Epidemiology and Cancer Prevention
Risk factors and age-incidence relationships for contralateral breast cancer
Article first published online: 22 NOV 2000
Copyright © 2000 Wiley-Liss, Inc.
International Journal of Cancer
Volume 88, Issue 6, pages 998–1002, 15 December 2000
How to Cite
Vaittinen, P. and Hemminki, K. (2000), Risk factors and age-incidence relationships for contralateral breast cancer. Int. J. Cancer, 88: 998–1002. doi: 10.1002/1097-0215(20001215)88:6<998::AID-IJC25>3.0.CO;2-0
- Issue published online: 22 NOV 2000
- Article first published online: 22 NOV 2000
- Manuscript Accepted: 3 AUG 2000
- Manuscript Revised: 31 JUL 2000
- Manuscript Received: 27 MAY 2000
- Swedish Cancer Fund
The nation-wide Swedish Family-Cancer Database was used to analyze the risk of contralateral breast cancer among 72,092 women with unilateral breast cancer. Contralateral breast cancer, defined as being diagnosed 6 months or more after the first breast cancer, affected 2,529 women (3.5%). In a young age group the incidence of contralateral breast cancer was 50 times higher than the incidence of first breast cancer; for all contralateral breast cancer the difference was 5-fold. Because only 1 breast was at risk for contralateral breast cancer, the true differences to unilateral cancer were 2 times higher. The age-incidence relationship was unusual, exhibiting a high incidence (800/105 person-years) component at an early age (25 to 49 years) and a lower incidence (460/105 person-years) component at a later age (50–80 years). The discrete components suggest population heterogeneity. Age at diagnosis of the first breast cancer and family history of breast cancer associated with the risk of contralateral breast cancer. Other, weaker risk factors were birth cohort, age at first childbirth, parity and interval between first and second breast cancer. The incidence of familial contralateral breast cancer was 1.5 times higher than that of sporadic disease, and its age-incidence curve also exhibited 2 separate components. The age-incidence relationships of contralateral breast cancer suggest that the disease affects a small and heterogeneous susceptible population. Int. J. Cancer 88:998–1002, 2000. © 2000 Wiley-Liss, Inc.