Hormone therapy for breast cancer
Since many breast tumours are stimulated by the bodies own female hormone oestrogen, the aim of hormone therapy for breast cancer is to prevent these hormones from reaching the tumour. This results in stopping the malignant cells to grow. In some cases they shrivel up and die (self destruct - apoptosis). The decision to recommend hormone therapy for breast cancer as well as the choice the therapy regimens depend on the characteristics of the individual patient. A special hormone receptor test is usually performed on tissue removed the tumour (oestrogen receptor). The table below lists the most commonly used breast cancer hormone therapy regimens including full description of the drugs, how they are given, what to expect and side effects.
Therapies work in two main ways:
1. Block the production of the bodies own oestrogen - this can be done by either surgical removal of the ovaries, by blocking the production of oestrogen chemically with medication (Zoladex), or with radiotherapy. In pre-menopausal women this is called ovarian ablation. This procedure is associated with considerable side effects due to the early and abrupt onset of the menopause. ( see - coping with the menopause; Living with hot flushes)
In post menopausal women there is still some production of oestrogen from the adrenal glands. Drugs are available which block the production of oestrogen from the adrenals. These only work in post menopausal women and the most commonly used in the UK is anastrazole (Arimidex) but two others are available Letrozole (Femara) & Exemestane (Aromasin). Progesterones also reduces oestrogen levels and may have a direct anticancer effect.
2. Block the hormone receptor itself - hormones cause many changes to take place within a cell. When a hormone reaches a cell, a receptor on the cell surface 'reads' the hormone's signal. When the receptor's on the cell is blocked, it cannot be influenced by the bodies hormones and thus believes no oestrogen is present. The most well known of these receptors is called oestrogen receptor which can be blocked with Tamoxifen (receptor antagonist) others include toremefine and fasladex.
There are three main reasons why hormone therapy for breast cancer is recommended:
Adjuvant - In this situation hormone therapy is recommended to patients after their breast cancer has been removed with surgery as an added insurance policy to reduce the chance of it returning in another part of the body in the future.
Neoadjuvant - For breast cancer this is usually reserved for situations were the surgeon does not feel the tumour could be safely removed at operation with lumpectomy and has recommended mastectomy. Hormones are occasionally given first in an attempt to shrink the tumour to make it possible to operate then receive radiotherapy. This procedure is normally reserved for elderly patients.
Palliative/ primary treatment - In this situation the aim is not to cure, but to control or shrink the tumour especially if it is causing a specific symptom. For example, it is used to control disease which has spread from the breast to another part of the body (metastasised) such as bone, liver or lung.
In these latter two categories, your oncologist would require a full re-assessment of your disease at regular intervals to check whether it is working effectively. If not, the regime could be stopped or changed.
(Tamoxifen or toremefine is occasionally also given to offer protection from breast cancer to women who have a high risk of developing the disease)
Further general information Your doctors and specialist nurses are in an ideal position to give you relevant information on your disease and treatment as they know your individual circumstances. Cancerbackup has a help line (0808 800 1234) and a prize winning video available in English, Italian, Urdu, Bengali, Gujarati & Hindi explaining Radiotherapy & Chemotherapy. Cancernet.co.uk has over 500 pages describing cancer, its management, practical tips and tool which patients, their carers and their doctors have found helpful during the cancer journey.