Impact of diagnosis-to-treatment interval on mortality in patients with early-stage breast cancer: a retrospective nationwide Korean cohort.

Background: The diagnosis-to-first-treatment interval (DFTI) is an important prognostic factor and a major concern for patients with breast cancer as well as their clinicians. It may be particularly important for patients with early-stage breast cancer. The aim of this study was to investigate the association between DFTI and risk of mortality in patients with new-onset early-stage breast cancer.

Methods: This nationwide, retrospective cohort study utilized data from the Korean National Health Insurance database and the Korea National Cancer Incidence Database (2006-2017). By using 1:5 propensity score matching, 3,625 participants with a DFTI < 60 days and 725 with a DFTI ≥ 60 days were included in the analysis. Cox proportional hazard regression models were used to examine the association between the DFTI and 5-year all-cause mortality risk.

Results: Compared with patients with breast cancer with a DFTI < 60 days, patients with a DFTI ≥ 60 days had a higher 5-year mortality risk (hazard ratio [95% confidence interval], 2.09 [1.43-3.06]). Similarly, sensitivity analysis with a 45-day threshold revealed higher mortality in patients with a DFTI ≥ 45 days (HR [95% CI], 1.49 [1.14-1.96]) than their counterparts with a DFTI < 45 days. This association was greater for patients with low household income, those who lived in rural areas, and those with a high Charlson comorbidity index.

Conclusions: A DFTI ≥ 60 days was associated with mortality risk in patients with early-stage breast cancer. These results emphasize the importance of closely monitoring the waiting times of this patients population and ensuring timely treatment.