686P - DLC1 determines the efficiency of fluoropyrimidine and oxaliplatin regimen in gastric cancer adjuvant chemotherapy

Date 29 September 2014
Event ESMO 2014
Session Poster Display session
Topics Anti-Cancer Agents & Biologic Therapy
Gastric Cancer
Translational Research
Presenter Wangjun Liao
Citation Annals of Oncology (2014) 25 (suppl_4): iv210-iv253. 10.1093/annonc/mdu334
Authors W. Liao, S. Yuqi, L. Lin, C. Pan, Y. Jiang, M. Zhou, L. Sun
  • Department Of Oncology, Nanfang Hospital, Southern Medical University, 510515 - Guangzhou/CN

Abstract

Aim

The Rho-GTPase-activating protein Deleted in liver cancer (DLC1) is recently known as a tumor suppressor and deficient in gastric cancer (GC) cells. However, the prognostic value of DLC1 in GC is still unclear. On the other hand, fluoropyrimidine and oxaliplatin (FP-LOHP) regimen is wildly used for GC adjuvant chemotherapy, but no reliable marker has been found to determine the efficiency of this regimen.

Methods

From 2004 to 2014, we retrospectively followed 251 Stage IB-III patients with radical resection. All patients received adjuvant chemotherapy with or without FP-LOHP. The DLC1 expression of in GC and their para-cancerous tissues was detected by immunohistochemical staining. The pathological factors, including time to recurrence (TTR) and overall survival time (OS), were analyzed.

Results

DLC1 was lowly expressed in most (185/251) GC samples compared to normal mucosa. Lower expression of DLC1 indicated larger tumor size, more advanced TNM stage, deeper tumor invasion, and more lymph node metastasis. On the contrary, relatively higher DLC1 expression demonstrated longer TTR (HR 2.232; 95% CI 1.295-3.857; P = 0.004) and OS (HR 2.910; 95% CI 1.543-5.488; P = 0.001). Patients applying FP-LOHP as adjuvant chemotherapy are less likely to suffer GC recurrence than those used other therapies. However, only the DLC1 positive GC patients receiving FP-LOHP [DLC1(+)/FP-LOHP(+)] showed more favorable TTR and OS than DLC1(-)/FP-LOHP(+) (TTR, χ2 = 26.364, P < 0.001; OS, χ2 = 18.703, P < 0.001) and DLC1(+)/FP-LOHP(-) (TTR, χ2 = 11.452, P = 0.001; OS, χ2 = 5.438, P = 0.020), whereas the low DLC1 GC patients received no better clinical outcome from FP-LOHP (TTR, χ2 = 1.217, P = 0.270; OS, χ2 = 1.662, P = 0.197) (data are shown in Table).

DCL1 FP-LOHP Total (%) TTR (month)Median (95% CI) 3-yr non-recurrence (%) OS (month)Median (95% CI) 5-yrsurvival (%)
+ + 13.9 / 89.6 / 74.5
+ - 12.4 37 (25.8-48.2) 51.4 / 58.6
- + 27.5 27 (21.6-32.4) 32.9 51 (33.2-68.8) 16.7
- - 46.2 22 (14.3-29.7) 23.3 36 (32.4-39.6) 28.2

Conclusions

Low expression of DLC1 is correlated with GC progression and predicts high risk of recurrence and mortality. Only the DLC1 positive patients may benefit from FP-LOHP as adjuvant chemotherapy in GC.

Disclosure

All authors have declared no conflicts of interest.