Diagnostic biopsy-to-treatment interval and risk of recurrence in localized pancreatic ductal adenocarcinoma: every week counts.

The impact of the interval between diagnostic biopsy and treatment initiation on oncologic outcomes in localized pancreatic ductal adenocarcinoma (PDAC) remains poorly characterized. We conducted an institutional review board (IRB)-approved retrospective cohort study of 91 consecutive patients diagnosed with localized PDAC between 2016 and 2024 at a tertiary care academic medical center. The primary exposure was the interval (days) from diagnostic biopsy to initiation of any curative-intent treatment. The primary outcome was time from treatment initiation to develop recurrence or distant metastasis. Kaplan-Meier analysis and Cox proportional hazards (PH) regression were used to assess associations. Models were adjusted for age, sex, radiation therapy, and surgery, and the PH assumption was verified using scaled Schoenfeld residual tests. Of 91 patients (39 male, 52 female), 61 (67%) developed recurrence or distant metastasis during follow-up. The median time to recurrence or metastasis was 21.7 months [95% confidence interval (CI): 17.9-24.9]. The median biopsy-to-treatment interval was 27 days [interquartile range (IQR): 21-38] among patients without recurrence or distant metastasis and 29 days (IQR: 24-44) among those with the event. Each additional 7-day delay from biopsy to treatment initiation was associated with a 9% increase in the hazard of recurrence or metastasis on multivariable analysis [adjusted hazard ratio (aHR), 1.09; 95% CI: 1.02-1.16; P=0.01]. Absence of surgery was also independently associated with worse outcomes (aHR, 2.54; 95% CI: 1.12-5.76; P=0.03). In this single-institution retrospective cohort, a longer biopsy-to-treatment interval was associated with an increased hazard of recurrence and distant metastasis. These findings should be interpreted cautiously given the retrospective single-center design, limited sample size, and absence of key prognostic covariates including resectability status; validation in larger prospective multi-institutional cohorts is warranted.