Adjuvant tamoxifen in early breast cancer: occurrence of new primary cancers

Lancet. 1989 Jan 21;1(8630):117-20. doi: 10.1016/s0140-6736(89)91141-0.


The frequency of new primary cancers was studied in 1846 postmenopausal patients included in a randomised trial of tamoxifen as an adjunct to primary surgery for early breast cancer. The median follow-up was 4.5 years (range 0.5-10.5 years). The number of new cancers in the tamoxifen group (n = 57) did not differ significantly from that in the control group (n = 70). However, in tamoxifen patients second breast cancers occurred less often and endometrial cancer occurred more often than in the controls. The increase in endometrial cancers was probably related to the agonistic oestrogenic effects of tamoxifen and was most pronounced in those treated for over 2 years.

Publication types

  • Clinical Trial
  • Comparative Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenocarcinoma / chemically induced*
  • Aged
  • Breast Neoplasms / drug therapy*
  • Breast Neoplasms / surgery
  • Clinical Trials as Topic
  • Combined Modality Therapy
  • Female
  • Follow-Up Studies
  • Humans
  • Neoplasm Recurrence, Local / prevention & control*
  • Random Allocation
  • Registries
  • Tamoxifen / adverse effects*
  • Time Factors
  • Uterine Neoplasms / chemically induced*


  • Tamoxifen