Optimal Duration of Fluorouracil-Based Adjuvant Chemotherapy for Patients with Resectable Gastric Cancer

BACKGROUND Although several clinical trials have suggested that postoperative adjuvant chemotherapy can improve survival of patients with gastric cancer, the optimal treatment duration has not been studied. This retrospective analysis evaluated the outcomes of patients with gastric cancer treated with six cycles of fluorouracil-based treatment compared with a cohort treated with four or eight cycles. METHODS We retrospectively identified 237 patients with stage IB-IIIC gastric cancer who received four, six, or eight cycles of fluorouracil-based adjuvant chemotherapy administered every 3 weeks after radical gastrectomy. The endpoint was overall survival (OS). Factors associated with prognosis were also analyzed. RESULTS The estimated 3-year OS rates for the four-, six-, and eight-cycle cohorts were 54.4%, 76.1%, and 68.9%, respectively; and the estimated 5-year OS rates were 41.2%, 74.0%, and 65.8%, respectively. Patients who received six cycles were more likely to have a better OS than those who received four cycles (P = 0.002). Eight cycles failed to show an additional survival benefit (P = 0.454). In the multivariate analysis, the number of chemotherapy cycles was associated with OS independent of clinical covariates (P<0.05). Subgroup analysis suggested that among patients in all age groups examined, male patients, and subgroups of fluorouracil plus oxaliplatin combined chemotherapy, stage III, poor differentiation, and gastrectomy with D2 lymphadenectomy, six cycles of adjuvant chemotherapy were associated with a statistically significant benefit of OS compared with four cycles (P<0.05). CONCLUSIONS Six cycles of adjuvant chemotherapy might lead to a favorable outcome for patients with gastric cancer, and two further cycles could not provide an additional clinical benefit.