title: Systematic review of the predictive effect of MSI status in colorectal cancer patients undergoing 5FU-based chemotherapy.
abstract: BACKGROUND
  We systematically reviewed the evidence for the interaction of microsatellite instability status (MSI) and treatment with 5FU in colorectal cancer to determine how well MSI status predicts health outcomes in patients undergoing 5FU-based chemotherapy.
  
  
  METHODS
  We conducted a search of four electronic databases through June 2013. We considered studies that included both colorectal cancer patients treated with 5FU-based chemotherapy and untreated patients with survival outcomes presented by MSI status.
  
  
  RESULTS
  We identified 16 studies for qualitative analysis (9,212 patients) with 14 studies eligible for meta-analysis. The microsatellite stable (MSS) group showed an effect of 5FU treatment on disease-free survival (HR of 0.62 [95% CI: 0.54, 0.71]) and overall survival (HR of 0.65 [95% CI: 0.54, 0.79]), indicating that MSS patients who received 5FU treatment had longer survival than MSS patients who were untreated. The effect of 5FU treatment was not statistically significant for microsatellite high (MSI-H) patients for disease-free survival (HR of 0.84 [95% CI: 0.53, 1.32]) or overall survival (HR 0.66 [95% CI: 0.43, 1.03]). However, the summarized point estimates of the effects of 5FU treatment for the MSS and MSI-H groups were not different at a statistically significant level.
  
  
  CONCLUSIONS
  Our analyses indicate that treatment with 5FU-based chemotherapy improves disease-free and overall survival in CRC patients, but that there is no difference in the effect of treatment based on MSI status. Therefore, the use of MSI status to guide treatment decisions about the use of 5FU treatment for CRC has no significant benefits for patients.
authors.affiliation: Center for Health Research - Kaiser Permanente Northwest, 3800 N Interstate Avenue, Portland, OR, 97227, USA. Elizabeth.M.Webber@kpchr.org.
authors.forename: Elizabeth M
authors.initials: EM
authors.lastname: Webber
authors.affiliation: Center for Health Research - Kaiser Permanente Northwest, 3800 N Interstate Avenue, Portland, OR, 97227, USA. Tia.L.Kauffman@kpchr.org.
authors.forename: Tia L
authors.initials: TL
authors.lastname: Kauffman
authors.affiliation: Center for Health Research - Kaiser Permanente Northwest, 3800 N Interstate Avenue, Portland, OR, 97227, USA. Elizabeth.O'Connor@kpchr.org.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: O'Connor
authors.affiliation: Center for Health Research - Kaiser Permanente Northwest, 3800 N Interstate Avenue, Portland, OR, 97227, USA. Katrina.ab.goddard@kpchr.org.
authors.forename: Katrina A B
authors.initials: KA
authors.lastname: Goddard
mesh_terms: D000964:Antimetabolites, Antineoplastic / Q000494:pharmacology / Q000627:therapeutic use*; D015179:Colorectal Neoplasms / Q000175:diagnosis / Q000188:drug therapy* / Q000235:genetics*; D005472:Fluorouracil / Q000494:pharmacology / Q000627:therapeutic use*; D006801:Humans; D053842:Microsatellite Instability / Q000187:drug effects; D011237:Predictive Value of Tests
chemical_list: D000964:Antimetabolites, Antineoplastic; D005472:Fluorouracil