Patient and tumor characteristics of bilateral breast cancer at screening mammography in the Netherlands, a population-based study

Wikke Setz-Pels*, Lucien E. M. Duijm, Johanna H. Groenewoud, Marieke W. J. Louwman, Frits H. Jansen, Mike van Beek, Menno L. Plaisier, Adri C. Voogd

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review


Few data are available on bilateral breast cancer in the screening population. The aim of this study was to determine patient and tumor characteristics of women with bilateral breast cancer at screening mammography. We included all 350,637 screening mammography examinations of women participating in a biennial screening program in a southern screening region of the Netherlands between May 1998 and January 2010. For referred women, all breast imaging reports, biopsy results, and surgery reports during one year after referral were collected. We compared patient and tumor characteristics of referred women with a diagnosis of bilateral breast cancer or unilateral breast cancer at workup. Bilateral or unilateral breast cancer had been diagnosed in respectively 40 (2.2%) and 1766 (97.8%) of 1806 referred women. Women with bilateral or unilateral breast cancer did not differ significantly in mean age, mammographic breast density, family history of breast cancer, or use of hormone replacement therapy. Compared with index cancers, contralateral cancers comprised significantly more lobular cancers (P = 0.02). Tumor size, mitotic activity, and estrogen receptor status were comparable for both groups, but contralateral cancers had a significantly lower risk of lymph node metastases (P = 0.03). Compared to unilateral breast cancer, contralateral malignancies in women with bilateral breast cancer comprised significantly more lobular cancers (P = 0.004) and lymph node negative cancers (P = 0.01). Contralateral breast cancers detected at screening comprise more lobular cancers and show less nodal involvement than index cancers or unilateral cancers. No differences are observed with respect to other patient and tumor characteristics.
Original languageEnglish
Pages (from-to)955-961
JournalBreast Cancer Research and Treatment
Issue number3
Publication statusPublished - Oct 2011


  • Bilateral breast cancer
  • Screening mammography
  • Index cancer
  • Contralateral cancer
  • Sensitivity

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