title: Investigating centre effects in a multi-centre clinical trial of superficial bladder cancer.
abstract: This paper examines the amount of variation among centres and estimates the overall effect of therapy in a multi-centre cancer clinical trial with censored failure time data. To investigate the centre effects, the variation in the treatment effect must be taken into consideration in addition to the variation in the baseline risk. We treat centre effects as random ones and extend the penalized partial likelihood approach proposed by McGilchrist to estimate the treatment-by-centre interaction as well as the baseline risk. This method is applied to data from a superficial bladder cancer clinical trial investigating the efficacy of intravesical chemotherapy after transurethral resection. In this trial, although there exists some degree of centre variation, especially in the baseline risk, the treatment is effective in preventing recurrence among the participating centres. This result indicates that the treatment effect is generalizable to the target population.
authors.affiliation: Department of Biostatistics/Epidemiology and Preventive Health Sciences, School of Health Sciences and Nursing, University of Tokyo, Japan. tyamagu@nihs.go.jp
authors.forename: T
authors.initials: T
authors.lastname: Yamaguchi
authors.forename: Y
authors.initials: Y
authors.lastname: Ohashi
mesh_terms: D000283:Administration, Intravesical; D000903:Antibiotics, Antineoplastic / Q000008:administration & dosage / Q000627:therapeutic use; D002295:Carcinoma, Transitional Cell / Q000188:drug therapy / Q000401:mortality / Q000601:surgery*; D017024:Chemotherapy, Adjuvant; D002986:Clinical Trials as Topic / Q000706:statistics & numerical data*; D015251:Epirubicin / Q000008:administration & dosage / Q000627:therapeutic use; D006801:Humans; D016013:Likelihood Functions; D015337:Multicenter Studies as Topic / Q000706:statistics & numerical data*; D009364:Neoplasm Recurrence, Local / Q000517:prevention & control*; D016016:Proportional Hazards Models; D013997:Time Factors; D016896:Treatment Outcome; D001743:Urinary Bladder / Q000601:surgery; D001749:Urinary Bladder Neoplasms / Q000188:drug therapy / Q000401:mortality / Q000601:surgery*
chemical_list: D000903:Antibiotics, Antineoplastic; D015251:Epirubicin