Local Thermal Ablation with Continuous EGFR Tyrosine Kinase Inhibitors for EGFR-Mutant Non-small Cell Lung Cancers that Developed Extra-Central Nervous System (CNS) Oligoprogressive Disease

Outcomes of First-Line Microwave Ablation of Treatment-Naive Epidermal Growth Factor Receptor-Mutated Advanced Lung Adenocarcinoma Treated with Tyrosine Kinase Inhibitors

PURPOSE

To investigate the outcomes of first-line image-guided microwave ablation (MWA) plus tyrosine kinase inhibitors (TKIs) in untreated epidermal growth factor receptor (EGFR)-mutant advanced lung adenocarcinoma (LUAD) and to compare with TKIs alone.

MATERIALS AND METHODS

This retrospective cohort study included patients between December 2015 and December 2021 and was divided into 2 groups (Group A: first-line MWA+TKIs; Group B: TKIs alone). Progression-free survival (PFS) was the primary end point, whereas overall survival (OS) was the secondary end point and were compared via the Kaplan-Meier methods. Univariate and multivariate analyses were used to investigate the predictors of PFS and OS. Propensity score matching (1:1 ratio) was applied between Group B and the subgroup of complete ablation in Group A.

RESULTS

A total of 117 patients were included (Group A: n = 43; Group B: n = 74). In a mean follow-up of 47.0 months (SD ± 19.4), Group A had significantly longer median PFS (19.0 vs 10.0 months; P < .001) and OS (41.0 vs 25.0 months; P = .044) than Group B. Predictors of PFS included first-line MWA (P < .001) and tumor stage (P = .020), while that of OS included first-line MWA (P = 0.039), tumor stage (P = 0.014), and usage of third-generation TKIs (P = 0.001). There were 23 pairs of patients obtained after propensity score matching (Group A1: complete ablation+TKIs; Group B1: TKIs alone). Group A1 had significantly longer median PFS (24.0 vs 10.0 months; P < .001) and OS (48.0 vs 24.0 months; P = .012) than Group B1.

CONCLUSIONS

First-line MWA significantly improved the outcomes of patients with untreated EGFR-mutant advanced LUAD treated with TKIs. Complete ablation predicted a better prognosis.

The clinical value of local consolidative therapy for oligo-residual disease in PD-1/PD-L1 inhibitors-treated non-small cell lung cancer

Background

Few real-world studies exist regarding the clinical value of local consolidative therapy (LCT) for oligo-residual disease (ORD) in NSCLC patients treated with immune checkpoint inhibitors. Therefore, we retrospectively evaluated whether LCT could improve the prognosis of NSCL patients with ORD after effective first-line PD-1/PD-L1 inhibitors treatment.

Methods

A total of 132 patients with metastatic NSCLC who had received first-line PD-1/PD-L1inhibitors-based systemic treatment and developed ORD (defined as residual tumors limited to three organs and five lesions) were included. The LCT group consisted of 41 patients received LCTs for oligo-residual lesions before treatment failure, and the remaining 91 patients, who did not receive local therapies, constituted the non-LCT group. The progression-free survival (PFS) and overall survival (OS) of the two groups were analyzed.

Results

With a median follow-up of 12.0 months, 86 patients developed progressive disease and 42 patients died. Compared with the non-LCT group, LCT group exhibited significant longer progression-free survival (PFS) (median 11.0 vs. 7.0 months, P=0.017) and overall survival (OS) (median 26.0 vs. 17.0 months, P=0.003). Multivariable analysis demonstrated that LCT was an independent predictor of prolonged PFS (HR=0.606, 95% CI=0.370-0.964, P=0.035) and OS (HR=0.467, 95% CI=0.229-0.949, P=0.035). Subgroup analysis revealed that the dominant population considerably benefited from LCT in terms of PFS and OS included patients with 1-2 residual tumor sites (mPFS: 11.0 vs. 7.0 months, P=0.013; mOS: 23.0 vs. 17.0 months, P=0.018) and those with high PD-L1 expression (mPFS: 13.0 vs. 7.0 months, P=0.018; mOS: 34.0 vs. 16.0 months, P=0.030). In addition, the All-LCT group had significantly longer PFS (mPFS 16.0 vs. 7.0, P=0.002) and OS (mOS 28.0 vs. 17.0, P= 0.002) than did the non-LCT group. However, patients who received LCT to only some of their lesions had not experienced improvements in PFS (P=0.546) or OS (P=0.198).

Conclusion

LCT may provide extra survival benefits among patients with oligo-residual NSCLC after effective first-line PD-1/PD-L1 inhibitors treatment, particularly in those patients with one or two residual lesions, high PD-L1 expression, or who had received LCT for all lesions. LCT may be a novel treatment option for this specific population.

Safety and efficacy of percutaneous cryoablation for primary and metastatic pleural based tumors

PURPOSE

Assess safety and local tumor progression-free survival (LTPFS) of percutaneous cryoablation for pleural-based thoracic malignancies.

MATERIALS AND METHODS

Retrospective study of 46 patients (17 treated for palliation; 9 for oligoprogression; 20 for curative intent), with 62 pleural-based thoracic lesions, treated in 59 cryoablation sessions. Patients were treated from 9/2005-11/2021 with CryoCare CS (Varian, Irvine, CA) or IceFORCE (Boston Scientific, Marlborough, MA) systems. For tumors treated with curative intent and/or oligoprogression, LTPFS of the treated tumor(s) and overall survival (OS) were estimated using Kaplan-Meier method. Post-operative complications were reported for all sessions, including those with palliative intent; univariate analyses were used to calculate factors associated with increased complication risk.

RESULTS

Median number of tumors treated in a single treatment session was 1 (range 1-4). Largest dimension of the treated tumor was 2.1 cm [IQR:0.9-5 cm]. Of the 59 treatments, 98.3 % were technically successful. Median LTPFS was 14.4 (95 % CI: 9.4-25.6) months. Tumor size was a significant predictor of LTPFS (HR: 1.21, 95 % CI: 1.03-1.44, p = 0.023). Median OS was 52.4 (28.1-NR) months. Complications occurred in 28/59 sessions (47.5 %); 2/59 (3.4 %) were ≥ grade D by Society of Interventional Radiology adverse event criteria (death; hypoxia requiring supplemental oxygen upon discharge). Pain and pneumothorax were the most common complications. The length of lung parenchyma traversed was a significant predictor of pneumothorax: HR 0.48 (95 %CI: 0.14-0.83), p = 0.0024.

CONCLUSION

Percutaneous cryoablation for pleural lesions is associated with a long duration of local control and most complications were minor and self-limited.

Efficacy and safety of microwave ablation and its synergistic potential in the treatment of early-stage non-small cell lung cancer

Lung cancer remains the primary cause of cancer-related mortality globally. In the case of early-stage non-small cell lung cancer (NSCLC), surgical resection, such as lobectomy and sub-lobectomy, continues to be the established standard treatment. However, for patients with insufficient cardiopulmonary function and multiple comorbidities who are unable to undergo surgical resection, nonoperative local therapies, including radiotherapy and thermal ablation, are preferred. In recent years, microwave ablation (MWA) has gained popularity for treating early-stage NSCLC due to its high heating efficiency, good tissue conductance, and heat conduction capabilities. This review provides a comprehensive summary of the current efficacy and safety data regarding MWA for early-stage NSCLC and discusses the potential benefits of combining MWA with other therapies.

The Emerging Role of Radiotherapy in Oligoprogressive Non-Small Cell Lung Cancer

Oligoprogressive disease (OPD) is an emerging concept that describes patients who have progression of disease in a limited number of metastatic sites while on systemic therapy. Growing evidence has suggested the integration of local ablative therapy with systemic agents in patients with OPD further improves survival. In oligoprogressive non-small cell lung cancer, stereotactic body radiotherapy may have an important role in the effective local control of selective progressing metastases, which may translate to better patient outcomes. This review explores the treatment paradigm of this subset of patients and provides an update on the current existing literature on this topic.

Percutaneous image-guided thermal ablation of lung cancer: What is the evidence?

Thermal ablation techniques have now been used for more than twenty years in the treatment of primary lung tumours, predominantly non-small cell lung cancer (NSCLC). Although primarily used for the treatment of early-stage disease in non-surgical patients, thermal ablation is now also being used in selected patients with oligometastatic and oligoprogressive disease. This review discusses the techniques available for thermal ablation, the evidence for use of thermal ablation in primary lung tumours in early- and advanced-stage disease and compares thermal ablation to alternative treatment strategies.

SPACES: Our team's experience in lung tumor microwave ablation

The standard treatment of stage I nonsmall cell lung cancer is lobectomy with systematic mediastinal lymph node evaluation. Unfortunately, up to 25% of patients with stage I nonsmall cell lung cancer are not candidates for surgery due to severe medical comorbidities (poor cardiopulmonary function). Image-guided thermal ablation is an alternative for those patients, includes radiofrequency ablation, microwave ablation (MWA), cryoablation, and laser ablation. Compared to them, MWA is a relatively new technique with some potential advantages, such as faster heating times, higher intralesional temperatures, larger ablation zones, less procedural pain, relative insensitivity to "heat sinks," and less sensitivity to tissue types. However, some advantages of MWA mentioned above (such as higher intralesional temperatures, larger ablation zones) also have potential risks and problems, and an innovative and standardized guidance system is needed to avoid and solve these risks and problems. This article combs our team's clinical experience over the past decade, summarizes a systematic and standardized guidance system, and names it SPACES (Selection, Procedure, Assessment, Complication, Evaluation, Systemic therapy). Both primary and metastatic pulmonary tumors can be efficiently treated with image-guided thermal ablation in selected candidates. The selection and use of ablation techniques should consider the size and location of the target tumor, the risk of complications, and the expertise and skills of the professionals, among which the size of the target tumor (<3 mm) is a major factor determining the success of ablation.

Issues and prospects of image-guided thermal ablation in the treatment of primary and metastatic lung tumors

The precise local minimally invasive or noninvasive treatment represents the important orientation for advancing the treatment of pulmonary malignant tumors. New local treatment methods have emerged as solutions to the shortcomings of minimally invasive or local treatment methods. Image-guided thermal ablation (IGTA) comes with the characteristics such as more accurate localization, less trauma, more definite efficacy, higher safety, stronger repeatability, fewer complications, and lower cost in treating lung tumors. This paper investigates the existing problems of IGTA in the treatment of lung tumors and puts forward the orientation of studies.

Stereotactic Radiotherapy for Oligoprogression in Metastatic Renal Cell Cancer Patients Receiving Tyrosine Kinase Inhibitor Therapy: A Phase 2 Prospective Multicenter Study

BACKGROUND

Despite the paucity of prospective evidence, stereotactic radiotherapy (SRT) is increasingly being considered in the setting of oligoprogression to delay the need to change systemic therapy.

OBJECTIVE

To determine the local control (LC), progression-free survival (PFS), cumulative incidence of changing systemic therapy, and overall survival (OS) after SRT to oligoprogressive metastatic renal cell carcinoma (mRCC) lesions in patients who are on tyrosine kinase inhibitor (TKI) therapy.

DESIGN, SETTING, AND PARTICIPANTS

A prospective multicenter study was performed to evaluate the use of SRT in oligoprogressive mRCC patients. Patients with mRCC who had previous stability or response after ≥3 mo of TKI therapy were eligible if they developed progression of five of fewer metastases. Thirty-seven patients with 57 oligoprogressive tumors were enrolled.

INTERVENTION

Oligoprogressive tumors were treated with SRT, and the same TKI therapy was continued afterward.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Competing risk analyses and the Kaplan-Meir methodology were used to report the outcomes of interest.

RESULTS AND LIMITATIONS

The median duration of TKI therapy prior to study entry was 18.6 mo; 1-yr LC of the irradiated tumors was 93% (95% confidence interval [CI] 71-98%). The median PFS after SRT was 9.3 mo (95% CI 7.5-15.7 mo). The cumulative incidence of changing systemic therapy was 47% (95% CI 32-68%) at 1 yr, with a median time to change in systemic therapy of 12.6 mo (95% CI 9.6-17.4 mo). One-year OS was 92% (95% CI 82-100%). There were no grade 3-5 SRT-related toxicities.

CONCLUSIONS

LC of irradiated oligoprogressive mRCC tumors was high, and the need to change systemic therapy was delayed for a median of >1 yr.

PATIENT SUMMARY

The use of stereotactic radiotherapy in metastatic kidney cancer patients, who develop growth of a few tumors while on oral targeted therapy, can significantly delay the need to change to the next line of drug therapy.

Current Management of Oligometastatic Lung Cancer and Future Perspectives: Results of Thermal Ablation as a Local Ablative Therapy

A growing body of evidence shows improved overall survival and progression-free survival after thermal ablation in non-small cell lung carcinoma (NSCLC) patients with a limited number of metastases, combined with chemotherapy or tyrosine kinase inhibitors or after local recurrence. Radiofrequency ablation and microwave ablation are the most evaluated modalities, and target tumor size <3 cm (and preferably <2 cm) is a key factor of technical success and efficacy. Although thermal ablation offers some advantages over surgery and radiotherapy in terms of repeatability, safety, and quality of life, optimal management of these patients requires a multidisciplinary approach, and further randomized controlled trials are required to help refine patient selection criteria. In this article, we present a comprehensive review of available thermal ablation modalities and recent results supporting their use in oligometastatic and oligoprogressive NSCLC disease along with their potential future implications in the emerging field of immunotherapy.

Epidemiology of oligometastatic non-small cell lung cancer: results from a systematic review and pooled analysis

Background

To describe the incidence and the clinical characteristics of oligometastatic non-small cell lung cancer (NSCLC) patients. Oligometastatic NSCLC is gaining recognition as a clinical condition with a different prognosis compared to multi metastatic disease. Usually, four different scenarios of oligometastatic disease can be described but not epidemiological data are available. To date, it is difficult to delineate an exhaustive epidemiological scenario because no uniform or shared definition of oligometastatic status exists, even though a recent consensus defined synchronous oligometastatic disease as having a maximum of 5 metastases in 3 different organs.

Methods

A systematic review and a pooled analysis of literature were performed. Article selection was based on the following characteristics: focus on lung cancers; dealing with oligometastatic settings and providing a definition of oligometastatic disease; number of metastatic lesions with or without the number of organs involved; providing some incidence or clinical characteristics of oligometastatic NSCLC patients. Series focusing on a specific single metastatic organ were excluded. The research was launched in MEDLINE (OvidSP) in March 2020. Full articles were individually and collectively read by the authors according to the previous criteria. Each author inspected the reference list included in the eligible articles. If the selection criteria were recognized, the article was reviewed by all authors and then included. Data on patient clinical features were pooled together from 31 articles selected.

Results

A total number of 31 articles have been selected for the analysis. The following variables were extracted from the publications: (I) number of metastases, (II) number of organs involved, (III) number of patients, (IV) number and percentage of males and females, (V) number and percentage of squamous and non-squamous histology, (VI) T and N status and/or stage of primary disease for oligometastatic setting. The data collected have been analyzed according to the oligometastatic setting.

Conclusions

Oligometastatic status is globally identified as a different clinical condition from multi metastatic NSCLC, although the clinical characteristics were consistent in the general metastatic population, even with a lower-than-expected TN status. The brain and bones were the most frequent organs involved. Lacking consensus definition, these results must be interpreted cautiously and a prospective evaluation is urgently needed.

Management of Oligometastasis and Oligoprogression in Patients with Epidermal Growth Factor Receptor Mutation-Positive NSCLC in the Era of Third-Generation Tyrosine Kinase Inhibitors

This review covers the importance of local consolidative therapy (LCT) in patients with epidermal growth factor receptor (EGFR) mutation-positive with oligometastatic and oligoprogressive non-small-cell lung cancer (NSCLC). With the advent of third-generation EGFR tyrosine kinase inhibitors, a more updated review is necessary. We review the efficacy of LCT, pathophysiological background, and treatment modalities other than radiotherapy. In addition, we also discussed when and how LCT should be applied to patients with oligometastatic and oligoprogressive NSCLC.

Microwave ablation for non-small cell lung cancer with synchronous solitary extracranial metastasis

AIMS

Local therapy including surgery or radiotherapy has been reported for the treatment of non-small cell lung cancer (NSCLC) with synchronous solitary metastasis, while studies with other local ablative treatment are rare. Here, we summarized our single-center experience of microwave ablation (MWA) for both primary and metastatic lesions in NSCLC patients with synchronous solitary extracranial metastases.

PATIENTS AND METHODS

We retrospectively screened our institute database from January 2014 to Jun 2019. NSCLC patients with synchronous extracranial solitary metastasis with primary and metastatic lesions that were treated with MWA were identified and analyzed.

RESULTS

Of the 1472 stage IV NSCLC patients found, 38 were diagnosed with synchronous extracranial solitary metastasis and 29 of them received MWA for primary and metastatic lesions. The most common distant metastases were contralateral lung metastases (14 cases), followed by bone (6), liver (4), adrenal gland (3) and pleura metastases (1). Median OS and PFS was 21.5 and 12.5 months, respectively. Patients with N0 had significantly longer PFS (median 18.5 vs. 8.0 months) and OS (median 42.7 vs. 19.0 months). In addition, systemic therapy was showed to be a prognostic factor for better PFS (12.9 vs. 7.5 months). Clinical pathological factors including age, histology, T stage, PS score, and metastasis locations are not significantly associated with survival.

CONCLUSIONS

MWA may serve as an alternative treatment for NSCLCs with synchronous solitary extracranial metastases.

Liquid biopsy, a paradigm shift in oncology: what interventional radiologists should know

The acquisition of adequate tumor sample is required to verify primary tumor type and specific biomarkers and to assess response to therapy. Historically, invasive surgical procedures were the standard methods to acquire tumor samples until advancements in imaging and minimally invasive equipment facilitated the paradigm shift image-guided biopsy. Image-guided biopsy has improved sampling yield and minimized risk to the patient; however, there are still limitations, such as its invasive nature and its consequent limitations to longitudinal tumor monitoring. The next paradigm shift in sampling technique will need to address these issues to provide a more reliable and less invasive technique. Recently, liquid biopsy (LB) has emerged as a non-invasive alternative to tissue sampling. This technique relies on direct sampling of blood or other bodily fluids in contact with the tumor in order to collect circulating tumor DNA (ctDNA), circulating tumor cells (CTCs), and circulating RNAs-in particular microRNA (miRNAs). Clinical applications of LB involve different steps of cancer patient management including screening, detection of disease recurrence, and evaluation of acquired resistance. With any paradigm shift, old techniques are often relegated to a secondary option. Although image-guided biopsies may appear as a passive spectator on the rapid advancement of LB, the two techniques may well be codependent. Interventional radiology may be integral to directly sample the liquid surrounding or draining from the tumor. In addition, LB may help to correctly select the patients for image-guided loco-regional treatments, to determine its treatment endpoint, and to early detect recurrence. KEY POINTS: • Liquid biopsy is a novel technology with potential high impact in the management of patients undergoing image-guided procedures. • Interventional radiology procedures may increase liquid biopsy sensitivity through direct fluid sampling. • Liquid biopsy techniques may provide a venue for improving patients' selection and enhance outcomes of interventional loco-regional therapies performed by interventional radiologists.

[Minimally Invasive Therapies for Early Stage Non-small Cell Lung Cancer]

肺癌是目前全球最常见的癌症和癌症死亡的主要原因，其中非小细胞肺癌（non-small-cell lung cancer, NSCLC）约占肺癌总数的85%。随着计算机断层扫描（computed tomography, CT）等影像学筛查手段得到不断普及，肺癌的病理类型从以往以晚期中央型肺鳞癌为主，转变为现在的以早期周围型磨玻璃样结节等为表现的肺腺癌为主。肺癌的早诊早治有着重要意义，而微创介入技术的不断发展完善，使得肺癌治疗有了更多的选择，例如立体定向放射、经皮穿刺消融、支气管介入等。本文将就目前临床常见的这些微创介入治疗的作用原理、优势、不足及展望做一评述。

Treatment of advanced non-small-cell lung cancer: The 2019 AIOM (Italian Association of Medical Oncology) clinical practice guidelines

The Italian Association of Medical Oncology (AIOM) has developed clinical practice guidelines for the treatment of patients with advanced non-small cell lung cancer (NSCLC). In the current paper a panel of AIOM experts in the field of thoracic malignancies discussed the available scientific evidences, with the final aim of providing a summary of clinical recommendations, which may guide physicians in their current practice.

Microwave ablation as local consolidative therapy for patients with extracranial oligometastatic EGFR-mutant non-small cell lung cancer without progression after first-line EGFR-TKIs treatment

OBJECTIVES

Evidence from multiple clinical trials showed that local consolidative therapy (LCT) improved survival in oligometastatic non-small cell lung cancer (NSCLC) patients. In the present study, we aim to explore the potential role of microwave ablation (MWA) as LCT for epidermal growth factor receptor (EGFR)-mutant advanced NSCLC patients with extracranial oligometastasis.

MATERIALS AND METHODS

From January 2015 to December 2018, a total of 86 EGFR-mutant stage IIIB or IV NSCLC patients with extracranial oligometastasis were enrolled for retrospective analysis. MWA was used as LCT for all oligometastatic lesions and/or primary tumors in 34 patients without progression after first-line EGFR-TKIs therapy (consolidation group), while the other 52 patients received only TKIs until disease progression (monotherapy group). We calculated and compared the progression-free survival (PFS) and overall survival (OS) of the two groups.

RESULTS AND CONCLUSION

Patients with MWA consolidation therapy had significantly improved PFS (median 16.7 vs. 12.9 months, HR 0.44, 95% CI 0.22-0.88, P = 0.02) and OS (median: 34.8 vs. 22.7 months, HR 0.45, 95% CI 0.24-0.88, P = 0.04) than monotherapy group. MWA for LCT was identified as the independent predictive factor for better PFS (HR 0.46, 95% CI 0.37-0.82, P < 0.01) and OS (HR 0.57, 95% CI 0.33-0.91, P = 0.02). Most toxicities were mild and well tolerated. No patient had to discontinue EGFR-TKIs because of MWA complications. These findings suggest that MWA as local consolidative therapy after first-line EGFR-TKIs treatment leads to better disease control and survival than TKIs monotherapy in EGFR-mutant advanced NSCLC patients with extracranial oligometastasis. MWA as a novel option of LCT might be considered for clinical management of these patients.

Microwave Ablation in Primary Lung Malignancies

Lung cancer is the leading cause of cancer-related mortality worldwide. Eighty-five percent of cases correspond to non-small cell lung cancer (NSCLC) and pivotal nonsurgical options for early-stage disease include percutaneous ablation and stereotactic body radiation therapy (SBRT). Microwave Ablation (MWA) is a locoregional treatment option that has many advantages over radiofrequency ablation and has been able to overcome the limitations of this technique in the treatment of early-stage NSCLC. In this review article, we highlight the current evidence supporting the use of MWA in patients with early-stage NSCLC and discuss the technical considerations of the procedure, including optimal patient selection and planning strategies, as well as the potential complications and reported outcomes. Finally, we mention future trends involving ablation in NSCLC, including its role in combination with SBRT in central tumors, management of post-SBRT local recurrence, and its potential as an adjuvant treatment option for patients with resistance to systemic therapy or in combination with checkpoint inhibitors.

Cryoablation of Lung Metastases: Review of Recent Literature and Ablation Technique

This article reviews the current indications for image-guided thermal ablation of pulmonary metastatic disease. It also summarizes data regarding the efficacy and complications of lung cryoablation and present techniques for performing lung cryoablation as informed by the recent literature.

Comparison of Survival Rates After a Combination of Local Treatment and Systemic Therapy vs Systemic Therapy Alone for Treatment of Stage IV Non-Small Cell Lung Cancer

IMPORTANCE

As many as 55% of patients with non-small cell lung cancer (NSCLC) present with stage IV disease at diagnosis. Although systemic therapy is the cornerstone for treatment of these patients, growing evidence suggests that local treatment of the primary tumor site may improve survival.

OBJECTIVE

To assess whether addition of local treatment for primary tumor site in stage IV NSCLC provides a survival benefit over systemic therapy alone.

DESIGN, SETTING, AND PARTICIPANTS

In this comparative effectiveness research study, the National Cancer Database (NCDB; 2018 version) was retrospectively queried from January 1, 2010, through December 31, 2015, for patients with a histopathologic diagnosis of stage IV NSCLC. Exclusion criteria were being younger than 18 years and missing information on tumor characteristics and follow-up data. Data were analyzed from November 1, 2018, through January 1, 2019.

EXPOSURES

Treatment groups were stratified as (1) surgical resection plus systemic therapy; (2) external beam radiotherapy (EBRT) or thermal ablation (TA; including cryosurgery and radiofrequency ablation) plus systemic therapy; and (3) systemic therapy alone.

MAIN OUTCOMES AND MEASURES

Overall survival was compared between treatment groups using multivariable Cox proportional hazards regression models and after propensity score matching. Subgroup analyses were planned a priori according to patient and tumor characteristics.

RESULTS

A total of 34 887 patients met inclusion criteria (19 002 male [54.5%]; median age, 68 years [interquartile range, 60-75 years]), among whom 835 underwent surgical resection plus systemic therapy; 9539, EBRT/TA plus systemic therapy; and 24 513, systemic therapy alone. Demographic and cancer-specific factors were associated with treatment allocation with a higher likelihood of surgical resection for oligometastatic NSCLC. After multivariable adjustment, surgical resection was associated with superior overall survival compared with EBRT/TA or systemic therapy alone (hazard ratio [HR] for EBRT/TA, 0.62; 95% CI, 0.57-0.67; P < .001; HR for systemic therapy alone, 0.59; 95% CI, 0.55-0.64; P < .001). Treatment with EBRT/TA demonstrated superior overall survival compared with systemic therapy alone (HR, 0.95; 95% CI, 0.93-0.98; P = .002). Interaction analyses identified heterogeneous associations with treatment; the EBRT/TA survival benefit was especially pronounced in stage IV squamous cell carcinoma with limited T and N category disease and oligometastases (HR, 0.68; 95% CI, 0.57-0.80; P < .001), with overall survival rates of 60.4% vs 45.4% at 1 year, 32.6% vs 19.2% at 2 years, and 20.2% vs 10.6% at 3 years for combination therapy vs systemic therapy alone.

CONCLUSIONS AND RELEVANCE

In stage IV NSCLC, surgical resection or EBRT/TA of the primary tumor site may provide survival benefits in addition to systemic therapy alone in selected patients. Specifically, EBRT/TA may be considered as a treatment option in select patients who are ineligible for surgical resection.