Fasting Blood Glucose Levels Provide Estimate of Duration and Progression of Pancreatic Cancer Before Diagnosis.

BACKGROUND & AIMS: It is unclear how long pancreatic ductal adenocarcinomas (PDACs) are present before diagnosis. Patients with PDAC usually develop hyperglycemia and diabetes before the tumor is identified. If early invasive PDACs are associated with hyperglycemia, the duration of hyperglycemia should associate with the time that they have had the tumor. METHODS: We collected data on patients with PDACs from medical databases in Olmsted County, Minnesota, from 2000 through 2015 and from the Mayo Clinic's tumor registry from January 1, 1976, through January 1, 2017. We compared glycemic profiles of patients with PDAC (cases) compared with patients without cancer, matched for age and sex (controls). We analyzed temporal fasting blood glucose (FBG) profiles collected for 60 months before patients received a PDAC diagnosis (index date) (n = 219) (cohort A), FBG profiles of patients with resected PDAC (n = 526) stratified by tumor volume and grade (cohort B), and temporal FBG profiles of patients with resected PDACs from whom long-term FBG data were available (n = 103) (cohort C). The primary outcome was to estimate duration of presence of invasive PDAC before its diagnosis based on hyperglycemia, defined as significantly higher (P < .05) FBG levels in cases compared with controls. RESULTS: In cohort A, the mean FBG did not differ significantly between cases and controls 36 months before the index date. Hyperglycemia was first noted 36 to 30 months before PDAC diagnosis in all cases, those with or without diabetes at baseline and those with or without resection at diagnosis. FBG level increased until diagnosis of PDAC. In cohort B, the mean FBG did not differ significantly in controls vs cases with PDACs below 1.0 mL. The smallest tumor volume associated with hyperglycemia was 1.1 to 2.0 mL; FBG level increased with tumor volume. FBG varied with tumor grade: well- or moderately differentiated tumors (5.8 mL) produced the same FBG levels as smaller, poorly differentiated tumors (1.5 mL) (P < .001). In cohort C, the duration of prediagnostic hyperglycemia for cases with large-, medium-, or small-volume PDACs was 36 to 24, 24 to 12, and 12 to 0 months, respectively. PDAC resection resolved hyperglycemia, regardless of tumor location. CONCLUSIONS: In a case-control study of patients with PDAC from 2 databases, we associated FBG level with time to PDAC diagnosis and tumor volume and grade. Patients are hyperglycemic for a mean period of 36 to 30 months before PDAC diagnosis; this information might be incorporated into strategies for early detection.

A diagnostic strategy to distinguish autoimmune pancreatitis from pancreatic cancer.

BACKGROUND & AIMS: Autoimmune pancreatitis (AIP) and pancreatic cancer (PaC) have similar presentations; a diagnostic strategy is needed to distinguish the 2 diseases. METHODS: We compared computed tomography images (for pancreas and other organ involvement), serum IgG4 levels, histology data, and the response to steroids between patients with AIP (n = 48) and those with PaC (n = 100). RESULTS: Pancreatic imaging findings stratified patients into 3 groups. Group 1 was highly suggestive of AIP, with diffuse pancreatic enlargement without group 3 features (n = 25, 100% AIP). Group 2 was indeterminate, with normal-sized pancreas or focal pancreatic enlargement without group 3 features (n = 20, 75% AIP). Group 3 was highly suggestive of PaC, with presence of >1 low-density mass, pancreatic duct cutoff, or upstream pancreatic atrophy (n = 103, 92% PaC). Although all patients in group 1 had AIP, only 20 of the 25 patients had increased serum IgG4 levels and/or other organ involvement. Of the patients in groups 2 and 3 who did not have cancer, all those with serum IgG4 levels >2-fold the upper limit of normal or a combination of increased serum IgG4 levels and other organ involvement (n = 15) had AIP. In AIP subjects without supportive serologic evidence or other organ involvement (n = 14), diagnosis required pancreatic core biopsy (n = 7), steroid trial (n = 5), or resection (n = 2). CONCLUSIONS: PaC can be distinguished from AIP by pancreatic imaging, measurement of serum IgG4 levels, and determination of other organ involvement. However, a pancreatic core biopsy, steroid trial, or surgery is required for diagnosis in approximately 30% of patients with AIP.