Single-shot celiac plexus radiosurgery in pancreatic cancer: Palliative and functional outcomes—Final results of a prospective clinical trial.

Abstract

309 Background: Pancreatic cancer is characterized by severe epigastric/lower back pain caused by infiltration of the celiac plexus. The celiac plexus is a network of nociceptive nerves, located along the abdominal aorta. Contemporary approaches (opioids, celiac plexus chemical neurolysis, systemic chemotherapy) are often inadequate. We hypothesized that ablative radiation targeted to the celiac plexus would alleviate pain. Here we report results for pancreatic cancer patients treated with a single fraction of radiation. Methods: We conducted a single-institution single-arm prospective clinical trial. Eligible cancer patients had celiac-pain > 4/10 on Numerical Rating Scale (NRS) and completed treatment per protocol with at least one post-treatment visit. The celiac plexus was irradiated from D12 to L2. Radiation was given as a single-fraction 25 Gy. The primary endpoint was NRS pain 3 weeks post-treatment. Secondary endpoints were toxicity, pain at 6w, analgesic use, and pain interference with daily activities as evaluated by the ‘The Brief Pain Inventory’. Analgesia was not restricted. Total daily dose of opioids was measured in morphine milligram equivalents (MME). Results: Seventeen patients were evaluable, 65% female, median age 68 yr (range 51-79), three had undergone pancreatic resection, nine had liver metastases, median ECOG = 1. Sixteen patients reported 3-week outcomes, and 10 reported 6-week outcomes. At time of treatment subjects were a median of 8.2 months from diagnosis, and had received a median of one systemic treatment (range 0-3). Toxicity was limited to grade 1. Median baseline pain was 6/10 (IQR 5-7), was reduced to 2.3/10 (IQR 0.9-3.6) (p < 0.0005) at 3 w, and to 2.5/10 (IQR 0-3.1) at 6 w post-treatment, for both p < 0.001. Median opioid consumption numerically decreased (baseline 52.9 MME, 3 w 43.9 MME, 6 w 37.5 MME, NS). ‘BPI pain interference’ improved significantly: median baseline score 7.1 dropped to 1.1 at 3 weeks and 0 at 6 weeks (p < 0.01 for both time points). Conclusions: Celiac plexus radiosurgery alleviates pain, and improves quality of life among patients with pancreatic cancer. A follow-up international trial is accruing. Clinical trial information: NCT02356406.