Evolution of treatment strategies for oligometastatic NSCLC patients - A systematic review of the literature

Oligometastatic NSCLC: Current Perspectives and Future Challenges

Oligometastatic non-small cell lung cancer (NSCLC) represents a separate entity with a different biology and prognosis compared to stage IV NSCLC. Challenges range from the very definition of oligometastatic disease to the timing and techniques of local treatments, and their benefit in prolonging patient survival. Most of the international consensus and guidelines agree on the need for shared criteria, such as appropriate stadiation and even tissue biopsy if needed, in order to select patients that could really benefit from personalised strategies. Multidisciplinary evaluation is crucial in order to define if every lesion is amenable to radical local treatment, which appears to be the most important criterion across different guidelines. A distinction must be made depending on the time of oligo-disease detection, separating de novo oligometastatic disease from oligorecurrence, oligoprogression and oligoresidual disease. These separate entities imply a different biology and prognosis, and treatment strategies consequently must be tailored. Locoregional approaches are therefore often contemplated in order to ensure the best outcome for the patient. In non-oncogene-addicted disease, the advent of immune checkpoint blockers (ICBs) allows physicians to take into consideration consolidative treatments, but timing, technique and subsequent systemic treatment remain open issues. In oncogene-addicted NSCLC, local treatments are nowadays preferably reserved to cases of oligoprogression, but the advent of new, more potent drugs might challenge that. In this review, we summarised the current knowledge, consensuses and data from retrospective and prospective trials, with the aim of shedding some light on the topic and emphasising the unmet clinical need.

The role of local ablative therapy in patients with advanced invasive mucinous adenocarcinoma of the lung

PURPOSE

Invasive mucinous adenocarcinoma (IMA) of the lungs is a rare subtype of lung adenocarcinoma with a limited understanding of its prognosis, particularly in advanced stages. This study aimed to assess the prognosis of patients with advanced IMA by focusing on treatment modalities.

METHODS

This single-center retrospective study evaluated 33 patients with IMAs diagnosed with advanced-stage disease or disease progression after curative treatment between 2011 and 2021. The primary outcome was overall survival (OS), and the secondary outcome was progression-free survival (PFS). OS and PFS were calculated from the date of the diagnosis of advanced IMA.

RESULTS

The study cohort included 13 patients at the initial advanced stage and 20 patients who progressed after curative treatment. Treatment modalities included conventional chemotherapy in 24 patients (72.7%), targeted therapy in seven (21.2%), immunotherapy in 13 (39.4%), and local ablative therapy (LAT) in 13 (39.4%). The median OS was 32 months (95% confidence interval [CI], 2.9-61.0), with LAT significantly associated with improved OS compared to non-LAT treatment (not reached vs. 11.3 months, p = 0.001). However, there was no significant difference in OS based on conventional chemotherapy (p = 0.396), targeted therapy (p = 0.655), or immunotherapy (p = 0.992). In multivariate analysis, LAT remained an independent prognostic factor for OS (hazard ratio, 0.125; 95% CI, 0.026-0.608; p = 0.01). PFS was 8.6 months (95% CI, 3.6-13.7), with no significant differences observed among the treatment modalities.

CONCLUSION

Our findings suggest that LAT may provide favorable survival outcomes in patients with advanced IMA.

Retrospective Analysis of Efficacy and Toxicity of Stereotactic Body Radiotherapy and Surgical Resection of Adrenal Metastases from Solid Tumors

BACKGROUND

This single-center retrospective study aimed to evaluate the efficacy and toxicity profiles of stereotactic body radiotherapy (SBRT) and surgical resection in patients with adrenal metastases originating from solid tumors.

METHODS/MATERIALS

Patients with advanced tumor conditions or comorbidities typically received SBRT, whereas those considered physically fit underwent standard surgical treatment. Endpoints included local control (LC), progression free survival (PFS), overall survival (OS), and complication rates (CR).

RESULTS

41 patients with 48 adrenal metastases were included, with 27 (65.9%) patients receiving SBRT and 14 (34.1%) patients undergoing adrenalectomy. One- and two-year LC values were 100% for both periods after adrenalectomy, and 70.0% and 52.5% after SBRT (p = 0.001). PFS showed values of 40.2% and 32.1% at one and two years after adrenalectomy and of 10.6% for both periods after SBRT (p = 0.223). OS was 83.3% both one and two years after surgery and 67.0% and 40.2% after SBRT (p = 0.031). There was no statistically significant difference between the two groups regarding acute complications (p = 0.123).

CONCLUSION

Despite potential confounders, adrenalectomy exhibited statistically significant superior LC and OS compared to SBRT in managing adrenal metastases, while both treatment methods displayed acceptable toxicity profiles. However, patient selection bias must be taken into account when directly comparing the two therapy modalities. Nevertheless, the study provides new and important results for the scientific and medical communities regarding oncological outcomes after SBRT or surgical resection of adrenal metastases.

An in-silico planning study of stereotactic body radiation therapy for polymetastatic patients with more than ten extra-cranial lesions

Background and purpose

Limited data is available about the feasibility of stereotactic body radiation therapy (SBRT) for treating more than five extra-cranial metastases, and almost no data for treating more than ten. The aim of this study was to investigate the feasibility of SBRT in this polymetatstatic setting.

Materials and methods

Consecutive metastatic melanoma patients with more than ten extra-cranial metastases and a maximum lesion diameter below 11 cm were selected from a single-center prospective registry for this in-silico planning study. For each patient, SBRT plans were generated to treat all metastases with a prescribed dose of 5x7Gy, and dose-limiting organs (OARs) were analyzed. A cell-kill based inverse planning approach was used to automatically determine the maximum deliverable dose to each lesion individually, while respecting all OARs constraints.

Results

A total of 23 polymetastatic patients with a medium of 17 metastases (range, 11-51) per patient were selected. SBRT plans with sufficient target coverage and respected OARs dose constraints were achieved in 16 out of 23 patients. In the remaining seven patients, the lungs V5Gy < 80 % and the liver D700 cm3 < 15Gy were most frequently the dose-limiting constraints. The cell-kill based planning approach allowed optimizing the dose administration depending on metastases total volume and location.

Conclusion

This retrospective planning study shows the feasibility of definitive SBRT for 70% of polymetastatic patients with more than ten extra-cranial lesions and proposes the cell-killing planning approach as an approach to individualize treatment planning in polymetastatic patients'.

Clinical experience of consolidative radiotherapy for localized metastatic non-small cell lung cancer who showed favorable tumor response after systemic treatment

BACKGROUND

Our study has aimed to assess the effects of consolidative high-dose radiotherapy on clinical outcomes in patients with localized metastatic non-small cell lung cancer (NSCLC) who showed favorable tumor response after systemic treatment.

METHODS

We retrospectively reviewed the medical records of 83 patients with localized metastatic NSCLC, who received systemic therapy followed by consolidative local radiotherapy at the Korea University Guro Hospital between March 2017 and June 2022. In the current study, we defined localized metastatic disease as the presence of one to three metastatic sites at the time of diagnosis. And patients who showed favorable tumor response after systemic treatment, including oligo-progressive disease at the thoracic site which was amenable to curative high-dose local radiotherapy, were included. The planned total dose and fraction size mainly depended on the location of lesions.

RESULTS

The median follow-up time after consolidative radiotherapy was 16 months (range: 5-52 months). The overall 2-year progression-free survival rates were 81.4%. Of 83 patients, only four (4.3%), treated with intensity-modulated radiation therapy, showed an in-field local recurrence. Interestingly, only one patient experienced a local failure among the 20 patients who showed an oligo-progressive disease at the thoracic site on the tumor response evaluation after systemic treatment. Regarding treatment-related pulmonary toxicity, three patients with grade-3 and one patient with grade-4 radiation pneumonitis were presented.

CONCLUSIONS

If the disease is sufficiently controlled and localized by systemic therapy, local consolidative radiotherapy is thought to improves local control rates with acceptable treatment-related toxicities in patients with localized metastatic NSCLC, especially those with oligo-progressive disease.

Designing clinical trials based on modern imaging and metastasis-directed treatments in patients with oligometastatic breast cancer: a consensus recommendation from the EORTC Imaging and Breast Cancer Groups

Breast cancer remains the most common cause of cancer death among women. Despite its considerable histological and molecular heterogeneity, those characteristics are not distinguished in most definitions of oligometastatic disease and clinical trials of oligometastatic breast cancer. After an exhaustive review of the literature covering all aspects of oligometastatic breast cancer, 35 experts from the European Organisation for Research and Treatment of Cancer Imaging and Breast Cancer Groups elaborated a Delphi questionnaire aimed at offering consensus recommendations, including oligometastatic breast cancer definition, optimal diagnostic pathways, and clinical trials required to evaluate the effect of diagnostic imaging strategies and metastasis-directed therapies. The main recommendations are the introduction of modern imaging methods in metastatic screening for an earlier diagnosis of oligometastatic breast cancer and the development of prospective trials also considering the histological and molecular complexity of breast cancer. Strategies for the randomisation of imaging methods and therapeutic approaches in different subsets of patients are also addressed.

A Bibliometric Analysis of the Oligometastatic State over the Last Two Decades: A Shifting Paradigm for Oncology? An AIRO Oligometastatic Study Group

The term "oligometastasis" represents a relatively novel idea, which denotes a condition characterized by cancer dissemination with a limited number of lesions (usually fewer than five). The aim of the present study is to report a bibliometric analysis of the oligometastatic disease/state, incorporating all relevant studies on the topic for more than 20 years. The research strategy included at least one the terms "Oligmetastases", "Oligometastasis", "Oligometastatic", "Oligoprogression, "Oligoprogressive", "Oligorecurrent", or "Oligorecurrency" in the title, abstract, and/or keywords. All English-language documents from 1 January 1995 (the year of the earliest available document in Scopus) to 31 December 2022 were considered for the analysis. R code (R version 4.2.0) with R Studio (version 2022.12.0-353) and the Bibliometrix package (version 4.0.1) were used for the analysis. A total of 3304 documents, mainly articles (n = 2083, 63.0%) and reviews (n = 813, 24.6%), were collected from 1995 to 2022. The average annual growth rate of literature on the topic was 26.7%. Overall 15,176 authors published on the topic, with an average of eight authors/publication. From 1995, 69 countries contributed to the literature, with the USA and Italy being the top contributors. Among all keywords used by authors, the top three were oligometastases (19%), SBRT (18%), and radiation therapy (8%). Themes regarding "locoregional treatment", "organ motion", and "immunotherapy" were the most recent trend topics, mainly developed from 2019 to 2022, while "high-dose chemotherapy", "whole-brain radiotherapy", and "metastatic breast cancer" saw their main development during 2009-2018. Our study shows the exceptionally flourishing scientific production on the oligometastatic state, summarizing the most influential studies and highlighting the future developments and interests. This analysis will serve as a benchmark to identify this area for the attention of researchers worldwide and contribute to the increasing scientific work.

Establishing the Swiss Spinal Tumor Registry (Swiss-STR): a prospective observation of surgical treatment patterns and long-term outcomes in patients with primary and metastatic spinal tumors

Background

Tumors of the vertebral column consist of primary spinal tumors and malignancies metastasizing to the spine. Although primary spine tumors are rare, metastases to the spine have gradually increased over past decades because of aging populations and improved survival for various cancer subtypes achieved by advances in cancer therapy. Metastases to the vertebral column occur in up to 70% of cancer patients, with 10% of patients demonstrating epidural spinal cord compression. Therefore, many cancer patients may face spinal surgical intervention during their chronic illness; such interventions range from simple cement augmentation over decompression of neural elements to extended instrumentation or spinal reconstruction. However, precise surgical treatment guidelines do not exist, likely due to the lack of robust, long-term clinical outcomes data and the overall heterogeneous nature of spinal tumors. Objectives of launching the Swiss Spinal Tumor Registry (Swiss-STR) are to collect and analyze high-quality, prospective, observational data on treatment patterns, clinical outcomes, and health-related quality of life (HRQoL) in adult patients undergoing spinal tumor surgery. This narrative review discusses our rationale and process of establishing this spinal cancer registry.

Methods

A REDCap-based registry was created for the standardized collection of clinical, radiographic, surgical, histological, radio-oncologial and oncological variables, as well as patient-reported outcome measures (PROMs).

Discussion

We propose that the Swiss-STR will inform on the effectiveness of current practices in spinal oncology and their impact on patient outcomes. Furthermore, the registry will enable better categorization of the various clinical presentations of spinal tumors, thereby facilitating treatment recommendations, defining the socio-economic burden on the healthcare system, and improving the quality of care. In cases of rare tumors, the multi-center data pooling will fill significant data gaps to yield better understanding of these entities. Finally, our two-step approach first implements a high-quality registry with efficient electronic data capture strategies across hospital sites in Switzerland, and second follows with potential to expand internationally, thus fostering future international scientific collaboration to further push the envelope in cancer research.

Radiotherapy for Lung Metastases: Conventional to Stereotactic Body Radiation Therapy

The lung parenchyma and adjacent tissues are one of the most common sites of metastatic disease. Traditionally, the approach to treatment of a patient with lung metastases has been with systemic therapy, with radiotherapy being reserved for palliative management of symptomatic disease. The concept of oligo metastatic disease has paved the way for more radical treatment options, administered either alone or as local consolidative therapy in addition to systemic treatment. The modern-day management of lung metastases is guided by a number of factors, including the number of lung metastases, extra-thoracic disease status, overall performance status, and life expectancy, which all help determine the goals of care. Stereotactic body radiotherapy (SBRT) has emerged as a safe and effective method in locally controlling lung metastases, in the oligo metastatic or oligo-recurrent setting. This article outlines the role of radiotherapy in multimodality management of lung metastases.

Unravelling oligometastatic disease from the perspective of radiation and medical oncology. Part I: non-small cell lung cancer and breast cancer

Oligometastatic disease (OMD) defines a cancer status that is intermediate between localized and widely spread metastatic disease, and can be treated with curative intent. While diagnostic imaging tools have considerably improved in recent years, unidentified micrometastases can still evade current detection techniques, allowing the disease to progress. The various OMD scenarios are mainly defined by the number of metastases, the biological and molecular tumour profiles, and the timing of the development of metastases. Increasing knowledge has contributed to the earlier and improved detection of OMD, underlining the importance of early disease control. In view of increasing OMD detection rates in current real-world clinical practice and the lack of standardized evidence-based guidelines to treat this cancer status, a board of experts from the Spanish Societies of Radiation Oncology (SEOR) and Medical Oncology (SEOM) organized a series of sessions to update the current state-of-the-art on OMD from a multidisciplinary perspective, and to discuss how results from clinical studies might translate into promising treatment options. This expert review series summarizes what is known and what it is pending clarification in the context of OMD in the scenarios of non-small cell lung cancer and breast cancer (Part I), and prostate cancer and colorectal cancer (Part II), aiming to offer specialists a pragmatic framework to help improve patient management.

The Effect of immunotherapy on oligometastatic non-small cell lung cancer patients by sites of metastasis

Introduction

The efficacy of immunotherapy for treatment of patients with oligometastatic non-small cell lung cancer (NSCLC) at different metastatic sites remains controversial. We investigated the effect of different metastatic sites on immunotherapy for oligometastatic NSCLC following local treatment (LT).

Methods

We retrospectively analyzed patients with oligometastatic NSCLC from the latest 2018 registry on the SEER Stat software (8.3.9. Version) and a Chinese single-center cohort. The effects of immunotherapy on OS (overall survival) and CSS (cancer specific survival) were estimated for patients with different metastatic sites.

Results

A total of 483 patients in the SEER-18 database and 344 patients in the single-center cohort were included. Immunotherapy was significantly correlated with improved OS (SEER: Hazard ratio 0.754, 95% CI 0.609–0.932; P=0.044; China: Hazard ratio 0.697, 95% CI 0.542–0.896; P=0.005) and CSS (SEER: Hazard ratio 0.743, 95% CI 0.596–0.928; P=0.009; China: Hazard ratio 0.725, 95% CI 0.556–0.945; P=0.018). Subgroup analysis showed that OS was improved after immunotherapy in the BRM (SEER: Hazard ratio 0.565, 95% CI 0.385–0.829; P=0.004; China: Hazard ratio 0.536, 95% CI 0.312–0.920; P=0.024) and MOM (SEER: Hazard ratio 0.524, 95% CI 0.290–0.947; P=0.032; China: Hazard ratio 0.469, 95% CI 0.235–0.937; P=0.032) subgroups, but not in the BOM (SEER: P=0.334; China: P=0.441), LIM (SEER: P=0.301; China: P=0.357), or OTM (SEER: P=0.868; China: P=0.489) subgroups.

Conclusions

This study showed that immunotherapy conferred survival benefits on patients with oligometastatic NSCLC. Our subgroup analysis suggested that patients with oligometastatic NSCLC in the brain or multiple organs may particularly benefit from aggressive front-line therapies.

Oligometastatic Non-Small Cell Lung Cancer: A Practical Review of Prospective Trials

Simple Summary

A significant number of patients diagnosed with non-small cell lung cancer (NSCLC) will have a metastatic Stage IV disease at presentation. Among those, patients with limited number of metastases are referred to as oligometastatic, and their treatment will combine systemic and possible local therapy. The aim of this article is to review the current definition of oligometastatic cancer, a historic perspective of lung cancer leading to modern oligometastatic disease and to present available prospective evidence for treatment of oligometastatic NSCLC. We describe trials exploring role of local therapy in oligometastatic NSCLC with actionable mutation in combination with TKI or without any actionable mutation and in combination with chemo-immunotherapy. We also discuss general treatment approaches adopted based on limited data. Finally, we discuss the on-going clinical trials for oligometastatic and oligoprogressive NSCLC.

Abstract

Oligometastatic non-small cell lung cancer (NSCLC) is an intermediate state between localized and widely metastatic NSCLC, where systemic therapy in combination with aggressive local therapy when feasible can yield a favorable outcome. While different societies have adopted different definitions for oligometastatic NSCLC, the feasibility of curative intent treatment remains a major determinant of the oligometastatic state. The management involves a multidisciplinary approach to identify such patients with oligometastatic stage, including the presence of symptomatic or potentially symptomatic brain metastasis, the presence of targetable mutations, and programmed death-ligand (PD-L1) expression. Treatment requires a personalized approach with the use of novel systemic agents such as tyrosine kinase inhibitors and immune checkpoint inhibitors with or without chemotherapy, and addition of local ablative therapy via surgery or stereotactic radiation therapy when appropriate.

Clinical Outcomes of Stereotactic Ablative Radiotherapy for All Stages of Non-Small Cell Lung Cancer; Definitive versus Consolidative

Background and Objectives: Stereotactic ablative radiotherapy (SABR) is not confined to early stage non-small cell lung cancer (NSCLC) and has a potential role in stage IV disease. We aimed to evaluate the effect of SABR on local control rates and survival outcomes in patients with all stages of NSCLC according to the treatment aim. Materials and Methods: We retrospectively reviewed the medical records of 88 patients with NSCLC who received SABR at the Korea University Guro Hospital between January 2015 and March 2021. Among these, 64 patients with stage I–II NSCLC ineligible for surgery were treated with a definitive aim. Twenty-four patients with stage IV limited metastatic NSCLC showing a favorable response to prior systemic therapy were treated with a consolidative aim. Results: The median follow-up time was 34 (range: 5–88) months. Thirty-one patients developed recurrence (35.2%), with distant metastasis being the most common (25/31, 80.6%). In-field local recurrence occurred in four patients (4/88 patients, 4.5%). For patients treated with definitive SABR, the 3-year overall survival (OS) and disease-free survival (DFS) rates were 91.8% and 58.6%, respectively. In patients treated with consolidative SABR, the 3-year OS and DFS rates were 86.7% and 53.8%, respectively. With respect to treatment-related pulmonary toxicity, grade 3 radiation pneumonitis incidence requiring hospitalization was 2.3% (2/88). Conclusions: Definitive SABR is appropriate for medically inoperable or high surgical risk patients with early stage NSCLC with acceptable treatment-related toxicities. Consolidative SABR improves local control rates and helps achieve long-term survival in patients with limited metastatic NSCLC.

Systemic and Oligo-Acquired Resistance to PD-(L)1 Blockade in Lung Cancer

PURPOSE

Clinical patterns and the associated optimal management of acquired resistance to PD-(L)1 blockade are poorly understood.

EXPERIMENTAL DESIGN

All cases of metastatic lung cancer treated with PD-(L)1 blockade at Memorial Sloan Kettering were reviewed. In acquired resistance (complete/partial response per RECIST, followed by progression), clinical patterns were distinguished as oligo (OligoAR ≤ 3 lesions of disease progression) or systemic (sAR). We analyzed the relationships between patient characteristics, burden/location of disease, outcomes, and efficacy of therapeutic interventions.

RESULTS

Of 1,536 patients, 312 (20%) had an initial response and 143 developed AR (9% overall, 46% of responders). OligoAR was the most common pattern (80/143, 56%). Baseline tumor mutational burden, depth of response, and duration of response were significantly increased in oligoAR compared with sAR (P < 0.001, P = 0.03, P = 0.04, respectively), whereas baseline PD-L1 and tumor burden were similar. Post-progression, oligoAR was associated with improved overall survival (median 28 months vs. 10 months, P < 0.001) compared with sAR. Within oligoAR, post-progression survival was greater among patients treated with locally-directed therapy (e.g., radiation, surgery; HR, 0.41; P = 0.039). Fifty-eight percent of patients with oligoAR treated with locally-directed therapy alone are progression-free at last follow-up (median 16 months), including 13 patients who are progression-free more than 2 years after local therapy.

CONCLUSIONS

OligoAR is a common and distinct pattern of acquired resistance to PD-(L)1 blockade compared with sAR. OligoAR is associated with improved post-progression survival and some cases can be effectively managed with local therapies with durable benefit.

Integrative Network Modeling Highlights the Crucial Roles of Rho-GDI Signaling Pathway in the Progression of Non-Small Cell Lung Cancer

Non-small cell lung cancer (NSCLC) is the most prevalent form of lung cancer and a leading cause of cancer-related deaths worldwide. Using an integrative approach, we analyzed a publicly available merged NSCLC transcriptome dataset using machine learning, protein-protein interaction (PPI) networks and bayesian modeling to pinpoint key cellular factors and pathways likely to be involved with the onset and progression of NSCLC. First, we generated multiple prediction models using various machine learning classifiers to classify NSCLC and healthy cohorts. Our models achieved prediction accuracies ranging from 0.83 to 1.0, with XGBoost emerging as the best performer. Next, using functional enrichment analysis (and gene co-expression network analysis with WGCNA) of the machine learning feature-selected genes, we determined that genes involved in Rho GTPase signaling that modulate actin stability and cytoskeleton were likely to be crucial in NSCLC. We further assembled a PPI network for the feature-selected genes that was partitioned using Markov clustering to detect protein complexes functionally relevant to NSCLC. Finally, we modeled the perturbations in RhoGDI signaling using a bayesian network; our simulations suggest that aberrations in ARHGEF19 and/or RAC2 gene activities contributed to impaired MAPK signaling and disrupted actin and cytoskeleton organization and were arguably key contributors to the onset of tumorigenesis in NSCLC. We hypothesize that targeted measures to restore aberrant ARHGEF19 and/or RAC2 functions could conceivably rescue the cancerous phenotype in NSCLC. Our findings offer promising avenues for early predictive biomarker discovery, targeted therapeutic intervention and improved clinical outcomes in NSCLC.

Current treatment landscape for oligometastatic non-small cell lung cancer

The management of patients with advanced non-small cell lung carcinoma (NSCLC) has undergone major changes in recent years. On the one hand, improved sensitivity of diagnostic tests, both radiological and endoscopic, has altered the way patients are staged. On the other hand, the arrival of new drugs with antitumoral activity, such as targeted therapies or immunotherapy, has changed the prognosis of patients, improving disease control and prolonging survival. Finally, the development of radiotherapy and surgical and interventional radiology techniques means that radical ablative treatments can be performed on metastases in any location in the body. All of these advances have impacted the treatment of patients with advanced lung cancer, especially in a subgroup of these patients in which all of these treatment modalities converge. This poses a challenge for physicians who must decide upon the best treatment strategy for each patient, without solid evidence for one optimal mode of treatment in this patient population. The aim of this article is to review, from a practical and multidisciplinary perspective, published evidence on the management of oligometastatic NSCLC patients. We evaluate the different alternatives for radical ablative treatments, the role of primary tumor resection or radiation, the impact of systemic treatments, and the therapeutic sequence. In short, the present document aims to provide clinicians with a practical guide for the treatment of oligometastatic patients in routine clinical practice.

Completeness of reporting oligometastatic disease characteristics in literature and influence on oligometastatic disease classification using the ESTRO/EORTC nomenclature

BACKGROUND

There is increasing evidence for the integration of locally ablative therapy into multimodality treatment of oligometastatic disease (OMD). To support standardised data collection, analysis, and comparison, a consensus OMD classification based on fundamental disease and treatment characteristics has previously been established. This study investigated the completeness of reporting the proposed OMD characteristics in literature and evaluated whether the proposed OMD classification system can be applied to the historical data.

METHODS

A systematic literature review was performed in Medline, Embase, and Cochrane, searching for prospective and retrospective studies, where SBRT was a treatment component of OMD. Reporting of the OMD characteristics as described in the EORTC/ESTRO classification was analyzed, feasibility to retrospectively classify the proposed OMD states was investigated and the impact of the categorisation on overall survival (OS) was evaluated.

RESULTS

Our study shows incomplete reporting of the proposed OMD characteristics. The most fully reported characteristic was 'type of involved organs' (88/95 studies); 'history of cancer progression' was the least reported (not mentioned in 50/95 studies). Retrospective OMD classification of existing literature was only possible for 7/95 studies. With respect to categorization as de novo, repeat or induced OMD, homogeneous patient cohorts were observed in 21/95 studies, most frequently de novo OMD, in 20 studies. Differences in OS at 2, 3, or 5 years were not statistically significant between the different states. OS was significantly influenced by primary tumor histology, with superior OS observed for prostate cancer and worst OS observed for non-small cell lung cancer.

CONCLUSION

The largely incomplete reporting of the proposed OMD characteristics hampers a retrospective classification of existing literature. To facilitate future comparison of individual studies, as well as validation of the OMD classification, comprehensive reporting of OMD characteristics using standardised terminology is recommended, as proposed by the EORTC/ESTRO classification system and following ESTRO-ASTRO consensus.

ESTRO ACROP guidelines for external beam radiotherapy of patients with uncomplicated bone metastases

After liver and lungs, bone is the third most common metastatic site (Nystrom et al., 1977). Almost all malignancies can metastasize to the skeleton but 80% of bone metastases originate from breast, prostate, lung, kidney and thyroid cancer (Mundy, 2002). Introduction of effective systemic treatment in many cancers has prolonged patients' survival, including those with bone metastases. Bone metastases may significantly reduce quality of life due to related symptoms and possible complications, such as pain and neurologic compromise. The most serious complications of bone metastases are skeletal-related events (SRE), defined as pathologic fracture, spinal cord compression, pain, or other symptoms requiring an urgent intervention such as surgery or radiotherapy. In turn, growing access to modern diagnostic tools allows early detection of asymptomatic bone metastases that could be successfully managed with local treatment avoiding development of SRE. The treatment for bone metastases should focus on relieving existing symptoms and preventing new ones. Radiotherapy is the standard of care for patients with symptomatic bone metastases, providing durable pain relief with minimal toxicity and reasonable cost-effectiveness. Historically, the dose was prescribed in one to five fractions and delivered using simple planning techniques. While 3D-conformal radiotherapy is still widely used for treating bone metastases, introduction of highlyconformal radiotherapy techniques such as stereotactic body radiotherapy (SBRT) have opened new therapeutic possibilities that should be considered in selected patients with bone metastases.

Evaluation of local aggressive lung therapy versus systemic therapy in oligometastatic non-small cell lung cancer: a systematic review and meta-analysis

Background

Previous studies have shown the feasibility and effectiveness of local aggressive thoracic therapy (surgery and radiotherapy) for oligometastatic non-small cell lung cancer compared with systemic therapy, but with small sample. This study aims to perform a pooled analysis to explore whether LT could improve outcomes of oligometastatic patients with non-small cell lung cancer.

Methods

Protocol of present study was registered on PROSPERO as number: CRD42021233095. PubMed, Embase and Web of knowledge were searched, and eligible studies investigating local therapy for non-small cell lung cancer with 1-5 metastases regardless of organs were included. Linear regression between survival and clinical characteristics were conducted. Hazard ratios of survival and adverse effects were merged. Pooled survival curves were carried out.

Results

Three randomized controlled trials and 5 cohort studies enrolling 499 patients were included. There was a trend that median overall survival declined with the increasing proportion of N2-3 positive patients in local therapy group, but with no statistical difference (P=0.09, R²=0.98). Undergoing local therapy for oligometastatic non-small cell lung cancer achieved reduction of 47% and 60% in the risk of death and cancer progression (P<0.001), respectively. In subgroup analysis, patients receiving local therapy including surgery showed hazard ratio of 0.33 on progression-free survival and 0.55 of these excluding surgery. Patients receiving consolidative local therapy (local therapy after systemic therapy) obtained hazard ratios 0.33 and 0.45 on progression-free and overall survival vs. systemic therapy, respectively. Hazard ratios of those receiving upfront local therapy (local therapy first) were 0.62 and 0.68 on progression-free and overall survival vs. systemic therapy. Pooled survival analysis showed median overall and progression-free survival of local therapy (21.6 and 14 months) group were both longer than systemic one (14.3 and 6.5 months). Odds ratio of adverse effects were no difference between 2 groups (P=0.16).

Conclusions

Local aggressive thoracic therapy could prolong 7 months overall and progression-free survival compared with systemic therapy in patients with oligometastatic non-small cell lung cancer. Consolidative local therapy might be a more favorable choice of local therapy. Benefits of local therapy for N2-3 positive patients should explored further.

Investigation of the Definition of De Novo Oligometastatic Nasopharyngeal Carcinoma: A Retrospective Study

Background

The prognosis of metastatic nasopharyngeal carcinoma (mNPC) is highly heterogeneous. As a special stage of distant metastasis of mNPC, quite a few oligometastatic NPC (omNPC) patients can still achieve a long-term survival after treatment. However, there is no uniform standard for the definition of omNPC until now.

Methods

We retrospectively analyzed the survival data of 191 patients with de novo mNPC at the Affiliated Cancer Hospital and Institute of Guangzhou Medical University between 2010 and 2017 and specifically analyzed the clinical outcomes associated with the number of metastatic organs/lesions and tried to find a cohort with relatively better prognosis to define as omNPC.

Results

The median overall survival (OS) of the entire group of patients was 21.5 months (95% CI 15.0–28.0), and the 1-year, 2-year, and 3-year OS rates were 72.2%, 46.1%, and 34.3%, respectively. Multiple-organ metastases (P < 0.001) and >5 metastatic lesions (P < 0.001) were adverse influencing factors of prognosis, and the number of metastatic lesions (P < 0.001) was the independent factor influencing the prognosis of de novo mNPC. The overall survival (OS) and progression-free survival (PFS) of patients with ≤5 metastatic lesions were significantly better than those of patients with >5 metastatic lesions.

Conclusion

Patients with ≤5 metastatic lesions presented a better survival, and this criterion may be a definition standard for the de novo omNPC.

Surgical Survival Benefits With Different Metastatic Patterns for Stage IV Extrathoracic Metastatic Non-Small Cell Lung Cancer: A SEER-Based Study

Background:

With the knowledge of oligometastases, primary surgery plays an increasingly vital role in metastatic non-small cell lung cancer. We aimed to evaluate the survival benefit of primary surgery based on metastatic patterns.

Materials and Methods:

The selected patients with stage IV extrathoracic metastatic (m1b) non-small cell lung cancer between 2010 and 2015 were included in a retrospective cohort study from the Surveillance, Epidemiology, and End Results (SEER) database. Multiple imputation was used for the missing data. Patients were divided into 2 groups depending on whether surgery was performed. After covariate balancing propensity score (CBPS) weighting, multivariate Cox regression models and Kaplan-Meier survival curve were built to identify the survival benefit of different metastatic patterns.

Results:

Surgery can potentially increase the overall survival (OS) (adjusted HR: 0.68, P < 0.001) of non-small cell lung cancer. The weighted 3-year OS in the surgical group was 16.9%, compared with 7.8% in the nonsurgical group. For single organ metastasis, surgery could improve the survival of metastatic non-small cell lung cancer. Meanwhile, no significant survival improvements in surgical group were observed in patients with multiple organ metastases.

Conclusion:

The surgical survival benefits for extrathoracic metastatic non-small cell lung cancer could be divided by metastatic pattern.

Defining oligometastatic non-small cell lung cancer: concept versus biology, a literature review

Objective

In this review, the concept of (synchronous) oligometastatic disease in patients with non-oncogene-driven non-small cell lung cancer (NSCLC) will be placed in the context of tumor biology and metastatic growth patterns. We will also provide considerations for clinical practice and future perspectives, which will ultimately lead to better patient selection and oligometastatic disease outcome.

Background

The treatment landscape of metastasized NSCLC has moved from "one-size fits all" to a personalized approach. Prognosis has traditionally been poor but new treatment options, such as immunotherapy and targeted therapy, brighten future perspectives. Another emerging development is the recognition of patients with so-called "oligometastatic" state of disease. Oligometastatic disease has been recognized as a distinct clinical presentation in which the tumor is stated to be early in its evolution of metastatic potential. It is suggested that this stage of disease has an indolent course, comes with a better prognosis and therefore could be considered for radical multimodality treatment.

Methods

Narrative overview of the literature synthesizing the findings of literature retrieved from searches of computerized databases, hand searches, and authoritative texts.

Conclusions

Oligometastatic NSCLC is a broad spectrum disease, with a variable prognosis. Although the biology and behavior of "intermediate state" of metastatic disease are not fully understood, there is evidence that a subgroup of patients can benefit from local radical treatment when integrated into a multimodality regime. The consensus definition of oligometastatic NSCLC, including accurate staging, may help to uniform future trials. The preferable treatment strategy seems to sequential systemic treatment with subsequent local radical treatment in patients with a partial response or stable disease. Prognostic factors such as N-stage, number and site of distant metastases, tumor volume, performance status, age, and tumor type should be considered. The local radical treatment strategy has to be discussed in a multidisciplinary team meeting, taking into account patient characteristics and invasiveness of the procedure. However, many aspects remain to be explored and learned about the cancer biology and characteristics of intermediate state tumors.

Current Evidence for Stereotactic Body Radiotherapy in Lung Metastases

Lung metastases are the second most common malignant neoplasms of the lung. It is estimated that 20–54% of cancer patients have lung metastases at some point during their disease course, and at least 50% of cancer-related deaths occur at this stage. Lung metastases are widely accepted to be oligometastatic when five lesions or less occur separately in up to three organs. Stereotactic body radiation therapy (SBRT) is a noninvasive, safe, and effective treatment for metastatic lung disease in carefully selected patients. There is no current consensus on the ideal dose and fractionation for SBRT in lung metastases, and it is the subject of study in ongoing clinical trials, which examines different locations in the lung (central and peripheral). This review discusses current indications, fractionations, challenges, and technical requirements for lung SBRT.

Safety Analysis of Salvage Surgery for Advanced Stages or Metastatic Lung Cancers

This case series aimed to analyze the outcomes of patients referred for salvage pulmonary resections after treatment with chemotherapy and immunotherapy for previously metastatic or unresectable tumors.From October 2016, after multidisciplinary board discussion, eight patients (median: 67 years, range: 52-78 years) underwent medical treatment due to advanced-stage diseases (stage cIIIA-cIVa). Four patients underwent cisplatin-based chemotherapy and, due to progression, were moved to an immunotherapy second line (nivolumab: two patients and pembrolizumab: two patients). Instead, four patients underwent combined cisplatin-based chemotherapy and immune checkpoint inhibitors (atezolizumab: two patients and pembrolizumab: two patients). After a multidisciplinary evaluation for salvage surgery, six patients underwent lobectomies, one patient underwent left pneumonectomy, and one patient underwent upper right lobectomy enlarged to the posterior arches of four ribs. The median duration of surgery was 179 minutes (range: 122-246 minutes). At the final pathological stage, three patients showed a complete major response (ypT0 ypN0), one patient was ypT1a ypN0, one ypT3 ypN0, 2 ypT3 ypN1, and one ypT4 ypN0. The hospital length of stay was 6 days (range: 3-23 days). Two patients had a postoperative complication. At the time of follow-up (median: 15.3 months [range: 1-32 months]), six patients were alive without evidence of the recurrence. Two patients died due to recurrence progression (N3 lymph nodes involvement) of the disease after 6 and 32 months.In stage IIIB-IVA nonsmall cell lung cancer, salvage lung surgeries after chemotherapy and immunotherapy are feasible, with high rates of R0 resection. Surgery can be technically tricky without significant morbidity and encouraging outcomes (even with a short-interval follow-up).

Local Ablative Therapy in Oligometastatic NSCLC

Oligometastatic non-small cell lung cancer (NSCLC) has been recognized as a unique, yet common, clinical entity over the past 2-3 decades. Numerous retrospective series and early phase single arm trials have demonstrated the efficacy and safety of aggressive approaches in select patients. In addition, results from recent randomized trials have demonstrated potential benefits of radiation therapy and surgery as a form of local ablative therapy (LAT) in prolonging disease-free survival and overall survival. However, more questions remain given the limitation of existing clinical evidence and the lack of well validated biomarkers. Advances in late stage randomized trials with biological correlatives may further clarify the role of LAT to assist with clinical decision making in treating patients with oligometastatic NSCLC. In this review, we discuss the clinical and biologic data surrounding patient selection for LAT in oligometastatic NSCLC, as well as future directions in prospective and translational studies.

Stereotactic Radiation for Lung Cancer: A Practical Approach to Challenging Scenarios

Stereotactic body radiation therapy (SBRT) is an effective and well-tolerated treatment for medically inoperable patients with early stage NSCLC. SBRT is a noninvasive treatment involving the delivery of ablative radiation doses with high precision in the course of a few treatments. Relative to conventionally fractionated radiation, SBRT achieves superior local control and survival. SBRT use has increased dramatically in the past 15 years and is currently considered the standard of care in cases of inoperable early stage NSCLC. It is being increasingly applied to more complex patient populations at higher risk of treatment-related toxicity. In these more complex patients, there is an increasing need to balance patient and treatment factors in selecting the optimal patients for SBRT. Here, we review several challenging clinical scenarios often encountered in thoracic multidisciplinary tumor boards.

Beyond First-Line Immunotherapy: Potential Therapeutic Strategies Based on Different Pattern Progressions: Oligo and Systemic Progression

First-line immune-checkpoint inhibitor (ICI)-based therapy has deeply changed the treatment landscape and prognosis in advanced non-small cell lung cancer (aNSCLC) patients with no targetable alterations. Nonetheless, a percentage of patients progressed on ICI as monotherapy or combinations. Open questions remain on patients' selection, the identification of biomarkers of primary resistance to immunotherapy and the treatment strategies to overcome secondary resistance to first-line immunotherapy. Local ablative approaches are the main therapeutic strategies in oligoprogressive disease, and their role is emerging in patients treated with immunotherapy. Many therapeutic strategies can be adapted in aNSCLC patients with systemic progression to personalize the treatment approach according to re-characterization of the tumors, previous ICI response, and type of progression. This review's aim is to highlight and discuss the current and potential therapeutic approaches beyond first-line ICI-based therapy in aNSCLC patients based on the pattern of disease progression (oligoprogression versus systemic progression).

MicroRNA-20a-5p suppresses tumor angiogenesis of non-small cell lung cancer through RRM2-mediated PI3K/Akt signaling pathway

The current therapeutic strategies for non-small cell lung cancer (NSCLC) are limited and unsatisfactory. MicroRNAs (miRNAs) participate in tumor angiogenesis in NSCLC. The aim of this study was to investigate the role of miR-20a-5p (miR-20a) in human NSCLC metastasis. In the current study, bioinformatics analysis and RT-PCR were performed to examine the expression level of miR-20a in tissues of NSCLC patients and NSCLC cell lines, respectively. Western blot was performed to test the protein levels. Cell proliferation, migration and angiogenesis capacity were tested by 5-ethynyl-29-deoxyuridine (EdU) assay, transwell assay and tube formation assay, respectively. Dual-luciferase reporter assay (DLR) was used to confirm the interaction between miR-20a and paired ribonucleotide reductase regulatory subunit M2 (RRM2). We found that the expression of RRM2 was upregulated, while the expression of miR-20a was downregulated in cancer tissues compared with adjacent tissues in NSCLC patients. We also detected the expression level of RRM2 and miR-20a in NSCLC cell lines, showing A549 cell line exhibited the lowest expression level of miR-20a and highest expression level of RRM2. Overexpressed miR-20a not only dramatically suppressed NSCLC cells proliferation, endothelial cells migration and tube formation in vitro, but also inhibited tumor growth and angiogenesis in vivo. It was demonstrated that miR-20a suppressed NSCLC growth by inhibiting RRM2-mediated PI3K/Akt signaling pathway. These findings indicate that the novel identified miR-20a could function as a tumor suppressor in NSCLC through modulating the RRM2-mediated PI3K/Akt axis, and it could be a valid molecular target for NSCLC treatment.

How to handle oligometastatic disease in nonsmall cell lung cancer

Patients with nonsmall cell lung cancer and limited metastatic disease have been defined as oligometastatic if local ablative therapy of all lesions is amenable. Evidence from different clinical retrospective series suggests that this subgroup harbours better prognosis than other stage IV patients. However, most reports have included patients with inconsistent numbers of metastases in different locations treated by a variety of invasive and noninvasive therapies. As long as further results from randomised clinical trials are awaited, treatment decision follows an interdisciplinary debate in each individual case. Surgery and radiotherapy should capture a dominant role in the treatment course offering the option of a curative-intended local therapy in combination with a systemic therapy based on an interdisciplinary decision. This review summarises the current treatment standard in oligometastatic lung cancer with focus on an ablative therapy for both lung primary and distant metastases in prognostically favourable locations.

Challenges to randomized trials in adult and congenital cardiac and thoracic surgery

Randomized trials in surgery face additional challenges compared to those in medicine. Some of the challenges are intrinsic to the nature of the field (such as issues with blinding, learning curve and surgeons experience and difficulties in defining the appropriate timing for comparative trials). Other issues are due to the surgical culture, the attitude of surgeons toward randomized trials and the lack of support by professional and national bodies. In this review a group with experience in trials in congenital and adult cardiac and thoracic surgery discusses the key issues with surgical trials and suggest potential solutions.

Role of imaging biomarkers in mutation-driven non-small cell lung cancer

Lung cancer remains the leading cause of cancer-related deaths worldwide. The treatment of non-small cell lung cancer (NSCLC), which accounts for a vast majority of lung cancers, has shifted to personalized, targeted therapy following discoveries of several targetable oncogenic mutations. Targeting of specific mutations has improved outcomes in many patients. This success has led to several target-specific agents replacing chemotherapy as first-line treatment in certain mutated NSCLC. Several researchers have reported that there may be imaging biomarkers that may be predictive of the presence of these mutations. These features, when present, have the potential in triaging patients into the most appropriate diagnostic and treatment algorithms. Distinct imaging features and patterns of metastases that have been associated with NSCLC with various targetable oncogenic mutations are presented in this review.

Image guidance in radiation therapy for better cure of cancer

The key goal and main challenge of radiation therapy is the elimination of tumors without any concurring damages of the surrounding healthy tissues and organs. Radiation doses required to achieve sufficient cancer-cell kill exceed in most clinical situations the dose that can be tolerated by the healthy tissues, especially when large parts of the affected organ are irradiated. High-precision radiation oncology aims at optimizing tumor coverage, while sparing normal tissues. Medical imaging during the preparation phase, as well as in the treatment room for localization of the tumor and directing the beam, referred to as image-guided radiotherapy (IGRT), is the cornerstone of precision radiation oncology. Sophisticated high-resolution real-time IGRT using X-rays, computer tomography, magnetic resonance imaging, or ultrasound, enables delivery of high radiation doses to tumors without significant damage of healthy organs. IGRT is the most convincing success story of radiation oncology over the last decades, and it remains a major driving force of innovation, contributing to the development of personalized oncology, for example, through the use of real-time imaging biomarkers for individualized dose delivery.

Significant reduction of oncologic pulmonary death by local control for pulmonary oligometastases treated with stereotactic body radiotherapy

BACKGROUND AND PURPOSE

The rate of oncologic pulmonary death after stereotactic body radiotherapy for pulmonary oligometastases has never been reported. The purpose of current study was to investigate the rate of freedom from oncologic pulmonary death (FOPD) and to analyze factors affecting for FOPD.

MATERIALS AND METHODS

The inclusion criteria for this retrospective study were that SBRT was performed between 2004 and 2015, the number of metastases was 5 or less, the primary lesion and extrathoracic metastases needed to be controlled before SBRT and a biological effective dose (BED₁₀) of 75 Gy or more was needed. The Kaplan-Meier estimator and the log-rank test were used to calculate and compare the stratified rates of FOPD. The Cox proportional hazards model was used for multivariate analyses (MVA). Primary disease death from a non-oncologic pulmonary cause was censored in model 1 and was excluded in model 2.

RESULTS

A total of 1172 patients with 1315 tumors were enrolled. During a median follow-up period of 24.5 months, oncologic pulmonary deaths accounted for 101 of 221 primary disease deaths. The 1-year, 3-year and 5-year FOPD rates in model 1 were 98.2%, 89.4% and 84.0%, respectively. MVA for FOPD revealed that local failure of the irradiated tumor, squamous cell carcinoma pathology, and chemotherapy after SBRT had significant relationships with lower FOPD rates in both model 1 and model 2.

CONCLUSIONS

Successful local control of pulmonary oligometastases by SBRT contributed to a higher FOPD rate.

Technology-driven research for radiotherapy innovation

Technology has a pivotal role in the continuous development of radiotherapy. The long road toward modern ‘high‐tech’ radiation oncology has been studded with discoveries and technological innovations that resulted from the interaction of various disciplines. In the last decades, a dramatic technology‐driven revolution has hugely improved the capability of accurately and safely delivering complex‐shaped dose distributions. This has contributed to many clinical improvements, such as the successful management of lung cancer and oligometastatic disease through stereotactic body radiotherapy. Technology‐driven research is an active and lively field with promising potential in several domains, including image guidance, adaptive radiotherapy, integration of artificial intelligence, heavy‐particle therapy, and ‘flash’ ultra‐high dose‐rate radiotherapy. The evolution toward personalized Oncology will deeply influence technology‐driven research, aiming to integrate predictive models and omics analyses into fast and efficient solutions to deliver the best treatment for each single patient. Personalized radiation oncology will need affordable technological solutions for middle‐/low‐income countries, as these are expected to experience the highest increase of cancer incidence and mortality. Moreover, technology solutions for automation of commissioning, quality assurance, safety tests, image segmentation, and plan optimization will be required. Although a large fraction of cancer patients receive radiotherapy, this is certainly not reflected in the worldwide budget for radiotherapy research. Differently from the pharmaceutical companies‐driven research, resources for research in radiotherapy are highly limited to equipment vendors, who can, in turn, initiate a limited number of collaborations with academic research centers. Thus, enhancement of investments in technology‐driven radiotherapy research via public funds, national governments, and the European Union would have a crucial societal impact. It would allow for radiotherapy to further strengthen its role as a highly effective and cost‐efficient cancer treatment modality, and it could facilitate a rapid and equalitarian large‐scale transfer of technology to clinic, with direct impact on patient care.

Clinicopathologic and Imaging Features of Non-Small-Cell Lung Cancer with MET Exon 14 Skipping Mutations

MET exon 14 (METex14) skipping mutations are an emerging potentially targetable oncogenic driver mutation in non-small-cell lung cancer (NSCLC). The imaging features and patterns of metastasis of NSCLC with primary METex14 skipping mutations (METex14-mutated NSCLC) are not well described. Our goal was to determine the clinicopathologic and imaging features that may suggest the presence of METex14 skipping mutations in NSCLC. This IRB-approved retrospective study included NSCLC patients with primary METex14 skipping mutations and pre-treatment imaging data between January 2013 and December 2018. The clinicopathologic characteristics were extracted from electronic medical records. The imaging features of the primary tumor and metastases were analyzed by two thoracic radiologists. In total, 84 patients with METex14-mutated NSCLC (mean age = 71.4 ± 10 years; F = 52, 61.9%, M = 32, 38.1%; smokers = 47, 56.0%, nonsmokers = 37, 44.0%) were included in the study. Most tumors were adenocarcinoma (72; 85.7%) and presented as masses (53/84; 63.1%) that were peripheral in location (62/84; 73.8%). More than one in five cancers were multifocal (19/84; 22.6%). Most patients with metastatic disease had only extrathoracic metastases (23/34; 67.6%). Fewer patients had both extrathoracic and intrathoracic metastases (10/34; 29.4%), and one patient had only intrathoracic metastases (1/34, 2.9%). The most common metastatic sites were the bones (14/34; 41.2%), the brain (7/34; 20.6%), and the adrenal glands (7/34; 20.6%). Four of the 34 patients (11.8%) had metastases only at a single site. METex14-mutated NSCLC has distinct clinicopathologic and radiologic features.

Local ablative radiotherapy for oligometastatic non-small cell lung cancer

In metastatic non-small cell lung cancer (NSCLC), the role of radiotherapy (RT) has been limited to palliation to alleviate the symptoms. However, with the development of advanced RT techniques, recent advances in immuno-oncology therapy targeting programmed death 1 (PD-1) and programmed death ligand 1 (PD-L1) and targeted agents for epidermal growth factor receptor (EGFR) mutation or anaplastic lymphoma kinase (ALK) translocation allowed new roles of RT in these patients. Within this metastatic population, there is a subset of patients with a limited number of sites of metastatic disease, termed as oligometastasis that can achieve long-term survival from aggressive local management. There is no consensus on the definition of oligometastasis; however, most clinical trials define oligometastasis as having 3 to 5 metastatic lesions. Recent phase II randomized clinical trials have shown that ablative RT, including stereotactic ablative body radiotherapy (SABR) and hypofractionated RT, to primary and metastatic sites improved progression-free survival (PFS) and overall survival (OS) in patients with oligometastatic NSCLC. The PEMBRO-RT study, a randomized phase II study comparing SABR prior to pembrolizumab therapy and pembrolizumab therapy alone, revealed that the addition of SABR improved the overall response, PFS, and OS in patients with advanced NSCLC. The efficacy of RT in oligometastatic lung cancer has only been studied in phase II studies; therefore, large-scale phase III studies are needed to confirm the benefit of local ablative RT in patients with oligometastatic NSCLC. Local intensified RT to primary and metastatic lesions is expected to become an important treatment paradigm in the near future in patients with metastatic lung cancer.