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- Tikk, Kaja, et al.
(author)
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Circulating prolactin and in situ breast cancer risk in the European EPIC cohort : a case-control study
- 2015
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In: Breast Cancer Research. - : Springer Science and Business Media LLC. - 1465-5411 .- 1465-542X. ; 17
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Journal article (peer-reviewed)abstract
- Introduction The relationship between circulating prolactin and invasive breast cancer has been investigated previously, but the association between prolactin levels and in situ breast cancer risk has received less attention.Methods We analysed the relationship between pre-diagnostic prolactin levels and the risk of in situ breast cancer overall, and by menopausal status and use of postmenopausal hormone therapy (HT) at blood donation. Conditional logistic regression was used to assess this association in a case-control study nested within the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort, including 307 in situ breast cancer cases and their matched control subjects.Results We found a significant positive association between higher circulating prolactin levels and risk of in situ breast cancer among all women [pre-and postmenopausal combined, ORlog2 = 1.35 (95% CI 1.04-1.76), P-trend = 0.03]. No statistically significant heterogeneity was found between prolactin levels and in situ cancer risk by menopausal status (P-het = 0.98) or baseline HT use (P-het = 0.20), although the observed association was more pronounced among postmenopausal women using HT compared to non-users (P-trend = 0.06 vs P-trend = 0.35). In subgroup analyses, the observed positive association was strongest in women diagnosed with in situ breast tumors <4 years compared to >= 4 years after blood donation (P-trend = 0.01 vs P-trend = 0.63; P-het = 0.04) and among nulliparous women compared to parous women (P-trend = 0.03 vs P-trend = 0.15; P-het = 0.07).Conclusions Our data extends prior research linking prolactin and invasive breast cancer to the outcome of in situ breast tumours and shows that higher circulating prolactin is associated with increased risk of in situ breast cancer.The relationship between circulating prolactin and invasive breast cancer has been investigated previously, but the association between prolactin levels and in situ breast cancer risk has received less attention.
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| 2. |
- Zamora-Ros, Raul, et al.
(author)
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Reproductive and menstrual factors and risk of differentiated thyroid carcinoma: The EPIC study
- 2015
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In: International Journal of Cancer. - : Wiley. - 0020-7136 .- 1097-0215. ; 136:5, s. 1218-1227
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Journal article (peer-reviewed)abstract
- Differentiated thyroid carcinoma (TC) is threefold more common in women than in men and, therefore, a role of female hormones in the etiology of differentiated TC has been suggested. We assessed these hypotheses in the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort. Among 345,157 women (mean age 51) followed for an average of 11 years, 508 differentiated TC cases were identified. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using Cox proportional hazards regression models. No significant associations were observed between differentiated TC risk and number of pregnancies, breast feeding, menopausal status, and age at menarche and at menopause. Significant associations were found with history of infertility problems (HR 1.70; 95% CI 1.12-2.60), a recent pregnancy (HR for 5 vs. >5 years before recruitment 3.87; 95% CI 1.43-10.46), menopause type (HR for surgical vs. natural menopause: 2.16; 95% CI 1.41-3.31), oral contraceptive (OC) use at recruitment (HR: 0.48; 95% CI 0.25-0.92) and duration of OC use (HR for 9 vs. 1 year: 0.66; 95% CI: 0.50-0.89). An increased risk was also found with hormone replacement therapy use at recruitment (HR=1.30, 95% CI 1.02-1.67), but this was not significant after adjustment for type of menopause (HR=1.22, 95% CI 0.95-1.57). Overall, our findings do not support a strong role of reproductive and menstrual factors, and female hormone use in the etiology of differentiated TC. The few observed associations may be real or accounted for by increased surveillance in women who had infertility problems, recent pregnancies or underwent surgical menopause.
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