Background:

It is well known that Menopausal Hormone therapy increases mammographic density. Increase in breast density may relate to breast cancer risk. Several computer assisted automatic methods for assessing mammographic density have been suggested by J.W. Byng (1996), N. Karssemeijer (1998), J.M. Boone(1998), S. Petroudi(2006), C. Tromans(2006) etc. All of these aim at reproducing the radiologist’s categorical rating system or at segmenting the dense tissue to get percentage density score. Since ninety percent of breast cancers arise from the ductal and lobular glands we choose to investigate features describing the local elongatedness or stripiness, especially trained to see the effect of HRT thereby providing a non-subjective and reproducible measure and compare it to the BIRADS and percentage density measure.

Objective:

1) To provide a framework for obtaining more accurate and sensitive measurements of breast density changes related to HRT. 2) To investigate whether transdermal low dose estradiol treatment induces changes in mammographic density compared to raloxifene and if these findings indicate elevation of breast cancer risk by treatment.

Material and Methods:

Digitised mammographies of 2x135 completers of a two year, randomised, trial formed the base of the present analysis. Active treatments were transdermal estradiol releasing 0.014mg E2/week and orally administered raloxifene hydrochloride, 60mg/day respectively. Influence of the therapies on breast density was assessed with our computer-based heterogeneity examination of radiographs (E2-HER) measure which uses scale space features in order to examine the heterogeneity with in mammogram.

Results:

At baseline no mammography scoring methodology could separate the two treatment groups of transdermal estradiol and raloxifene. No treatment induced significant density changes measured by BI-RADS. Both treatments made the area percentage density increase and the estradiol significantly. Both treatments induced significant changes in E2-specific heterogeneity scoring (E2-HER) and the raloxifene treatment a significantly higher change.

Conclusion:

The proposed methodology shows substantial merit as it qualify considerably better in consistency and ROC statistics than both BIRADS and percentage density method. This approach can be trained to detect changes due to HRT. From the experiment, we also conclude that, Low dose transdermal estradiol and raloxifene induced comparable changes in breast density and heterogeneity. The current study does not yield evidence against the hypothesis that “neither raloxifene nor low dose transdermal estradiol treatment increase the breast cancer risk”.