases. The pooled hazard ratios (HRs) for overall survival (OS) were analyzed for the overall population, as well as for pathologically node-negative (pN0) and pathologically node-positive (pN+) patients. We also assessed the pooled HRs for brain metastasis-free survival (BMFS) in all patients. Sensitivity analyses were conducted to validate these results.

RESULTS

A total of 13 retrospective studies were included, encompassing 3,530 postoperative SCLC patients, of whom 880 received PCI treatment. In the overall patient population, PCI significantly improved OS compared to non-PCI group (HR: 0.66, 95% CI 0.58-0.74, p < 0.001). For pN0 patients, there was no significant OS benefit from PCI (HR: 0.85, 95% CI 0.65-1.10, p = 0.22). In contrast, pN + patients showed a significant OS improvement with PCI (HR: 0.52, 95% CI 0.41-0.66, p < 0.001). Furthermore, PCI significantly improved BMFS in all patients (HR: 0.42, 95% CI 0.29-0.60, p < 0.001). Sensitivity analyses confirmed the stability of these results.

CONCLUSIONS

PCI was associated with a significant improvement in OS and BMFS in resected early stage SCLC patients. The benefits of PCI were particularly pronounced in pN + patients, whereas pN0 patients did not experience a significant OS benefit. These findings supported the selective use of PCI based on nodal status to optimize treatment outcomes in postoperative SCLC patients.

Prophylactic cranial irradiation in patients with resected small-cell lung cancer: A systematic review and meta-analysis

Prophylactic cranial irradiation (PCI) was recommended for limited-stage small-cell lung cancer (SCLC) patients with complete or partial response to primary chemoradiotherapy. But it is still controversial regarding its role in SCLC patients who have had radical resection. This meta-analysis aims to evaluate the efficacy of PCI in resected SCLC patients. We searched PubMed, EMBASE, Web of Science, CENTRAl, and ClinicalTrials for controlled trials and cohort studies regarding PCI in postoperative SCLC patients. The correlation between PCI and post-operative outcomes in SCLC patients, including survival and brain metastasis rate (BMR), was examined using hazard ratios (HRs) and risk ratios with corresponding 95% confidence intervals. Quality of studies was assessed by the Newcastle-Ottawa Scale (NOS), and publication bias was assessed by Begg's test. Meta-analysis of eight studies with 2688 patients in total showed PCI was associated with improved overall survival (OS) for resected SCLC (HR: 0.65, 95% CI: 0.57-0.75, p < 0.01). In addition, subgroup analysis on three studies including 923 patients confirmed the protective role of postoperative PCI in N0 SCLC patients (HR: 0.79, 95% CI: 0.61-0.97, p < 0.05). There was also a significant reduction in BMR in the PCI group pooled from six studies (HR: 0.58, 95% CI: 0.40-0.85, p < 0.01). The use of PCI delayed brain recurrence and improved OS in patients with resected, stage I-III SCLC. Importantly, patients with N0 SCLC can also benefit from postoperative PCI. In future studies, PCI's role in patients with resected N0 SCLC at different T stage may need to be explored.

A systematic literature review of real-world treatment outcomes of small cell lung cancer

BACKGROUND

Robust evidence from real-world studies is needed to aid decision-makers and other stakeholders in choosing the best treatment options for patients. The objective of this work was to assess real-world outcomes of treatment strategies for limited- and extensive-stage small cell lung cancer (SCLC) prior to the global introduction of immunotherapies for this disease.

METHODS

Searches were conducted in MEDLINE and Embase to identify articles published in English from October 1, 2015, through May 20, 2020. Searches were designed using a combination of Medical Subject Heading (Medline), Emtree (Embase subject headings), and free-text terms such as SCLC. Observational studies reporting data on outcomes of initial treatment strategies in patients with limited- and extensive-stage SCLC were included. Studies with limited sample sizes (<100 patients), enrolled all patients prior to 2010, or did not report outcomes for limited- and extensive-stage SCLC separately were excluded. Data were extracted into a predesigned template by a single researcher. All extractions were validated by a second researcher, with disagreements resolved via consensus.

RESULTS

Forty articles were included in this review. Most enrolled patients from the United States (n = 18 articles) or China (n = 12 articles). Most examined limited-stage (n = 27 articles) SCLC. All studies examined overall survival as the primary outcome. Articles investigating limited-stage SCLC reported outcomes for surgery, chemotherapy and/or radiotherapy, and adjuvant prophylactic cranial irradiation. In studies examining multiple treatment strategies, chemoradiotherapy was the most commonly utilized therapy (56%-82%), with chemotherapy used in 18% to 44% of patients. Across studies, median overall survival was generally higher for chemoradiotherapy (15-45 months) compared with chemotherapy alone (6.0-15.6 months). Studies of extensive-stage SCLC primarily reported on chemotherapy alone, consolidative thoracic radiotherapy, and radiotherapy for patients presenting with brain metastases. Overall survival was generally lower for patients receiving chemotherapy alone (median: 6.4-16.5 months; 3 years, 5%-14.9%) compared with chemotherapy in combination with consolidative thoracic radiotherapy (median: 12.1-18.0 months; 3 years, 15.0%-18.1%). Studies examining whole-brain radiotherapy for brain metastases reported lower median overall survival (5.6-8.7 months) compared with stereotactic radiosurgery (10.0-14.5 months).

CONCLUSIONS

Under current standard of care, which has remained relatively unchanged over the past few decades, prognosis remains poor for patients with SCLC.

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.

Effect of surgery on survival in patients with stage III N2 small cell lung cancer: propensity score matching analysis and nomogram development and validation

Background

The standard treatment of stage III N2 small cell lung cancer (SCLC) is concurrent chemoradiation, and surgery is not recommended. This study was aimed to evaluate whether surgery has survival benefits in patients with stage III N2 SCLC and investigate the factors influencing survival of surgery.

Methods

Patients diagnosed with stage T1-4N2M0 SCLC from 2004 to 2015 were selected from the Surveillance Epidemiology End Results database. Propensity score matching (PSM) was used to balance confounders between patients who underwent surgery and those treated with radiation and/or chemotherapy. We compared overall survival (OS) of the two groups using Kaplan-Meier curves and a Cox proportional hazard model. We also identified prognostic factors in patients with surgical resection, and a nomogram was developed and validated for predicting postoperative OS.

Results

−A total of 5576 patients were included in the analysis; of these, 211 patients underwent surgery. PSM balanced the differences between the two groups. The median OS was longer in the surgery group than in the non-surgery group (20 vs. 15 months; p = 0.0024). Surgery was an independent prognostic factor for longer OS in the multivariate Cox regression analysis, and subgroup analysis revealed a higher survival rate in T1 stage patients treated with surgery (hazard ratio = 0.565, 95% confidence interval: 0.401–0.798; p = 0.001). In patients who underwent surgery, four prognostic factors, including age, T stage, number of positive lymph nodes, and radiation, were selected into nomogram development for predicting postoperative OS. C-index, decision curve analyses, integrated discrimination improvement, and time-dependent receiver operating characteristics showed better performance in nomogram than in the tumor-node-metastasis staging system. Calibration plots demonstrated good consistency between nomogram predicted survival and actual observed survival. The patients were stratified into three different risk groups by prognostic scores and Kaplan-Meier curves showed significant difference between these groups.

Conclusions

These results indicate that surgery can prolong survival in patients with operable stage III N2 SCLC, particularly those with T1 disease. A nomogram that includes age, T stage, number of positive lymph nodes, and radiation can be used to predict their long-term postoperative survival.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12957-021-02364-6.

pN1 but not pN0/N2 predicts survival benefits of prophylactic cranial irradiation in small-cell lung cancer patients after surgery

Background

Prophylactic cranial irradiation has been shown to reduce brain metastases and provide survival benefits in small-cell lung cancer (SCLC). However, its role in limited-stage SCLC patients after surgery remains unclear. Further, it is unknown whether the effect of prophylactic cranial irradiation is generalizable in these patients with different pathological nodal (N0-N2) stages, a state indicating the presence of tumor metastases.

Methods

We combined data from a single medical center and Surveillance, Epidemiology, and End Results database. Propensity score matching analyses were performed (1:2) to evaluate the role of prophylactic cranial irradiation in SCLC patients after surgery. Cox proportional hazards regression model was used to identify predictors of survival.

Results

124 (18.7%) out of 664 surgically-treated SCLC patients received prophylactic cranial irradiation treatment. Within the entire cohort, multivariate Cox regression analysis identified dataset source, age, pathological T and N stages, adjuvant chemotherapy, resection type, and histology as independent prognostic factors for overall survival. Prophylactic cranial irradiation appeared to be associated with a better overall survival, but the difference is marginally significant (P=0.063). Further, we stratified patients based on the pathological N0-N2 stages using propensity score matching analyses, which showed that prophylactic cranial irradiation treatment was superior to non-prophylactic cranial irradiation treatment for surgically-treated SCLC patients with N1 stage only (univariate analysis: P=0.026; multivariate Cox: P=0.004), but not N0/N2 stage (univariate analysis: P=0.65 and P=0.28, respectively; multivariate Cox: P=0.99 and P=0.35, respectively).

Conclusions

Prophylactic cranial irradiation provides survival benefits for SCLC patients with pN1 after surgery but not with pathological N0/N2 stage. Our findings may provide helpful stratifications for clinical decision-making of prophylactic cranial irradiation intervention in SCLC patients.

Impact of treatment modality on long-term survival of stage IA small-cell lung cancer patients: a cohort study of the U.S. SEER database

Background

The optimal treatment modality for patients with stage IA (T1N0M0) small-cell lung cancer (SCLC) is still unclear.

Methods

Patients who received surgical resection or chemo-radiotherapy (CRT) between January 2004 and December 2014 were identified from The Surveillance, Epidemiology and End Results (SEER) database. Surgical resection included lobectomy, wedge resection, segmentectomy with lymphadenectomy [examined lymph node (ELN) ≥1]. Propensity score match analysis was utilized to balance the baseline characteristics.

Results

A total of 686 stage IA SCLC cases were included: 337 patients underwent surgery and 349 patients were treated by CRT alone. Surgery achieved a better outcome than CRT alone, with an adjusted hazard ratio (HR) of 0.495. Patients who underwent lobectomy demonstrated a longer overall survival (OS), compared to those who received sublobectomy (crude cohort, median OS, 69 vs. 38 months; match cohort, median OS, 67 vs. 38 months). Patients with ELN >7 presented with longer OS than those with ELN ≤7 (crude cohort, median OS, 91 vs. 49 months; matched cohort, median OS, 91 vs. 54 months). The additional efficacy of chemotherapy or radiotherapy in patients receiving lobectomy was observed. The best prognosis was achieved in the lobectomy plus CRT cohort, with a 5-year survival rate of 73.5%.

Conclusions

The prolonged survival associated with lobectomy and chemotherapy or radiotherapy presents a viable treatment option in the management of patients with stage IA SCLC.

Review: Brain Metastases in Bladder Cancer

Nearly 50% of bladder cancer patients either present with metastatic disease or relapse distantly following initial local therapy. Prior to platinum-based chemotherapy, the incidence of bladder cancer central nervous system metastases was approximately 1%; however, their incidence has increased to 3–16% following definitive treatment as platinum-based regimens have changed the natural history of the disease. Bladder cancer brain metastases are generally managed similarly to those from more common malignancies such as non-small cell lung cancer, with surgery +/–adjuvant radiotherapy, or radiotherapy alone using stereotactic radiosurgery or whole brain radiotherapy. Limited data suggest that patients with inoperable urothelial carcinoma brain metastases who are not candidates for stereotactic radiosurgery may benefit from shorter whole brain radiation therapy courses compared to other histologies, but data is hypothesis-generating. Given improvements in the efficacy of systemic therapy and supportive care strategies for metastatic urothelial carcinoma translating in improved survival, the incidence of intracranial failures may increase. Immune checkpoint blockade therapy may benefit cisplatin-ineligible metastatic urothelial carcinoma patients as first-line therapy; however, the effectiveness of immune checkpoint blockade to treat central nervous system disease has not been established. In this review, we discuss the incidence and management of bladder cancer brain metastases and considerations regarding variations in management relative to more commonly encountered non-urothelial histologies.

Hsa-miR-217 Inhibits the Proliferation, Migration, and Invasion in Non-small Cell Lung Cancer Cells Via Targeting SIRT1 and P53/KAI1 Signaling

Background:

Brain metastasis is a major cause of cancer death in patients with lung cancer. Sirtuin 1 and hsa-miR-217 have been identified to mediate the development of non-small cell lung cancer.

Aims:

To investigate the roles of hsa-miR-217, its target sirtuin 1, and the P53/KAI1 axis in the brain metastasis from non-small cell lung cancer.

Study Design:

Cell culture study.

Methods:

Human pulmonary adenocarcinoma brain metastasis cell line PC-14/B were incubated and treated with constructed lentiviral plasmids expressing miR-217 and/or sirtuin 1. BEAS-2B cell line was used as a control. The targeted regulation of miR-217 to sirtuin 1was examined using a dual-luciferase reporter assay. Cell proliferation, migration, invasion, and related protein expression were detected to examine the effect of the miR-217/sirtuin 1 expression on metastasis.

Results:

PC-14/B cells expressed higher sirtuin 1 and lower P53 and KAI1 compared with BEAS-2B control cells (p<0.05). Sirtuin 1 was a direct target of miR-217. MiR-217 expression suppressed PC-14/B cell invasion (p=0.004), migration (p=0.001), and proliferation (p<0.05), whereas sirtuin 1 overexpression reversed all processes. sirtuin 1 expression inhibited P53, KAI1/CD82, matrix metalloproteinase-9, and β-catenin but upregulated E-cadherin protein. MiR-217 overexpression induced reverse changes.

Conclusion:

Hsa-miR-217 and its target sirtuin 1 acted as metastasis suppressor and promoter gene in non-small cell lung cancer, respectively. The hsa-miR-217/sirtuin 1/P53/KAI1 metastasis regulatory pathway showed novel and crucial roles in brain metastasis from non-small cell lung cancer. This axis might be a potential target for the treatment of brain metastasis of lung cancer.