Mammography
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ultrasound | mammography | mri

Mammography

 

This is simply a special type of x-ray of the breasts. It has three main indications:

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To show the features of the breast lump (is it cancer?).

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To show if there are any other concerning features in the breast that the patient or the doctor cannot feel - this is called searching for an "impalpable lesion".

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To screen for breast cancer (to detect early breast cancer before a lump becomes palpable).

 

Method
Two compression (breast flattening) views of each breast are taken. It is a relatively safe investigation, as the amount of irradiation to the patient is minimal (less than 0.2 cGy of radiation). A ballpark figure of risk of actually getting a new breast cancer as a result of this irradiation is one breast cancer per one million mammograms per year, with a latent period of ten years or more for the cancer to become evident. This shows that mammography is a safe procedure and the benefit far outweighs the risk involved. We are exposed to more radiation in our environment than with mammography.

The accuracy of mammography increases with age and it is not used for  women under thirty-five years old unless for specific indications. In young women, the breasts are dense, due to the presence of florid glandular tissue and ducts. After forty years, the breast glands and ducts are replaced by fat, which is radiolucent and thus promotes satisfactory mammography. This means that cancers are easier to detect in fatty breasts, using mammography.

 

The features of breast cancer on a mammogram are:

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Dense rounded mass with radiating spicules (small spikes). It should be noted however that a benign condition called a radial scar can also have this appearance, and biopsy is mandatory to differentiate these two conditions.

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Small regions of calcification (micro calcification).

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Areas of linear (line) or punctuate (point) calcification.

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Distortion of the breast architecture.

The mammogram machine  must be of excellent quality, to help the doctor make the correct assessment. The radiologist needs the best available equipment, including high quality x-ray films. It is important to look for a centre which specialises in mammography when choosing a place to go for this investigation.

 

Screening
Screening mammography is recommended annually for all women of forty years and older. Screening will pick up the impalpable breast cancer. It has been shown in extensive studies in the United Kingdom, the USA, Europe and Canada, that regular screening reduces mortality from breast cancer by about 20%. This is a very significant figure and it supports this approach. Many recent reports have looked at the negative impact of mammography and questioned whether it alters survival.

 

There is an enormous body of consistent evidence on the relationship between tumour size, disease stage, and survival. As tumours increase in size the likelihood of nodal involvement and distant metastases increases and this  is associated with a poorer prognosis. Strong evidence suggests that tumours detected on mammography are smaller in size than palpable tumours. Poor quality of mammography can result in a decrease in identifying tumours and result in the implication that mammography misses breast cancers.

 

These small mammographically detected cancers may be treated with breast conserving surgery or mastectomy with immediate reconstruction. Screening requires both a clinical examination by a physician and mammography.In a country with limited resources like South Africa, free screening all women is not possible or cost effective. The more people who go for screening mammography, the cheaper it is to run mammogram units.

 

Under ideal circumstances, annual screening for all women over forty is recommended. A baseline mammogram between 35 and 40 followed by a mammogram every year or two for women is recommended.

In those women with a family history of breast cancer screening should start 10 years before the youngest relative developed a breast cancer.