['Although hyperfibrinogenemia has been reported in patients with colorectal cancer, neither its clinical implications nor the effect of chemoradiotherapy (CRT) on the fibrinogen levels have been fully investigated. We investigated the clinical significance of pre- and post-CRT fibrinogen levels in patients with rectal cancer.', 'The medical records of 82 patients with rectal cancer, who had received CRT followed by surgical resection, were retrospectively reviewed. The correlation between the clinicopathological variables and the pre- and post-CRT plasma fibrinogen levels, and that between the changes of fibrinogen, C-reactive protein (CRP), or carcinoembryonic antigen (CEA) levels after CRT and the pathological tumor regression grading was analyzed. Furthermore, the impact of post-CRT fibrinogen levels on the prognosis of these patients was assessed.', 'Plasma fibrinogen markedly decreased after CRT. The post-CRT fibrinogen level significantly correlated with lymphatic invasion, venous invasion, tumor size, depth of invasion, and the pathological tumor regression grading. The CRT-induced pathological tumor regression grading well correlated with the decrease of fibrinogen level, but not with that of CRP or CEA. Furthermore, patients with high post-CRT fibrinogen had significantly shorter disease-free survival.'] Does hyperfibrinogenemia after preoperative chemoradiotherapy predict poor response and poor prognosis in rectal cancer?