Observational study of prevalence, management, and outcomes of synchronous oligometastatic non-small cell lung cancer.

Abstract

e20516 Background: Oligometastatic non-small cell lung cancer (NSCLC), characterized by one to five metastatic lesions in up to three organs, represents a distinct therapeutic window for localized treatment. The management of oligometastatic lung cancer is evolving with advancements in local therapies such as surgery and local ablative treatments. In the Indian context, the prevalence and outcomes of oligometastatic NSCLC remain underexplored, highlighting the need for further research in this area. Methods: This retrospective, single-center study at Tata Memorial Centre, Mumbai, evaluated patients with synchronous oligometastatic NSCLC diagnosed in 2023. Eligible patients were identified from the thoracic disease management group (DMG) cancer registry and electronic medical records. Inclusion criteria was histologic diagnosis of NSCLC with metastases limited to three organs and one to five lesions. Data collected included demographics, tumor characteristics, treatment modalities, and outcomes. Event-free survival (EFS) and overall survival (OS) were assessed using Kaplan-Meier methods, and toxicity was graded according to Common Terminology Criteria for Adverse Events version 5 (CTCAE v5). Results: Out of 4,122 patients registered in 2023, 1,574 had evaluable NSCLC with baseline imaging. Among them, 82.2% had metastatic disease, and 4.8% had oligometastatic NSCLC. The median age was 64 years, with a male-to-female ratio of 3:1. Most patients (83%) had an ECOG performance status ≤1, 53.2% were smokers and 65% had adenocarcinoma. The majority of patients (67.7%) had metastases confined to one site, with the brain being the most common (46.8%), followed by bone (32.2%). Most patients had one metastatic lesion (54.8%), followed by two (25.8%) and three lesions (14.5%). Twenty-two percent of patients received systemic therapy with curative radiation, 24% with palliative radiation, 16% had WBRT(whole brain radiotherapy) followed by systemic therapy, and 37% received systemic therapy alone. At a median follow-up of 9.69 months, 70% were alive, with an overall response rate of 68%. The 1-year OS was 63.5% for curative intent vs. 59.8% for palliative intent (p=0.58), and 1-EFS was 45.4% vs. 52.9%, respectively (p=0.89).The most common adverse events were hyponatremia (59.7%), anemia (51.6%), and fatigue (45.2%). Conclusions: Oligometastatic NSCLC comprises a small but significant subset (4.8%) of metastatic cases. Survival outcomes were similar between curative and palliative approaches, highlighting the need for further optimization of treatment strategies. Brain metastases did not significantly impact survival or EFS, suggesting that aggressive management, including stereotactic and ablative therapies, may be beneficial. Larger, multicenter, prospective studies are needed to validate these findings and refine treatment strategies for oligometastatic NSCLC.