Mammography is an X-ray examination (X-ray mammography) of the female, but if necessary also of the male mamma (breast). It is currently (still) the most important imaging procedure in breast diagnostics (breast diagnostics).The breast is a symbol of femininity and for most women it is of fundamental importance for their self-esteem.Mammary carcinoma (breast cancer) is the most common cancer among women in Germany. More than 47,000 women are diagnosed with breast cancer every year. More than 17,000 women die each year as a result of the disease. A mammogram is performed for various reasons: It is used to clarify unclear findings, for example, if a lump or induration has been palpated whose cause is not clear. In women at high risk of breast cancer, mammograms can be performed regularly to detect malignant changes at a curable stage. Any change in the breast should prompt a checkup! Possible abnormalities include changes in the nipple, new differences in the size of the breasts in relation to each other, indentations of the breast, retractions of the nipple (nipple), persistent redness or unilateral secretions from a nipple (galactorrhea). The purpose of mammography is to visualize precancerous lesions (precancerous lesions) in the form of microcalcifications. The indications for screening mammography and curative mammography are presented below.
Indications (areas of application)
- Close relatives – mother, sisters, aunts – with breast carcinoma.
- Women with increased risk of breast cancer due to gene mutations (BRCA1 and BRCA2 genes).
- From the age of 25 or 5 years before the earliest age of disease of affected relatives.
- From the age of 40 at intervals of 1-2 years.
- Depending on the age of life:
- Women from the age of 50 – 69 every two years (cancer screening measures (KFEM): benefit of the statutory health insurance).
- Women from 40 – 49 years of age a “may” recommendation (grade C; United States Preventive Services Task Force (USPSTF)) depending on family history and preferences of the woman; a meta-analysis supports this decision
- Women from 45-54 years of age annually and every two years thereafter until 74 years of age (US guideline)
- Women who have been found to have mastopathy (proliferative and regressive changes in mammary gland tissue, e.g., nodular cystic mammary glands) on palpation
- Patients with unclear changes in the mammary gland – lumps, swelling, painfulness, indentations of the breast (with arms raised), galactorrhea (abnormal mammary discharge) (= curative mammography).
- Condition after breast cancer (breast cancer disease; follow-up).
Contraindications
- There are no absolute contraindications; even pregnancy is not an absolute contraindication.
- Before the age of 35, but especially before the age of 20, mammography should be performed only when strictly indicated (urgent suspicion of breast carcinoma) because of radiation exposure. In such cases, an attempt should be made to establish the diagnosis by means of a mammary sonography or a mammary MRI.
Before the examination
Please make sure you do not use deodorants or antiperspirants (“sweat inhibitors”) before your mammogram. These often contain ingredients such as aluminum, which may show up as white spots on the X-ray.A screening mammogram should be canceled if the breasts are swollen or painful.An ideal time for screening is the first half of the menstrual cycle (14 days from the end of your period), since compression of the breasts (necessary for mammography) is then less painful and pregnancy is ruled out. Gymnastics before the mammogram helps to reduce the painfulness of the mammogram during and after the examination; plugging exercises with the arms work best.
The procedure
In accordance with the quality criteria of the EU guidelines for optimized breast cancer diagnostics, a digital full-field mammography (digital mammography) is usually performed today. In this process, the X-ray photons are converted directly into electricity by the solid-state detector (crystal), which serves as the receiver, without any detour via visible light.The data captured in the detector is digitally transferred to a computer and converted to grayscale. This produces an image similar to conventional X-ray with the advantages listed below:
- Lower radiation exposure (about 40%; gentle procedure even for young women).
- No false exposures
- Better post-processing of images possible, e.g. marking and measuring (e.g. tumor size display in mm size), zooming (magnification).
- Windowing, i.e. displaying a specific area in the image with magnification, etc.
Two radiographs are taken for each breast. The breast is compressed and x-rayed once from top to bottom (craniocaudal beam path (cc) and once obliquely from inside bottom to outside top (mediolateral oblique beam path (mlo). Compression not only reduces motion blur in the image, but at the same time increases contrast and the detectability of the smallest structures. In addition, good compression reduces radiation exposure, to about half with compression of 1 cm. Self-compression of the mammary gland by the patient led to higher pressure values in examinations and immediately caused less pain. Pattern of findings on mammography: focal findings are evaluated by shape, contour, radiation density, type of calcifications (typically benign; suspicious), and distribution pattern. The American College of Radiology (ACR) has developed the BI-RADS (Breast Imaging – Reporting And Data System) classification to standardize the description of changes and therapeutic consequence [see below ACR BI-RADS Atlas of Breast Diagnostics/Guidelines].
| BI-RADS classification | Interpretation and recommendation |
| BI-RADS-0 | Diagnosis incomplete; completion of diagnosis, e.g., target images, magnification images, sonography, magnetic resonance imaging (MRI), etc., is required |
| BI-RADS-1 | No changes worth mentioning, unremarkable findings |
| BI-RADS-2 | The described changes are certainly benign. No clarification required |
| BI-RADS-3 | The change found is most likely benign (probability: 98%). To ensure the stability of the change, a control examination is required at short intervals (6 months). If there is no change in the findings during the control examination after 6 months, a further control is carried out in 6 months. If the change remains constant for 24 months, downgrading to BI-RADS-2 is performed. |
| BI-RADS-4 |
A suspicious change is found, which has no characteristic but a possible indication of malignancy (malignancy). Further subdivision is possible into.
Histologic workup by ultrasound-targeted or stereotactically targeted punch needle biopsy or vacuum biopsy/open biopsy (= surgery) is required. |
| BI-RADS-5 | High probability of the presence of breast carcinoma (carcinoma should be confirmed in at least 95% of cases). Surgical intervention is absolutely necessary, and preoperative histologic (fine tissue) evaluation by punch needle biopsy or vacuum biopsy should be performed. |
| BI-RADS-6 | Histologically (fine-tissue) confirmed breast carcinoma, prior to definitive therapy |
ACR classification describes the nature of the glandular tissue/breast assessability:
| ACR classification | Description |
| ACR 1 | (Nearly) complete involution (regression of the glandular body), i.e., the breast consists almost entirely of adipose tissue (glandular content <25%), i.e. |
| ACR 2 | Advanced involution, i.e., scattered fibroglandular condensations (glandular content 25-50%) |
| ACR 3 | Moderate involution, i.e., predominantly dense breast (glandular content 51-75%); 1 to 2 cm lesions may be missed |
| ACR 4 | Extreme density (glandular content > 75%; lesions > 2 cm may be missed |
Note: The sensitivity of mammography is significantly decreased in ACR 3 and 4. Further notes
- In young women with dense breast tissue, mammary ultrasonography (breast ultrasound) is more informative than X-ray examination – mammary ultrasonography detects up to 90% of tumors, mammography only 50%.The additional use of mammary ultrasonography – in addition to mammography – gives an additional reliability of information of about 20%.
- Mammography screening
- Mammography screening leads to overdiagnosis (including false-positive diagnoses). One study estimates the rate of overdiagnosis at about 25 percent.
- In the mammography screening in Germany in 2012 in which about 2,800,000 women were examined, including about 700,000 initial examination, about 131,000 (4.6%) were reinstated for clarification of an abnormality. In approximately 35,000 women (1.2%), a biopsy (tissue sampling) was required. In every second woman, the suspicion of breast carcinoma was confirmed (17,300 breast carcinoma diagnoses), which corresponds to approximately 6 cases of breast carcinoma per 1,000 women examined. Approx 19% of carcinomas detected were non-invasive.
- Among the precancerous lesions detected during biennial mammographic screening, ductal carcinoma in situ is the most common tumor with a high degree of malignancy. This is very significant because this tumor is biologically very aggressive and carries the highest risk of transitioning to invasive carcinoma
- A Norwegian study showed that the introduction of organized mammography screening detected significantly more low-malignant tumors, but the proportion of women with a grade III or IV tumor at diagnosis did not decrease.
- Interval carcinomas
- After false positive mammography screening results, these women are three times more likely to develop breast carcinoma in the screening interval between two mammograms compared to women with negative screening results.
- A Canadian study analyzed data from approximately 69,000 women aged 50 to 64 years with more than 212,500 screening rounds: a total of 1687 breast cancer diagnoses were made, of which 750 were screening and 206 were interval, that is, 0 to 24 months after a normal screening finding. The interval cancers were more frequently higher-grade and estrogen receptor-negative tumors than at screening; the cancer-specific mortality of the interval cancers was increased 3, 5-fold.Conclusion: more generous use of magnetic resonance imaging, if necessary. Supplemental MRI screening in women with very dense breast tissue may reduce the rate of interval cancers.
- Annual mammography screening at age 40 years resulted in 125 screening/radiation exposure-related breast cancers per 100,000 women screened, 16 of which lead to patient death. At the same time, screening would prevent 968 breast cancer deaths.Annual mammography screening at age 50 halves these risks; biennial screening frequency reduces the risk by another 50%.
- For women who have a family history of varying degrees: determine a risk-adjusted starting age for early breast cancer detection, taking into account the number of first- and second-degree relatives with the disease and the age of onset of the first-degree relatives.
- According to the fact sheet sent to women with the invitation to mammography screening since 2010, which was revised by IQWiG, one to two of every 1,000 women who participate in screening for 10 years are saved from death from breast cancer.
- According to a Cochrane review, mammography screening reduced the number of women who die from breast cancer (2,000 women without versus with screening: 11 versus 10). However, this had no effect on the total number of women who died of cancer.
- Twenty cohort studies and 20 case-control studies from Europe, Australia, and North America confirm the benefit of mammography for the 50-69 age group. According to the International Agency for Research on Cancer (IARC) study, women who regularly participate in mammography screening at this age can reduce their risk of dying from breast cancer by about 40%.
- As an aside, calcium deposits in the mammary arteries (BAC), which are prominent in screening mammograms, correlated with coronary calcium score and predicted cardiovascular risk better than other risk factors.
- Digital breast tomosynthesis (DBT), unlike conventional digital mammography (2D), produces a series of 1-mm gapless slices through the entire breast (3D imaging), allowing structures to be better highlighted without overlays; in addition to 2D mammography, it may reduce the rate of checkups. According to experts, breast tomosynthesis detects approximately 34% more breast carcinomas compared to current standard mammography screening. Further studies in this regard remain to be seen.The European Society of Breast Imaging states, “DBT improves cancer detection and reduces recall.” EUSOBI, in agreement with 30 national professional societies, sees this method as the future routine procedure for mammography screening.Radiation Exposure Note: Radiation dose from tomosynthesis is ten to 20 percent higher than mammography, but well below the limit.
- Breast lesions in the BI-RADS-3 category (see Table above: BI-RADS classification/interpretation and recommendation): in a study of more than 45,000 women, approximately 58% of cancers were diagnosed at or immediately after 6-month follow-up. The study authors conclude that follow-up at 6 months is important for this patient population.
- Magnetic resonance imaging (MRI) of the breast (breast MRI): a supplemental MRI scan in women with very dense breast tissue may reduce the rate of interval carcinomas.Note: Interval carcinomas are carcinomas that occur between the index mammogram and the scheduled follow-up interval.
The lifetime risk of developing malignancy (cancer) due to regular participation in mammography screening was 42.21 cases per million participants for a screening program in Malta. In Malta, women between the ages of 50 and 60 who participate in screening have a mammogram every three years (= 4 screening visits). In the United States, the long-term risk was 1,099.67 malignancy cases per million. This was the screening program recommended by the US National Cancer Comprehensive Network for high-risk patients. In these patients, mammography is performed annually from age 25 years to age 75 years (= 51 screening visits).In Germany, the lifetime risk is reported to be 71.45 cancer cases per million.
