title: Introduction of bias by merging patients with initial surgery and reoperations in analysis of survival.
authors.forename: Andreas
authors.initials: A
authors.lastname: Machens
authors.forename: Henning
authors.initials: H
authors.lastname: Dralle
mesh_terms: D018276:Carcinoma, Medullary / Q000401:mortality* / Q000601:surgery*; D015340:Epidemiologic Research Design; D006801:Humans; D053208:Kaplan-Meier Estimate; D012017:Referral and Consultation; D012086:Reoperation; D015983:Selection Bias; D015996:Survival Rate; D013964:Thyroid Neoplasms / Q000401:mortality* / Q000601:surgery*; D013997:Time Factors; D016896:Treatment Outcome