2140 - Recurrence risk evaluation in stage IB/IIA gastric cancer with TP53 codon 72 polymorphisms

Background

Post-operative adjuvant chemotherapy is not indicated for stage IB/IIA gastric cancer. However, approximately 10-30% of these patients experience recurrence and metastasis. In this study, we investigated the risk of recurrence after treatment of stage IB/IIA gastric cancer patients carrying the TP53 codon 72 polymorphism and attempted to identify a subpopulation that should receive post-operative adjuvant chemotherapy.

Methods

Among 658 gastric cancer patients who received gastrectomy with curative-intent, 130 stage IB and 73 stage IIA patients were enrolled in the present study. Overall survival rate (OS) and relapse-free survival rate (RFS) were analyzed based on the status of TP53 codon 72 polymorphism Arg/Arg, Arg/Pro, and Pro/Pro. The hazard ratio for each subgroup was compared by TP53 codon 72 polymorphism. All interaction p values were calculated using the likelihood test.

Results

Of the 189 patients for whom polymorphism analysis results were available, the 5- and 10-year OS was 84.9% and 65.1%, respectively. The 5- and 10-year RFS was 81.8% and 65.4%, respectively. When the study cohort was divided into two groups according to polymorphism status (i.e., "Arg/Arg and Arg/Pro" vs. Pro/Pro), both the OS (hazard ratio [HR], 2.799; 95% confidence interval [CI], 1.071-7.315, p = 0.036) and RFS (HR, 2.639; 95% CI, 1.025-6.794, p = 0.044) of the Pro/Pro group were significantly lower than those for the Arg/Arg and Arg/Pro groups across the entire observation period.

Conclusions

Among stage IB/IIA gastric cancer patients that underwent gastrectomy with curative-intent, post-operative adjuvant chemotherapy may be considered for patients carrying the TP53 codon 72 Pro/Pro polymorphism.

Clinical trial identification

NCT01905969.

Editorial acknowledgement

Christopher Brooks of Bioscience Editing Solutions.

Legal entity responsible for the study

The authors.

Funding

Ministry of Education, Culture, Sports, Science and Technology, Japan.

Disclosure

Y. Ohmori: Full / Part-time employment: Astellas Pharma Inc.