A population-based study on the impact of social determinants of health on time to treatment of stage I lung cancer in Ontario, Canada

Abstract

Background: Timely treatment of Stage I non-small cell lung cancer (NSCLC) is essential to improving outcomes, yet disparities persist in access to treatment across patient populations. This study aimed to assess the association between social determinants of health (SDOH) and time to treatment for patients with Stage I NSCLC in Ontario, Canada. Methods: We conducted a population-based retrospective cohort study using linked administrative databases. Adults diagnosed with Stage I lung cancer between 2007 and 2023 were included if they underwent either surgery or radiotherapy. Patients receiving chemotherapy, or surgery and radiotherapy were excluded. Flexible parametric models were used to evaluate associations between SDOH and time to treatment, stratified by treatment modality. Results: Among 10,734 patients with Stage I NSCLC, 7,366 (68.6%) received surgery only and 3,022 (28.2%) received radiotherapy only. Only 346 (3.2%) received both surgery and radiation. Increased time to treatment was significantly associated with advanced age (> 80 years: HR = 0.61, p < 0.001), higher comorbidity burden (> 5 comorbidities: HR = 0.80, p = 0.004), and being virtually rostered with a family physician (HR = 0.91, p = 0.001). Patients in the lowest neighbourhood income quintile had significantly longer time to treatment compared to higher quintiles (Q5: HR = 1.13, p < 0.001). Those living 50–100 km from a cancer centre experienced longer time to treatment (HR = 0.93, p = 0.011), as did patients treated in the Eastern region (HR = 0.79, p < 0.001) compared to those in the Central region. Time to treatment shortened over time, with improvements seen in 2015–2023 compared to 2007–2009. Conclusions: This study identifies age, comorbidity, socioeconomic status, geographic distance, and regional location as key SDOH associated with prolonged time to treatment for Stage I NSCLC in Ontario. These findings highlight ongoing inequities in cancer care and underscore the need for targeted policy and system-level interventions to improve timely treatment for vulnerable populations.