MA25.01 EORTC Lung Cancer Group Survey to Define Synchronous Oligometastatic Disease in NSCLC

Proposing synchronous oligometastatic non-small-cell lung cancer based on progression after first-line systemic therapy

Despite the importance of accurate disease definitions for effective management and treatment decisions, there is currently no consensus on what constitutes oligometastatic non–small‐cell lung cancer (NSCLC). Predominant patterns of initial progressive disease (PD) after first‐line systemic therapy have been shown to be a substantial basis for local ablative therapy (LAT) for all disease sites in patients with oligometastatic NSCLC, suggesting that these patterns could be helpful in defining synchronous oligometastatic NSCLC. Therefore, this retrospective study aimed to propose a threshold number of metastases for synchronous oligometastatic NSCLC, based on the pattern of initial PD after first‐line systemic therapy. The cut‐off threshold number of metastases compatible with synchronous oligometastatic NSCLC was determined using receiver operating characteristic (ROC) curve analyses of PD at the initially involved sites alone. ROC analysis of 175 patients revealed that the presence of 1‐3 metastases before first‐line treatment (sensitivity, 85.9%; specificity, 97.3%; area under the curve, 0.91) was compatible with oligometastatic NSCLC, therefore we divided patients into oligometastatic NSCLC and non‐oligometastatic NSCLC groups. Multivariate logistic regression analyses revealed oligometastatic NSCLC to be the only independent predictor of PD at initially involved sites alone (odds ratio 165.7; P < .001). The median survival times in patients with oligometastatic or non‐oligometastatic NSCLC were 23.0 and 10.9 mo (hazard ratio, 0.51; P = .002), respectively. Based on these findings, we propose synchronous oligometastatic NSCLC as 1‐3 metastases in accordance with patterns of initial progression. The result of our study might be contributory to provide a common definition of synchronous oligometastatic NSCLC.

Definition of Synchronous Oligometastatic Non-Small Cell Lung Cancer-A Consensus Report

INTRODUCTION

Improved outcome has been shown in patients with synchronous oligometastatic (sOM) NSCLC when treated with radical intent. As a uniform definition of sOM NSCLC is lacking, we developed a definition and diagnostic criteria by a consensus process.

METHODS

A pan-European multidisciplinary consensus group was established. Consensus questions were built on the basis of current controversies, and definitions were extracted from a survey, cases and a systematic review. This statement was formulated during a consensus meeting.

RESULTS

It was determined that definition of sOM NSCLC is relevant when a radical treatment that may modify the disease course (leading to long-term disease control) is technically feasible for all tumor sites with acceptable toxicity. On the basis of the review, a maximum of five metastases and three organs was proposed. Mediastinal lymph node involvement was not counted as a metastatic site. Fludeoxyglucose F 18 positron emission tomography-computed tomography and brain imaging were considered mandatory. A dedicated liver magnetic resonance imaging scan was advised for a solitary liver metastasis, and thoracoscopy and biopsies of distant ipsilateral pleural sites were recommended for a solitary pleural metastasis. For mediastinal staging, fludeoxyglucose F 18 positron emission tomography-computed tomography was deemed the minimum requirement, with pathological confirmation recommended if this influences the treatment strategy. Biopsy of a solitary metastatic location was mandated unless the multidisciplinary team is of the opinion that the risks outweigh the benefits.

CONCLUSION

A multidisciplinary consensus statement on the definition and staging of sOM NSCLC has been formulated. This statement will help to standardize inclusion criteria in future clinical trials.

Defining Synchronous Oligometastatic Non-Small Cell Lung Cancer: A Systematic Review

INTRODUCTION

Synchronous oligometastatic (sOM) disease is an oncological concept characterized by a limited cancer burden. Patients with oligometastasis could potentially benefit from local radical treatments. Despite the fact that the sOM condition is well recognized, a universal definition, including a specific definition for NSCLC, is not yet available. The aim of this systematic review was to summarize the definitions of and staging requirements for use of the term synchronous oligometastatic in the context of NSCLC.

METHODS

The key issue was formulated in one research question according to the population, intervention, comparator, and outcomes strategy. The question was introduced in MEDLINE (OvidSP). All articles dealing with sOM NSCLC and providing a definition of synchronous oligometastasis in NSCLC were selected and analyzed.

RESULTS

A total of 21 eligible articles focusing on sOM NSCLC were retrieved and analyzed. In 17 studies (81%), patients had to be staged with magnetic resonance imaging or computed tomography of the brain, thoracic and abdominal computed tomography, and positron emission tomography. The total number of metastases allowed in the definitions ranged from one to eight, but in 38.1% of studies the maximum number was 5. Most of the publications did not define the number of involved organs or the maximum number of metastases per organ. For mediastinal lymph node involvement, only five articles (27.8%) counted this as a metastatic site.

CONCLUSIONS

No uniform definition of sOM NSCLC could be retrieved by this systematic review. However, extended staging was mandated in most of the studies. An accepted oncological definition of synchronous oligometastasis is essential for patient selection to define prospective clinical trials.