1. Department of Radiation Oncology, Keelung Chang Gung Memorial Hospital, Keelung, Taiwan
2. Division of Radiation Oncology, Department of Oncology, National Taiwan University Hospital, Taipei, Taiwan
3. Cancer Research Center, National Taiwan University College of Medicine, Taipei, Taiwan
4. Graduate Institute of Clinical Medicine, National Taiwan University College of Medicine, Taipei, Taiwan
5. Clinical Trial Center, Chang Gung Memorial Hospital, Linkou, Taiwan.
6. Department of Radiation Oncology, Proton and radiation therapy center, Linkou Chang Gung Memorial Hospital, Taoyuan, Taiwan
7. Department of Surgery, Linkou Chang Gung Memorial Hospital, Taoyuan, Taiwan
8. Division of Hematology and Oncology, Department of Internal Medicine, Keelung Chang Gung Memorial Hospital, Keelung, Taiwan
9. College of Medicine, Chang Gung University, Taoyuan, Taiwan
10. Department of Food Science, National Taiwan Ocean University, Keelung, Taiwan
11. Division of general surgery, Department of surgery, Keelung Chang Gung Memorial Hospital, Keelung, Taiwan
12. Department of Ophthalmology, Keelung Chang Gung Memorial Hospital, Keelung, Taiwan
13. Graduate Institute of Clinical Medical Science, Chang Gung University, Taoyuan, Taiwan
Background: In clinical trials, adjuvant therapy (AT) has been shown to improve the prognosis in patients with gastric adenocarcinoma who undergo curative gastrectomy and adequate lymph node dissection. However, the optimal timing for initiating AT is still unclear.
Method: We collected data from 538 patients with stage II-III gastric cancer who underwent curative gastrectomy and AT in two tertiary hospitals from 2006 to 2013. Patients were divided into the early group (≤8 weeks, n=393) and the late group (>8 weeks, n=145), based on the interval between gastrectomy and initiation of AT. Propensity score matching was applied according to baseline characteristics.
Results: After 1:1 propensity score matching, an even distribution of characteristics in both groups (143:143) was achieved. The 5-year overall survival (OS) rates were 56.6% and 40.2% in the matched early and late groups, respectively (p=0.062), while the corresponding 5-year recurrence-free survival (RFS) rates were 57.6% and 46.4%, respectively (p=0.028). The time to AT initiation was correlated with RFS and had a positive association with OS. The 5-year distant metastasis-free survival was also significantly better (HR 0.682, 95% CI 0.472-0.985, p=0.040), suggesting an early AT results in a better outcome in patients.
Conclusion: We observed that initiation of AT within 8 weeks of curative gastrectomy produces better disease control and may contribute to better overall survival.
Keywords: adjuvant therapy, gastric cancer, survival, gastrectomy, propensity score