650 - HGCSG1503 : A retrospective cohort study evaluating the safety and efficacy of TAS-102 in patients with metastatic colorectal cancer : Analysis of GERCOR index.

Background

In the treatment for metastatic colorectal cancer (mCRC), it is essential for understanding the prognosis of each individual patient. GERCOR index (GI) based on performance status and serum LDH has been previously proposed. However, in the later line setting, the validity of GI has not been reported in patients treated by TAS-102.

Methods

411 patients with mCRC treated by TAS-102 were retrospectively registered from 28 centers in Japan. Selection criteria for this analysis were: (1) ECOG performance status 0-2, (2) presence of serum LDH before the start of TAS-102, and (3) presence of KRAS mutational status. Univariate and multivariate analysis for overall survival (OS) and progression-free survival (PFS) were performed using patient characteristics. Survival analyses were performed with Kaplan-Meier method, log-rank test and Cox proportional hazards model.

Results

In 389 patients, all data were available for prognostic categorization. Median OS and PFS were 7.4 and 2.2 months in this analysis set. The distribution of GI were Low risk (L: n = 64), Intermediate risk (I: n = 158), and High risk (H: n = 167). The median OS of L, I, and H were 13.5, 8.4, and 5.3 months, respectively. For OS, there were significant difference between L and H (p < 0.001), I and H (p < 0.001), and L and I (p = 0.003). The median PFS of L, I, and H were 2.8, 2.6, and 1.9 months, respectively. For PFS, there were significant difference between L and H (p < 0.001), I and H (p = 0.015), and L and I (p = 0.007). In Cox multivariate analysis, GI showed an independent prognostic (L vs I; HR 1.566, p = 0.008 / L vs H; HR 2.476, p < 0.001) and predictive impact (L vs I; HR 1.427, p = 0.022 / L vs H; HR 1.932, p < 0.001).

Conclusions

In this analysis, GI might be a predictive and prognostic factor in later line treatment with TAS-102 for patients with mCRC. The prospective evaluation is needed for the further validation.

Editorial acknowledgement

Clinical trial identification

UMIN000020551, 2016/02/02.

Legal entity responsible for the study

Non-profit Organization: Hokkaido Gastrointestinal Cancer Study Group.

Funding

Non-profit Organization: Hokkaido Gastrointestinal Cancer Study Group.

Disclosure

S. Yuki: Honoraria: Taiho Pharmaceutical Co., Ltd. Y. Komatsu: Honoraria, donation, research fund: Taiho Pharmaceutical. All other authors have declared no conflicts of interest.