Borderline resectable pancreatic cancer: need for standardization and methods for optimal clinical trial design

Abstract

Background: Methodological limitations of prior studies have prevented progress in the treatment of patients with borderline resectable pancreatic adenocarcinoma. Shortcomings have included an absence of staging and treatment standards and pre-existing biases with regard to the use of neoadjuvant therapy and the role of vascular resection at pancreatectomy.

Methods: In this manuscript, we review limitations of studies of borderline resectable PDAC reported to date, highlight important controversies related to this disease stage, emphasize the research infrastructure necessary for its future study, and present a recently-approved Intergroup pilot study (Alliance A021101) that will provide a foundation upon which subsequent well-designed clinical trials can be performed.

Results: We identified twenty-three studies published since 2001 which report outcomes of patients with tumors labeled as borderline resectable and who were treated with neoadjuvant therapy prior to planned pancreatectomy. These studies were heterogeneous in terms of the populations studied, the metrics used to characterize therapeutic response, and the indications used to select patients for surgery. Mechanisms used to standardize these and other issues that are incorporated into Alliance A021101 are reviewed.

Conclusions: Rigorous standards of clinical trial design incorporated into trials of other disease stages must be adopted in all future studies of borderline resectable pancreatic cancer. The Intergroup trial should serve as a paradigm for such investigations.

Figure 1

Study schema from intergroup trial (Alliance Trial #A021101). BLR PDAC, borderline resectable pancreatic adenocarcinoma; mFOLFIRINOX, modified FOLFIRINOX; EBRT, external beam radiation therapy; CAPE, capecitabine; GEM, gemcitabine.

Figure 2

Radiographic findings consistent with borderline resectable PDAC. A) An interface between the primary tumor and the superior mesenteric vein measuring at least 180° of the circumference of the vessel wall; B) An interface between the tumor and superior mesenteric artery measuring less than 180° of the circumference of the vessel wall; C) Circumferential interface between the tumor and the common hepatic artery. T, tumor; A, superior mesenteric artery; V, superior mesenteric vein; H, common hepatic artery; C, celiac trunk.