Open AccessSmoking, Radiation Therapy, and Contralateral Breast Cancer Risk in Young Women
Author(s) -
Anne S. Reiner,
Gordon P. Watt,
Esther M. John,
Charles F. Lynch,
Jennifer Brooks,
Lene Mellemkjær,
John D. Boice,
Julia A. Knight,
Patrick Concan,
Susan A. Smith,
Xiaolin Liang,
Meghan Woods,
Roy E. Shore,
Kathleen E. Malone,
Leslie Bernstein,
Jonine L. Bernstein
Publication year - 2021
Publication title -
journal of the national cancer institute
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.797
H-Index - 356
eISSN - 1460-2105
pISSN - 0027-8874
DOI - 10.1093/jnci/djab047
Subject(s) - medicine , breast cancer , radiation therapy , confidence interval , relative risk , case control study , logistic regression , absolute risk reduction , cancer
Evidence is mounting that cigarette smoking contributes to second primary contralateral breast cancer (CBC) risk. Whether radiation therapy (RT) interacts with smoking to modify this risk is unknown. In this multicenter, individually matched, case-control study, we examined the association between RT, smoking, and CBC risk. The study included 1521 CBC cases and 2212 controls with unilateral breast cancer, all diagnosed with first invasive breast cancer between 1985 and 2008 aged younger than 55 years. Absorbed radiation doses to contralateral breast regions were estimated with thermoluminescent dosimeters in tissue-equivalent anthropomorphic phantoms, and smoking history was collected by interview. Rate ratios (RRs) and 95% confidence intervals (CIs) for CBC risk were estimated by multivariable conditional logistic regression. There was no interaction between any measure of smoking with RT to increase CBC risk (eg, the interaction of continuous RT dose with smoking at first breast cancer diagnosis [ever/never]: RR = 1.00, 95% CI = 0.89 to 1.14; continuous RT dose with years smoked: RR = 1.00, 95% CI = 0.99 to 1.01; and continuous RT dose with lifetime pack-years: RR = 1.00, 95% CI = 0.99 to 1.01). There was no evidence that RT further increased CBC risk in young women with first primary breast cancer who were current smokers or had smoking history.