Neoadjuvant/downstaging radiochemotherapy in marginally resectable pancreatic cancer

Pancreatic cancer is a challenging disease due to the low resection rate at the time of initial diagnosis. A relatively new classification of marginally resectable pancreatic cancer has emerged and there is some evidence that this subgroup of patients may benefit from neoadjuvant radiochemotherapy. The first major definition of marginally resectable pancreatic cancer was made at M. D. Anderson Cancer Center and published in 2006. This definition was purely anatomical and CT-based and only handles the relationship of the pancreatic, tumor to its surrounding major vessels. Later on, two other subtypes have been added to this definition: suspicion or known metastasis in regional lymph nodes (N1 disease), or severe pre-existing medical comorbidities requiring prolonged evaluation or recovery and precluding immediate surgery. Other definitions (anatomical and CT-based) for marginally resectable pancreatic cancer have also been established. For systematic research on neoadjuvant therapy in marginally resectable pancreatic cancer, however, the lack of uniform definitions and randomized trials have been troublesome. Nevertheless, several small cohort studies have demonstrated that 40-80% of the marginally resectable patients could proceed to resection after neoadjuvant treatment and also reporting some promising effects on microscopic resection margins, lymph node status and survival.