Kataoka Masako, Atkinson Charlotte, Warren Ruth, Sala Evis, Day Nicholas E, Highnam Ralph, Warsi Iqbal, Bingham Sheila A
Department of Radiology, University of Cambridge, Addenbrooke's Hospital, Cambridge, UK.
Maturitas. 2008 Apr 20;59(4):350-7. doi: 10.1016/j.maturitas.2008.03.005. Epub 2008 May 20.
Mammographic density is a useful biomarker of breast cancer risk. Computer-based methods can provide continuous data suitable for analysis. This study aimed to compare a semi-automated computer-assisted method (Cumulus) and a fully automated volumetric computer method (standard mammogram form (SMF)) for assessing mammographic density using data from a previously conducted randomised placebo-controlled trial of an isoflavone supplement.
Mammograms were obtained from participants in the intervention study. A total of 177 women completed the study. Baseline and follow-up mammograms were digitised and density was estimated using Cumulus (read by two readers) and SMF. Left-right correlation, changes in density over time, and difference between intervention and control groups were evaluated. Changes of density over time, and changes between intervention group and control group were examined using paired t-test and Student's t-test, respectively.
Inter-reader correlation coefficient by Cumulus was 0.90 for dense area, and 0.86 for percentage density. Left-right correlation of percent density was lower in SMF than in Cumulus. Among all women, percentage density by Cumulus decreased significantly over time, but no change was seen for SMF percentage density. The intervention group showed marginally significant greater reduction of percent density by Cumulus compared to controls (p=0.04), but the difference became weak after adjustment for baseline percent density (p=0.06). No other measurement demonstrated significant difference between intervention and control groups.
This comparison suggests that slightly different conclusions could be drawn from different methods used to assess breast density. The development of a more robust fully automated method is awaited.
乳腺钼靶密度是乳腺癌风险的一种有用生物标志物。基于计算机的方法可以提供适合分析的连续数据。本研究旨在使用先前进行的一项异黄酮补充剂随机安慰剂对照试验的数据，比较一种半自动计算机辅助方法（Cumulus）和一种全自动体积计算机方法（标准乳腺钼靶形式（SMF））来评估乳腺钼靶密度。
从干预研究的参与者中获取乳腺钼靶图像。共有177名女性完成了该研究。将基线和随访乳腺钼靶图像数字化，并使用Cumulus（由两名阅片者读取）和SMF估计密度。评估左右相关性、密度随时间的变化以及干预组与对照组之间的差异。分别使用配对t检验和学生t检验来检查密度随时间的变化以及干预组与对照组之间的变化。
Cumulus阅片者间致密面积的相关系数为0.90，密度百分比的相关系数为0.86。SMF中密度百分比的左右相关性低于Cumulus。在所有女性中，Cumulus的密度百分比随时间显著降低，但SMF的密度百分比未见变化。与对照组相比，干预组Cumulus的密度百分比降低幅度略大（p = 0.04），但在对基线密度百分比进行调整后，差异减弱（p = 0.06）。其他测量均未显示干预组与对照组之间存在显著差异。
这种比较表明，使用不同方法评估乳腺密度可能得出略有不同的结论。期待开发出更强大的全自动方法。
