Anyone had plexus nerve block for cancer pain?

My mom is 81 and she was just diagnosed with pancreatic cancer stage IV that has metastasized to her liver. Her oncologist has suggested that her treatment be Octreotide injections monthly, which is supposed to stop the growth of the cancer. She is having severe back pain from the cancer and is currently on fentanyl patches and oxycontin. He suggested she get a Celiac Block (ablation) for the pain.

Has anyone had either of these and have any feedback for me?