Optimal duration of fluorouracil-based adjuvant chemotherapy for patients with resectable gastric cancer

Abstract

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.

Figure 1. Kaplan-Meier survival curves by number of treatment cycles in all patients.

Figure 2. Kaplan-Meier survival curves by number of treatment cycles in the FU plus oxaliplatin subgroup.

Figure 3. Kaplan-Meier survival curves by number of treatment cycles in patients with stage III cancer.

Figure 4. Kaplan-Meier survival curves by number of treatment cycles in patients who underwent D2 gastrectomy.

Figure 5. Hazard ratios (HRs) for death and 95% confidence intervals (CIs).

In subgroup analyses, (A) six cycles of treatment were associated with an improved survival in most subgroups compared with four cycles, and (B) overall survival showed no significant difference between six and eight cycles.