At Ascot Radiology, Auckland, mammography can be used either for breast screening or diagnosis, and also plays a key role in early breast cancer detection.
What is a mammogram?
A mammogram is a special soft-tissue x-ray of the breasts designed to detect tumors and other abnormalities. Mammography can be used either for screening or for diagnostic purposes in evaluating a breast lump. It also plays a key role in early breast cancer detection as a mammogram may detect a breast cancer before a lump is felt. Early detection and treatment significantly increases the chances of a full recovery.
Screening mammography: Screening mammography is used to detect breast changes in women who have no signs or symptoms or observable breast abnormalities. The goal is to detect cancer before clinical signs are noticeable. A screening mammogram consists of two mammogram images of each breast taken from different angles.
Diagnostic mammography: Diagnostic mammography is used to investigate suspicious breast changes, such as a breast lump, breast pain, an unusual skin appearance, nipple thickening or nipple discharge. It’s also used to evaluate abnormal findings on a screening mammogram. A diagnostic mammogram can include additional mammogram images, such as magnification and compression views.
Despite using x-rays, the radiation dose of a mammogram is very low. For most women, the benefits of regular mammograms outweigh the risks posed by this amount of radiation.
What conditions does a mammogram show?
A mammogram helps to identify the following conditions:
- Calcifications: These are tiny mineral deposits within the breast tissue. There are two categories of calcifications:
- Macrocalcifications: These are coarse calcium deposits that usually indicate degenerative changes in the breasts, such as aging of the breast arteries, old injuries or inflammations.
- Microcalcifications: These are tiny specks of calcium. When many microcalcifications are seen in one area, they are referred to as a cluster.
- Masses: These may occur with or without associated calcifications, and may be due to different causes, including the following:
- Cyst: A non-cancerous collection of fluid in the breast. Cysts cannot be diagnosed by physical examination alone or by mammography alone. Either breast ultrasound or aspiration with a needle is required. If a mass is not a cyst, then further imaging may be necessary.
- Benign breast conditions: Masses can be monitored with periodic mammography, but others may require immediate or delayed biopsy. About 80 percent of all breast changes that are biopsied are found to be benign (non-cancerous) when looked at under the microscope.
- Breast cancer.
When should I have a mammogram?
Mammograms should be performed every 1-2 years depending on your age, clinical indications and family history:
- If you are a woman over the age of 40.
- If you are a woman with a strong family history of breast cancer.
- If you develop a lump or notices a change in your breasts (if you are aged 30 and over)
- If you are a woman with a previous history of breast cancer.
The nationally funded breast screening programme, BreastScreen Aotearoa, is available for women aged between 45 and 69 years. This programme funds mammograms every two years for asymptomatic women.
How accurate is mammography?
Digitally enhanced mammograms have outstanding clarity and contrast and although most cancers can be detected by a mammogram, some cannot, especially in dense breasts. The breasts of younger women contain more glands and ligaments than those of older women, resulting in dense breast tissue that can obscure signs of cancer. With age, breast tissue becomes fattier and has fewer glands, making it easier to interpret and detect changes on mammograms. However, mammography is still the best screening technique available to date.
Before a mammogram
- You do not need a doctor’s referral for a routine screening mammogram after the age of 40. However, we do recommend that you see your GP first for a clinical examination.
- If you have a breast problem, it’s a good idea to see your GP first and obtain a referral form.
- Try to organise your mammography appointment when your breasts are likely to be the least tender i.e. the week after your period.
- Avoid using deodorants, talcum powders, lotions, creams or perfumes under your arms or on your breasts. These often contain traces of aluminum which may show up on the mammogram.
- It is a good idea to wear trousers or a skirt to the appointment, as you’ll be asked to undress from the waist up.
- Remember to bring any previous mammograms or other breast imaging with you.
During a mammogram
You’ll be asked to remove neck jewellery and clothing from the waist up and will be given a gown to wear. A specially trained radiographer will take two images of each breast. For each image, the breast is compressed for a few seconds between the x-ray plate and a clear plastic paddle. Compression is essential for better visualization of the breast tissue, and also holds your breast still to decrease blurring from movement and minimises the dose of radiation needed. You’ll be asked to stand still and hold your breath while the exposure is made and the compression is released immediately afterwards. Most women find this mildly uncomfortable but not painful. The entire procedure usually takes less than 30 minutes.
After a mammogram
Two radiologists will review your mammograms and their combined report will be sent to your doctor, usually within a week. This timeframe often depends on the availability of previous studies for comparison.
Other breast imaging techniques
These can be used in conjunction with a mammogram and clinical examination:
- Ultrasound can determine whether a lump is solid, and may need a biopsy, or if it is a simple cyst.
- An MRI scan can be performed to clarify the number of lesions within a breast and their relationship to the chest wall.
- Image-guided core biopsies can be performed on indeterminate lesions to provide information for follow-up treatment.