Stereotactic body radiation therapy for the treatment of locally recurrent pancreatic cancer after surgical resection.

Background: To report on a cohort of radiation-naïve patients with pancreatic cancer who developed isolated local recurrence following surgical resection and were subsequently treated with stereotactic body radiation therapy (SBRT).
Methods: Patients with pancreatic cancer who were treated with SBRT for isolated local recurrence after surgical resection were retrospectively reviewed. Clinical outcomes were calculated from completion of SBRT and included overall survival (OS), local progression-free survival (LPFS), distant metastasis-free survival (DMFS), and progression-free survival (PFS). Univariate (UVA) analysis was performed to identify variables associated with clinical outcomes. Kaplan-Meier method was used for survival outcomes. Toxicity was assessed using the Common Terminology Criteria for Adverse Events version 4.0.
Results: From September 2012 to November 2018, a total of 19 patients with localized pancreatic cancer were treated with SBRT for isolated local recurrence after initial surgical resection. No patients had prior radiation. The median biologically effective dose (BED ₁₀ ) was 54.8 Gy (range, 37.5-54.8 Gy). Median OS was 17.1 months, with 6-month and 1-year OS rates of 94.4% and 69.6%, respectively. Nine patients (47.4%) developed local failure after SBRT. Pattern of first failure after SBRT was distant in 7 patients (46.7%), local in 5 patients (33.3%), and synchronous distant and local in 3 patients (20.0%). One patient developed local failure after developing distant disease first. Of the 9 local failures, 3 (33.3%) were out-of-field. Median LPFS was 22.2 months, with 6-month and 1-year LPFS rates of 86.9% and 63.2%, respectively. A BED ₁₀ <54.8 Gy was associated with inferior LPFS (1-year, 25.0% vs. 80.2%, P<0.009). Median DMFS and PFS were 15.6 months. There was 1 case (5.3 %) of grade 3 gastric perforation. There were no cases of grade 4-5 toxicity events.
Conclusions: SBRT for locally recurrent pancreatic cancer after initial curative resection is safe and feasible. A BED ₁₀ <54.8 Gy was significantly associated with inferior local control. Further studies investigating dose escalation and optimal treatment volumes in the locally recurrent setting are warranted.
Competing Interests: Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://jgo.amegroups.com/article/view/10.21037/jgo-22-38/coif). JMH serves as an unpaid editorial board member of Journal of Gastrointestinal Oncology from January 2021 to December 2022. JMH is a former employee of pancreatic action network and consultant for the 1440 foundation. JMH currently has a grant through the 1440 foundation where funds are provided to Northwell for protected time to lead the Canopy Cancer Collective Learning Health Network. JM receives royalties from Uptodate and Springer and honorarium from Springer. The other authors have no conflicts of interest to declare.
(2022 Journal of Gastrointestinal Oncology. All rights reserved.)