Aims: The role of concomitant chemotherapy with radiotherapy (CRT) in locally advanced pancreatic cancer (LAPC) is controversial. The aim of this study was to report the outcomes of patients with LAPC treated with CRT over a 10-year period within a single institution and to identify those patients who derived the most benefit.

Methods: Patients with LAPC who received radical radiotherapy (> 45Gy) between January 2004 – October 2014 were identified. The Electronic Patient Record was reviewed to collect data regarding staging, treatment, response and outcome. The Kaplan-Meier and Cox regression methods were used to analyse survival outcomes and compare survival rates between groups. Results: 138 patients were identified. Patients who had a response on imaging after induction chemotherapy had a median OS of 17.4 months compared to 10.3 months in non-responders (HR 0.55, 95% CI 0.35–0.87, p=0.01). At three months post-radiotherapy, patients who had achieved a response on CT had a median OS of 56 months compared to 10.7 months (HR 0.28, 95% CI 0.12–0.65, p=0.003). However, a reduction in CA19-9 prior to radiotherapy was not significantly associated with progression free survival (PFS) or Overall survival (OS). Patients with a response in CA19-9 levels at 3-months post-radiotherapy compared to baseline had an OS of 19.1 months compared to 10.5 months in non-responders (HR 0.42, 95% CI 0.26–0.68, p<0.001).

Conclusion: Patients with LAPC who responded to chemotherapy on imaging prior to radiotherapy had improved PFS and OS than non-responders and therefore appeared to benefit the most from CRT. A decrease in CA19-9 prior to radiotherapy was not associated with improved survival and proved less useful for patient selection for CRT.

Keywords: Chemoradiotherapy, Pancreatic cancer, PET-CT