SPAN-C: Results of a Phase II Clinical Trial of Stereotactic Body Radiotherapy in Pancreatic Ductal Adenocarcinoma.

Abstract

Introduction: The role of stereotactic body radiotherapy (SBRT) remains unclear in the setting of pancreatic ductal adenocarcinoma (PDAC). This study aims to investigate the safety, feasibility and benefits of SBRT for PDAC in a clinical trial setting.

Methods: SPAN-C was a single centre, single-arm, phase II clinical trial. Patients with locally advanced, borderline resectable, and metastatic PDAC suitable for high dose radiation were enrolled. Fiducial marker placement was mandated. Following induction chemotherapy, patients were treated with 40-45Gy in 5 fractions of external beam radiotherapy. Freedom from local failure at 12 months was the primary endpoint. Secondary endpoints included disease recurrence endpoints, acute and late toxicity, surgical outcomes, and palliative endpoints.

Results: Thirty patients were enrolled. Median follow up of alive patients was 5 years (min 31 months). Twenty-six completed treatment as per protocol. Nine patients (34.6%) underwent a resection, 5 of whom had a R0 resection and 2 had a complete pathologic response. The 12-month freedom from local failure was 100% for the resected subgroup and 76.5% for the unresected subgroup. Seven patients (26.9%) had local recurrences, with 5 of these in the unresected group (29.4%). Median OS was 37.9 months for the resected subgroup and 10.7 months for the unresected subgroup. Three patients had grade 3 acute toxicity, and no patients had late high-grade toxicity.

Conclusions: SBRT was safe and feasible with high rates of local control at 12 months and low rates of toxicity. It appears a valid alternative to chemo-irradiation in both the pre-operative and inoperable setting.

Trial registration: ClinicalTrials.gov identifier: NCT03505229.