Multiple Tumour Recurrence Data for Patients with Bladder Cancer

Abstract

These data were obtained in a randomized clinical trial conducted by the Veterans Administration Co-operative Urological Research Group (VACURG). All patients had superficial bladder tumours when they entered the trial. These tumours were removed transurethrally and patients were assigned randomly to one of three treatments: placebo pills, pyridoxine (vitamin B ₆) pills, or periodic instillation of a chemotherapeutic agent, thiotepa, into the bladder. The rationale for the latter two treatments is given in Byar, Blackard and VACURG (1977). At subsequent follow-up visits any tumours noticed were removed and the treatment was continued. The goal of the analysis should be to determine the effect of treatment on the frequency of tumour recurrence. For the purpose of this analysis, the word recurrence will refer to a visit at which one or more tumours are found in the bladder regardless of whether these are thought to be recurrences or new tumours. This term is not to be confused with the number of tumours present at any single visit because the tumours are often multiple. The data, Table 45.1, consist of the number of recurrences experienced by each of 118 patients, the number of tumours present initially at the time of randomization in the trial and the diameter of the largest of these, the months from the beginning of the study until each recurrence, the number of tumours present at each recurrence, and the diameter of the largest of these. An analysis of perhaps secondary importance would compare treatments with respect to numbers and size of tumours.