O1-13-4 - Lower Cea and Ca19-9 Levels May Predict Longer Pfs in Patients with Her2 Positive Gc Treated by T-Mab Based Chemotherapy

Abstract

Background: ToGA study showed significant survival benefit of trastuzumab (T-mab) in patients with HER2 positive gastric cancer (GC); however, clinical factors which can predict its efficacy prior to treatment are still unknown. We examined associations between clinical factors and prognosis in patients with HER2 positive GC treated by T-mab based chemotherapy.Methods: Fourty-two HER2 positive GC patients, who were treated by T-mab with chemotherapy in our institute from 2011 March to 2013 September, were enrolled. We retrospectively analyzed whether baseline clinical factors according to ToGA study and tumor markers could impact progression-free survival (PFS) and overall survival (OS). These endpoints were estimated using by Kaplan-Meier methods and compared by the log-rank test.Results: Median follow-up period was 12.9 months. Median age was 61.4 y.o. and 62% of the patients were male. PS 0-1, GEJ cancer, visceral metastasis (lung or liver), previous gastorectomy, previous chemotherapy, number of metastatic site (1-2), and number of metastatic lesion (1-4) were found in 98%, 29%, 57%, 31%, 19%, 79%, and 24% of the patients, respectively. Sixty-nine% and 93% of the patients were differentiated type and HER2 3+ by IHC, respectively. Median baseline CEA and CA19-9 levels were 5.6 ng/ml and 91.6 U/ml, respectively. Median PFS was 9.5 months (95% CI: 5.5-13.5) and median OS was not reached, respectively. Overall response rate by RECIST was 64%. In the univariate analysis, lower CEA levels were associated with longer PFS (HR: 0.42 [95%CI: 0.20-0.91], p = 0.024). In addition, lower CA19-9 levels were also associated with longer PFS (HR: 0.36 [95%CI: 0.17-0.78], p = 0.007). In the multivariate analysis, these associations retained significant both in CEA (HR: 0.42 [95%CI: 0.19-0.92], p = 0.03) and CA 19-9 (HR: 0.36 [95%CI: 0.16-0.78], p = 0.010), respectively. No clinical factors were associated with OS.Conclusions: Lower baseline CEA and CA19-9 levels may predict longer PFS.