Impact of earlier adjuvant chemotherapy after surgery on prognosis in patients with operable gastric cancer: A propensity score matched analysis.

Abstract

4057 Background: Adjuvant chemotherapy improves survival after curative D2 gastrectomy in patients with operable gastric cancer. However, the optimal timing of initiation of adjuvant chemotherapy after surgery is not clearly defined. Methods: Patients with operable gastric cancer who had undergone adjuvant chemotherapy after D2 gastrectomy for stage II and III gastric cancer from January 2009 to December 2012 at National Cancer Center, South Korea were included. Patients were classified into the two groups ( ≤ 6 weeks vs. > 6 weeks) according to the time to initiation of adjuvant chemotherapy after surgery. Propensity score matching (PSM) was performed to adjust the difference of baseline clinicopathologic characteristics between the two groups. Survival outcomes were compared between groups after PSM. Results: Of 484 enrolled patients, 367 patients started adjuvant chemotherapy within 6 weeks after surgery (early group), and 117 patients started adjuvant chemotherapy more than 6 weeks after surgery (late group). After PSM, 232 patients were included (116 in the early group vs. 116 in the late group). In pre-PSM analysis, baseline characteristics were significantly different for age, surgical complication, the type of chemotherapy regimen and the degree of chemotherapy completion between the early and late groups. With median follow up of 60 months (range, 37.3 – 85.5), the 5-year overall survival (OS) rate was 71.4% in the early group and 74.5% in the late group (P = 0.864). The 5-year disease-free survival (DFS) was 66.6% vs. 69.8%, respectively (P = 0.801). After PSM, baseline characteristics were well balanced between groups, but there was no significant difference for survival outcomes between groups: for 5-year OS rate, 76.4% vs. 75.1% (P = 0.741), for 5-year DFS rate, 70.2% vs. 70.4% (P = 0.550). Conclusions: This study suggests that adjuvant chemotherapy is equally effective regardless of the initiation of adjuvant chemotherapy within 6 weeks after surgery. Clinicians should consider allowing adequate time for patient recovery after D2 gastrectomy.