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Increased incidence of small and well-differentiated breast tumours in post-menopausal women following hormone-replacement therapy

Manjer, Jonas LU ; Malina, Janne; Berglund, Göran LU ; Bondeson, Lennart LU ; Garne, Jens Peter and Janzon, Lars LU (2001) In International Journal of Cancer 92(6). p.919-922
Abstract
Exposure to hormone-replacement therapy (HRT) has consistently been associated with an increased incidence of breast cancer, particularly of small tumours. Other tumour characteristics in relation to HRT have received less scientific attention. Our aim in this population-based prospective cohort study was to assess whether HRT is associated with an increased incidence of breast-cancer subgroups defined in terms of stage, type (according to the WHO system), Nottingham grade and the Nottingham Prognostic Index (NPI). Evaluation was based on a cohort of 5,865 post-menopausal women followed for an average of 9.8 years. Twenty percent of women reported current use of HRT at the time of the baseline interview. Record linkage with the Swedish... (More)
Exposure to hormone-replacement therapy (HRT) has consistently been associated with an increased incidence of breast cancer, particularly of small tumours. Other tumour characteristics in relation to HRT have received less scientific attention. Our aim in this population-based prospective cohort study was to assess whether HRT is associated with an increased incidence of breast-cancer subgroups defined in terms of stage, type (according to the WHO system), Nottingham grade and the Nottingham Prognostic Index (NPI). Evaluation was based on a cohort of 5,865 post-menopausal women followed for an average of 9.8 years. Twenty percent of women reported current use of HRT at the time of the baseline interview. Record linkage with the Swedish Cancer Registry and local clinical registries identified 141 incident invasive breast-cancer cases. All tumours were reclassified by 1 pathologist. The incidence of breast cancer in HRT users was 377/10(5) and in non-users 221/10(5) person-years [relative risk (RR) = 1.72, 95% confidence interval (CI) 1.17-2.52]. This risk remained statistically significant after adjustment for established risk factors in a Cox proportional hazards analysis (RR = 1.66, 95% CI 1.12-2.45). Among HRT users, there was over-representation of cases with stage I tumours (adjusted RR = 2.33, 95% CI 1.44-3.76), of lobular carcinomas (RR = 4.38, 95% CI 1.60-12.0) and of tubular tumours (RR = 4.81, 95% CI 1.37-16.8). Nottingham grade I/II carcinomas (RR = 2.02, 95% CI 1.29-3.16) and cases with NPI < or = 3.4 (RR = 2.29, 95% CI 1.41-3.72) were similarly over-represented among HRT users. Incidence of breast cancer was increased in post-menopausal women who used HRT at baseline. Among HRT users, there was over-representation of tumours that, with regard to stage, type and grade, are associated with a favourable prognosis. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
breast cancer, stage, histologic type, differentiation, Nottingham Prognostic Index, hormone-replacement therapy
in
International Journal of Cancer
volume
92
issue
6
pages
919 - 922
publisher
John Wiley & Sons
external identifiers
  • pmid:11351317
  • scopus:0035877232
ISSN
0020-7136
DOI
10.1002/ijc.1279
language
English
LU publication?
yes
id
efba73a2-078e-4cd1-b759-6c6ba1f67301 (old id 1120183)
date added to LUP
2008-07-04 14:04:20
date last changed
2018-01-07 05:16:44
@article{efba73a2-078e-4cd1-b759-6c6ba1f67301,
  abstract     = {Exposure to hormone-replacement therapy (HRT) has consistently been associated with an increased incidence of breast cancer, particularly of small tumours. Other tumour characteristics in relation to HRT have received less scientific attention. Our aim in this population-based prospective cohort study was to assess whether HRT is associated with an increased incidence of breast-cancer subgroups defined in terms of stage, type (according to the WHO system), Nottingham grade and the Nottingham Prognostic Index (NPI). Evaluation was based on a cohort of 5,865 post-menopausal women followed for an average of 9.8 years. Twenty percent of women reported current use of HRT at the time of the baseline interview. Record linkage with the Swedish Cancer Registry and local clinical registries identified 141 incident invasive breast-cancer cases. All tumours were reclassified by 1 pathologist. The incidence of breast cancer in HRT users was 377/10(5) and in non-users 221/10(5) person-years [relative risk (RR) = 1.72, 95% confidence interval (CI) 1.17-2.52]. This risk remained statistically significant after adjustment for established risk factors in a Cox proportional hazards analysis (RR = 1.66, 95% CI 1.12-2.45). Among HRT users, there was over-representation of cases with stage I tumours (adjusted RR = 2.33, 95% CI 1.44-3.76), of lobular carcinomas (RR = 4.38, 95% CI 1.60-12.0) and of tubular tumours (RR = 4.81, 95% CI 1.37-16.8). Nottingham grade I/II carcinomas (RR = 2.02, 95% CI 1.29-3.16) and cases with NPI &lt; or = 3.4 (RR = 2.29, 95% CI 1.41-3.72) were similarly over-represented among HRT users. Incidence of breast cancer was increased in post-menopausal women who used HRT at baseline. Among HRT users, there was over-representation of tumours that, with regard to stage, type and grade, are associated with a favourable prognosis.},
  author       = {Manjer, Jonas and Malina, Janne and Berglund, Göran and Bondeson, Lennart and Garne, Jens Peter and Janzon, Lars},
  issn         = {0020-7136},
  keyword      = {breast cancer,stage,histologic type,differentiation,Nottingham Prognostic Index,hormone-replacement therapy},
  language     = {eng},
  number       = {6},
  pages        = {919--922},
  publisher    = {John Wiley & Sons},
  series       = {International Journal of Cancer},
  title        = {Increased incidence of small and well-differentiated breast tumours in post-menopausal women following hormone-replacement therapy},
  url          = {http://dx.doi.org/10.1002/ijc.1279},
  volume       = {92},
  year         = {2001},
}