title: Post-operative aspirin use and colorectal cancer-specific survival in patients with stage I-III colorectal cancer.
abstract: BACKGROUND
  Recent observational studies suggest that postoperative aspirin use may improve Colorectal cancer (CRC)-specific survival and overall survival (OS). In this study, we aimed to assess the effects of aspirin use on outcomes in a predominantly Asian cohort of patients with CRC.
  
  
  METHODS
  Case records of patients undergoing curative resection for stage I-III CRC were retrieved for clinical data and patterns of aspirin use and vital data were determined from hospital electronic prescription records, hospital pharmacy dispensing records, national clinical and prescription databases. CRC-specific and recurrence-free survival (RFS) amongst aspirin users and non-users were analyzed and compared using the Cox proportional hazards model.
  
  
  RESULTS
  Out of 726 patients with CRC, 103 were regular aspirin users and 623 were non-users. The median age of the cohort was 65 years (range=22-94 years) and the majority of patients were Chinese (90%). Nineteen percent, 31% and 47% had stage I, II and III CRC respectively; tumor staging was unknown for 3%. After adjusting for prognostic factors (age, stage, lymph node stage, grade, lesion site, perineural invasion, lymphvascular invasion), the risk of CRC relapse or death from CRC was approximately 60% lower compared to patients who were not postoperative aspirin users (Hazard Ratio=0.38, 95% Confidence Interval=0.17-0.84, p=0.017). No benefit was observed for preoperative use of aspirin.
  
  
  CONCLUSIONS
  In this single-Institution study, with long-term follow-up of patients with stage I-III-resected CRC, postoperative aspirin use was associated with reduced risk of relapse of and death from CRC.
authors.affiliation: Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.
authors.forename: Chin Hock
authors.initials: CH
authors.lastname: Goh
authors.forename: Hin Hock
authors.initials: HH
authors.lastname: Goh
authors.affiliation: Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.
authors.forename: Wei Qi
authors.initials: WQ
authors.lastname: Leong
authors.affiliation: Department of Colorectal Surgery, Singapore General Hospital, Singapore, Singapore.
authors.forename: Min Hoe
authors.initials: MH
authors.lastname: Chew
authors.affiliation: Department of Medical Oncology, National Cancer Centre Singapore, Singapore, Singapore.
authors.forename: Yihui Summer
authors.initials: YS
authors.lastname: Pan
authors.affiliation: Department of Pathology, Singapore General Hospital, Singapore, Singapore.
authors.forename: Lim Kiat Hon
authors.initials: LK
authors.lastname: Tony
authors.affiliation: Department of Medical Oncology, National Cancer Centre Singapore, Singapore, Singapore.
authors.forename: Lita
authors.initials: L
authors.lastname: Chew
authors.affiliation: Department of Medical Oncology, National Cancer Centre Singapore, Singapore, Singapore.
authors.forename: Iain Bee Huat
authors.initials: IB
authors.lastname: Tan
authors.affiliation: Department of Medical Oncology, National Cancer Centre Singapore, Singapore, Singapore.
authors.forename: Han Chong
authors.initials: HC
authors.lastname: Toh
authors.affiliation: Department of Colorectal Surgery, Singapore General Hospital, Singapore, Singapore.
authors.forename: Choong Leong
authors.initials: CL
authors.lastname: Tang
authors.affiliation: Department of Colorectal Surgery, Singapore General Hospital, Singapore, Singapore.
authors.forename: Wan Pei Cherylin
authors.initials: WP
authors.lastname: Fu
authors.affiliation: Department of Medical Oncology, National Cancer Centre Singapore, Singapore, Singapore nmocwk@nccs.com.sg.
authors.forename: Whay Kuang
authors.initials: WK
authors.lastname: Chia
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D044466:Asian People; D001241:Aspirin / Q000008:administration & dosage*; D015179:Colorectal Neoplasms / Q000401:mortality* / Q000473:pathology / Q000601:surgery*; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000517:prevention & control*; D009367:Neoplasm Staging; D011184:Postoperative Period; D016016:Proportional Hazards Models; D055815:Young Adult
chemical_list: D001241:Aspirin
keywords: Colorectal cancer; aspirin