Description

Data on recurrences of bladder cancer, used by many people to demonstrate methodology for recurrent event modelling.

Bladder1 is the full data set from the study. It contains all three treatment arms and all recurrences for 118 subjects; the maximum observed number of recurrences is 9.

Bladder is the data set that appears most commonly in the literature. It uses only the 85 subjects with nonzero follow-up who were assigned to either thiotepa or placebo, and only the first four recurrences for any patient. The status variable is 1 for recurrence and 0 for everything else (including death for any reason). The data set is laid out in the competing risks format of the paper by Wei, Lin, and Weissfeld.

Bladder2 uses the same subset of subjects as bladder, but formatted in the (start, stop] or Anderson-Gill style. Note that in transforming from the WLW to the AG style data set there is a quite common programming mistake that leads to extra follow-up time for 12 subjects: all those with follow-up beyond their 4th recurrence. This "follow-up" is a side effect of throwing away all events after the fourth while retaining the last follow-up time variable from the original data. The bladder2 data set found here does not make this mistake, but some analyses in the literature have done so; it results in the addition of a small amount of immortal time bias and shrinks the fitted coefficients towards zero.

Usage

bladder1
data(cancer, package="survival")


Format

 id: Patient id treatment: Placebo, pyridoxine (vitamin B6), or thiotepa number: Initial number of tumours (8=8 or more) size: Size (cm) of largest initial tumour recur: Number of recurrences start,stop: The start and end time of each time interval status: End of interval code, 0=censored, 1=recurrence, 2=death from bladder disease, 3=death other/unknown cause rtumor: Number of tumors found at the time of a recurrence rsize: Size of largest tumor at a recurrence enum: Event number (observation number within patient)

 id: Patient id rx: Treatment 1=placebo 2=thiotepa number: Initial number of tumours (8=8 or more) size: size (cm) of largest initial tumour stop: recurrence or censoring time enum: which recurrence (up to 4)