More than five years of tamoxifen is no longer justified

A major clinical trial of long term adjuvant treatment with tamoxifen in women with primary breast cancer has been stopped by the National Cancer Institute of America on the grounds that treatment for more than five years is unlikely to be beneficial.1 The institute's report relates to trials carried out by the National Surgical Adjuvant Breast and Bowel Project in Pittsburgh. Between 1981 and 1993 over 4000 women who had undergone surgery with or without radiotherapy for oestrogen receptor positive breast cancer but who had no lymph node involvement were recruited into two randomised clinical trials.

The first of these examined the effect on survival of adjuvant therapy with tamoxifen. Ten years after primary treatment, patients receiving the drug had an overall survival of 78% compared with 75% in the placebo group, results which are in line with those in an overview of 133 randomised controlled trials published in 1992.2 The difference, while small, is significant. Whether …