Combined multiagent chemotherapy and radiotherapy is associated with prolonged overall survival in patients with non-operatively managed stage II-III pancreatic adenocarcinoma.

Abstract

BACKGROUND\nMost patients with pancreatic adenocarcinoma (PDAC) do not undergo surgical resection. The role of radiotherapy (RT) in non-operatively managed localized pancreatic adenocarcinoma is unclear.\n\n\nMETHODS\nThe National Cancer Database (2010-2016) was queried for patients with clinical stage II-III PDAC treated with multiagent systemic chemotherapy (CT)\xa0+/- RT but not surgery. Factors associated with the receipt of RT and overall survival were compared after adjusting for patient demographics and clinical characteristics.\n\n\nRESULTS\nA total of 14,921 patients were included, of whom 9279 received CT and 5382 received CT\xa0+\xa0RT. Patients treated with CT\xa0+\xa0RT were more likely to be younger (65vs66yrs), treated at non-academic facilities (48.8%vs46.7%), have private insurance (40.3%vs36.5%), and have clinical T4 tumors (53.6%vs48.7%). Most patients who were treated with RT received external beam radiotherapy (89.3%), and the median dose was 5,000\xa0cGy. Median time to start of RT was 129 days. CT\xa0+\xa0RT was associated with longer overall survival (15.9vs11.8mos,p\xa0<\xa00.001), and remained associated with survival on multivariable analysis (HR 0.74, 95%CI 0.70-0.78). On a 4-month conditional survival analysis, combined CT\xa0+\xa0RT remained associated with improved survival compared to CT alone (16.0vs13.1mos,p\xa0<\xa00.001).\n\n\nCONCLUSIONS\nIn patients with non-operatively managed localized pancreatic adenocarcinoma, combined radiotherapy and multiagent systemic chemotherapy is associated with improved overall survival compared to chemotherapy alone.