BREAST CANCER: DIAGNOSTIC INVESTIGATIONS CARRIED OUT

Ultrasonography

Ultrasonography – also known as ultrasound – is another imaging technique which, rather than using X-rays, involves passing high-frequency sound waves into the breast. It is the same process as that used for fetal scanning in pregnant women. When the sound waves meet a solid object within the breast, they are reflected back like an echo. The waves are processed by a computer, and a picture can be built up which is displayed on a screen and interpreted by someone trained in ultrasonography. The picture will show the normal glandular tissue and fat quite clearly, as well as any prominent ducts, cysts and tumours. Ultrasound is particularly useful in differentiating between fluid-filled cysts and solid lumps, and ideally should be used with mammography and fine needle aspiration to distinguish clearly between the two. It is the imaging investigation of choice when breast lumps are suspected in women below the age of 30. However, its use is not routine as it is a time-consuming process, is not able to detect calcium deposits, and its results are operator dependent.

Biopsy

Diagnosis of a breast lump often used to involve the surgical removal of a small piece of tissue. Although this is occasionally still necessary, there are now other techniques which can normally be used instead, which do not require a general anesthetic, and which can often be done by a surgeon at an out-patients’ clinic.

Fine needle aspiration biopsy

Fine needle aspiration is a cytological examination (i.e. one which involves the examination of cells) which is often helpful in confirming the diagnosis of a non-malignant tumour or cyst. However, although it can confirm that a suspicious lump is a cancer – and when a cancer is present it is rare for it to be missed using this technique – a negative result does not necessarily mean that it is not: the needle may have been inserted into normal tissue around a malignant tumour. Further tests may therefore be done to confirm a negative result.

The skin is usually wiped with an alcohol wipe prior to inserting a fine needle – about the same size as one that would be used to take blood from the arm – through the skin of the breast. The needle is repeatedly pushed into the lump, which the surgeon holds firmly between the fingers. Suction is applied to a syringe behind the needle and a few cells from the lump are sucked up through the needle and into the syringe. This sample of a small number of cells is then spread on a glass slide which is sent to the laboratory for examination under a microscope by a cytologist. Malignant and pre-malignant cells can be identified, as well as those from a benign lump or from normal breast tissue. Fluid aspirated from a cyst will also be sent to the laboratory in a bottle if it is at all suspicious.

You will be asked to press on the area once the needle has been withdrawn. This is simply to try to prevent serious bruising – which usually occurs despite this precaution and may last for several days or more. Therefore, as needle biopsies may cause swelling and bruising of the breast which may make palpation difficult and a mammogram unclear, they are better not done by a GP before a clinic visit.

Although a small minority of women does find the procedure painful, it is usually only uncomfortable. Local anesthetic is not used as it would destroy the cells the cytologist needs to make a diagnosis.

A non-palpable breast lump, i.e. one which cannot be felt, can be localized by ultrasound or by mammography using a special mammographic attachment which can guide the needle into the lump.

Tru-Cut biopsy

This is a histological examination which involves taking a slightly larger sample of solid tissue rather than cells. It is sometimes done when a fine needle aspiration biopsy of a palpable lump has proved unhelpful. It is used less commonly today than in the past, although some surgeons routinely perform Tru-Cut biopsies for all suspicious breast lumps.

The needle is of a wider bore than that used for fine needle aspiration, and it has another needle within it. Local anesthetic is usually used for this procedure, a small amount being placed into the skin over the site of the suspicious breast lump before the Tru-Cut needle is inserted. A long, very thin core of tissue is then removed as the needle is withdrawn, and is sent to the laboratory to be examined under a microscope.

Although a Tru-Cut biopsy is quite an accurate process, the tissue sample can only be taken from one site, and it is therefore possible for the needle to miss the appropriate part of the lump when it is inserted. This biopsy is more traumatic to the breast than a fine needle aspiration, and it is gradually being replaced by this cytological test.

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