title: Cytotoxic chemotherapy has minimal direct effect on gastric myoelectric activity in children with 5HT(3) antagonist prophylaxis.
abstract: BACKGROUND
  Cancer patients receiving cytotoxic chemotherapy frequently develop nausea and vomiting. The direct effect of chemotherapy on gastric pacemaker is not clear. The objective of this study was to assess the direct interference of gastric electrical activity by chemotherapeutic agents as a possible cause of vomiting using electrogastrography (EGG).
  
  
  METHODS
  Fasting surface EGGs were recorded in 24 children with malignancy and 24 age-matched controls. All oncology patients received the intravenous prophylatic ondansetron. According to the known emetic potential of the medications they received, the children were divided into mild, moderate, and severe groups. The EGG recordings of oncology patients were segmented into prechemotherapy period, chemotherapy period, and emetic period. The EGG data from each period were collected and analyzed (paired t-test and Mann-Whitney U test).
  
  
  RESULTS
  There were 24 children (M:F ratio: 14:10), with a mean age of 9.6 years. Eight children vomited during the course of recording (0/3 from the mild group, 2/6 from the moderate group, and 6/15 from the severe group). The average duration of intravenous medication infusion was 7.8 hr (range 2 min to 24 hr). There was no difference between the EGG of normal control and the prechemotherapy EGG of the oncology patients. No difference was detected between the EGG data from the prechemotherapy period and the chemotherapy period. A statistically significant increase in tachygastria was detected in emetic periods (28 episodes, mean duration 5 min; P = 0.01).
  
  
  CONCLUSIONS
  Insignificant EGG changes during chemotherapy suggest that chemotherapy has a minimal direct effect on gastric pacemaker. Tachygastria seemed to be a secondary effect of vomiting rather than the cause of it. These preliminary findings suggest that efforts to modify gastric electrical rhythm as a means of management of chemotherapy-induced vomiting may be futile. Further studies to identify factors responsible for vomiting are warranted.
authors.affiliation: Division of Paediatric Surgery, Department of Surgery, Queen Mary Hospital, University of Hong Kong Medical Centre, Hong Kong, China.
authors.forename: W
authors.initials: W
authors.lastname: Cheng
authors.forename: G C
authors.initials: GC
authors.lastname: Chan
authors.forename: P K
authors.initials: PK
authors.lastname: Tam
mesh_terms: D000293:Adolescent; D000932:Antiemetics / Q000627:therapeutic use*; D000970:Antineoplastic Agents / Q000009:adverse effects*; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D005260:Female; D005769:Gastrointestinal Motility / Q000187:drug effects; D006801:Humans; D007223:Infant; D008297:Male; D016065:Myoelectric Complex, Migrating / Q000187:drug effects*; D012702:Serotonin Antagonists / Q000627:therapeutic use*; D014839:Vomiting / Q000139:chemically induced / Q000517:prevention & control*
chemical_list: D000932:Antiemetics; D000970:Antineoplastic Agents; D012702:Serotonin Antagonists