Harms of Mammograms?


Mammograms, like all x-rays do transmit radiation and theoretically, this radiation in large enough doses could cause cancer. However, there has never been any proof that patients receiving x-rays or mammograms have developed cancers from the radiation. The radiation dose from a mammogram is miniscule(less than the radiation you are exposed to living in Johannesburg for one year).

The theoretical likelihood of getting a breast cancer from mammograms is 1 in 70,000. Your chance of getting a breast cancer during your lifetime (with or without mammograms) is 1 in 8. Clearly the benefits of early detection of such a common and treatable cancer outweigh the remote theoretical risks!

There is also a bizarre theory that the compression of the breasts during a mammogram will create a cancer or cause a cancer to disseminate. This concept is without any scientific reasoning

One of the biggest criticisms of screening mammograms , both from the lay and medical press, is that of overdiagnosis. In other words, the allegation is that mammograms pick up too many cancers and since many of those cancers will either regress or remain static, many patients undergo unnecessary treatment some of which is harmful.

None knows the exact figure for overdiagnosis. It is generally based on assumption, not fact. Despite some claims of 30 – 40% of breast cancers being called “harmless” and therefore diagnosed unnecessarily, the real figure is probably closer to 2 – 3%. There has never been a documented case of spontaneous breast cancer regression. And although some cancers are very slow growing, we cannot know which without at least doing a biopsy and pathology tests.

Treatment these days is dependent on the type of cancer as diagnosed with biopsy. Cancers which are high grade, hormone receptor negative and rapidly growing are treated more aggressively, while low grade hormone responsive, slow growing cancers are treated less aggressively.

Mammograms are not compulsory. They are elective. If as an informed adult, you choose to have mammogram screening, you are electing to find out if you have a cancer, slow growing or fast. The diagnosis isn’t the point. It’s a question of overtreatment or not. The treatment decided on must be appropriate for your type of cancer. And that is largely dependent on detailed pathology and astute breast surgeons and oncologists.

Lastly, we know that mammogram screening has reduced death from breast cancer by ±30%. That’s a well proven fact. The supposed harm from overdiagnosis is largely hypothetical. Not to say treatments such as mastectomy, chemotherapy and radiation aren’t without risks or complications. However, death and severe disability for modern breast cancer treatments are negligible.  The benefit  : risk ratio is pretty clear.

No. Mammograms do NOT cause thyroid cancer. The radiation from a mammogram is extremely low and insignificant dosages reach the thyroid gland. We certainly do not see increased rates of thyroid cancer in women who have had many mammograms. Although there is an increase in thyroid cancer numbers this is for men too (who are not receiving mammograms!)

A thyroid shield is unnecessary and may effect the quality of the mammogram

It is extremely important for women over the age of 40 to have regular mammograms. If the mobile mammogram service is your only opportunity, then by all means, have your mammogram with them.


Mobile mammograms. An excellent initiative but not as comprehensive or accurate as mammograms and sonars performed in a specialist department with doctors on-site

There are, however, many reasons that having your mammogram in a dedicated specialist department is better than in a mobile unit;

Most mobile units use the older 2D mammogram machines. This is significantly inferior to the new 3D Tomo machines in terms of cancer detection.

Having your mammogram in the same department every year allows the radiologist to compare old and new images. This is very important when it comes to detecting early cancer changes.

Breast Ultrasound – in most specialist departments an ultrasound is done with every mammogram. Mammograms cannot pick up every cancer. In fact they pick up only ±70% of cancers at best. In women who have dense breast tissue - ±50% of the population – mammograms are even less effective, picking up only 30 – 40% of cancers. To compensate for this, we do ultrasound exams of the breasts on every patient. The combined tests can pick up 80 – 90% of cancers! The ultrasounds are performed immediately after the doctor has assessed your mammogram.

Mammogram: No cancer visible due to dense breast tissue


Ultrasound clearly shows a large cancer (2,6cm)


Personal interaction with a specialist breast radiologist. Your questions and concerns are addressed face-to-face by a medical specialist with many years of experience in breast cancer detection. Any abnormalities on your mammogram or ultrasound are discussed straight away. No delay getting results!

Procedures that need to be done eg biopsies (sampling of breast lumps to tell if they are cancerous) and cyst aspirations are done in the same department by the same doctor who has done your mammogram and ultrasound.
If further tests such as a breast MRI is needed (certain difficult cases), they are referred within the unit and again, interpreted by the very same breast radiologists.

If cancers are found, you are already in the system. The radiologists are part of a highly experienced multidisciplinary breast cancer team – breast surgeons, oncologists, pathologist and plastic surgeons. Your case goes immediately through to this team who ensure that you receive the very best level of care available.

No extra cost!! The addition of a 3D mammogram, sonar and specialist doctor consultation are all included in the same tariff.(medical aid rates apply). It costs the same as a mobile mammogram that lacks all of the above ..