The normal breast and its variations in mammography (2005). J. Stines & H. Tristant. European Journal of Radiology. 54: 26-36.
The Paper’s Findings
Unlike other scientific papers with a study and an objective, this particular paper is not an experimental study. This paper focuses on the breast as a whole including their origin, how they change throughout a woman’s life and how they are analyzed via a mammogram. The paper is a collection of facts and information from various sources that meld together to give a comprehensive view of the study and diagnosis of breasts including factors that make it more difficult to analyze mammograms. So, there are really no ‘results’ to report as no experiment was conducted. However, there were many important facts to take from this paper that could be considered results.
First, how the breasts begin development was described beginning with in the womb and continuing up to puberty. This description was more of background information for the readers. Next, the different components of the breasts were described in terms of how they appear on a mammogram. A mammograph is a technique that uses a tissues absorbance of X-ray waves to gain an inside look at the tissues of the breast. This method is used in diagnosis of problems with the breast including determinations of tumors or cancers. First it was explained that the mammogram is result of summation of all anatomical structures of the breast, which is a three dimensional structure itself. The greater the amount of fatty tissue in the breast, the better the view of the fibrous tissue. The difference between the two tissues is called radiological contrast which is the ability of one type of tissue to absorb more or less radiation waves than the other, thus making it visibly distinguishable. To increase this contrast and gain a better view of the breast molybdenum target is used which affects filtration of waves and the overall output. Also, a grid with low kilovoltage is used which increases the exposure time to the waves.
An important factor with the mammogram is hydratation of the breast. This refers to the fatty content that was mentioned briefly earlier. Again, the more fatty tissue present the better the view of the breast. Denser tissue, like the tissue present in younger females, is harder for the waves to penetrate and thus harder to gain a picture. This makes diagnosis of younger females more difficult as the tissue is denser and gives hard to read pictures. It was also stated in the paper that generally the denser the tissue the higher the associated risk with breast cancer, which is disheartening as dense tissue is harder to diagnose. With this in mind there are also problems associated with mammography. Firstly, when a lower kilovoltage is used to gain a better look it comes with the price of blurring if the patients moves, thus compromising the picture. Secondly, the topography of the breast itself causes problems. Due to the rounded shape and the curvature of the chest wall one mammogram will never give a complete view of the entire gland or all the tissues. Two methods are therefore used to view the breast – the oblique view and the lateral view. The oblique view is not really used anymore and the lateral view is more widely adopted. This view unfortunately does not detect cancer, but does help give the precise location of lesions. Another well known problem with the mammogram is its difficulties in distinguishing between normal fibrous structural components and tumor growth.
Next the paper went into different abnormalities in breasts which ranged from size abnormalities to nipple abnormalities. The paper went a step further by describing the mammographic difficulties and how to evaluate these conditions. For example, hypertrophy is a condition described by rapid growth within months and is linked to increased sensitivity to estrogen receptors responsible for growth. This can be analyzed by a craniocaudal view.
The next section of this paper covers variations in the breast density due to age, menstrual cycle, pregnancy and hormonal treatment. In terms of age, it is found that as woman age their breast density decreases, making it easier to pick up on cancer abnormalities as there is less dense tissue to block the view. In the second part of the menstrual cycle the density is increased, which decreases accuracy of the mammogram. As the breasts grow very quickly with pregnancy the glandular tissue expands. However, the density does not always increase, therefore mammograms can still be useful in diagnosis. Hormonal treatments can also change the density of breasts. These treatments usually reduce breast density, however if these treatments are implemented after a long period without hormonal prescription the density can increase.
The very last section of the paper briefly discusses the false positives associated with mammograms. The risk of false positives increases with the density of the breast from 1.7 when the breast is covered in 5-24% of dense tissue to 4.3 if the breast is covered in 65% or more dense tissue.
Analysis of the paper
From a reader’s perspective the paper was easy to read and understand. It also contained a lot of valuable information that every woman needs to know, including the general gist of the mammogram itself and how important it is in diagnoses. This paper also approached different developmental stages of a woman’s life and explained how each one changes in terms of breast density and how this affects mammograms. The abnormality section was interesting and additional information that rounded off the paper.
I found the tables useful, especially Table 4 which described the different photographic aspects of the mammogram. Another interesting table was Table 3 which gave densities of everyday entities such as water and vegetal oil as a means of comparison to understand the densities of different mammary structures. The pictures were great in the fact that they compared different types of tissues and depicted what the differences are.
So, in terms of the results I think that the facts are all nicely summarized in the tables and the pictures certainly help clarify some of the conditions described throughout the paper.