BreastCentre Zurich

Chemotherapy is also known as cytostatic therapy. The active substances inhibit the proliferation of tumour cells, hence the name cytostatics or "cell stoppers". Chemotherapy has different aims in breast cancer. Depending on the stage of breast cancer, we distinguish between three different applications:

1. Adjuvant chemotherapy: Chemotherapy is used after the first or second operation if the tumour is confined to the breast and possibly to the axillary lymph nodes. The aim of chemotherapy is to destroy any tumour cells that may still be present in the body (so-called micrometastases or a small amount of tumour cell seeding). Studies have shown that this additional treatment is worthwhile for certain types of tumour: the risk of recurrence and mortality is reduced in both the short and long term with supportive chemotherapy compared to surgery alone. However, not all women need chemotherapy after breast cancer surgery. Chemotherapy is preferably used for young women or women with biologically unfavourable or advanced tumours. Older women can also benefit from chemotherapy. However, the prerequisite here is the absence of additional serious concomitant diseases.
2. Primary or neoadjuvant chemotherapy: Chemotherapy is given before surgery. The aim is to shrink the breast cancer. This can make breast-conserving surgery possible and destroy existing tumour cells in the body. It is therefore used for large, rapidly growing or inflammatory tumours. The advantage of this method is that we can observe how the tumour responds to chemotherapy. This gives us an idea of the tumour's sensitivity to specific chemotherapies. More aggressive breast tumours in particular often respond very well to primary chemotherapy as they grow quickly. Unfortunately, the use of chemotherapy before surgery cannot yet completely destroy micrometastases. If tumour remnants are still found in the surgical specimen after primary chemotherapy, further chemotherapy or immunotherapy is now recommended after the operation, depending on the nature of the tumour. This further improves the prognosis.
3. Palliative chemotherapy: The main aim is to reduce the size of visible metastases that have already settled in the body and to reduce the symptoms caused by the tumour. This can include symptoms such as pain, breathlessness, loss of appetite and others. In this way, we maintain your quality of life and try to prolong your life and alleviate possible pain.

With all types of chemotherapy, you will receive active substances that inhibit the proliferation of tumour cells. These are primarily substances that prevent normal cell division. The affected cells die as a result. The faster the tumour cells multiply, the more effective they are. As breast cancer cells often have a high multiplication rate, i.e. they divide quickly, they are more sensitive to chemotherapy.

Unfortunately, chemotherapy also attacks healthy cells. Its effect on healthy, rapidly dividing body tissue such as bone marrow (blood cell formation), hair roots, mucous membranes of the mouth and gastrointestinal tract explains frequently encountered side effects such as increased susceptibility to infections, hair loss, inflammation of the oral mucosa, fatigue and diarrhoea. Therefore, not every form of breast cancer can and must be treated with chemotherapy. There are also certain tumours that are insensitive (resistant) to chemotherapy.

There are different groups of cytostatic drugs that intervene in different phases of the cell cycle. The combination of different active substances and mechanisms of action increases the chance of destroying many tumour cells. The following drug classes are mainly used for breast cancer:

• Alkylants: Cyclophosphamide is one of the alkylating agents used in breast cancer. It attaches itself to the human genetic material (DNA) in the cell nucleus and either causes the DNA strands to break apart or to become closely linked. This prevents the genetic material from being passed on during cell division. Cyclophosphamide is used in breast cancer exclusively in combination with other active substances.
• Anthracyclines: Anthracyclines belong to the group of antibiotics and inhibit the synthesis of the human genome (DNA and RNA). The anthracyclines doxorubicin and epirubicin are mainly used in combination with taxanes, fluorouracil (5-FU) and/or cyclophosphamide.
• Antimetabolites: The class of antimetabolites includes fluorouracil (5-FU), one of the oldest cytostatics, capecitabine, methotrexate (MTX) and gemcitabine. They resemble the building blocks of the tumour. When building up the genetic material, these incorrect building blocks then lead to the disruption of cell proliferation. Antimetabolites are often combined with other cytostatic drugs (especially anthracyclines and cyclophosphamide).
• Taxanes: The taxanes paclitaxel and docetaxel are extracted from the yew tree and are among the most effective chemotherapeutic agents against breast cancer. Patients with involvement of the axillary lymph nodes or particularly aggressive tumours without involvement of the axillary lymph nodes benefit most in the adjuvant therapy situation. Taxanes are usually administered in combination with anthracyclines. They affect the so-called spindle apparatus, which is responsible for the exact division of the cancer cell. They also damage the genetic material and the cell wall of the cancer cell.
• Vinca alkaloids: Vinca alkaloids such as vinorelbine or vincristine are derived from the plant species pink catharanthus (periwinkle). They prevent cell division and affect rapidly dividing cancer cells in particular.

Cytostatic drugs can be administered in different ways. There are the following types:

• Monotherapies with the use of only one substance
• Polychemotherapies with the use of several substances
• Sequential therapies with the use of different substances one after the other
• Dose-dense therapies with administration of chemotherapy at shortened intervals

In the case of polychemotherapies, the combinations are usually named with the abbreviations of the first letters of the cytostatic agents used.

The chemotherapy regimens have different strengths and are selected in the adjuvant therapy situation depending on the underlying risk of relapse.

Most chemotherapies are now administered on an outpatient basis. The treatment is administered via an infusion. We usually use a vein on the side of the arm not affected by the breast cancer. Before the chemotherapy is administered, you will usually be given modern medication against nausea and vomiting.

In the case of chemotherapy that irritates the arm veins or if the veins are tender, the chemotherapy can also be administered via a so-called Port-a-Cath. This is a chamber system implanted under the skin of the chest or on the arm with a connection to a large internal body vein, which can be pierced from the outside using special needles. Piercing and administering the therapy is not painful at the port. Oral cytostatic drugs, i.e. taken as tablets, play a subordinate role.

Chemotherapies have become much better tolerated in recent decades thanks to greater knowledge and supportive medication. Nevertheless, side effects are still common. These include

• Nausea and vomiting
• diarrhoea
• Loss of appetite
• Inflammation of the oral mucosa
• Pain when swallowing
• Hair loss
• Blood formation disorders with anaemia
• Increased susceptibility to infections (immunodeficiency)
• Sensory disorders in the hands and feet (so-called polyneuropathy)
• Persistent exhaustion and tiredness
• Temporary impairment of mental functions, for example poor concentration and impaired memory
• Cardiac insufficiency due to anthracyclines (mainly doxorubicin, less frequently with epirubicin). The disorder is dose-dependent, which is why a fixed total dose of anthracyclines should not be exceeded.

The side effects occur in different sequences after therapy, sometimes rapidly, sometimes with long delays. They are usually only temporary. They are treated as well as possible, for example with medication for nausea or constipation, wig adjustments, possibly. Transfusions of red blood cells or injections to speed up the recovery of white blood cells. If the side effects are severe, chemotherapy is paused until recovery or the dose of medication administered is reduced.