Even though there is some consistency in the AJCC definitions of resectability, these become blurred when describing borderline resectable pancreatic adenocarcinoma. At the University of Texas M.D. Anderson Cancer Center (MDACC), patients with (anatomic) borderline resectable pancreatic cancer were originally defined to include those whose tumors exhibit: short-segment encasement of the hepatic artery which is amenable to resection and reconstruction without evidence of tumor extension to the celiac axis; abutment of the SMA to involve less than or equal to180 degrees of the circumference of the artery; or short-segment occlusion of the SMV, PV, or SMPV confluence with a suitable option for vascular reconstruction due to a normal SMV below, and PV above the area of tumor involvement (7). Since then the criteria have been extended to include additional patients where the surgery could prove to be technically challenging. The American hepato-pancreatico-biliary (AHPBA) association consensus conference on pancreatic cancer (2009) expanded the venous involvement criteria to allow tumor abutment of the SMV/PV with or without impingment and narrowing of the lumen (in addition to venous encasement or short segment occlusion). NCCN has adopted some of these AHPBA guidelines in its most recent version (2.2011) and allows SMV/portal vein abutment with impingment and narrowing of the lumen . The criteria for arterial involvement (SMA and hepatic artery) are clear and similar across the board.
The above definitions describe the anatomic subset of borderline resectability that deal only with tumor-vessel orientation (referred to as type A). Katz and colleagues have described two additional subsets, types B and C, which attempt to define additional criteria for borderline resectability beyond the imaging based principles . Most physicians encounter patients with operable pancreatic cancer who are not quite ready for immediate surgery and require extra time off to sort out host or tumor related concerns. Some of these patients have subtle indeterminate subcentimeter liver lesions or peritoneal / omental nodules that are suspicious for metastatic disease they are too small to proceed with a diagnostic FNA- biopsy or additional imaging tests (PET-CT or MRI). These patients fit the MDACC type B definition of borderline resectable pancreatic cancer. Type B patients may have had a technically resectable or a borderline resectable primary tumor as defined on CT images. Another subset of patients is those who have associated medical comorbidities that need time to evaluate or a reversible borderline performance status (typically ECOG 3). Good examples of these presentation is a patient who has a small asymptomatic pulmonary embolism on routine imaging or a patient with a low prealbumin and decline in nutrition and performance status in the presence of obstructive jaundice and cholangitis though progress is noted after biliary decompression and a close eye on nutritional supplementation. This subset constitutes Type C category (and patients in this category may also have had a radiographic potentially resectable or a borderline resectable primary tumor).
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