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Prolonged Tamoxifen Compared With Shorter Tamoxifen in Treating Patients Who Have Breast Cancer

The recruitment status of this study is unknown. The completion date has passed and the status has not been verified in more than two years.
Verified October 2002 by National Cancer Institute (NCI).
Recruitment status was:  Active, not recruiting
ClinicalTrials.gov Identifier:
First Posted: January 27, 2003
Last Update Posted: February 9, 2009
The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details.
Information provided by:
National Cancer Institute (NCI)

RATIONALE: Estrogen can stimulate the growth of breast cancer cells. Hormone therapy using tamoxifen may fight breast cancer by reducing the production of estrogen. It is not yet known if prolonged tamoxifen is more effective than shorter tamoxifen therapy following curative treatment for breast cancer.

PURPOSE: This randomized phase III trial is studying giving tamoxifen over a prolonged period of time to see how well it works compared to giving tamoxifen over a shorter period of time in treating patients who have had a breast tumor removed.

Condition Intervention Phase
Breast Cancer Drug: tamoxifen citrate Procedure: adjuvant therapy Phase 3

Study Type: Interventional
Study Design: Allocation: Randomized
Primary Purpose: Treatment
Official Title: Reliable Assessment of the Efficacy and Safety of Prolonging the Use of Adjuvant Tamoxifen: A Large, Simple, Randomised Study

Resource links provided by NLM:

Further study details as provided by National Cancer Institute (NCI):

Primary Outcome Measures:
  • Overall survival (i.e., all-cause mortality)

Secondary Outcome Measures:
  • Specific-cause mortality
  • Incidence of second primary tumors

Estimated Enrollment: 20000
Study Start Date: October 1995
Detailed Description:


  • Assess the balance of risks and benefits in prolonging the duration of adjuvant tamoxifen by at least 5 years in patients with curatively treated breast cancer who have already had about 5 years of adjuvant tamoxifen.

OUTLINE: This is a randomized study. After about 5 years of adjuvant tamoxifen, recurrence-free patients are randomized to stop tamoxifen treatment immediately or to continue tamoxifen treatment for at least 5 more years.

Patients are followed annually.

PROJECTED ACCRUAL: Approximately 20,000 patients will be accrued for this study.


Information from the National Library of Medicine

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the contacts provided below. For general information, Learn About Clinical Studies.

Ages Eligible for Study:   Child, Adult, Senior
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No


  • Curatively treated carcinoma of the breast
  • Currently taking adjuvant tamoxifen

    • Must be substantial uncertainty as to whether or not to continue tamoxifen (i.e., no clear indication or definite contraindication to further treatment with tamoxifen)



  • Any age

Performance status:

  • Not specified

Life expectancy:

  • Not specified


  • Not specified


  • Not specified


  • Not specified


  • Not pregnant or nursing
  • No contraindications to receiving tamoxifen
  • No other serious medical problems


Biologic therapy:

  • Prior biologic therapy allowed


  • Prior chemotherapy allowed

Endocrine therapy:

  • See Disease Characteristics


  • Prior radiotherapy allowed


  • Prior surgery allowed
  Contacts and Locations
Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT00003016

United Kingdom
Atlas Trial Office
Oxford, England, United Kingdom, OX2 6HE
Sponsors and Collaborators
University of Oxford
Study Chair: Rodrigo Arriagada, MD Karolinska Institutet
  More Information

ClinicalTrials.gov Identifier: NCT00003016     History of Changes
Other Study ID Numbers: CDR0000065596
First Submitted: November 1, 1999
First Posted: January 27, 2003
Last Update Posted: February 9, 2009
Last Verified: October 2002

Keywords provided by National Cancer Institute (NCI):
stage I breast cancer
stage II breast cancer
stage IIIA breast cancer
stage IIIB breast cancer
stage IIIC breast cancer

Additional relevant MeSH terms:
Breast Neoplasms
Neoplasms by Site
Breast Diseases
Skin Diseases
Estrogen Antagonists
Hormone Antagonists
Hormones, Hormone Substitutes, and Hormone Antagonists
Physiological Effects of Drugs
Antineoplastic Agents, Hormonal
Antineoplastic Agents
Selective Estrogen Receptor Modulators
Estrogen Receptor Modulators
Bone Density Conservation Agents