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Adjuvant treatment for breast cancer patients

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VOL: 96, ISSUE: 49, PAGE NO: 34

Victoria Harmer, RN, BSc, AKC, is breast care nurse specialist, St Mary’s Hospital, London

As new evidence emerges, the indications for different treatments change. Currently, the management of breast cancer not only involves discussion about surgery but also on the adjuvant modalities: radiotherapy, chemotherapy and endocrine (hormone) therapy.

 

As new evidence emerges, the indications for different treatments change. Currently, the management of breast cancer not only involves discussion about surgery but also on the adjuvant modalities: radiotherapy, chemotherapy and endocrine (hormone) therapy.

 

 

These additional treatments are necessary because even if the cancer appears to be in one site only, there may be less visible malignant or premalignant areas in the breast. It is also a frightening fact that in about 70% of cases, micrometastases are likely to have spread to other parts of the body by the time the cancer has been diagnosed (Baum et al, 1994).

 

 

Radiotherapy
Patients with breast cancer who have had a wide local incision, which is known as a lumpectomy, are usually offered radiotherapy to treat the rest of the breast tissue. Without this there is a high risk of local recurrence, even if histological reports suggest that complete excision has been achieved (Tschudin, 1988).

 

 

The effectiveness of radiotherapy was first noted in the late 1890s. It is a local therapy that uses ionising radiation to destroy cells by disrupting their chemical structure, leading to damage and ultimately cell death. When the ionising radiation reaches the targeted tissues, it causes the atoms in the tissues to lose or gain an electron. This destabilises the atoms, leading to secondary reactions that destroy the cellular structure and function through interactions with DNA. Complete inhibition produces sterile cells that cannot divide (Holmes, 1996).

 

 

Radiotherapy can also damage normal cells, but these are more capable of repairing themselves and can do so more quickly than malignant ones. However, neither normal nor malignant cells can recover from total damage.

 

 

Radiotherapy is given in fractions of small daily doses. This ensures that normal cells have an opportunity to repair themselves while the cancer cells are killed off. It is usually given through a linear accelerator machine, which penetrates deep into the tissues while sparing the skin. Brass wedges may be used to alter the shape of the beam as required and protect the underlying vital organs - the lungs and heart (Bates and Evans, 1995).

 

 

A radiotherapy planning session will be held before treatment and usually takes about an hour. The patient is marked or has small permanent tattoos on the chest to enable speed and accuracy when setting up the treatment, which is usually given five days a week for four to six weeks. In the last week, booster treatment is given during which the specific site of the original tumour receives particular attention.

 

 

If an axillary node clearance has been performed, showing few or no nodes containing cancer cells, radiotherapy will not be given to the axilla as it can result in unnecessary damage to the blood vessels and nerves already compromised through surgery (Bates and Evans, 1995). However, if the axillary lymph nodes have been grossly invaded, radiotherapy may be prescribed to the axilla, the nodes in the supraclavicular fossa and also the chest wall (Maher Committee, 1995).

 

 

Radiotherapy is usually fairly well tolerated, even by elderly patients, but may be associated with fatigue and depression. This is generally the result of a combination of factors, including psychological distress as a result of the diagnosis, fatigue as the body tries to repair itself and the impact of daily journeys to hospital. Other side-effects involving the skin may include red, sore and weepy areas, fibrosis, tightening, atrophy and pigmentation.

 

 

During a course of radiotherapy, the patient should therefore take special care of the skin around the radiotherapy field, with only creams and soaps they have been advised to use as some scented products can increase the possibility of reactions and pain (Sampson and Fenlon, 2000).

 

 

Chemotherapy
Cytotoxic chemotherapy can be distressing and has arguably the worst reputation of all the treatment modalities available for breast cancer (Fallowfield and Clark, 1991). However, a meta-analysis of all patients who have taken part in chemotherapy trials is available to support therapy decisions.

 

 

Chemotherapy can decrease the risk of dying from breast cancer by 25%. If a patient has an 80% chance of dying of breast cancer, chemotherapy will reduce this risk to 60%. However, if the patient has a 10% chance of dying, chemotherapy will reduce the risk to only 7.5%. For this reason, patients with a good prognosis and a low risk of dying from breast cancer are not usually advised to have chemotherapy.

 

 

Chemotherapy damages the reproductive integrity of cells, with various groups of drugs targeting the different stages of the cell cycle (Fig 1). A combination of drugs is therefore usually used, with administration synchronised with each phase of the cell cycle (Souhami and Tobias, 1995).

 

 

Chemotherapy can damage normal cells but, as with radiotherapy, they take less time to recover than cancerous cells and the treatment is ‘pulsed’ to ensure optimum damage to the cancer cells. Each cycle of chemotherapy usually takes place three weeks after the previous cycle, causing damage in the G2 and M phases of the cell cycle (Fig 1).

 

 

Most cytotoxic drugs are given intravenously through a secure drip line administered by a pump, although some chemotherapy drugs can be taken orally. It is a systemic treatment that affects the whole body to various degrees and is used to mop up micrometastases. Only years of controlled trials and systematic reviews can demonstrate the effectiveness of these drugs, and new therapies are likely to emerge as evidence of their effectiveness grows.

 

 

During chemotherapy treatment patients may have gastrointestinal upsets such as nausea, vomiting, constipation and/or diarrhoea. They may also become tired, develop pyrexia and, as the bone-marrow cells deplete in number, suffer from neutropenia.

 

 

Some chemotherapy agents can cause long-term side-effects including depression, loss of libido or fertility problems, pulmonary fibrosis, heart disease and liver and renal toxicity, as well as hair loss, although this is temporary (Denton, 1996).

 

 

The older patient are, the less likely they are to benefit from being treated with cytotoxic drugs and the more likely they are to have side-effects (Sampson and Fenlon, 2000).

 

 

Chemotherapy can be administered preoperatively (neoadjuvant). Initially, it was hoped this would result in improved survival rates, but the evidence has not shown this to be the case. However, it can shrink the tumour to such a degree that a breast-conserving operation may be possible (Baum et al, 1994).

 

 

By promoting an understanding of the biological basis and indications for chemotherapy, patients may be counselled and helped with their choice of treatment/management.

 

 

Endocrine (hormone) therapies
Some cancers have receptors for sex hormones and their growth is partly dependent on hormonal stimulation. These are known as the oestrogen receptor (ER) positive and/or progesterone receptor (PR) positive cancers. When a hormone reaches the cell it enters by diffusion. The hormone then binds with a protein and crosses the nucleus to stimulate growth.

 

 

In the first half of the last century, many hormone agents were used in an attempt to modify the course of breast cancer. These had considerable side-effects, including the development of male secondary sexual characteristics, fluid retention and vaginal bleeding.

 

 

The development of tamoxifen and anastrozole have changed hormone treatment for the better. Tamoxifen, which is taken once a day for five years, can produce side-effects but these tend to be short lived. For example, younger women may experience unpleasant hot flushes. Gamolenic acid in evening primrose oil, clonidine and, more recently, drugs such as fluoxetine have been shown to ease this.

 

 

Vaginal dryness may also occur, but the most serious side-effect of tamoxifen is endometrial carcinoma, or cancer of the lining of the uterus. Although rare, it is important that women who are taking tamoxifen are warned not to ignore unusual or postmenopausal vaginal bleeding.

 

 

As the presence of oestrogens can stimulate the growth of ER-positive cancers, premenopausal women may be offered an o[op6]phorectomy. This can be done through surgery or radiotherapy to the ovaries.

 

 

However, there are also drugs that temporarily stop the ovaries from working, for example, goserelin. Given every month, usually subcutaneously by injection, their effect is reversible. They may cause side-effects such as hot flushes but these are rare (Denton, 1996).

 

 

Nurses caring for patients who are receiving hormone therapies should be aware that they can result in early signs and symptoms of the menopause. Women who have already had one blow to their sexuality and femininity from surgery to the breast may again feel challenged and less feminine. Nurses should therefore create opportunities and allow time for patients to discuss these feelings.

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