Age-Based Left-Digit Bias in the Treatment of Pancreatic Adenocarcinoma

Left digit bias, where the left-most digit disproportionately influences decision-making, can impact treatment decisions and patient outcomes. This study examines how such bias may affect treatment decisions for patients with pancreatic adenocarcinoma (PDAC), focusing on differences between patients aged 79 and 80. A retrospective cohort study using the National Cancer Database (2004–2020) analyzed patients with PDAC aged 79 and 80. The primary exposure was age-based left-digit bias. The main outcomes measured included differences in treatment received and overall survival. Statistical analyses included chi-square tests, regression discontinuity analysis, multivariate analysis, Kaplan-Meier survival curves, and Cox proportional hazards models. Among 5,304 patients (2,718 aged 79, 2,586 aged 80), chemotherapy use was higher in 79-year-olds (50.3%) than 80-year-olds (45.1%) (OR 0.79, 95% CI 0.70–0.89, p < 0.01). No significant differences were found in surgery or radiation. Chemotherapy was associated with lower mortality risk (HR 0.85, 95% CI 0.79–0.92, p < 0.01). Adjusted overall survival was similar between groups (HR 1.00, 95% CI 0.93–1.07, p = 0.91). Left digit bias was observed in the treatment of PDAC, with a tendency to favor chemotherapy for patients aged 79 over 80. This highlights the need for age-neutral decision-making in treatment planning to avoid biases that could impact patient care and outcomes.