Social Vulnerability Effects on Timeliness-to-Treatment for Patients with Localized Non-Small Cell Lung Cancer

J. E. Williams¹, F. Jacobson-Davies¹, R. C. Jacobs², D. D. Odell^1
1University of Michigan, Ann Arbor, Michigan ²Northwestern University Feinberg School of Medicine, Boston, Massachusetts

Purpose: To evaluate the association between Social Vulnerability Index and time-to-treatment for patients with non-metastatic clinical N0 non-small cell lung cancer (NSCLC). For patients with clinical N0 NSCLC, delays between diagnosis and treatment confer worse overall survival. The effect of social vulnerability on time-to-treatment for patients with early-stage NSCLC is unknown.

Methods: Leveraging data from the Michigan Cancer Surveillance Program, all adult patients treated for localized (N0) NSCLC between January 1, 2015 and December 31, 2020 were identified. Social Vulnerability Index (SVI) was identified using patient county of residence. Patients were partitioned into cohorts by SVI quartile for analysis. Time-to-treatment was defined as days between diagnosis and initiation of first treatment. Bivariate analysis was used to describe demographic and clinical differences between SVI patient cohorts. Multivariable linear regression was performed to evaluate the association of time-to-treatment and SVI-quartile. Subgroup multivariable linear regression analyses were performed to evaluate the association of time-to-treatment and SVI quartile stratified by first course of treatment utilized (surgical resection, radiation therapy, or systemic therapy).

Results: 8,949 patients with clinical N0 NSCLC were included for analysis. Mean SVI score was 39.4 (SD 20.4). Compared to patients in the lowest SVI quartile, patients in the highest SVI quartile were younger (69.3 vs 71.4 years, p< 0.001), more often Medicaid insured (8% vs 4%, p< 0.001), and less likely to live in a metropolitan area (38.3% vs 59.6%, p< 0.001). Time-to-treatment significantly increased in each subsequent SVI quartile. Compared to patients in the lowest SVI quartile, patients in the highest SVI quartile had a 3.0 day longer time-to-treatment (95% CI 0.8-5.1, p=0.006). When stratified by treatment modality, patients in the highest SVI quartile had longer time-to-treatment for both radiation therapy and systemic therapy but no difference in time-to-resection was evident.

Conclusion: Early-stage NSCLC patients with high social vulnerability demonstrate longer wait times to initiate treatment, particularly for multimodality therapy. This may influence oncologic treatment outcomes. These findings motivate further investigations and interventions addressing social determinants of health to maximize population-level access to high-quality lung cancer care.

Identify the source of the funding for this research project: Dr. Williams is supported by NIH 5T32-DK108740.
Dr. Odell is supported by NIH 1R01-HS029343-01A1.