Clinical outcomes and prognostic factors of stereotactic body radiation therapy combined with gemcitabine plus capecitabine for locally advanced unresectable pancreatic cancer

Purpose This study aimed to evaluate the clinical outcomes, toxicity, and prognostic factors of SBRT combined with gemcitabine plus capecitabine (GEM-CAP) in treating locally advanced pancreatic cancer (LAPC). Methods A total of 56 patients with LAPC treated with SBRT combined with GEM-CAP were reviewed from October 2010 to October 2016. The median total prescription dose at five fractions was 40 Gy (30–50 Gy). The patients were subjected to two cycles of GEM-CAP before SBRT. GEM-CAP chemotherapy was then offered for four cycles or until disease tolerance or progression. The primary endpoints included overall survival (OS) and progression-free survival (PFS). Results The median OS and PFS from the date of diagnosis was 19 (95% CI 14.6–23.4) and 12 months (95% CI 8.34–15.66), respectively. The 1-year and 2-year survival rates were 82.1% and 35.7%, whereas the 1-year and 2-year PFS rates were 48.2% and 14.3%, respectively. The median carbohydrate antigen 19-9-determined PFS time was 11 months (95% CI 5.77–16.24). Multivariate analysis demonstrated that tumor diameter, lymph node metastasis, pre-treatment CA19-9 level, and post-treatment CA19-9 decline were independent prognostic factors ( p < 0.05). Acute toxicity was minimal, with two cases (3.6%) experiencing grade 3 duodenal obstruction. No adverse events greater than grade 3 occurred. In late toxicity, three patients (5.4%) developed grade 3 gastrointestinal toxicity and two (3.6%) suffered from perforation caused by grade 4 radiation enteritis and intestinal fistula. Conclusions The combination of Cyberknife SBRT and GEM-CAP achieved excellent efficacy with acceptable toxicity for LAPC.