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Deficits in plasma oestradiol measurement in studies and management of breast cancer.

Dowsett M, Folkerd E - Breast Cancer Res. (2004)

Bottom Line: Commercially available analytical methods, which measure the hormone levels without prior purification, have been successfully developed for measuring oestradiol in premenopausal women.The application of these methodologies to the quantification of the very low levels of oestradiol in postmenopausal women is more problematic in terms of accuracy and interpretation.The importance of using appropriate methodology is discussed and illustrated with data demonstrating the disparity in the results obtained when low levels of oestradiol were quantified using direct and indirect methods.

View Article: PubMed Central - HTML - PubMed

Affiliation: Academic Department of Biochemistry, The Royal Marsden Hospital, London, UK. mitch.dowsett@icr.ac.uk

ABSTRACT
The determination of plasma oestradiol has numerous applications in epidemiology, reproductive medicine and breast cancer management. Commercially available analytical methods, which measure the hormone levels without prior purification, have been successfully developed for measuring oestradiol in premenopausal women. The application of these methodologies to the quantification of the very low levels of oestradiol in postmenopausal women is more problematic in terms of accuracy and interpretation. The importance of using appropriate methodology is discussed and illustrated with data demonstrating the disparity in the results obtained when low levels of oestradiol were quantified using direct and indirect methods.

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Related in: MedlinePlus

Relative risk (RR) of breast cancer by increasing quintiles of oestradiol concentration from a pooled analysis of nine studies (modified from [3]). The position of each square indicates the magnitude of the RR, and the area of the square is proportional to the amount of statistical information available. The length of the horizontal line through the square indicates the 95% confidence interval (CI).
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Figure 1: Relative risk (RR) of breast cancer by increasing quintiles of oestradiol concentration from a pooled analysis of nine studies (modified from [3]). The position of each square indicates the magnitude of the RR, and the area of the square is proportional to the amount of statistical information available. The length of the horizontal line through the square indicates the 95% confidence interval (CI).

Mentions: An overview study by the Endogenous Hormones and Breast Cancer Collaborative Group of prospective collections of plasma and subsequent measurements of oestradiol and associated steroids in women that eventually developed breast cancer illustrates both the importance of plasma oestradiol in postmenopausal women and the inaccuracies of analysis [3]. Inconsistent results had been published on the relationship between plasma oestradiol levels and breast cancer risk, but this overview analysis of nine studies revealed a highly significant relationship (Fig. 1) in which there was an overall increase in relative risk of 1.29 (95% confidence interval, 1.15–1.44; P < 0.001) for every doubling of oestradiol concentration. The true risk is probably higher since the measurements were made on single samples and it has been estimated that taking account of within-subject variability by taking multiple samples may lead to a doubling of estimates of relative risk [4]. The problems in analysis are illustrated by the mean oestradiol levels in the postmenopausal controls reported by the various laboratories varying about fivefold, and ranging from 21.7 pmol/l to 101 pmol/l. Four of the nine studies used different direct radioimmunoassays and the other five studies used an organic extraction prior to radioimmunoassay. Quoted detection limits ranged in value from 3 pmol/l to 37 pmol/l.


Deficits in plasma oestradiol measurement in studies and management of breast cancer.

Dowsett M, Folkerd E - Breast Cancer Res. (2004)

Relative risk (RR) of breast cancer by increasing quintiles of oestradiol concentration from a pooled analysis of nine studies (modified from [3]). The position of each square indicates the magnitude of the RR, and the area of the square is proportional to the amount of statistical information available. The length of the horizontal line through the square indicates the 95% confidence interval (CI).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC1064106&req=5

Figure 1: Relative risk (RR) of breast cancer by increasing quintiles of oestradiol concentration from a pooled analysis of nine studies (modified from [3]). The position of each square indicates the magnitude of the RR, and the area of the square is proportional to the amount of statistical information available. The length of the horizontal line through the square indicates the 95% confidence interval (CI).
Mentions: An overview study by the Endogenous Hormones and Breast Cancer Collaborative Group of prospective collections of plasma and subsequent measurements of oestradiol and associated steroids in women that eventually developed breast cancer illustrates both the importance of plasma oestradiol in postmenopausal women and the inaccuracies of analysis [3]. Inconsistent results had been published on the relationship between plasma oestradiol levels and breast cancer risk, but this overview analysis of nine studies revealed a highly significant relationship (Fig. 1) in which there was an overall increase in relative risk of 1.29 (95% confidence interval, 1.15–1.44; P < 0.001) for every doubling of oestradiol concentration. The true risk is probably higher since the measurements were made on single samples and it has been estimated that taking account of within-subject variability by taking multiple samples may lead to a doubling of estimates of relative risk [4]. The problems in analysis are illustrated by the mean oestradiol levels in the postmenopausal controls reported by the various laboratories varying about fivefold, and ranging from 21.7 pmol/l to 101 pmol/l. Four of the nine studies used different direct radioimmunoassays and the other five studies used an organic extraction prior to radioimmunoassay. Quoted detection limits ranged in value from 3 pmol/l to 37 pmol/l.

Bottom Line: Commercially available analytical methods, which measure the hormone levels without prior purification, have been successfully developed for measuring oestradiol in premenopausal women.The application of these methodologies to the quantification of the very low levels of oestradiol in postmenopausal women is more problematic in terms of accuracy and interpretation.The importance of using appropriate methodology is discussed and illustrated with data demonstrating the disparity in the results obtained when low levels of oestradiol were quantified using direct and indirect methods.

View Article: PubMed Central - HTML - PubMed

Affiliation: Academic Department of Biochemistry, The Royal Marsden Hospital, London, UK. mitch.dowsett@icr.ac.uk

ABSTRACT
The determination of plasma oestradiol has numerous applications in epidemiology, reproductive medicine and breast cancer management. Commercially available analytical methods, which measure the hormone levels without prior purification, have been successfully developed for measuring oestradiol in premenopausal women. The application of these methodologies to the quantification of the very low levels of oestradiol in postmenopausal women is more problematic in terms of accuracy and interpretation. The importance of using appropriate methodology is discussed and illustrated with data demonstrating the disparity in the results obtained when low levels of oestradiol were quantified using direct and indirect methods.

Show MeSH
Related in: MedlinePlus