Radiation therapy in operable and locally advanced pancreatic cancer

It is well established that the development of distant metastatic disease represents the dominant pattern of tumor recurrence/progression among patients with operable and locally advanced pancreatic cancer. However, the contribution of localized or locoregional tumor burden to pancreatic cancer-associated morbidity and mortality may be underappreciated, and therefore balancing competing considerations of systemic versus local disease control becomes important in therapeutic decision-making. The role of local therapies, particularly radiation therapy, has remained somewhat controversial in this disease context. Several phase II and III trials have sought to address the relative importance and role of radiation in both the localized and locally advanced settings, including the sequencing of this modality relative to systemic therapy and its optimal means of administration. However, differences and limitations in study design have produced mixed results, particularly in terms of the contribution of radiation to overall survival benefit. An emerging paradigm that makes conceptual sense and remains the subject of active investigation is to start with a defined period of systemic treatment, thus limiting radiation to the subset of patients who do not manifest with metastatic disease during initial therapy and are therefore most likely to benefit from local control.