Alteration of tumor markers may predict survival in colorectal cancer patients treated with TAS-102 or regorafenib as salvage-line chemotherapy: a single- institutional experience

Objectives: TAS-102 and regorafenib are novel antineoplastic drugs recommended for salvage-line chemotherapy. The objective of this study was to elucidate useful markers with predictive values for the effectiveness of these drugs. Methods: Between August 2013 and April 2016, 23 patients with refractory colorectal cancer received salvage-line chemotherapy at Teikyo University Hospital, Japan. 15 patients received TAS-102 monotherapy and 15 received regorafenib, including seven who had dual therapies. Tumor markers were analyzed for possible correlations with tumor response and the patients’ prognoses after these treatments. Results: Twelve patients of each group had radiologically measurable tumors. None of the TAS-102-treated patients achieved complete response (CR) or partial response (PR). After regorafenib therapy, no patients achieved CR, but one (8%) patient showed PR. These and the lack of correlation between the tumor responses and the patients’ overall survival (OS) suggested a limited predictive value of RECIST-based tumor evaluation in our study. Nonetheless, the OS of the patients with a decreased CA19-9 level after initial treatment with TAS-102 tended to be longer than that of the patients with an increased CA19-9 level (p=0.058). The OS of the patients with decreased CEA after initial regorafenib treatment was significantly longer than that of patients with increased CEA (p=0.03). Conclusions: The results of the present analysis suggest that CEA and CA19-9 may be more practical and useful as predictive/prognostic markers for refractory CRC patients treated with TAS-102 and regorafenib even when the predictive value of the tumor response measured using RECIST is not clear. Correspondence to: Keiji Matsuda, M.D., Ph.D., The Department of Surgery, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi-ku, Tokyo, Japan, Tel: 81-3-3964-1211; Fax: 81-3-5375-6097; E-mail: [email protected]