title: Association between praziquantel and cholangiocarcinoma in patients infected with Opisthorchis viverrini: a systematic review and meta-analysis.
abstract: BACKGROUND
  The liver fluke, Opisthorchis viverrini, and the associated incidence of subsequent cholangiocarcinoma (CCA) are still a public health problem in Thailand, and praziquantel (PZQ) remains the antihelminthic drug of choice for treatment. Evidence in hamsters shows that repeated infection and PZQ treatments could increase the risk of CCA. However, the existing evidence in humans is inconclusive regarding increased risk of CCA with frequency of PZQ intake.
  
  
  OBJECTIVE
  To investigate the relationship between number of repeated PZQ treatments and CCA in patients with O viverrini infection.
  
  
  METHODS
  The reviewed studies were searched in EMBASE, MEDLINE, ProQuest, PubMed and SCOPUS from inception to October, 2012 using prespecified keywords. The risk of bias (ROB) of included studies was independently assessed by two reviewers using a quality scale from the Newcastle-Ottawa Scale (NOS). Risk effect of PZQ was estimated as a pooled odds ratio (OR) with its 95% confidence interval (95%CI) in the random-effects model using DerSimonian and Laird's estimator.
  
  
  RESULTS
  Three studies involving 637 patients were included. Based on the random effects model performed in two included studies of 237 patients, the association between PZQ treatments and CCA was not statistical significant with a pooled OR of 1.8 (95%CI; 0.81 to 4.16).
  
  
  CONCLUSIONS
  The present systematic review and meta-analysis provides inconclusive evidence of risk effect of PZQ on increasing the risk of CCA and significant methodological limitations. Further research is urgently needed to address the shortcomings found in this review, especially the requirement for histological confirmation.
authors.affiliation: Cancer Unit, Srinagarind Hospital, Khon Kaen University, Thailand E-mail : joevajara@gmail.com.
authors.forename: Supot
authors.initials: S
authors.lastname: Kamsa-ard
authors.forename: Malinee
authors.initials: M
authors.lastname: Laopaiboon
authors.forename: Vor
authors.initials: V
authors.lastname: Luvira
authors.forename: Vajarabhongsa
authors.initials: V
authors.lastname: Bhudhisawasdi
mesh_terms: D000818:Animals; D000871:Anthelmintics / Q000008:administration & dosage / Q000009:adverse effects; D001650:Bile Duct Neoplasms / Q000139:chemically induced* / Q000188:drug therapy; D001653:Bile Ducts, Intrahepatic / Q000187:drug effects* / Q000469:parasitology; D018281:Cholangiocarcinoma / Q000139:chemically induced* / Q000188:drug therapy / Q000469:parasitology; D006801:Humans; D009889:Opisthorchiasis / Q000188:drug therapy*; D009891:Opisthorchis / Q000472:pathogenicity; D011223:Praziquantel / Q000008:administration & dosage / Q000009:adverse effects*; D011379:Prognosis
chemical_list: D000871:Anthelmintics; D011223:Praziquantel