title: Adjuvant S-1 chemotherapy after curative resection of gastric cancer in Chinese patients: assessment of treatment tolerability and associated risk factors.
abstract: BACKGROUND
  The use of adjuvant chemotherapy with S-1 (tegafur, gimeracil, and oteracil potassium) has been shown to improve the outcome of patients with gastric cancer. There are limited data on the tolerability of S-1 in Chinese patients. In this multicentre retrospective study, we assessed the toxicity profile in local patients.
  
  
  METHODS
  Patients with stage II-IIIC gastric adenocarcinoma who had undergone curative resection and who had received S-1 adjuvant chemotherapy were included in the study. Patient demographics, tumour characteristics, chemotherapy records, as well as biochemical, haematological, and other toxicity profiles were extracted from medical charts. Potential factors associated with grade 2-4 toxicities were identified.
  
  
  RESULTS
  Adjuvant S-1 was administered to 30 patients. Overall, 19 (63%) patients completed eight cycles. The most common grade 3-4 adverse events included neutropaenia (10%), anaemia (6.7%), septic episode (16.7%), diarrhoea (6.7%), hyperbilirubinaemia (6.7%), and syncope (6.7%). Dose reductions were made in 22 (73.3%) patients and 12 (40.0%) patients had dose delays. Univariate analyses showed that patients who underwent total gastrectomy were more likely to experience adverse haematological events (P=0.034). Patients with nodal involvement were more likely to report adverse non-haematological events (P=0.031). Patients with a history of regular alcohol intake were more likely to have earlier treatment withdrawal (P=0.044). Lower body weight (P=0.007) and lower body surface area (P=0.017) were associated with dose interruptions.
  
  
  CONCLUSIONS
  The tolerability of adjuvant S-1 in our patient population was similar to that in other Asian patient populations. The awareness of S-1-related toxicities and increasing knowledge of potential associated factors may enable optimisation of S-1 therapy.
authors.affiliation: Department of Clinical Oncology, The Chinese University of Hong Kong, Shatin, Hong Kong.
authors.forename: W
authors.initials: W
authors.lastname: Yeo
authors.affiliation: Department of Clinical Oncology, The University of Hong Kong, Pokfulam, Hong Kong.
authors.forename: K O
authors.initials: KO
authors.lastname: Lam
authors.affiliation: Department of Clinical Oncology, Pamela Youde Nethersole Eastern Hospital, Chai Wan, Hong Kong.
authors.forename: A Ly
authors.initials: AL
authors.lastname: Law
authors.affiliation: Department of Clinical Oncology, Princess Margaret Hospital, Laichikok, Hong Kong.
authors.forename: C Cy
authors.initials: CC
authors.lastname: Lee
authors.affiliation: Department of Clinical Oncology, Tuen Mun Hospital, Tuen Mun, Hong Kong.
authors.forename: C L
authors.initials: CL
authors.lastname: Chiang
authors.affiliation: Department of Clinical Oncology, United Christian Hospital, Kwun Tong, Hong Kong.
authors.forename: K H
authors.initials: KH
authors.lastname: Au
authors.affiliation: Comprehensive Clinical Trials Unit, Department of Clinical Oncology, The Chinese University of Hong Kong, Shatin, Hong Kong.
authors.forename: F Kf
authors.initials: FK
authors.lastname: Mo
authors.affiliation: Department of Clinical Oncology, The University of Hong Kong, Pokfulam, Hong Kong.
authors.forename: T H
authors.initials: TH
authors.lastname: So
authors.affiliation: Department of Clinical Oncology, Prince of Wales Hospital, Shatin, Hong Kong.
authors.forename: K C
authors.initials: KC
authors.lastname: Lam
authors.affiliation: Department of Clinical Oncology, Pamela Youde Nethersole Eastern Hospital, Chai Wan, Hong Kong.
authors.forename: W T
authors.initials: WT
authors.lastname: Ng
authors.affiliation: Department of Clinical Oncology, Prince of Wales Hospital, Shatin, Hong Kong.
authors.forename: L
authors.initials: L
authors.lastname: Li
mesh_terms: D000230:Adenocarcinoma / Q000628:therapy*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000740:Anemia / Q000209:etiology; D000964:Antimetabolites, Antineoplastic / Q000008:administration & dosage* / Q000009:adverse effects; D017024:Chemotherapy, Adjuvant / Q000009:adverse effects; D004338:Drug Combinations; D005260:Female; D005500:Follow-Up Studies; D005743:Gastrectomy; D006723:Hong Kong; D006801:Humans; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000188:drug therapy; D009503:Neutropenia / Q000209:etiology; D010094:Oxonic Acid / Q000008:administration & dosage* / Q000009:adverse effects; D012189:Retrospective Studies; D012307:Risk Factors; D013274:Stomach Neoplasms / Q000628:therapy*; D016019:Survival Analysis; D005641:Tegafur / Q000008:administration & dosage* / Q000009:adverse effects; D016896:Treatment Outcome
chemical_list: D000964:Antimetabolites, Antineoplastic; D004338:Drug Combinations; C079198:S 1 (combination); D005641:Tegafur; D010094:Oxonic Acid
keywords: Drug combinations; Risk factors; Stomach neoplasms/drug therapy; Treatment outcome