Oncology treatment

Oncology treatment drugs are often used in various combinations as decided by the multidisciplinary team that is treating the patient. An oncologist uses medication to fight cancer cells.

Oncology treatment plays a fundamental role in the treatment of all women presenting with breast cancer even when the breast cancer is diagnosed early and is still confined to the breast.

Hormone (endocrine) manipulation and/or chemotherapy will be used shortly after surgical treatment of early breast cancer.This will achieve a higher cure rate and is called adjuvant therapy. Adjuvant Therapy is additional cancer treatment given after the primary treatment to lower the risk that the cancer will come back. In the past couple of years, many oncologists (cancer physicians) are using such therapy even before they operate. This is called neo adjuvant therapy (primary medical treatment or induction chemotherapy). Should your doctor suggest this please see the relevant reading on the subject.

The term chemotherapy encompasses treatment with many different drugs that can be used in combination or alone. These drugs target growing cells throughout the body and are therefore very efficient in killing cancer cells that are fast growing. The drugs are given as several courses administered at intervals of a few weeks and so the treatment period may range over several months. Some drugs are given by mouth and some are given by intravenous injection.

Today more and more women receive chemotherapy as part of their treatment. A good analogy is to compare chemotherapy to antibacterial hand spray even though your hands may look clean you still clean them. It is the same with chemotherapy: we give it to sterilise the body not because we think that you have cancer elsewhere but because early breast cancer sometimes has micrometastases (tiny single cells sitting elsewhere) at the time of first presentation to the doctor.

A general guide as to who gets chemotherapy is as follows:

	most pre-menopausal women;
	all tumours greater than 1,50cm or 1cm in women fit for chemotherapy;
	all patients whose tumours have spread to one or more lymph nodes (glands);
	all patients whose tumours over express HER2neu (C erb B2 family of genes);
	tumours which are oestrogen and progesterone receptor negative
	tumour behaviour (biology) that shows signs of aggression (poorly differentiated cancers, cancers with lymph vascular invasion)

There are also different types of chemotherapy that can be used and these need to be discussed with your treatment team.

Hormone therapy is the use of drugs to target hormones. It is the second form of oncology teatment. Hormones are substances that control the normal body functions, as well as affecting some cancer cells. This is particularly true of some female hormones such as oestrogen. Some cancer patients can be treated with drugs that either contain hormones or inhibit their action. Hormone drugs are safe to use and their side effects are rarely serious and are often tolerated better than the side effects of chemotherapy. All breast cancers that show positive oestrogen and progesterone receptors should receive cancer hormone block therapy irrespective of the age or menopausal status of the patient.

Oncology options in breast cancer
Over the last 30 years although the incidence of breast cancer has increased, the mortality from the disease has decreased by over 20%. The reasons for this decrease is early detection and the use of adjuvant therapy particularly chemotherapy. Survival has been improved by the use of anthracycline regimens as well as the optimum use of taxanes and now through the use of Herceptin. The realisation that early breast cancer sometimes has micrometastases at the time of first presentation to the doctor has led to the concept of adjuvant therapy. Micrometastatic disease is present in 10%-30% of lymph node negative cancers and in 35%-90% of lymph node positive patients. This means using hormone (endocrine) manipulation and/or chemotherapy shortly after surgical treatment of early breast cancer. The goal of adjuvant chemotherapy is to eradicate any micrometastases while their overall volume is low, thus eliminating the risk of systemic relapse at a time when the tumour burden from the micrometastases is small.

There are however a subset of early breast cancers who do develop recurrences and metastatic disease. As our understanding of cancer improves we are better able to predict which patients these are. Tumour biology and bone marrow aspirates and HER2neu tests help us to work out exactly which patients with small tumours require chemotherapy.

Remember these modalities (chemotherapies) are generally not used for in situ breast cancer. Thus a core biopsy is essential, so that invasive cancer can be diagnosed. Fine needle aspiration cytology(FNAC) tells the doctor that cancer is present, not whether it is in situ or invasive.

Cytotoxic chemotherapy regimens should be discussed with patients by the cancer specialist looking at the toxicity of the treatment proposed and the patient's own beliefs and goals.

The use of a computer model such as http://www.AdjuvantOnline.com can provide accurate information for patients on the absolute reduction in the risks of relapse and death for the individual. The optimal timing of chemotherapy after surgery is not known, but currently it is recommended to start chemotherapy 4-6 weeks after surgery.

Delay of adjuvant radiation therapy due to the administration of adjuvant chemotherapy has not proven to decrease disease disease survival.

The length of time that adjuvant chemotherapy is given for is four to eight months depending on the type of chemotherapy given.

The chemotherapy is more effective when the drugs are given in combination. They are given intravenously, usually intermittently in a pulsed fashion. The most commonly used technique is as an infusion into a vein in the hand or arm through a small plastic tube called a cannula or a port is placed into a central vein (a permanent vein catheter). These drugs are generally given at intervals over a certain weeks for a period of between four and eight months.

Note that birth control measures must be used during chemotherapy. Pregnancy must be avoided as some anticancer drugs may cause birth defects, particularly during the first trimester of pregnancy (first twelve weeks).

The following chemotherapeutics are used for breast cancer in various combinations:

	Anthracyclines Doxorubicin is the anthracycline most commonly used in the USA whereas epirubicin (4’-epimer of doxorubicin ) is commonly administered in Europe and Canada .Adriamycin is one of the most active agents against breast cancer. Current data supports the use of either, optimum duration (four versus six cycles ) should be decided by your oncologist.
	CMF (cyclophospamide is an alkylating agent while methotrexate and five fluouracil are antimetabolites).
	Taxanes. This antineoplastic cytotoxic is active against breast cancer (and certain lung cancers). It appears to be highly effective and can even be used when conventional chemotherapy fails (such as the anthracyclines and the platinum based cell poisons). It interferes with spindle regeneration during cellular mitosis.
	Herceptin is not chemotherapy and it is not a hormone therapy. It is called a monoclonal antibody and is one of two innovative cancer therapies that utilise the natural immune system. In the case of breast cancer a section of DNA is different (a gene called an oncogene). This oncogene called HER2 is part of a family of genes called c-erbB-2. Each HER2 gene has a receptor on the surface of the cell. If it is "over expressed" there are hundreds more of these receptors on the cancer cells than the normal cells and they can therefore be used as a target for therapies.

Technology now exists to make antibodies in the laboratory (the normal chemicals used by the immune system to detect and attack foreign particles in the body). These antibodies have been made to detect HER2 receptors. The antibody is therefore known as anti-HER2 otherwise called trastuzumab or by its commercial name Herceptin.

Research has shown that 20%-25% of ladies have tumours that over express Her2. This can be measured on a sample of cancer taken from the breast - even if it was removed many months or years ago. In these patients it is possible to give Herceptin to attack cancer cells that may still remain in the body. In the body Herceptin finds the cancer cells wherever they may be hiding and sticks to the Her2. This then is thought to trigger a self-destruct mechanism within the cell (apoptosis). It also encourages the body’s normal immune cells to attack the tumour and there is also some evidence that it conditions the cancer cell to be more sensitive to subsequent chemotherapy. Scientific studies have shown modest responses when given to patients on its own (15% of women responded) but it has been shown to work much better when given with chemotherapy (response rate about 60%). Many trials are currently underway to establish which types of chemotherapy Herceptin should be given with and to which patients.

When given with chemotherapy the side effects normally relate to the chemotherapy (see chemotherapy). Herceptin generally does not make these worse. The only exception is if it is given in combination with chemotherapy agents called anthracyclines (e.g. adriamycin). Trials have shown that Herceptin can increase the risks of adriamycin damaging the heart. No such effect appears to occur with other drugs.

Herceptin does have some mild side effects of its own particularly related to infusion related reactions such as fever, chills and rigors, throat irritation, a runny nose and flushing or pain in the sites of the tumours. These are usually mild but can be distressing in some patients. They usually occur 30 minutes to two hours after starting the infusion and are more common after faster infusions. These symptoms can be diminished by taking a paracetamol and an anti-histamine. Many oncologists (cancer physicians) today are using such therapy even before surgery. This is called neo adjuvant therapy (primary medical treatment or induction chemotherapy).