Overall time interval (“Total diagnostic delay”) and mortality in symptomatic oral cancer: A U-shaped association

Abstract Objectives To assess the impact on survival of the total time interval since the first bodily change (sign/symptom) until the start of treatment in symptomatic oral cancer patients. Methods Retrospective, hospital-based study designed within the “Aarhus Statement” conceptual framework, using the overall interval to treatment of 183 oral cancer patients to analyse their survival rates. Results Overall time interval (T5): 107.1 ± 85.2 days. Overall survival rate: 58.4 (CI: 51.3–66.4%). Recurrence time (median): 724 days (IQR, 223–2963.5). Median survival time: 1744 days (IQR, 479.5–3438). Overall delay (T5) and mortality showed a U-shaped association, where patients with short (24.0–55.5 days) and long T5 intervals (127.5–420 days) had higher mortality than those with medium T5 intervals (55.5–127.5 days). Conclusion There is a non-monotonic association between time interval and mortality. Higher mortality rates are linked to shorter and longer time intervals. This may induce underestimation of the association when time intervals are considered dichotomously.