Metastatic location of extensive stage small-cell lung cancer: implications for thoracic radiation

Efficacy and safety of thoracic radiotherapy for extensive stage small cell lung cancer after immunotherapy in real world

The immunotherapy combined chemotherapy has been the standard treatment strategy for extensive-stage small lung cancer (ES-SCLC). The CREST trial reported consolidative thoracic radiotherapy (cTRT) improved overall survival (OS) for ES-SCLC with intrathoracic residual after chemotherapy. In this study, patients with ES-SCLC who received immunotherapy were assigned to receive either TRT or no TRT. TRT significantly improved progression-free survival (PFS), local recurrence-free survival (LRFS) and OS with well tolerated toxicity. Further sub-cohort analysis, TRT significantly improved LRFS in patients with oligo-metastasis and without liver metastasis.

Radiotherapy for extensive-stage small-cell lung cancer in the immunotherapy era

Currently, chemoimmunotherapy is the first-line treatment for extensive-stage small-cell lung cancer (ES-SCLC). However, only 0.8%-2.5% of the patients presented complete response after chemoimmunotherapy. Considering that ES-SCLC is highly sensitive to radiotherapy, the addition of radiotherapy after first-line treatment for ES-SCLC could further improve local control, which may be beneficial for patients' survival. Prior studies have shown that consolidative thoracic radiotherapy (cTRT) can decrease disease progression and improve overall survival in patients with ES-SCLC who respond well to chemotherapy. However, the efficacy and safety of cTRT in the immunotherapy era remain unclear owing to a lack of prospective studies. Prophylactic cranial irradiation (PCI) has been shown to decrease brain metastasis (BM) and prolong survival in patients with limited-stage SCLC in previous reports. However, according to current guidelines, PCI is not commonly recommended for ES-SCLC. Immunotherapy has the potential to reduce the incidence of BM. Whether PCI can be replaced with regular magnetic resonance imaging surveillance for ES-SCLC in the era of immunotherapy remains controversial. Whole brain radiation therapy (WBRT) is the standard treatment for BM in SCLC patients. Stereotactic radiosurgery (SRS) has shown promise in the treatment of limited BM. Considering the potential of immunotherapy to decrease BM, it is controversial whether SRS can replace WBRT for limited BM in the immunotherapy era. Additionally, with the addition of immunotherapy, the role of palliative radiotherapy may be weakened in patients with asymptomatic metastatic lesions. However, it is still indispensable and urgent for patients with obvious symptoms of metastatic disease, such as spinal cord compression, superior vena cava syndrome, lobar obstruction, and weight-bearing metastases, which may critically damage the quality of life and prognosis. To improve the outcome of ES-SCLC, we discuss the feasibility of radiotherapy, including cTRT, PCI, WBRT/SRS, and palliative radiotherapy with immunotherapy based on existing evidence, which may offer specific prospects for further randomized trials and clinical applications.

Role of consolidative thoracic radiation in extensive-stage small-cell lung cancer with first-line chemoimmunotherapy: a retrospective study from a single cancer center

OBJECTIVE

To investigate the role of consolidative thoracic radiation (TRT) in extensive-stage small-cell lung cancer (ES-SCLC) receiving first-line chemo-immunotherapy followed by immunotherapy maintenance.

PATIENTS AND METHODS

Outcomes of patients without disease progression after first-line chemotherapy were retrospectively reviewed (January 2020 to December 2021). Based on TRT or not, patients were allocated to TRT group or non-TRT group. Progression-free survival (PFS), overall survival (OS) and local-recurrence free survival (LRFS) were calculated by the Kaplan-Meier method and compared by log-rank test.

RESULTS

Of 100 patients, 47 received TRT and 53 non-TRT. The median follow-up was 20.3 months. The median PFS and OS in TRT were 9.1 months and 21.8 months, versus 8.8 months (p = 0.93) and 24.3 months (p = 0.63), respectively, in non-TRT. The median LRFS time in TRT was not reached, but significantly longer than 10.8 months in non-TRT (HR = 0.27, p < 0.01). Second-line chemotherapy significantly prolonged survival compared to that with chemo-free patients (mOS: 24.5 vs. 21.4 months, p = 0.026). The subgroup analysis showed a trend of patients with brain metastases benefit from TRT (21.8 versus 13.7 months, HR 0.61, p = 0.38) while liver metastases did not. Of 47 patients with TRT, only 10.6% of patients experienced grade 3 radiation-induced pneumonitis, while no grade 4 or 5 adverse events occurred.

CONCLUSION

Consolidative TRT in the period of immunotherapy maintenance followed first-line chemo-immunotherapy did not prolong OS and PFS but associated with improved LRFS in ES-SCLC.

The prognostic risk stratification model for metastatic small-cell lung cancer: An analysis of the SEER database

Distant metastases of small-cell lung cancer (DM-SCLC) is an important factor in the selection of treatment strategies. In this study, we established a nomogram to predict DM-SCLC and determine the benefit of radiotherapy (RT) for DM-SCLC. We analyzed DM-SCLC prognosis based on surveillance, epidemiology, and end result database (SEER) data. A comprehensive and practical nomogram that predicts the overall survival (OS) of DM-SCLC was constructed and the results were compared with the 7th edition of the American Joint Committee on Cancer (AJCC) TNM stage system. A concordance index (C-index) and receiver operating characteristic plot were generated to evaluate the nomogram discrimination. The calibration was evaluated with a calibration plot, and its effectiveness was evaluated by a decision curve analysis (DCA). A score was assigned to each variable, and a total score was established for the risk stratification model. A total of 13,403 DM-SCLC patients were included. Eight characteristic variables were identified as independent prognostic variables. The C-index of the validation and training cohorts was 0.716 and 0.734, respectively. The area under the receiver operating characteristic curve (AUC) values of the nomogram used to predict 1-, 2-, and 3-year OS were 0.751, 0.744, and 0.786 in the validation cohorts (0.761, 0.777, 0.787 in the training cohorts), respectively. The calibration curve of 1-, 2-, 3-year survival rates showed that the prediction of the nomogram was in good agreement with the actual observation. The nomogram exhibited higher clinical utility after evaluation with the 1-, 2-, 3-year DCA compared with the AJCC stage system. A predictive nomogram and risk stratification model have been constructed to evaluate the prognosis of DM-SCLC effectively and accurately. This nomogram may provide a reference for prognosis stratification and treatment decisions.

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.

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.

Development and validation of a nomogram for assessing survival in extensive-stage small-cell lung cancer patients with superior vena cava syndrome referred for thoracic radiotherapy: a comparison of upfront vs. consolidative approaches

PURPOSE

This study sought to design and validate a nomogram capable of predicting outcomes in extensive-stage small-cell lung cancer (ES-SCLC) patients with superior vena cava syndrome (SVCS) based upon the timing of their radiotherapy treatment.

METHODS

We retrospectively analyzed data from 175 ES-SCLC patients with SCVS, comparing outcomes between those that underwent upfront thoracic radiotherapy (initial radiotherapy with simultaneous chemotherapy) and those that underwent consolidative thoracic radiotherapy (following 4-6 cycles of chemotherapy). Significant predictors of patient outcomes were identified using a Cox proportional hazard model and were used to construct our nomogram. This model was subsequently validated using receiver operating characteristic (ROC) curves, concordance index (C-index) values, and a risk classification system in order to evaluate its discriminative and predictive accuracy.

RESULTS

The overall survival (OS) of ES-SCLC patients with SVCS that underwent chemotherapy (CT), consolidative thoracic radiotherapy (cc-TRT), and upfront thoracic radiotherapy (cu-TRT) was 8.2, 11.7, and 14.9 months, respectively (p < 0.001), with respective progression-free survival (PFS) durations of 3.3, 5.0, and 7.3 months (p < 0.001). A multivariate regression analysis revealed age, gender, ECOG performance status, sites of tumor metastasis, and treatment approach to all be independent predictors of survival outcomes. A nomogram was therefore developed incorporating these factors. C‑index values upon internal and external validation of this nomogram were 0.7625 and 0.7959, respectively, and ROC and calibration curves revealed this model to be accurate and consistent.

CONCLUSIONS

We found that upfront thoracic radiotherapy in combination with chemotherapy may be associated with a positive impact on outcomes in ES-SCLC patients with SVCS.

Role of thoracic radiotherapy in extensive stage small cell lung cancer: a systemic review and meta-analysis

Background

The role of thoracic consolidation radiotherapy in patients with extensive stage small cell lung cancer (ES-SCLC) remains controversial. This study aimed to evaluate the efficacy of thoracic radiotherapy (TRT) in these patients.

Methods

A systematic literature search was performed in PubMed, Embase, and the Cochrane library to identify qualified clinical studies. The hazard ratios (HRs) and 95% confidence intervals (CIs) of overall survival (OS), progression-free survival (PFS) and local recurrence-free survival (LRFS) were extracted, and toxicity of the TRT group versus non-TRT group was analyzed.

Results

A total of 12 studies were included in this meta-analysis, including 936 patients in the TRT group and 1,059 patients in the non-TRT group. The combined results showed that TRT significantly improved OS (HR =0.65; 95% CI: 0.55–0.77, P<0.00001), PFS (HR =0.64; 95% CI: 0.56–0.72, P<0.00001) and LRFS (HR =0.38, 95% CI: 0.26–0.53, P<0.00001). Subgroup analysis showed that OS benefits were observed in patients receiving sequential TRT (HR =0.67; 95% CI: 0.54–0.84, P=0.0006). The addition of TRT significantly improved OS in patients over 65 years of age (HR =0.55; 95% CI: 0.40–0.74, P=0.0001). For patients with only one organ metastasis, there was no significant difference in OS between the two groups (HR =0.61; 95% CI: 0.36–1.01, P=0.06). There was no statistical difference in hematologic toxicity (leukopenia, thrombocytopenia, anemia) and non-hematologic toxicity (nausea or vomiting) between the two groups. The incidence of grade ≥3 esophageal toxicity was 4.6% in the TRT group and 0% in the non-TRT group (P=0.0001). Grade ≥3 bronchopulmonary toxicity was 2.9% in the TRT group and 0.8% in the non-TRT group (P=0.02).

Conclusions

TRT improves OS, PFS and LRFS in patients with ES-SCLC, with a low increase in esophageal and bronchopulmonary toxicity. More randomized controlled trials (RCTs) are expected to confirm our conclusions.

PROSPERO registration number

CRD42020190575.

Radiotherapy for primary tumor in lung cancer with synchronous metastases: Overview from the past and proposal for the future

The management of metastatic lung cancers, either of the small-cell (SCLC) or the non-small cell (NSCLC) subtype, largely based on systemic treatments so far, has been the subject of breakthrough advances over the past few years, with notably the wide use of immunotherapy changing the landscape of these harmful prognosis diseases. In parallel with this major progress, the increasing use of radiotherapy (RT) for the treatment of the primary thoracic lesion±the distant lesions, may contribute to improving the condition of these metastatic patients, both in terms of progression-free survival (PFS) and overall survival (OS). This review proposes to summarize and explain the findings provided by the different studies published in the last years experiencing RT of the primary tumor in metastatic lung cancers, either associated or not with the local ablative treatment of a low number of distant lesions. It will also expose the respective limits encountered in these studies and, in the light of all these elements, suggests various promising issues and fields of research for the future.