Resected pancreatic neuroendocrine tumors: Patterns of failure and disease-related outcomes with or without radiotherapy

Purpose: Pancreatic neuroendocrine tumors (NET) are rare and have better disease-related outcomes compared with pancreatic adenocarcinoma. Surgical resection remains the standard of care, although many patients present with locally advanced or metastatic disease. Little is known regarding the use of radiotherapy in the prevention of local recurrence after resection. To better define the role of radiotherapy, we performed an analysis of resected patients at our institution. Methods: Between 1994 and 2009, 33 patients with NET of the pancreatic head and neck underwent treatment with curative intent at Duke University Medical Center. Sixteen patients were treated with surgical resection alone while an additional 17 underwent resection with adjuvant or neoadjuvant radiation therapy, usually with concurrent fluoropyrimidine-based chemotherapy (CMT). Median radiation dose was 50.4 Gy and median follow-up 28 months. Results: Thirteen patients (39%) experienced treatment failure. Eleven of the initial failures were distant, one was local only and one was local and distant. Two-year overall survival was 77% for all patients. Two-year local control for all patients was 87%: 85% for the CMT group and 90% for the surgery alone group (p = 0.38). Two-year distant metastasis-free survival was 56% for all patients: 46% and 69% for the CMT and surgery patients, respectively (p = 0.10). Conclusions: The primary mode of failure is distant which often results in mortality, with local failure occurring much less commonly. The role of radiotherapy in the adjuvant management of NET remains unclear.