Current Patterns of Care for Patients with Extensive-Stage SCLC: Survey of U.S. Radiation Oncologists on Their Recommendations Regarding Prophylactic Cranial Irradiation

Radiation therapy for extensive-stage small-cell lung cancer in the era of immunotherapy

Unlike non-small-cell lung cancer (NSCLC), the progression of small-cell lung cancer (SCLC) is slow. Extensive-stage SCLC (ES-SCLC) is a serious threat to human health, with a 5-year survival rate of <7%. Chemotherapy has been the first-line treatment for the past 30 years. The anti-PD-L1 checkpoint blockades durvalumab and atezolizumab have greatly prolonged overall survival and have become the standard first-line therapy for ES-SCLC since the CASPIAN and IMpower133 trials. In the era of chemotherapy, radiation therapy (RT), including thoracic radiation therapy (TRT) and brain radiation therapy (BRT), has shown clinical effects in randomized and retrospective studies on ES-SCLC. RT-immunotherapy has shown exciting synergistic effects in NSCLC. For ES-SCLC, the clinical effects of combining TRT/BRT with immunotherapy have not yet been systematically explored. In this review, we found that studies on RT-immunotherapy in ES-SCLC are relatively few and limited to early phase studies focusing on toxicity. The efficacy and safety profiles of early phase studies encourage prospective clinical trials. In this review, we discuss the best population, optimum TRT dose, proper TRT time, and strategies for reducing radiation-induced neurotoxicity. Furthermore, we suggest that biomarkers and patient performance status should be fully assessed before RT-immunotherapy treatment. Prospective trials are needed to provide more evidence for RT-immunotherapy applications in ES-SCLC.

Survival impact of prophylactic cranial irradiation in small-cell lung cancer in the modern era of magnetic resonance imaging staging

Background

In the modern era of magnetic resonance imaging (MRI) staging, the benefit of prophylactic cranial irradiation (PCI) in patients with small-cell lung cancer (SCLC) has been controversial. This study evaluated the prognostic impact of PCI in patients with limited- or extensive-stage SCLC who had no brain metastases at diagnosis according to MRI.

Methods

Data from newly diagnosed patients in 2014 from the Korean Association for Lung Cancer Registry database were used. Patients with limited- or extensive-stage SCLC who had no brain metastases according to MRI were identified. Univariate and multivariate survival analyses were conducted to assess the prognostic association of PCI.

Results

Of 107 and 122 patients with limited- and extensive-stage SCLC, 24% and 14% received PCI, respectively. In the limited-stage SCLC group, the 2-year overall survival (OS) rates of patients who received PCI and those who did not were 50% and 29% (P = 0.018), respectively. However, there was no significant difference in OS for patients with extensive-stage SCLC (P = 0.336). After adjusting for other covariates, PCI was found to be associated with improved OS in the limited-stage SCLC group (P = 0.005). Based on the time-course hazard rate function plots in the limited-stage SCLC group, the OS benefit of PCI was maximized within the first year of follow-up.

Conclusions

In the modern era of MRI staging, PCI might be beneficial for patients with limited-stage SCLC but not for those with extensive-stage SCLC. Further studies with a large sample size are needed to verify the prognostic association of PCI.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13014-022-01994-8.

Prophylactic cranial irradiation in patients with small cell lung cancer in The Netherlands: A population-based study

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Prophylactic cranial irradiation (PCI) use declined in The Netherlands.

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Independent predictors for prescription of PCI were identified.

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An alarming increase of practice variation was observed.

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Alternative MRI surveillance is not strictly adhered to.

Introduction

Controversy has arisen regarding the benefit of prophylactic cranial irradiation (PCI) in patients with small cell lung cancer (SCLC), particularly since the 2017 Takahashi trial publication that supports MRI surveillance in extensive-stage (ES-)SCLC. The primary aim of this study was to assess trends and determinants in PCI use over the years 2010–2018. A secondary aim was to determine contemporary practice considerations among radiation oncologists (ROs).

Methods

A nationwide population-based cohort study was conducted using the Netherlands Cancer Registry data on all newly diagnosed SCLC patients (2010–2018). The change in PCI frequency over the years and determinants for PCI were analyzed using logistic regression models. Second, an online survey was performed among Dutch lung cancer ROs in 2020.

Results

Among 10,264 eligible patients, 4,894 (47%) received PCI. Compared to 2010–2014, PCI use significantly decreased in 2017–2018 in ES-SCLC (OR 0.68, 95%CI 0.60–0.77) and LS-SCLC (OR 0.56, 95%CI 0.47–0.67). Incidence year, age, performance status, and thoracic radiotherapy were independent determinants for PCI. Among 41 survey participants, PCI was recommended always/sometimes/never by 22%/71%/7% in ES-SCLC and 54%/44%/2% in LS-SCLC. For ES-SCLC and LS-SCLC, 63% and 25% of ROs, respectively, confirmed influence of the Takahashi trial on PCI recommendations. Denial of such influence was associated with insufficient institutional MRI capacity.

Conclusions

A significant declining trend of PCI use in both ES-SCLC and LS-SCLC was observed in The Netherlands since 2017. The Takahashi trial seems an explanation for this trend even in LS-SCLC, with differential influence of the trial depending on institutional MRI capacity. An alarming increase in practice variation regarding PCI was found which stresses the importance of ongoing trials.

Evolving Practice Patterns in the Use of Prophylactic Cranial Irradiation for Extensive-Stage Small Cell Lung Cancer

This survey study compares use of prophylactic cranial irradiation in patients with extensive-stage small cell lung cancer before and after the publication of a phase 3 trial that demonstrated no overall survival benefit for this therapy.

Limited-Stage Small Cell Lung Cancer: Is Prophylactic Cranial Irradiation Necessary?

PURPOSE

Prophylactic cranial irradiation (PCI) reduces the incidence of brain metastases in patients with limited stage small cell lung cancer (LS-SCLC). However, PCI is associated with neurotoxicity. Previous studies have not consistently used pretreatment magnetic resonance imaging. Modern imaging improvements continue to enhance early metastasis detection, potentially decreasing the utility of PCI. We sought to determine whether PCI was associated with improved outcomes in LS-SCLC patients with modern imaging.

METHODS AND MATERIALS

We identified LS-SCLC patients with no intracranial disease who were treated between 2007 and 2018. Kaplan-Meier estimates of overall survival (OS) and progression-free survival (PFS) were calculated and multivariate Cox proportional hazards models were generated. The cumulative incidence of brain metastases was estimated using competing risks methodology.

RESULTS

Ninety-two patients were identified without intracranial disease at initial staging, 39 of whom received PCI. Median follow-up was 56.7 months. The median OS for the cohort was 35.5 months (95% CI, 25.8-49.3), and median PFS was 19.1 months (95% CI, 12.3-30.5). Median OS with PCI versus observation was 37.9 months (95% CI, 31.8-not reached) versus 30.5 months (95% CI, 14.6-56.1; P = .07), whereas median PFS was 26.3 months (95% CI 19.1-not reached) versus 12.3 months (95% CI, 8.5-30.5; P = .02), respectively. Overall, at 2 years, the cumulative incidence of brain metastases was 10% with PCI and 29% without; this increased to 32% and 29% by 4 years (P = .66). In those patients who had negative magnetic resonance imaging of the brain after completing initial treatment, the 1-year cumulative incidence of brain metastasis was not significantly different at 8% versus 11% (P = .46) respectively. Both PCI and treatment response were independent predictors for PFS on multivariate analysis. Stratified by disease response, patients with a complete response did not benefit from PCI (P = .50), whereas those with partial response or stable disease experienced improved PFS (P = .01).

CONCLUSIONS

Overall, PCI was associated with improved PFS and reduced early incidence of brain metastases. Patients achieving a complete response to initial therapy did not experience a PFS benefit with PCI. This may indicate that subsets of LS-SCLC patients can potentially be spared from PCI in the era of modern imaging.

Prophylactic cranial irradiation in small cell lung cancer: a systematic review and meta-analysis

BACKGROUND

The efficacy of prophylactic cranial irradiation (PCI) in treating patients with small cell lung cancer (SCLC) has not been clear, and recent randomized studies have demonstrated conflicting results from previously published findings. The purpose of this study was to reevaluate the efficacy of PCI in patients with SCLC and to assess factors associated with its efficacy.

METHODS

We conducted a quantitative meta-analysis to explore the efficacy of PCI in patients with SCLC. A literature search was performed using EMBASE, MEDLINE, Cochrane and ClinicalTrials.gov databases. We pooled the data and compared overall survival (OS) and brain metastasis (BM) between patients treated with PCI (PCI group) and patients without PCI treatment (observation group).

RESULTS

Of the 1074 studies identified in our analysis, we selected seven studies including 2114 patients for the current meta-analysis. Our results showed that the PCI group showed decreased BM (HR = 0.45, 95% CI: 0.38-0.55, P < 0.001) and prolonged OS (HR = 0.81, 95% CI: 0.67-0.99, P < 0.001). However, in terms of OS, the pooled analysis showed a high heterogeneity (I² = 74.1%, P = 0.001). In subgroup analyses of OS, we found that the heterogeneity mainly came from patients with brain imaging after initial chemoradiotherapy (HR = 0.94, 95% CI: 0.74-1.18, P = 0.59).

CONCLUSIONS

The results of this study showed that PCI has a significant effect on decreasing BM but little benefit in prolonging OS when brain imaging was introduced to confirm lack of BM after initial chemoradiotherapy and before irradiation.

Effect of Prophylactic Cranial Irradiation on Overall Survival in Metastatic Small-Cell Lung Cancer: A Propensity Score-Matched Analysis

INTRODUCTION

Patients with small-cell lung cancer (SCLC) have a high incidence of occult brain metastases and are often treated with prophylactic cranial irradiation (PCI). Despite a small survival advantage in some studies, the role of PCI in extensive stage SCLC remains controversial. We used the National Cancer Database to assess survival of patients with metastatic SCLC treated with PCI.

PATIENTS AND METHODS

Metastatic SCLC patients without brain metastases were identified. To minimize treatment selection bias, patients with an overall survival (OS) < 6 months were excluded. Cox regression identified variables associated with OS. Patients were propensity score-matched on factors associated with receipt of PCI or OS. The effect of PCI on OS was examined using Kaplan-Meier estimates.

RESULTS

In the overall cohort (n = 4257), treatment with PCI (n = 473) was associated with improved survival (hazard ratio, 0.66; 95% confidence interval, 0.60-0.74; P < .0001). Comparisons of propensity score-matched cohorts revealed a significant survival benefit for patients who received PCI in median OS (13.9 vs. 11.1 months; P < .0001), as well as 1- and 2-year OS (61.2% vs. 44.0% and 19.8% vs. 11.5%, respectively; P < .0001). This survival benefit persisted even after excluding patients who survived < 9 months (median: 15.3 vs. 12.9 months; P < .0001). In multivariable analysis, predictors of receipt of PCI were Caucasian race, younger age, and lower Charlson-Deyo score.

CONCLUSION

Using a modern population-based data set, we showed that metastatic SCLC patients treated with PCI have significantly improved OS. This large retrospective study helps address the conflicting prospective data.

Radiation therapy in small cell lung cancer: a national Italian survey

INTRODUCTION

Radiation therapy plays an important role in the management of SCLC both in curative and palliative setting, however, conflicting data from clinical trials incite debate over the appropriate use of radiation therapy regarding prophylactic cranial irradiation (PCI) and/or thoracic consolidative in extensive-stage SCLC (ES-SCLC). This survey is conducted to evaluate the current pattern of care among Italian radiation oncologists.

METHODS

In June 2016, all Italian radiation oncologists were invited to a web-based survey. The survey contained 34 questions regarding the role of RT in SCLC. Questions pertaining the role of RT in the clinical management of both limited-stage (LS) and ES-SCLC were included.

RESULTS

We received 48 responses from Italian radiation oncologists. More than half of respondents had been practicing for more than 10 years after completing residency training and 55% are subspecialists in lung cancer. Preferred management of LS-SCLC favored primary concurrent chemoradiotherapy (89%), even if the 36.9% usually delivered RT during or after the cycle 3 of chemotherapy, due to organizational issues. The most common dose and fractionation schedule in this setting was 60 Gy in 30 once-daily fractions. Furthermore, almost all respondents recommended PCI in patients with LS-SCLC. For ES-SCLC scenario, chemotherapy was defined the standard treatment by all respondents. PCI was recommended in ES-SCLC patients with thoracic complete remission (63% of respondents), with thoracic partial response (45%) and with thoracic stable disease (17%) after first-line chemotherapy. Lastly, the thoracic consolidative RT was recommended by 51% of respondents in patients with ES-SCLC in good response after first-line chemotherapy and a great variability was shown in clinical target volume definition, doses and fractionation schedules.

CONCLUSIONS

Our analysis showed a high adherence to current guidelines among the respondents in regard to chemoradiation approach in LS-SCLC patients and to PCI indications and doses. The great variability in radiation therapy doses and volumes in the thoracic consolidative radiotherapy in ES-SCLC is concerning. Future clinical trials are needed to standardize these treatment approaches to improve treatment outcomes among patients with ES-SCLC.

The Role of Prophylactic Cranial Irradiation in Patients With Extensive Stage Small Cell Lung Cancer: A Systematic Review and Meta-Analysis

INTRODUCTION

The role of prophylactic cranial irradiation (PCI) is controversial in patients with extensive stage small cell lung cancer. The aim of this study was to determine the impact of PCI in these patients.

METHODS

We performed a systematic review and meta-analysis in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. A systematic literature search was conducted in MEDLINE, EMBASE, and the Cochrane Central Register. The primary outcome was overall survival (OS).

RESULTS

We identified five studies comprising 984 patients, of whom 448 received PCI and 536 did not receive PCI. In pooled estimates, PCI did not statistically improve OS compared with controls (hazard ratio [HR] = 0.82; 95% confidence interval [CI]: 0.60-1.11; I² = 77%; p = 0.19). However, the PCI group had a significant advantage in 1-year survival compared to the no-PCI group (37.1% versus 27.1%; risk ratio = 0.87; 95% CI: 0.80-0.95; I² = 47%; p = 0.002), and the pooled estimates indicated that progression-free survival and the risk of brain metastasis were associated with significant benefit in the PCI group (HR = 0.83; 95% CI: 0.70-0.98; I² = 22%; p = 0.03; and HR = 0.34; 95% CI: 0.23-0.50; I² = 0%; p < 0.001, respectively).

CONCLUSIONS

Our findings suggest that PCI in patients with extensive stage small cell lung cancer may lead to a significant benefit in 1-year survival, progression-free survival, and the risk of brain metastasis, despite the lack of a significant advantage in OS.

Prophylactic Cranial Irradiation for Limited-Stage Small-Cell Lung Cancer: Survey of US Radiation Oncologists on Current Practice Patterns

PURPOSE

Prophylactic cranial irradiation (PCI) in patients with limited-stage small-cell lung cancer (LS-SCLC) is considered the standard of care. Meta-analysis of 7 clinical trials indicates a survival benefit to PCI, but all of these trials were conducted in the pre-magnetic resonance imaging (MRI) era. Therefore, routine brain imaging with MRI before PCI-as recommended by National Comprehensive Cancer Network guidelines-is not directly supported by the evidence. Current US practice patterns for patients with LS-SCLC are unknown.

MATERIALS AND METHODS

We surveyed practicing US radiation oncologists via an institutional review board-approved online questionnaire. Questions covered demographic information and treatment recommendations for LS-SCLC.

RESULTS

We received 309 responses from US radiation oncologists. Ninety-eight percent recommended PCI for patients with LS-SCLC, 96% obtained brain MRI before PCI, 33% obtained serial brain imaging with MRI after PCI to detect new metastases, and 35% recommended memantine for patients undergoing PCI. Recommending memantine was associated with fewer years of practice (P < .001), fewer lung cancer patients treated per year (P = .045), and fewer LS-SCLC patients treated per year (P = .024).

CONCLUSION

Almost all responding radiation oncologists recommended PCI and pre-PCI brain MRI for LS-SCLC patients with disease responsive to initial therapy. Only a third of respondents followed these patients with serial brain MRI. Approximately one third provided memantine therapy to try to limit neurocognitive effects of PCI. Further research is warranted to determine the best treatment for patients with LS-SCLC. This survey can inform the development of future trials that depend on participation from radiation oncologists.

Current Practice Patterns Surrounding Fertility Concerns in Stage I Seminoma Patients: Survey of United States Radiation Oncologists

PURPOSE

Patients with testicular seminoma may face fertility issues because of their underlying disease as well as treatments they undergo. The current patterns of practice among U.S. radiation oncologists aimed at assessing and preserving fertility in patients with Stage I seminoma are unknown.

METHODS

We surveyed practicing U.S. radiation oncologists via an Institutional Review Board-approved online questionnaire. Respondents' characteristics and perceived patient infertility rates were analyzed for association with treatment recommendations.

RESULTS

We received 353 responses, of whom one quarter (23%) consider themselves experts. A vast majority (84%) recommend observation as a default strategy. Fifty-two percent routinely advise fertility assessment for patients before observation or chemotherapy, and 74% routinely do so before adjuvant radiation therapy (RT). Forty-one percent and 43% believe that 10% and 30% of patients are infertile following orchiectomy, respectively. Thirty-seven percent and 22% believe infertility rates following para-aortic RT to be 30% and 50%, respectively. Eighty percent routinely use clamshell scrotal shielding. Responders with higher perceived infertility rates are more likely to recommend fertility assessment/sperm banking (Fisher's exact p < 0.0001). Responders who routinely advised fertility assessment were more likely to use clamshell shielding (Cochran-Armitage trend test p = 0.0007). Clamshell use was positively correlated with higher perceived infertility rates following para-aortic RT (Spearman's correlation coefficient = 0.006).

CONCLUSIONS

Despite a clear knowledge of fertility issues in men diagnosed with seminoma, there is no universal adoption of fertility assessment among U.S. radiation oncologists.

Usage of Prophylactic Cranial Irradiation in Elderly Patients With Small-cell Lung Cancer

BACKGROUND

Prophylactic cranial irradiation (PCI) reduces the risk of overt brain metastases in patients with small-cell lung cancer (SCLC) and is currently recommended in guidelines for both limited and extensive disease. Given the concerns about the greater frequency of neurologic side effects in elderly patients, we studied the association among age, PCI usage, and survival for SCLC patients in the Netherlands.

PATIENTS AND METHODS

Data from the Netherlands Cancer Registry for patients diagnosed with SCLC from 2009 to 2013 were queried. Separate analyses were performed for patients with stage I to III, treated with chemoradiotherapy (n = 1684) and patients with stage IV, treated with chemotherapy or chemoradiotherapy (n = 3481). Patients with brain metastasis at diagnosis were excluded.

RESULTS

For patients with stage I to III, the overall PCI usage rate was 74%, and the rate decreased with age, from 78% for patients aged 18 to 59 years to 66% for patients aged ≥ 80 years. For patients with stage IV, the overall PCI usage rate was 41% and decreased with age, from 46% for patients aged 18 to 59 years to 23% for patients aged ≥ 80 years. Gender and socioeconomic status did not affect the PCI rates. For patients aged < 70 years and treated with PCI, the median survival was 45, 24, and 12 months for stage I and II, III, and IV, respectively. For patients aged ≥ 70 years treated with PCI, the corresponding survival duration was 33, 17, and 10 months.

CONCLUSION

In the Dutch population, PCI usage rates were fairly high but were significantly lower for elderly patients.

Radiation Therapy in Extensive Stage Small Cell Lung Cancer

Lung cancer is the major cancer killer in the Western world, with the small cell lung cancer (SCLC) representing around 15–20% of all lung cancers. Extensive disease small cell lung cancer (ED SCLC) is found in approximately two-thirds of all cases, composed of both metastatic (M1) and non-metastatic (but presumably with tumor burden too large for locoregional-only approach) variant. Standard treatment options involve chemotherapy (CHT) over the past several decades. Radiation therapy (RT) had mostly been used in palliation of locoregional and/or metastatic disease. In contrast to its established role in treating metastatic disease, thoracic RT (TRT) had never been established as important part of the treatment aspects in this setting. In the past two decades, thoracic oncologists have witnessed wide introduction of modern RT and CHT aspects in ED SCLC, which led to more frequent use of RT and rise in the number of clinical studies. Since the pivotal study of Jeremic et al., who were the first to show importance of TRT in ED SCLC, a number of single-institutional studies have reconfirmed this observation, while recent prospective randomized trials (CREST and RTOG 0937) brought more substance to this issue. Similarly, the issue of prophylactic cranial irradiation was investigated in EORTC and the Japanese study, respectively, bringing somewhat conflicting results and calling for additional research in this setting. Future studies in ED SCLC could incorporate questions of RT dose and fractionation as well as the number of CHT cycles and type of combined Rt-CHT (sequential vs concurrent).

Nine-year Experience: Prophylactic Cranial Irradiation in Extensive Disease Small-cell Lung Cancer

BACKGROUND

In 2007, the European Organization for Research and Treatment of Cancer (EORTC) study (ClinicalTrials.gov identifier, NCT00016211) demonstrated a beneficial effect on overall survival (OS) with the use of prophylactic cranial irradiation (PCI) for extensive disease (ED) small-cell lung cancer (SCLC). Nevertheless, debate is ongoing regarding the role of PCI, because the patients in that trial did not undergo magnetic resonance imaging (MRI) of the brain before treatment. Also, a recent Japanese randomized trial showed a detrimental effect of PCI on OS in patients with negative pretreatment brain MRI findings.

MATERIALS AND METHODS

We examined the medical records of 136 patients with ED SCLC who had initially responded to chemotherapy and undergone PCI from 2007 to 2015. The outcomes, radiation toxicity, neurologic progression-free survival, and OS after PCI were analyzed. Survival and correlations were calculated using log-rank and univariate Cox proportional hazard ratio analyses.

RESULTS

The median OS and the median neurologic progression-free survival after PCI was 12 and 19 months, respectively. No significant survival difference was seen for patients who had undergone MRI before PCI compared with patients who had undergone contrast-enhanced computed tomography (P = .20). Univariate analysis for OS did not show a statistically significant effect for known cofactors.

CONCLUSION

In the present cohort, PCI was associated with improved survival compared with the PCI arm of the EORTC trial, with a nearly doubled median OS period. Also, the median OS was prolonged by 2 months compared with the irradiation arm of the Japanese trial.