Stomach Dose-Volume Predicts Acute Gastrointestinal Toxicity in Chemoradiotherapy for Locally Advanced Pancreatic Cancer.

•Acute gastrointestinal toxicity was analysed for chemoradiotherapy of locally advanced pancreatic cancer in two prospective phase II trials.•Stomach dose–volume (in the ‘moderate’ dose region of 35–45 Gy) and patient clinical factors were identified as predictive for risk of toxicity on multivariate analysis.•Stomach dose–volume was predictive of severity of toxicity. This is the first time this has been shown in pancreatic cancer chemoradiotherapy.•Toxicity was shown to be associated with reduced overall survival but this was not attributable to failure to complete treatment.•Radiotherapy planning optimisation objectives have been derived with the aim of reducing risk for prospective patients.