Abstract 1018: Time to secondary treatment initiation affects overall survival in early-stage lung cancer
Authors: Rowe Dianna J. , Kammer Michael , Lehman Jonathan , Maldonado Fabien 
Published: June 2022

Abstract
Rationale: Lung cancer is the leading cause of cancer-related deaths in the US and worldwide. The 5-year overall survival (OS) for lung cancer patients is below 20%, lower than most other common cancers. In general, timely care can positively affect the survival of patients. However, previous studies of lung cancer and the effect of time-to-treatment on patient outcomes have been inconclusive. Some studies report adverse effects, while others report the association referred to as the ‘waiting time paradox’, where patients with severe diagnosis receive quicker care, but have poorer outcomes due to advanced disease. These studies investigate time-to-treatment of any type, but association between time-to-treatment for secondary treatments and outcomes for lung cancer has not been conclusively defined.
Methods: Treatment data from 714 patients with lung cancer diagnosis at Vanderbilt University Medical Center between 2001 and 2021 was used for this analysis. Secondary treatment data included data in three categories: chemotherapy (N=577), radiation therapy (N=126), and target therapies(N=11). Cox regression and Kaplan-Meir curves were used to model the effect of time-to-treatment on overall survival, adjusted for demographic and clinical factors, including if surgical resection was performed before secondary treatment start date. Time-to-treatment was defined as the interval of days between diagnosis or initial surgical procedure and treatment start date in four categories: 0-10 days (1), 11-20 days (2), 21-30 days (3), 31-45 days (4).
Results: Cox proportion regression analysis of patients treated within 30 days, including stage and time-to-treatment, had a significant difference in overall survival when stratified by cox linear predictor median (value = 0.0912). Patients with linear predictors values above the median (high) in the cox proportion model had a lower 3-year survival than patients with linear predictor values lower than the median (low) (p=0.0021). This contrast is seen clearly in early-stage lung cancer patients, who received chemotherapy as secondary treatment, where patients with longer time-to-treatment start (15-30 days) had a lower 3-year survival than patients with shorter time-to-treatment (0-15 days) (p=0.047).
Conclusions: The effect of changes in time-to-treatment initiation in lung cancer patients receiving secondary treatment appears to be sensitive to initiation within a 30-day period. Although past studies have focused on treatment start time initiation categories within weeks or months, our study is the first to elucidate a possible sensitivity to secondary initiation within just a few days period. Further examination aims to further detail treatment types, by investigating changes in dosage, treatment combinations, or institutions differences to better understand time-to-treatment effects on the survival rates of lung cancer patients.
Citation Format: Dianna J. Rowe, Michael Kammer, Jonathan Lehman, Fabien Maldonado. Time to secondary treatment initiation affects overall survival in early-stage lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1018.