Introduction to breast disease

Virtually every woman with a breast lump, breast pain or discharge from the nipple fears she has cancer. The anxiety results from the unknown course of the disease, the threat of mutilation and the fear of dying. This has often prevented women from seeking medical advice, but publicity about self-examination and screening (see Ch. 6) and the potential benefits of early treatment has encouraged earlier presentation.

Anxiety may be heightened by friends’ or relatives’ experiences of breast cancer or a recent ‘celebrity diagnosis’; for this reason, reassuring the ‘worried well’ is important. The effects of breast surgery on attractiveness and femininity must be considered; breast care nurses can provide psychological support throughout investigation and treatment.

Rates of referral to breast clinics have increased, reflecting easier access, widespread breast screening and public awareness of breast cancer. Despite the fears of those referred, in the UK less than 15% prove to have cancer. The rest include benign breast conditions and others within the normal range of anatomy and physiology (see Box 45.1).

Anatomy of the female breast

The breast consists of 15–20 lobes containing lobules linked by ductules that combine to form ducts. The glandular tissue is supported by fibrous tissue connected by Astley Cooper’s ligaments and lies over pectoralis major and minor. It is supplied by branches of the axillary and internal mammary arteries. Lymph drains primarily to the axillary nodes.

Special points in history taking

A detailed history can provide important clues to the pathology of a breast problem. Age alters the probability of different breast disorders (see Fig. 45.2); in particular, the risk of malignancy rises with age. The duration of symptoms should be established at the outset; cancers are usually slow-growing, whilst cysts can appear rapidly, sometimes almost overnight. Benign conditions such as fibroadenosis and fibroadenoma may present with lumps that fluctuate with the menstrual cycle or have decreased in size since first noticed. They are also more likely to be painful and tender than a malignant lesion.

A previous history of breast conditions, particularly malignancy, cysts or fibrocystic change, can be an indicator of the nature of a current breast problem. The greatest single risk factor for breast cancer is a previous history of the condition, however long ago (1% risk per year) (see Box 45.2). There is some evidence that patients with recurrent benign breast disorders are more liable to cancer.

Trauma from seatbelt injuries is common and patients should be asked whether bruising of the breast was followed by the appearance of a lump.

Drug history, particularly of the oral contraceptive pill (OCP) or hormone replacement therapy (HRT), should be recorded, including the duration and how recently the drug has been used. These drugs modulate the hormonal environment of breast tissue and tend to increase the risk of breast cancer. Other hormone-related risk factors for cancer include late age at first full-term pregnancy, lower parity (number of pregnancies) and early age of menarche and late age of menopause. Enquiry should be made about a family history of breast or ovarian cancer, including number of first- and second-degree relatives, age of onset and bilaterality. Some families have mutations in the tumour suppressor genes BRCA1 or BRCA2, which strongly predispose to breast and other cancers.

Examination of the breasts

There are several accepted methods for examining the breasts; one is shown in Figure 45.3. All areas of the breast must be examined, with particular attention to the axillary tail and retro-areolar regions. Breast examination involves six distinct manoeuvres:

During inspection, the signs to be looked for are listed in Figure 45.1.

Palpation may be done circumferentially using the flat of one hand, starting at the nipple then moving in progressively larger circles; radially from the nipple outwards like the spokes of a wheel; or by sectors, examining each quadrant in turn. Axillary lymph nodes are palpated whilst the examiner’s other hand supports the patient’s arm (Fig. 45.3g, h). This helps relax the muscles and aids assessment of the nodal groups (medial, lateral, anterior, posterior and apical). Note that clinical assessment of axillary nodes is unreliable, with a 30% false positive and a 30% false negative rate.

A history of nipple discharge can often be confirmed by pressure over the appropriate sector near the areola. Discharges not obviously blood-stained should be tested for blood using urinalysis dipsticks. In all cases, a smear preparation should be examined for cytological abnormalities.

Imaging

Mammography (breast radiography) is an important method of radiological assessment of the breasts. In women over 40 years, it has a sensitivity of 88% for carcinoma. It is less sensitive in younger women because the breast tissue is denser, and is rarely performed below 35 years.

During mammography, the breast is compressed firmly in the machine. This spreads the tissue to an even thickness to give correct exposure for all the breast tissue to make it easier to detect any mass lesion. Radiological views are taken in two directions, medio-lateral oblique (MLO) and cranio-caudal (CC). Localised compression views can reduce the problem of superimposed structures simulating a mass. Focused magnified views can better display any abnormal area. Full digital mammography, which permits post-processing enhancement of the image, has nearly replaced film mammography.

Features looked for on a mammogram include:

A typical carcinoma appears as a spiculated mass lesion (dense centre with radiating lines) which may have malignant-type fine linear or granular microcalcification (Fig. 45.5). Fine granular microcalcification within a spiculate lesion is virtually pathognomonic of cancer. Tumours as small as 2–3 mm are sometimes detectable radiologically, long before they become palpable.

Benign-type microcalcification is coarse and ‘chunky’ (Fig. 45.6). Fine branching microcalcification is characteristic of ductal carcinoma-in-situ (DCIS). Architectural distortion and asymmetry are subtle radiological signs but should be viewed with suspicion.

Ultrasound has long been used to distinguish solid lesions from cysts and has a specificity of 100% for this. Modern B-mode ultrasound demonstrates breast anatomy in great detail and is complementary to mammography. Benign lesions can be distinguished from malignancy with a sensitivity for cancer of at least 85%. Ultrasound can accurately measure the size of a cancer (Fig. 45.7) and can guide percutaneous needle biopsies and cyst aspiration (Fig. 45.8).

The strength of breast imaging comes from performing mammography and ultrasound together as the physical characteristics tested by the two techniques are different. The information acquired by mammography results from attenuation of the X-ray beam through breast structures whilst ultrasound tests the reflectivity of a pulsed ultrasound beam (of about 12 mHz) caused by subtle attenuation changes at tissue interfaces within the breast.

Biopsy

Most palpable and all non-palpable image-detected masses are biopsied under image guidance, as are suspicious areas of calcification. Fine needle aspiration cytology (FNAC) specimens are rarely used for tissue diagnosis now (see Box 45.4). FNAC has a sensitivity of 95% for detecting malignancy but cannot distinguish between in situ and invasive cancers. By contrast, core biopsy has a sensitivity of 98%. The tissue architecture is preserved so that invasion can be confidently diagnosed on histology and tumours can be pathologically graded. After core biopsy patients need to return later for the results as the pathology has to be read after the specimen has been fixed. This has the advantage that any bad news can be broken in a phased manner. If needle biopsy is negative or equivocal, a discrete lump should be completely excised with a wide margin of apparently normal breast tissue and the specimen examined histologically. This procedure, excision biopsy, can also form the first step in controlling local disease.

Eczematous lesions suspicious for Paget’s disease of the nipple can be ‘punch’ biopsied under local anaesthesia in the clinic.

Introduction

In Western societies, breast cancer is the leading cause of death in 35–55-year-olds. About 1 in 10 women will develop breast cancer (i.e. a lifetime risk of 10%) and 1 in 18 will die from it. In the UK, 25 000 new cases are diagnosed annually and 15 000 women die each year. Worldwide, there are about half a million deaths from breast cancer annually but despite an increasing global incidence, mortality rates have gradually fallen with earlier diagnosis and improved treatments, including advances in hormonal therapy.

Risk factors