Patterns of Failure in Patients with Borderline Resectable/Locally Advanced Pancreatic Cancer after Preoperative Chemotherapy and Stereotactic Body Radiation Therapy

Background The role of preoperative stereotactic body radiation therapy (SBRT) in pancreatic cancer is controversial and questions regarding the optimal dose and radiation treatment field remain. To better inform future investigations of SBRT dose and radiation fields, we evaluated the patterns of failure in patients with borderline resectable/locally advanced pancreatic cancer (BR/LAPC) after preoperative chemotherapy and SBRT in patients who underwent surgical resection. Methods We performed a single institution retrospective review of consecutive patients treated from September 2017 to January 2022 with BR/LAPC. Patients who underwent preoperative chemotherapy and SBRT followed by surgical resection were reviewed. SBRT was delivered to a dose of 33 Gy in five fractions. Kaplan-Meier overall survival and progression-free survival estimates were calculated. Results In total, 18 patients (12 BRPC, 6 LAPC) were included. Median age was 69 years (range 41 – 84 years). Median follow up was 30 months (range 13 – 59 months). Seventeen patients (94%) had a R0 resection and 13 (72%) underwent vascular reconstruction. Median overall survival and progression-free survival (PFS) was 42 months (range 13 – 59 months) and 23 months (range 1 – 45 months), respectively. In total, 61% (11/18) patients experienced progression at any point during follow-up. Of the patients who experienced recurrence, 27% (3/11) experienced local progression as component of their first recurrence, whereas 100% (11/11) experienced distant progression as a component of their first recurrence. When examining all recurrences that occurred at any point in follow-up, 28% (5/18) of patients experienced local or locoregional recurrence and 61% (11/18) experienced distant progression. Conclusions Local control and margin negative resection rates were excellent with preoperative chemotherapy and non-dose escalated SBRT in surgically resected patients with BR/LAPC. Distant recurrence was the predominant site of failure with lower incidences of isolated locoregional recurrences. Additional research is needed to determine the ideal treatment volume and patients who may benefit from dose escalation.