Is diabetes mellitus a risk factor for pancreatic cancer?

Abstract

The relationship between diabetes mellitus and the risk of pancreatic cancer has been a matter of study for a long period of time. The importance of this topic is due to two main causes: the possible use of recent onset diabetes as a marker of the disease and, in particular, as a specific marker of pancreatic cancer, and the selection of a population at risk for pancreatic cancer. Thus, we decided to make an in-depth study of this topic; thus, we carried out an extensive literature search in order to re-assess the current knowledge on this topic. Even if diabetes is found a decade before the appearance of pancreatic cancer as reported in meta-analytic studies, we cannot select those patients already having non detectable pancreatic cancer, at least with the imaging and biological techniques available today. We believe that more studies are necessary in order to definitively identify diabetes mellitus as a risk factor for pancreatic cancer taking into consideration that approximately 10 years are needed to diagnose symptomatic pancreatic cancer. At present, the answer to the as to whether diabetes and pancreatic cancer comes first similar to the adage of the chicken and the egg is that diabetes is the egg.

Keywords: Clinical studies; Diabetes mellitus; Obesity; Pancreatic neoplasms; Risk factors.

Figure 1

Relative risks and quantitative analysis. Panel A: Relative risks (RR) for the association between diabetes and pancreatic cancer according to the duration of the diabetes (originated from[63]). The risk disappears after 10 years; Panel B: Quantitative analysis of the timing of the genetic evolution of pancreatic cancer indicates that at least a decade is necessary between the occurrence of the initiating mutation and the birth of the parental, non-metastatic founder cell, that at least five more years are required for the acquisition of metastatic ability and patients usually die on an average of 2 years thereafter (originated from[87]).