Image-guided intensity modulated radiation therapy (IG-IMRT) affords increased survival for biliary tract tumors: Results from preliminary analysis
4131 Background: The purpose of this study is to determine the effect of image-guided radiotherapy on survival in adenocarcinoma of the biliary tract. Methods: Between 1995 and 2005, 43 pts with primary biliary tract (gallbladder or bile duct) neoplasms were treated with radiotherapy. 26 of the pts were female and 17 were male. Their average age at registration was 64, and ranged from 25 to 86. Twenty-five pts (58%) were Hispanic, while 18 (42%) were white. 31 pts (72%) underwent surgical treatment, most having cholecystecomy (50%). 29 pts (67%) had chemotherapy: 21 (72%) were given fluorouracil-based drugs, 2 (7%) received gemcitabine, and 6 (21%) received other agents. 23 pts (53%) received conventional radiation treatment using AP/PA, AP/PA with opposing lateral, or AP with opposing lateral fields. 20 pts (47%) received IG-IMRT using Nomos Peacock and daily ultrasound image guidance (BAT, Nomos, Cranberry, PA). For daily ultrasound-based image-guidance, sagittal and axial ultrasound images were acquired, and used to align pt anatomy through superimposition of CT derived organ and vascular guidance structures. Pts were treated using a boost technique to a reduced volume at gross disease after an initial dose to gross tumor and clinically evident microscopic disease. Results: Median dose to target was 54 Gy, with median conventional and IG-IMRT total doses of 48.6 and 60 Gy respectively (p=0.05). Treatment was well tolerated, with only two patients reporting RTOG grade 3 toxicity. All other patients exhibited Grade ≤2, with 23/43 reporting Grade ≤1 The median survival time from the date of registration for all patients was 8.7 months; conventional RT pts had a median survival of 6.1 months, while the IG-IMRT cohort had a median survival of 11.4 months (p = .02). Conclusions: Ultrasound-based image-guided IMRT is a feasible mechanism of delivering moderate dose escalation in conjunction with tighter safety margins, resulting in acceptable acute toxicities. Early survival data with this novel technique are encouraging and demonstrate a notable survival differential using image guided radiotherapy as component of multi-modaility regimens. No significant financial relationships to disclose.