Pancreatic cancer: systemic combination therapies for a heterogeneous disease.

Pancreatic cancer is the only human malignancy for which patients' survival has not improved substantially during the past 30 years. Despite advances in the comprehension of the molecular mechanisms underlying pancreatic carcinogenesis, current systemic treatments offer only a modest benefit in tumor-related symptoms and survival. Over the past decades, gemcitabine and its combination with other standard cytotoxic agents have been the reference treatments for advanced pancreatic cancer patients. The recent introduction of the three-drug combination regimen FOLFIRINOX or the new taxane nab-paclitaxel represent key advances for a better control of the disease. Novel agents targeting molecular mechanisms involved in cancer development and maintenance are currently under clinical investigation. This review describes the most important findings in the field of systemic combination therapies for the treatment of pancreatic cancer. We discuss the emerging evidences for the clinical activity of combination treatments with standard chemotherapy plus novel agents targeting tumor cell-autonomous and tumor microenvironment signaling pathways. We present some of the most important advances in the comprehension of the molecular mechanisms responsible for the chemoresistance of pancreatic cancer and the emerging therapeutic targets to overcome this resistance.