Reproductive Status at First Diagnosis Influences Risk of Radiation-Induced Second Primary Contralateral Breast Cancer in the WECARE Study

Jennifer D Brooks; John D Boice; Marilyn Stovall; Anne S Reiner; Leslie Bernstein; Esther M John; Charles F Lynch; Lene Mellemkjær; Julia A Knight; Duncan C Thomas; Robert W Haile; Susan A Smith; Marinela Capanu; Jonine L Bernstein; Roy E Shore; The WECARE Collaborative Group

doi:10.1016/j.ijrobp.2012.01.047

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Reproductive Status at First Diagnosis Influences Risk of Radiation-Induced Second Primary Contralateral Breast Cancer in the WECARE Study

Journal article

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Reproductive Status at First Diagnosis Influences Risk of Radiation-Induced Second Primary Contralateral Breast Cancer in the WECARE Study

Jennifer D Brooks, John D Boice, Marilyn Stovall, Anne S Reiner, Leslie Bernstein, Esther M John, Charles F Lynch, Lene Mellemkjær, Julia A Knight, Duncan C Thomas, …

International journal of radiation oncology, biology, physics, Vol.84(4), pp.917-924

11/15/2012

DOI: 10.1016/j.ijrobp.2012.01.047

PMCID: PMC3394928

PMID: 22483700

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Abstract

Our study examined whether reproductive and hormonal factors before, at the time of, or after radiation treatment for a first primary breast cancer modify the risk of radiation-induced second primary breast cancer. The Women’s Environmental, Cancer and Radiation Epidemiology (WECARE) Study is a multicenter, population-based study of 708 women (cases) with asynchronous contralateral breast cancer (CBC) and 1399 women (controls) with unilateral breast cancer. Radiotherapy (RT) records, coupled with anthropomorphic phantom simulations, were used to estimate quadrant-specific radiation dose to the contralateral breast for each patient. Rate ratios (RR) and 95% confidence intervals (CI) were computed to assess the relationship between reproductive factors and risk of CBC. Women who were nulliparous at diagnosis and exposed to ≥1 Gy to the contralateral breast had a greater risk for CBC than did matched unexposed nulliparous women (RR = 2.2; 95% CI, 1.2–4.0). No increased risk was seen in RT-exposed parous women (RR = 1.1; 95% CI, 0.8–1.4). Women treated with RT who later became pregnant (8 cases and 9 controls) had a greater risk for CBC (RR = 6.0; 95% CI, 1.3–28.4) than unexposed women (4 cases and 7 controls) who also became pregnant. The association of radiation with risk of CBC did not vary by number of pregnancies, history of breastfeeding, or menopausal status at the time of first breast cancer diagnosis. Nulliparous women treated with RT were at an increased risk for CBC. Although based on small numbers, women who become pregnant after first diagnosis also seem to be at an increased risk for radiation-induced CBC.

Radiation treatment

Second primary contralateral breast cancer

Reproductive factors

Details

Title: Subtitle: Reproductive Status at First Diagnosis Influences Risk of Radiation-Induced Second Primary Contralateral Breast Cancer in the WECARE Study
Creators: Jennifer D Brooks - Department of Epidemiology and Biostatistics, Memorial Sloan-Kettering Cancer Center, New York, NY
John D Boice - International Epidemiology Institute, Rockville, MD and Department of Medicine, Vanderbilt Epidemiology Center, Vanderbilt-Ingram Cancer Center, Vanderbilt School of Medicine, Nashville, TN
Marilyn Stovall - Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, TX
Anne S Reiner - Department of Epidemiology and Biostatistics, Memorial Sloan-Kettering Cancer Center, New York, NY
Leslie Bernstein - Division of Cancer Etiology, Department of Population Sciences, Beckman Research Institute and City of Hope Comprehensive Cancer Center, Duarte, CA
Esther M John - Cancer Prevention Institute of California, Fremont, CA, and Stanford University School of Medicine and Stanford Cancer Institute, Stanford, CA
Charles F Lynch - Department of Epidemiology, University of Iowa, Iowa City, IA
Lene Mellemkjær - Institute of Cancer Epidemiology, Danish Cancer Society, Copenhagen, Denmark
Julia A Knight - Dalla Lana School of Public Health, University of Toronto and Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada
Duncan C Thomas - Department of Preventive Medicine, University of Southern California, Los Angeles, CA
Robert W Haile - Department of Preventive Medicine, University of Southern California, Los Angeles, CA
Susan A Smith - Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, TX
Marinela Capanu - Department of Epidemiology and Biostatistics, Memorial Sloan-Kettering Cancer Center, New York, NY
Jonine L Bernstein - Department of Epidemiology and Biostatistics, Memorial Sloan-Kettering Cancer Center, New York, NY
Roy E Shore - Department of Environmental Medicine, New York University, New York, NY; and Radiation Effects Research Foundation, Hiroshima, Japan
The WECARE Collaborative Group
Resource Type: Journal article
Publication Details: International journal of radiation oncology, biology, physics, Vol.84(4), pp.917-924
DOI: 10.1016/j.ijrobp.2012.01.047
PMID: 22483700
PMCID: PMC3394928
NLM abbreviation: Int J Radiat Oncol Biol Phys
ISSN: 0360-3016
eISSN: 1879-355X
Publisher: Elsevier Inc
Grant note: R01CA114236; R01CA29639; U01CA083178 / National Cancer Institute
Language: English
Date published: 11/15/2012
Academic Unit: Epidemiology
Record Identifier: 9983995035502771

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