New hope for breast cancer survivors: extended hormone therapy may keep cancer away

NCT ID NCT00003140

First seen Apr 28, 2026 · Last updated May 14, 2026 · Updated 3 times

Summary

This study tested the drug letrozole in over 5,000 women with breast cancer who had already taken tamoxifen for at least 5 years. The goal was to see if letrozole could help prevent the cancer from coming back. Participants took either letrozole or a placebo pill daily. The main measure was how long women lived without their cancer returning.

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This is a summary of the original study . Summaries may miss details or leave out important information. Before applying or accepting participation, make sure you have read and understood the full study. Curemydisease.com takes no responsibility whatsoever for anything missed, misunderstood, or acted upon as a result of our summary — we know it does not capture everything.

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Contacts and locations

Locations

  • Algoma District Cancer Program

    Sault Ste. Marie, Ontario, P6B 0A8, Canada

  • Allan Blair Cancer Centre

    Regina, Saskatchewan, S4T 7T1, Canada

  • Atlantic Health Sciences Corporation

    Saint John, New Brunswick, E2L 4L2, Canada

  • BCCA - Cancer Centre for the Southern Interior

    Kelowna, British Columbia, V1Y 5L3, Canada

  • BCCA - Fraser Valley Cancer Centre

    Surrey, British Columbia, V3V 1Z2, Canada

  • BCCA - Vancouver Cancer Centre

    Vancouver, British Columbia, V5Z 4E6, Canada

  • BCCA - Vancouver Island Cancer Centre

    Victoria, British Columbia, V8R 6V5, Canada

  • CHA-Hopital Du St-Sacrement

    Québec, Quebec, G1S 4L8, Canada

  • CHUM - Hopital Notre-Dame

    Montreal, Quebec, H2L 4M1, Canada

  • CHUM - Hotel Dieu du Montreal

    Montreal, Quebec, H2W 1T8, Canada

  • CHUM - Pavillon Saint-Luc

    Montreal, Quebec, H3X 3J4, Canada

  • CHUQ-Pavillon Hotel-Dieu de Quebec

    Québec, Quebec, G1R 2J6, Canada

  • Cancer Centre of Southeastern Ontario at Kingston

    Kingston, Ontario, K7L 5P9, Canada

  • CancerCare Manitoba

    Winnipeg, Manitoba, R3E 0V9, Canada

  • Centre de Sante et de services sociaux de Gatineau

    Gatineau, Quebec, J8P 7H2, Canada

  • Centre hospitalier universitaire de Sherbrooke

    Sherbrooke, Quebec, J1H 5N4, Canada

  • Christie's Hospital NHS Trust

    Manchester, M2O 4BX, United Kingdom

  • Credit Valley Hospital

    Mississauga, Ontario, L5M 2N1, Canada

  • Dr. H. Bliss Murphy Cancer Centre

    St. John's, Newfoundland and Labrador, AIB 3V6, Canada

  • Hopital Maisonneuve-Rosemont

    Montreal, Quebec, H1T 2M4, Canada

  • Hopital du Sacre-Coeur de Montreal

    Montreal, Quebec, H4J 1C5, Canada

  • Humber River Regional Hospital

    Toronto, Ontario, M9N 1N8, Canada

  • Juravinski Cancer Centre at Hamilton Health Sciences

    Hamilton, Ontario, L8V 5C2, Canada

  • L'Hotel-Dieu de Levis

    Lévis, Quebec, G6V 3Z1, Canada

  • Lakeridge Health Oshawa

    Oshawa, Ontario, L1G 2B9, Canada

  • Lethbridge Cancer Centre

    Lethbridge, Alberta, T1J 1W5, Canada

  • London Regional Cancer Program

    London, Ontario, N6A 4L6, Canada

  • Markham Stouffville Hospital

    Markham, Ontario, L6B 1A1, Canada

  • McGill University - Dept. Oncology

    Montreal, Quebec, H2W 1S6, Canada

  • Mount Sinai Hospital

    Toronto, Ontario, M5G 1X5, Canada

  • NRGH - Nanaimo Cancer Clinic

    Nanaimo, British Columbia, V9S 2B7, Canada

  • Niagara Health System

    St. Catharines, Ontario, L2R 7C6, Canada

  • North York General Hospital

    Toronto, Ontario, M2K 1E1, Canada

  • Odette Cancer Centre

    Toronto, Ontario, M4N 3M5, Canada

  • Ottawa Health Research Institute - General Division

    Ottawa, Ontario, K1H 8L6, Canada

  • PEI Cancer Treatment Centre,Queen Elizabeth Hospital

    Charlottetown, Prince Edward Island, C1A 8T5, Canada

  • Penticton Regional Hospital

    Penticton, British Columbia, V2A 3G6, Canada

  • Peterborough Regional Health Centre

    Peterborough, Ontario, K9H 7B6, Canada

  • QEII Health Sciences Center

    Halifax, Nova Scotia, B3H 1V7, Canada

  • Regional Cancer Program of the Hopital Regional

    Greater Sudbury, Ontario, P3E 5J1, Canada

  • Saskatoon Cancer Centre

    Saskatoon, Saskatchewan, S7N 4H4, Canada

  • St. Joseph's Health Centre

    Toronto, Ontario, M6R 1B5, Canada

  • St. Michael's Hospital

    Toronto, Ontario, M5B 1W8, Canada

  • Stronach Regional Health Centre at Southlake

    Newmarket, Ontario, L3Y 2P9, Canada

  • The Moncton Hospital

    Moncton, New Brunswick, E1C 6Z8, Canada

  • The Royal Marsden NHS Foundation Trust

    London, SW3 6JJ, United Kingdom

  • The Royal Marsden NHS Foundation Trust - Sutton

    Surrey, SM2 5PT, United Kingdom

  • The Royal Victoria Hospital

    Barrie, Ontario, L4M 6M2, Canada

  • The Vitalite Health Network - Dr. Leon Richard

    Moncton, New Brunswick, E1C 8X3, Canada

  • Thunder Bay Regional Health Science Centre

    Thunder Bay, Ontario, P7B 6V4, Canada

  • Toronto East General Hospital

    Toronto, Ontario, M4C 3E7, Canada

  • Trillium Health Centre - West Toronto

    Toronto, Ontario, M9C 1A5, Canada

  • Univ. Health Network-Princess Margaret Hospital

    Toronto, Ontario, M5G 2M9, Canada

  • Univ. Health Network-The Toronto General Hospital

    Toronto, Ontario, M5G 2C4, Canada

  • University Institute of Cardiology and

    Québec, Quebec, G1V 4G5, Canada

  • Windsor Regional Cancer Centre

    Windsor, Ontario, N8W 2X3, Canada

  • Wythenshawe Hospital

    Manchester, M23 9LT, United Kingdom

Conditions

Explore the condition pages connected to this study.