Prognostic and Predictive Impact of Circulating Tumor DNA in Gastric Cancer Treatment

The evaluation of the chemotherapy efficacy for gastric cancer patients is usually evaluated by computer tomography scans with RECIST criteria that are performed every two months during the treatment. The management of treatment for gastric cancer needs the development of early biomarkers to evaluate the efficacy in order to avoid unnecessary toxicity in case of early chemotherapy resistance. In this prospective study, we will compare the monitoring of circulating tumor DNA with the results of CT scan according the RECIST criteria and the blood level of CEA and CA 19-9 tumor markers. Thus, the objective of this study is to identify a prognostic and/or predictive biomarker of tumor response according to the tumor DNA circulating assessment in gastric cancer treatment, in order (i) to avoid an unnecessary toxicity of an ineffective treatment that it would be continued uselessly, (ii) and to allow a early changing to an alternative chemotherapy regimen.

Sex

All

Minimum age

18 Years

Inclusion Criteria:

* patients aged over 18 years
* histologically proven adenocarcinoma of gastric or gastro-oesophageal junction
* And receiving treatment:

  * For localized tumor stage: surgical resection associated with perioperative chemotherapy, adjuvant chemotherapy or adjuvant chemoradiotherapy
  * For advanced tumor stage: first-line palliative chemotherapy

Exclusion Criteria:

* All patients unable to undergo medical monitoring study for geographical, social or psychic reasons ;
* Patients under guardianship or unable to read, understand and sign the information sheet and consent form;
* Non-affiliated to the French social security institution