Risk factors for contralateral breast cancer in postmenopausal breast cancer survivors in the NIH-AARP Diet and Health Study

Purpose The role of established breast cancer risk factors and clinical characteristics of the first breast cancer in the development of contralateral breast cancer (CBC) among postmenopausal women is unclear. Methods We identified 10,934 postmenopausal women diagnosed with a first primary breast ca...

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Bibliographic Details
Published in:Cancer causes & control 2021-08, Vol.32 (8), p.803-813
Main Authors: Ramin, Cody, Mullooly, Maeve, Schonfeld, Sara J., Advani, Pragati G., Bodelon, Clara, Gierach, Gretchen L., de González, Amy Berrington
Format: Article
Language:English
Subjects:
Age
Biomedical and Life Sciences
Biomedicine
Body mass
Body mass index
Body size
Breast cancer
Cancer Research
Confidence intervals
Diagnosis
Diet
Endocrine therapy
Epidemiology
Etiology
Family medical history
Genetics
Health risks
Hematology
Invasiveness
Lifestyles
Menarche
Menopause
Oncology
Original Paper
Physical activity
Post-menopause
Public Health
Risk analysis
Risk factors
Statistical analysis
Womens health
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Summary:Purpose The role of established breast cancer risk factors and clinical characteristics of the first breast cancer in the development of contralateral breast cancer (CBC) among postmenopausal women is unclear. Methods We identified 10,934 postmenopausal women diagnosed with a first primary breast cancer between 1995 and 2011 in the NIH-AARP Diet and Health Study. CBC was defined as a second primary breast cancer diagnosed in the contralateral breast ≥ 3 months after the first breast cancer. Exposures included pre-diagnosis risk factors (lifestyle, reproductive, family history) and clinical characteristics of the first breast cancer. We used multivariable Cox proportional hazards regression to estimate hazard ratios (HRs) and 95% confidence intervals (CIs). Results Over a median follow-up of 6.8 years, 436 women developed CBC. We observed an increasing trend in CBC risk by age ( p -trend = 0.002) and decreasing trend by year of diagnosis ( p -trend = 0.001) of the first breast cancer. Additional risk factor associations were most pronounced for endocrine therapy (HR 0.68, 95% CI 0.53–0.87) and family history of breast cancer (HR 1.38, 95% CI 1.06–1.80, restricted to invasive first breast cancer). No associations were found for lifestyle (body mass index, physical activity, smoking, alcohol) or reproductive factors (age at menarche, parity, age at first birth, age at menopause). Conclusions This study suggests that clinical characteristics of the first breast cancer and family history of breast cancer, but not pre-diagnosis lifestyle and reproductive factors, are strongly associated with CBC risk among postmenopausal women. Future studies are needed to understand how these factors contribute to CBC etiology and to identify further opportunities for prevention.
ISSN:0957-5243
1573-7225
DOI:10.1007/s10552-021-01432-2