There are many reasons behind the increasing rates of breast cancer in developing countries including Egypt; among these reasons is increasing breast density in women above age of 40 years [3]. So, in women over 40 years of age, breast cancer remains one of the main reasons of death [4].
Increasing breast cancer survival rate with a possibility of complete cure is mostly the result of early detection that is why annual screening mammography is a must [5].
Annual screening for breast cancer is important in detecting women with asymptomatic breast cancer and as result better outcomes [1].
Mammogram films are usually a combination of both non-radiolucent areas and radiolucent areas representing a mixture of both fibroglandular tissue and fat, so ladies with increasing percent of fibroglandular tissue of 75% or more usually show more risk of developing breast cancer by 4 to 6 folds in comparison to those with increasing fatty component in mammogram [6].
Some of the studies used Wolfe classification instead of BI-RADS density classification in explaining the relation between the risk for breast density and breast cancer risk. Use of the BI-RADS classification has resulted in a similar but milder relation of risk with respect to breast density [7]. One study of the Vermont population from the BCSC registry that implied the BI-RADS density classifications stated that extremely dense breasts in women have increased breast cancer relative risk ratio in premenopausal than in post-menopausal females [8].
Ahmadinjad et al. showed that the occurrence of malignancy in dense breast patients (61.2%) is more than in those with low breast densities (37.3%) (P= 0.007) as stated in our study that the frequency of breast cancer in groups ACR C and ACR D is more than the frequency rate in groups ACR A and ACR B [9].
According to the BI-RADS edition 2013, cases were classified into the following: 11,569 were ACR-A (23%), 24,135 were ACR-B (49%), 12,250 were ACR-C (25%), and 1455 were ACR-D (3%).
Our study included 49,409 women, 1500 cases were pathologically proven with breast cancer out of the total. Out of the 1500 breast cancer cases, 250 were depicted in ACR-A class and 650 in ACR-B class, 400 cases in the ACR-C class, and 200 in the ACR-D class.
Cases were ordered in a descending pattern depending on the frequency of carcinoma positive cases:
D (13.7%), C (3.3%), B (2.7%), A (2.2%)
The positive relationship between increasing the risk of breast cancer in women with increasing breast mammographic density has been reported in many cohort studies [10]. Byrne et al. stated that women with breast density of 75% or more showed four-fold increase in the risk affection with breast cancer than those with mammographic density of 0% [11].
As stated in our study, Maskarinec et al. also discovered that the risk for breast cancer affection increases by 3.6 times in women with breast density more than 50% than women with density less than 10% [12].
Some studies reported that the relative cancer risk for breasts that were 50–74% dense was 2.92 and 4.64 for breasts that were 75% or more dense; as a result, there is a linear increasing trend between the relation of the breast cancer relative risk and increasing tissue breast density which was also reported in our study [7].
In our study, we found that women with ACR mammographic density class D and C have statistically increase frequency of positive carcinoma patients than class A and B.