2190 - Comparative Local Control in Pancreatic Adenocarcinoma after Surgical Resection or Ablative Radiotherapy

Purpose/Objective(s): Pancreatic adenocarcinoma is a malignancy with poor prognosis and increasing incidence. Surgical resection is the standard of care for patients with non-metastatic disease but morbidity is common. Modern techniques allow for delivery of ablative doses of radiotherapy with low rates of major adverse effects, making it an increasingly attractive option for definitive local therapy. In this study we seek to compare rates of local control between surgical resection and ablative radiotherapy delivered with on-table adaptation.

Materials/Methods: Using prospectively maintained databases at a single high-volume cancer center, we conducted a retrospective cohort study analyzing outcomes in patients with non-metastatic disease who received neoadjuvant chemotherapy prior to definitive therapy with surgical resection or ablative radiotherapy during the period 2015 – 2020.

Results: The surgical and radiotherapy cohorts included 163 and 121 patients, respectively. Patients who underwent radiotherapy were more likely to have locally advanced disease and higher CA19-9 levels. Rates of local recurrence (12 months – 16.6% vs 6.7%, 24 months – 32.3% vs 22.3%; p = 0.599) were statistically similar. Recurrence-free (12 months – 82.2% vs 56.3%, 24 months – 42.4% vs 23.1%; p = 0.020) and overall survival (12 months – 91.3% vs 71.8%, 24 months – 64.2% vs 31.7%; p = 0.003) favored the surgery cohort. Major adverse events were more common in the surgery cohort (28.8% vs 11.6%; p < 0.005).

Conclusion: Rates of local control were statistically similar between cohorts. Recurrence-free and overall survival were superior in the surgical cohort, though patients in the radiation cohort had more advanced disease. Further studies, including well-designed trials, are required to determine to what extent this difference is due to patient selection or therapeutic modality.

Abstract 2190 – Table 1