Classifying Oligometastatic Non-Small Cell Lung Cancer.

Alisa N Blumenthaler,Mara B Antonoff

doi:10.3390/cancers13194822

Abstract

Simple SummaryAround half of patients with non-small cell lung cancer (NSCLC) have metastatic disease at the time of diagnosis. Some patients will have a limited number of metastatic sites, termed oligometastasis, rather than widespread disease. Aggressive treatment of oligometastasis has been supported by improved survival rates in retrospective studies, meta-analyses, and randomized phase II trials. Patient selection for aggressive local treatment of oligometastatic NSCLC would be facilitated by a common definition of what constitutes oligometastasis. We review the definitions of oligometastatic NSCLC proposed by consensus statements and those used in current treatment guidelines and previous trials of local consolidative therapy.An oligometastatic cancer state was first postulated in the 1990s by Hellman and Weichselbaum and described limited metastatic spread to a single or few sites of disease. It was hypothesized that this metastatic entity falls along a continuum of the natural history of cancer progression from a localized primary tumor to widespread metastases. Support for oligometastatic non-small cell lung cancer (NSCLC) has since been provided by multiple retrospective studies and then prospective randomized trials demonstrating better survival in this patient population after aggressive consolidative treatment. However, the lack of a universal definition of oligometastatic NSCLC has hindered a comparison between different studies and prevented well-defined recommendations for local consolidative treatment in this patient population. Attempts have been made to establish a common definition for use in clinical management and for the identification of inclusion criteria for future trials. In this review, we seek to summarize the current definitions of oligometastatic NSCLC based on recent expert consensus statements, previous randomized trials, and current treatment guidelines and to highlight the continued variability in current practice.

Highlights

The concept of oligometastatic cancer was first postulated by Hellman and Weichselbaum in 1995, as they described an intermediate state of neoplastic malignant potential with limited metastatic spread and potential, existing on a continuum ranging from localized to widely disseminated disease states [1]
Oligometastatic non-small cell lung cancer (NSCLC) represents a subset of patients with limited metastatic spread and the potential for achieving long-term survival, or even cure, with LCT to all sites of disease
The EORTC-LCG consensus definition has provided a common understanding that can be a basis to establish inclusion criteria for future clinical trials, though even this definition is limited by the paucity of prospective data identifying the maximum number of lesions that stand to benefit from LCT

Summary

Introduction

The concept of oligometastatic cancer was first postulated by Hellman and Weichselbaum in 1995, as they described an intermediate state of neoplastic malignant potential with limited metastatic spread and potential, existing on a continuum ranging from localized to widely disseminated disease states [1]. The National Comprehensive Cancer Network (NCCN) treatment guidelines do not define what is referred to as “limited” metastatic disease for which LCT for oligometastasis can be considered, though it is noted in the guidelines that prior clinical trials have included limitations of three to five metastases [34]. The 2018 European Society for Medical Oncology (ESMO) guidelines recommend LCT for patients with less than three metastatic lesions, without specifying a limit of number of organs that can be included in the oligometastatic state [35] This variability in the understanding of what constitutes an oligometastatic state has posed significant challenges when comparing outcomes across different trials, as well as when determining treatment paradigms for specific patient groups. Attempts have been made to establish a single definition for oligometastatic NSCLC to better guide inclusion criteria for future clinical trials

Required Staging Workup

Synchronous versus Metachronous Oligometastasis

Oligoprogression

Risk Stratification and Who Benefits Most from LCT

Findings

Conclusions