Mammography is the examination/study of breasts by a specific type of imaging that uses low-dose x-rays and the procedure is called mammogram, which is used to aid in the early detection and diagnosis of breast diseases in women.Common Uses of Mammogram
Mammogram is used as a screening test to detect early breast cancer in women experiencing no symptoms and to detect and diagnose breast cancer in women with a lump or pain in breast/s, or nipple discharge. The two basic applications of mammography are screening and diagnosis of breast cancer.Screening Mammography
Mammography plays a major role in early detection of breast cancer because it can show changes in the breast up to two years before a patient or physician can feel the changes. Current recommendations are that screening mammography should be done every one to two years for all women, beginning at the age of 40 years. Women who have had breast cancer and those who are at increased risk due to a genetic history of breast cancer should begin screening before the age of 40 years. Diagnostic Mammography
This is used to evaluate a patient with abnormal clinical findings, such as a breast lump/s that have been detected by the woman or her doctor. Diagnostic Mammography can also be done after an abnormal screening mammogram in order to evaluate the area of concern on the screening exam.Conditions that require attention & evaluation
- Any new discreet lump
- New lump in pre-existing nodularity
- Nodularity that persists at review after menstruation
- Cyst, persistently refilling or recurrent
- If associated with a lump
- Intractable pain, not responding to reassurance or simple measures such as wearing a well-supporting bra and common pain killing drugs
- Unilateral (one sided) persistent pain in post (after) menopausal women
3. Nipple Discharge
- In all women aged 50 years and above
- In women under 50 years of age with bilateral discharge sufficient to stain clothes, blood-stained discharge or persistent discharge from a one side nipple.
4. Changes in skin
5. Family history of breast cancerPreparation for Mammogram
- A clinical examination of the breasts is advisable before imaging
- The patient should discuss any new findings or problems in their breasts with their doctor. History of any prior surgeries, hormone use, and family or personal history of breast cancer should be noted.
- The ideal time for mammogram is one week following menses, as the breasts are usually tender (painful) before the periods
- Make sure that the patient is not pregnant
The American Cancer Society also recommends the following for women undergoing mammogram:
- Do not use deodorant, talcum powder or lotion under your arm or on your breasts on the day of the examination, as these can appear on the mammogram as calcium spots
- Describe any breast symptoms or problems to the technician performing the examination
- If possible, obtain prior mammograms (if done in the past) and make them available to the radiologist at the time of the current examination for comparison
- Ask when your results will be available; do not presume that the results are normal if you do not hear from your doctor or the mammography facility
Benefits Vs Risks
- An x- ray machine is used to produce a small burst of radiation that passes through the body. Bones appear white on the x-ray, soft tissues show up in shades of grey and black
- During mammography, a specially qualified radiology technician will position the breast in the mammography unit. The breast will be placed on a special platform and compressed with a paddle. The technician will gradually compress the breast.
- For suspected malignancy (cancer), mammography with two views (mediolateral oblique and cranio-caudal projections) of each breast should be performed
- Ability to detect small tumours
- Detection of tumours not felt by either the patient or physician
- No radiation remains in a patient’s body after an x ray examination
Radiation risks in Mammography
- A slight or very negligible chance of cancer from exposure to radiation exists, but the benefits of an accurate diagnosis far outweigh the risk.
- False positive (no tumour yet test comes positive) mammograms – 5% to 15% of screening mammograms may require further investigations.
- False negative (tumour present yet test comes negative) mammograms – can occur in women with denser breasts, usually in younger women.
Limitations of Mammography
- The risk of a radiation-induced cancer for a woman attending mammographic screening is about 1 in 20000 cases
- An absolute risk in women over the age of 35 years of 0.4 to 0.7 excess cancers per million women per year per screening examination. In women 40 to 49 years, the benefit is anywhere from 40 to 80 times greater than the risk. In woman aged 50 years and over, the benefit to risk ratio is more than 100:1
Recent advances in Mammography
- In suspicious cases, further diagnostic studies are needed
- Interpretation of result can be difficult because a normal breast can appear differently in different women
- Not all breast cancer can be detected by mammography
- Breast implants can also impede (obstruct) accurate mammogram readings
These are digital mammography and computer- aided detection.
Digital MammographyWhat is BI-RADS?
Also called full field digital mammography (FFDM), is a mammography system in which the x-ray film is replaced by solid state detectors that convert x-rays into electrical signals. The images of the breast can be seen on a computer screen.
Computer- aided detection (CAD) in mammography
CAD systems use a digitized mammographic image that can be obtained from either a conventional film mammogram or a digitally acquired mammogram.
It is a uniform way for radiologists to standardize reporting of mammogram findings. The system called Breast Imaging Reporting and Database System includes seven standardized categories or levels.
Level 0–Incomplete; 1-Negative; 2-Benogn findings; 3-probably benign; 4-suspicious abnormality; 5-highly suspicious of malignancy; 6-known biopsy with proven malignancy