Dose-escalated radiation for locally advanced unresectable pancreatic cancer.

Abstract

750 Background: Patients with unresectable locally advanced pancreatic cancer have limited therapeutic options. Historical treatments have included systemic chemotherapy or palliative radiation. New advanced radiotherapy treatment techniques have allowed dose escalated ablative radiotherapy to be delivered for patients with cancer limited to the pancreas. This study retrospectively reviews the long term outcomes of patients receiving dose escalated radiation for unresectable localized pancreatic cancer. Methods: Patients with locally advanced unresectable pancreatic underwent neoadjuvant chemotherapy with either gemcitabine or FOLFIRINOX based regimens. When maximum response was achieved with chemotherapy or this was no longer tolerated, patients were reassessed with imaging. Patients with localized unresectable disease then proceeded to definitive dose escalated radiation with either SBRT radiosurgery (40Gy in 5 fractions) or IMRT radiation (65-70Gy in 30-35 fractions) with concurrent 5FU. Surveillance of disease was performed with CT imaging and Ca19-9 biomarker assessment. Results: A total of 38 patients (21 male, 17 female) underwent definitive radiation. Radiation technique was determined by treating physician based on patient anatomy, with 7 patients having SBRT and 31 IMRT/5FU. Average patient age at diagnosis was 71. All patients underwent at least 6 months of follow up and mean follow up was 14 months. At time of latest follow up, 30 patients had no evidence of local progression and 12 patients had no evidence of progression at any site. The most common side effect at last follow up was grade 2/3 duodenal ulcer experienced by 7 patients. Conclusions: Advances in systemic chemotherapy have increased the population of patients with locally advanced unresectable pancreatic cancer who have persistent pancreatic disease after induction chemotherapy. Definitive dose escalated radiation is a new and effective technique to provide local control in this setting. This approach is well tolerated with manageable toxicity and effective durable local control. Patients continue to experience distant disease failure despite improving local control rates, though at a lower rate than historical controls. Control of primary pancreatic malignancy with dose escalated radiation can potentially improve quality of life and function for these patients for whom additional chemotherapy or surgery is not indicated.