An ultrasound machine uses sound waves to image parts of the body,
including breast lumps. The sound waves are transmitted through a
probe, which is placed over the breast. Lubricating gel is placed on
the breast skin to improve contact. The sound waves are reflected
within the breast back to the ultrasound machine, which transforms
them into a computer image viewed on a display monitor.
The ultrasound examination is carried out by the radiologist, who
decides whether the lump is a cyst (bag full of fluid) or a solid lump
(Figure 5). A solid lump is more likely to be a cancer, particularly
if it has irregular borders, vertical orientation and an increased
blood supply. A breast cyst can be treated straight away using a
needle and syringe.
Ultrasound is highly accurate in
distinguishing cysts from solid lumps, and in assessing the lump size.
Ultrasound examination does not usually cause pain, but occasional
mild discomfort may be experienced due to the ultrasound device
pressing against the breast. This is particularly true if the scan is
performed around the time of the period in a younger woman. Ultrasound
scan is recommended in all younger women (less than 35 years of age)
who have breast lumps.
As mentioned earlier in the section entitled Mammography (Breast
X-ray), mammograms (Figure 6) are difficult to interpret in young
women (below the age of 35). Therefore the specialist may not suggest
this test in a younger woman who has a lump in the breast, unless
there is a very strong family history of breast cancer. A cancer
usually appears as a white shadow with an irregular edge and with
breast distortion, or as fine white spots (called
micro-calcifications). It is important to know that a normal mammogram
does not exclude cancer - up to 15% of breast cancers are missed by
mammography. Digital mammography with computer-aided detection has
recently been introduced in some centres. The technology achieves
better image quality and allows easier storage, transmission and
manipulation of images.
This test is performed under local anaesthetic using a wide needle
(wider than that used in the fine needle test mentioned earlier)
to allow a larger number of cells to be collected. The test causes
more bruising than the fine needle test, but has the advantage of
distinguishing between invasive and non-invasive breast cancer.
The test is not essential in most cases as the fine needle test
is usually adequate in making a diagnosis.
If the physical examination, fine needle test, mammogram and ultrasound
scan do not detect a cancer, then the breast lump can be safely
left alone if the patient so wishes, provided that the lump is re-evaluated
in six months' time. It is the author's opinion that all palpable
lumps should be excised in women over the age of 40 to ensure that
breast cancer diagnosis is not missed. In many breast units, it
is often possible to undergo all the tests mentioned above and obtain
the results on the same day. Such clinics are called 'one-stop breast
clinics'.
