Mscmcc Gastric Cancer Cohort: Indirect Comparison Between Adjuvant Chemoradiation And Perioperative Chemotherapy In Gastric Cancer Patients In A Referral Site

Introduction: In the western world gastric cancer patients are either treated with peri-operative chemotherapy or adjuvant chemoradiation. There are no direct comparisons of these two treatment strategies and ongoing studies will not be able to clearly distinguish which strategy gives better oncological outcomes and what subgroups of patients benefit from either of these modalities. In our referral gastric cancer treatment site at Maria Sklodowska-Curie Memorial Cancer Center (MSCMCC) we have changed in January 2013 the treatment strategy from adjuvant chemoradiation (like in INT-0116 study) to peri-operative chemotherapy (ECF or CF regimen). Here we report a single institution indirect comparison of two treatment strategies in the treatment of gastric cancer patients. Methods: 83 consecutive patients who underwent gastrectomy between 2011-2014 treated at MSCMCC in Warsaw were identified in a cohort manner (2011-2012 - radiochemotherapy: 46 pts; 2013-2014 - peri-operative chemotherapy: 37 pts). The patients' clinical characteristics were collected from medical records. All patients were followed for relapse and survival with median observation time of 50 and 27 months for chemoradiation and peri-operative chemotherapy respectively. Results: The patients' characteristics were similar in two groups including, age, sex, ECOG status and Lauren-classification types. The disease free survival was similar in both arms with 55% of patients in radiochemotherapy and 62% of peri-operative chemotherapy patients without relapse at 2 years cut-off. Although overall survival was insignificantly different between the groups, there is a potential separation of survival curves and further follow up is needed to assess if there is no survival benefit for peri-operative chemotherapy. The toxicity profile was similar in two cohorts, with only leucopenia reported more often in the chemoradiation group (41% vs 19%. p = 0.029) and vomiting more often observed in the peri-operative chemotherapy group (32% vs 13%, p = 0.033). Notable, no differences were reported for neutropenia, mucositis or anemia. Conclusion: Despite the short observation period, this indirect comparison suggests that results of two modalities are similar in terms of relapse free survival. Further follow up is needed to assess the impact on survival.