CyberKnife stereotactic body radiation therapy for palliation and local control in patients with advanced pancreatic cancer: A retrospective review.

Abstract

e14506 Background: Stereotactic body radiation therapy (SBRT) offers a non-invasive, and short-in-duration option for patients with advanced pancreatic adenocarinoma for palliation or local control. Methods: Gold fiducial seed markers (1-4) were placed in, or around, the tumor in the pancreas to guide tracking of the tumor. Triple phase contrast CT images, and as necessary PET/CT, or MRI images were obtained for treatment planning. Treatment planning was performed using the MultiPlan treatment planning (Accuray Incorporated, Sunnyvale, CA). Treatment was performed using the CyberKnife with Synchrony motion tracking. A 3-5 mm margin was added to gross disease to specify the planning target volume (PTV). Results: Between July 2007 and January 2010, 26 pancreatic cancer patients were treated for 27 tumors with SBRT at CyberKnife Centers of San Diego. 12 patients were locally advanced, 12 patients had metastatic disease, 1 patient had recurrence following surgery, and 1 patient refused surgery. 9 patients had prior external radiation therapy (45-50.4 Gy) with concurrent chemotherapy. Twelve patients had received prior chemotherapy alone. The median lesion volume was 46.7 cc (10.1-263.8 cc). Typical prescribed doses was 35 Gy in 5 fractions. All patients tolerated treatments well with no grade 3 or 4 toxicities. Five grade 2 acute toxicities and two grade 2 late toxicities were observed. Fourteen of the patients presented with pain; of these 12 (86%) had substantial pain relief from SBRT, 1 (7%) minor and 1 (7%) had no pain relief. For the 18 patients with a minimum of 3 months follow-up (3-24 months), 14 (78%) were locally controlled, 3 had local failures and 1 had unknown local control. Median overall survival from time of diagnosis was 10.9 months (range, 3-31 months). The median overall survival length from time of SBRT was 5.4 months (range, 1-24 months). Kaplan-Meier estimated overall survival from time of diagnosis was 96%, 88%, 42% and 12% at 3, 6, 12 and 24 months, respectively. Conclusions: In this group of heavily pre-treated patients with advanced pancreatic cancer, CyberKnife SBRT was well tolerated and offered a quick palliation with good local control.