Date of Award

January 2025

Document Type

Open Access Thesis

Degree Name

Master of Public Health (MPH)

Department

School of Public Health

First Advisor

Shi-yi Wang

Abstract

BackgroundThe Eastern Cooperative Oncology Group (ECOG) performance status (PS) is a critical factor in treatment decisions and prognosis for advanced non-small cell lung cancer (NSCLC). However, documentation gaps exist in clinical practice. The characteristics of patients with missing ECOG PS and the prognostic implications of this missingness are poorly understood. This study aimed to identify demographic and clinical predictors associated with missing ECOG PS documentation and to evaluate whether missing ECOG PS is associated with overall survival (OS) in a large real-world cohort of advanced NSCLC patients.

MethodsThis retrospective cohort study utilized the Flatiron Health electronic health record-derived, de-identified database. The cohort included 55,775 patients diagnosed with advanced NSCLC between 2011 and 2023 who initiated first-line therapy within 90 days of diagnosis. ECOG PS at treatment initiation was categorized as 0–1, 2–4, or missing. Multivariable logistic regression identified independent predictors of missing ECOG status. Kaplan-Meier methods and Cox proportional hazards regression (tested for and addressing non-proportionality) were used to compare OS among the three ECOG groups (Missing, 0-1, 2-4).

ResultsECOG PS was missing in 19.7% (n=10,993) of patients. The proportion of missing ECOG decreased significantly over time, from 50.2% in 2011 to 14.7% in 2023. Independent predictors of higher odds of missing ECOG included earlier diagnosis period (2011-2014 reference), "Other" race (OR 1.70 vs. White), older age (OR 1.01 per year), treatment in the West (OR 3.78 vs. Midwest) or South (OR 1.14 vs. Midwest) regions, academic practice setting (Community practice OR 0.53 vs. Academic), NSCLC NOS histology (OR 1.24 vs. Non-squamous), unknown/not documented (OR 9.81 vs. History) or no history of smoking (OR 1.09 vs. History), Medicaid (OR 1.13 vs. Commercial) or Other insurance (OR 1.15 vs. Commercial), and 'No Testing' for biomarkers (OR 2.04 vs. PD-L1 <1%) or ALK Positive status (OR 1.24 vs. PD-L1 <1%). Asian race (OR 0.73 vs. White), Medicare insurance (OR 0.82 vs. Commercial), and Squamous histology (OR 0.75 vs. Non-squamous) were associated with lower odds. Median OS was 18.4 months for ECOG 0-1, 12.0 months for ECOG 2-4, and 8.3 months for Missing ECOG. The multivariate logistic regression for 2-year survival showed that, compared to ECOG 2-4, ECOG 0-1 was associated with higher odds of survival (OR 1.49, 95% CI: 1.41-1.57), while Missing ECOG was associated with significantly lower odds of survival (OR 0.53, 95% CI: 0.49-0.57).

ConclusionWhile ECOG documentation in advanced NSCLC has improved, missingness persists (19.7% overall) and is associated with specific patient and system factors, including race, geographic region, practice setting, and lack of biomarker testing. Crucially, patients with missing ECOG exhibited the poorest survival outcomes, worse even than those documented as ECOG 2-4, both in unadjusted median survival and adjusted 2-year survival odds. Addressing documentation gaps through improved workflows and standardized data collection, particularly in identified high-risk groups and settings, is crucial for equitable care, reducing bias in real-world evidence, and appropriately accounting for the significant negative prognostic implication of missing performance status in oncology research.

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This is an Open Access Thesis.

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