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Risk of second cancer among women with breast cancer
Author(s) -
Mellemkjær Lene,
Friis Søren,
Olsen Jørgen H.,
Scélo Ghislaine,
Hemminki Kari,
Tracey Elizabeth,
Andersen Aage,
Brewster David H.,
Pukkala Eero,
McBride Mary L.,
Kliewer Erich V.,
Tonita Jon M.,
KeeSeng Chia,
PompeKirn Vera,
Martos Carmen,
Jonasson Jon G.,
Boffetta Paolo,
Brennan Paul
Publication year - 2005
Publication title -
international journal of cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.475
H-Index - 234
eISSN - 1097-0215
pISSN - 0020-7136
DOI - 10.1002/ijc.21651
Subject(s) - breast cancer , cancer , medicine , thyroid cancer , population , oncology , kidney cancer , endometrial cancer , epidemiology of cancer , gynecology , environmental health
A large number of women survive a diagnosis of breast cancer. Knowledge of their risk of developing a new primary cancer is important not only in relation to potential side effects of their cancer treatment, but also in relation to the possibility of shared etiology with other types of cancer. A cohort of 525,527 women with primary breast cancer was identified from 13 population‐based cancer registries in Europe, Canada, Australia and Singapore, and followed for second primary cancers within the period 1943–2000. We used cancer incidence rates of first primary cancer for the calculation of standardized incidence ratios (SIRs) of second primary cancer. Risk of second primary breast cancer after various types of nonbreast cancer was also computed. For all second cancer sites combined, except contralateral breast cancer, we found a SIR of 1.25 (95% CI = 1.24–1.26) on the basis of 31,399 observed cases after first primary breast cancer. The overall risk increased with increasing time since breast cancer diagnosis and decreased by increasing age at breast cancer diagnosis. There were significant excesses of many different cancer sites; among these the excess was larger than 150 cases for stomach (SIR = 1.35), colorectal (SIR = 1.22), lung (SIR = 1.24), soft tissue sarcoma (SIR = 2.25), melanoma (SIR = 1.29), non‐melanoma skin (SIR = 1.58), endometrium (SIR = 1.52), ovary (SIR = 1.48), kidney (SIR = 1.27), thyroid gland (SIR = 1.62) and leukaemia (SIR = 1.52). The excess of cancer after a breast cancer diagnosis is likely to be explained by treatment for breast cancer and by shared genetic or environmental risk factors, although the general excess of cancer suggests that there may be additional explanations such as increased surveillance and general cancer susceptibility. © 2005 Wiley‐Liss, Inc.