Resection of Locally Advanced Pancreatic Cancer without Regression of Arterial Encasement After Modern-Era Neoadjuvant Therapy.

Introduction: Modern-era systemic therapy for locally advanced pancreatic adenocarcinoma (LAPC) offers improved survival relative to historical regimens but not necessarily improved radiographic downstaging to allow more patients to undergo resection. The aim of this study was to evaluate the survival, progression, and pathologic outcomes after resection of LAPC that did not regress from > 180 degrees arterial encasement after neoadjuvant therapy.

Methods: Sixty-one LAPC patients were brought to the operating room after neoadjuvant therapy for NCCN-defined unresectable pancreatic cancer between 2012 and 2017. Pts were explored with intent of pancreatectomy and irreversible electroporation for margin extension; 5 (8%) had metastatic lesions on exploratory laparoscopy and were excluded from analyses. Imaging was re-examined to confirm LAPC prior to surgery. Data were analyzed from a prospective pancreatic cancer database.

Results: Patients had arterial involvement of the celiac axis (37.5%) and/or superior mesenteric artery (42.9%) and/or an extended length of the common hepatic (n = 44.6%) artery. Twenty-nine males and 27 females, median 65 years of age, received neoadjuvant gemcitabine-based (58.9%) or FOLFIRINOX (35.7%) chemotherapy and stereotactic body (42.9%) or intensity-modulated (51.8%) radiation therapy. Median months from initiation of neoadjuvant therapy to surgery was 7.5. Sixty-one percent underwent Whipple, 21% distal, and 18% modified Appleby procedures; 57% patients underwent venous reconstruction. Ninety-day mortality was 2%. An R0 margin was achieved in 80%, and 53% were N0. Median overall and progression-free survival was 18.5 (95%CI 12.27-32.33) and 8.5 months (95%CI 6.0-15.0), respectively. One- and 3-year survival from surgery was 68.5% (95%CI 53.0-79.7) and 39.0% (95%CI 23.7-53.8), respectively.

Conclusion: With modern-era neoadjuvant therapy, R0 resections can be achieved in a majority of non-metastatic patients with locally advanced, unresectable disease based on cross-sectional imaging.