Exercise Eight: Treatment of Breast Cancer

An investigator conducts a randomized clinical trial of a new treatment for stage III breast cancer by randomizing 100 women to the new treatment and 100 women to standard therapy.

Women are entered into the investigation as they present for treatment from January 2000 through January 2004. All participants are followed from the time of their entry until death or through January 2005 when the study is terminated. No patients are lost to follow-up.

Let us use the flowchart of statistics to address two basic questions of analysis.

1. Estimation: What measurement should be used to summarize the data which we have found in this investigation?

2. Inference: How can we use the study data to investigate whether there is a real difference between survival with the new treatment and the standard treatment in the population from which the investigator's sample was selected?