Celiac Plexus Radiosurgery for Pain Management

Inclusion Criteria: * Patients with upper abdominal cancer (pancreatic/gastric/colon/hepato-biliary cancer) with typical retroperitoneal pain syndrome (somatic pain that radiates from the upper abdomen to the back) thought to be secondary to celiac plexus involvement, directly or indirectly, and have high level of pain despite opioids usage (NRS \>4). Patients with other cancer types metastatic to the celiac lymph nodes will also be eligible * Recent abdominal imaging (CT, PET or MRI) should be at most 2 months old. * Prior chemotherapy or biological treatment is allowed, but any active oncological treatment should be stopped at least 1 week prior to radiation and renewed at least 1 week following radiation. Following gemcitabine 2 weeks are required between final dose and commencement of radiation * Absence of any psychological, familial, sociological or geographical condition potentially hampering compliance with the study protocol and follow-up schedule; those conditions should be discussed with the patient before registration in the trial Exclusion Criteria: * Patients under 18 years of age * Patients who are well balanced in terms of pain control * Patients with life expectancy \<8 weeks * Patients with ECOG (Eastern cooperative oncology group) performance status 4 * Any concurrent chemotherapy or biologic treatment is prohibited during 1 week before until 1 week following radiotherapy * Special populations: pregnant women, prisoners, patients with major psychiatric illnesses * Previous radiotherapy to upper abdomen * Conditions associated with increased side effects to radiotherapy (IBD (inflammatory bowel disease) for example)