Efficacy and toxicity of limited field concurrent chemoradiotherapy (CRT) with capecitabine for locally advanced pancreatic cancer (LAPC)

Abstract

15586 Background: Treatment outcome in LAPC remains poor. As treatment-related toxicity limits CRT dose-intensification, we evaluated the efficacy/toxicity of capecitabine based CRT in LAPC patients using limited field irradiation, excluding elective nodal areas. Methods: 25 consecutive LAPC patients eligible for CRT were treated at a single institute. Capecitabine was administered at 500–600 mg/m2/b.i.d continuously (including weekends) from day one to completion of radiotherapy (RT). RT was delivered conformally to a dose of 50.4Gy in 28 fractions over 5.5 weeks. The gross tumour volume consisting of the pancreatic tumour and any involved peri-pancreatic nodes was isometrically expanded by 0.5 cm to generate the clinical target volume (CTV). The planning target volume (PTV) comprised the CTV plus a 1cm margin AP/LR and a 1.5 - 2 cm margin SI. Patients were reviewed weekly to monitor weight and collect toxicity data. Time to disease progression and survival were calculated from diagnosis. Results: Median age of the 25 patients (17 M; 8 F) was 66 years (range 45- 74). Tumour was located in the pancreatic head in 23 patients (92%) and histology available in 17 patients (68%). The median (range) PTV volume was 378 (146–860) cc. 2 patients did not complete treatment due to disease progression and post-surgical complication. Treatment was well tolerated with nausea and fatigue being the most common toxicities. Only one patient developed any grade 3 toxicity (nausea). With a median follow up of 8.3 months, the median time to progression was 9.7 months, with 25% remaining progression-free at 1 year. All patients had progressed by 2 years. Isolated loco-regional relapse was observed in only one patient. At progression, six patients were suitable for palliative chemotherapy. The median overall survival for all patients was 11.6 months with 1 year survival of 38%. Median survival for the 6 patients who received palliative chemotherapy at disease progression was 17 months. Conclusion: Limited field CRT using capecitabine 500–600 mg/m2 twice daily in LAPC is very well tolerated, with similar efficacy to historical CRT regimens. Avoiding elective nodal irradiation may allow CRT dose-intensification and combination with other anti-cancer agents. No significant financial relationships to disclose.