The standard cancer treatment, chemotherapy is based on the use of different drugs in a personalized treatment protocol. This “chemical cocktail” attacks cancer cells either by destroying them or by blocking their multiplication. But because it also affects healthy cells, its side effects are not trivial. However, increasingly targeted treatments make it possible to reduce them.

Chemotherapy is one of the basic treatments for cancer. It consists of administering different drugs that will act either by killing cancer cells or by preventing them from multiplying.

Different molecules are used in chemotherapy, often in combination (multidrug therapy). They fight cancer with different mechanisms of action. Some affect the synthesis or function of DNA, preventing them from dividing; others interact with RNA and proteins. There are thus 4 main classes of chemotherapy drugs according to their mode of action:

• DNA modifiers, among which topoisomerase inhibitors, topoisomerase II inhibitors, anthracyclines (which intercalate in the DNA cell);
• the spindle poisons, which work by blocking the formation of the chromatic spindle allowing the separation of chromosomes during mitosis, thus preventing cell division;
• alkylating agents, which hinder the processes of replication and transcription of DNA by producing covalent lesions between the strands of DNA by an alkylation effect (a hydrogen proton is replaced by an alkyl group, non-functional). For example: Cyclophosphamide, Ifosfamide, Melphalan, Busulfan.
• antimetabolites, which act by inhibiting the synthesis of nucleic acids, the first step necessary for any cell multiplication. Some antimetabolites: methotrexate, 5-fluorouracil, pyrimidic analogues, Tégafur, Capecitabine, Azacitidine…

The vast majority of these molecules are administered intravenously; others orally, by intramuscular or subcutaneous injection.

Chemotherapy is currently experiencing two major trends:

• the development of oral chemotherapy;
• precision medicine, with personalized treatments based on the analysis of the biological and genetic characteristics of the patient’s tumor.

Chemotherapy sessions take place in conventional hospitalization (at the start of treatment for example or during intensive chemotherapy), on an outpatient basis or at home (HAD).

The treatment protocol is personalized: the molecules and their dosage, the number and frequency of sessions depend on the type of tumor, its stage, the general state of health of the patient, his age, the response of the organism to this treatment. Some chemotherapies are daily (especially those taken by mouth), others once a week, every 15 days, etc. The duration of the session varies from 10 minutes to more than 72 hours for the longest sessions.

The term “cycle” is used to refer to the period comprising the days during which the treatment is actually administered and the “rest period” to the days during which the treatment is not delivered. This rest period is essential so that healthy cells have time to renew themselves. The number of cycles of chemotherapy also varies depending on the type of cancer and the patient. Consultations are planned throughout the treatment in order to monitor the progression of the disease and the tolerance of the organism, and adapt the therapeutic protocol if necessary.

Medicines are usually administered intravenously. To avoid having to prick the patient at each chemotherapy session, a catheter or an implantable chamber (in a vein located in the neck) can be put in place throughout the treatment. Additional treatments can be given, before or after the infusion, to limit the side effects.

A pillar of anti-cancer treatment, chemotherapy is used in many cancers at different stages.

According to a report on cancer chemotherapy in France, in 2014, five types of cancer combined nearly 87% of stays and sessions for / with chemotherapy:

• cancers of the digestive system: 26,7%;
• breast cancer: 21,9%;
• hematological cancers: 18,3%;
• cancers of the respiratory system: 12,6%;
• gynecological cancers: 7,0%.

Chemotherapy can be used alone or in addition to surgery (tumor removal or tumeroctomy). We then distinguish:

• neoadjuvant chemotherapy : performed before surgery, it aims to reduce the size of the tumor and thus facilitate its abalation, as well as to reduce the risk of recurrence of the disease;
• adjuvant chemotherapy : prescribed after surgery, it aims to reduce the risk of recurrence at the site of the original tumor or elsewhere in the body.

Chemotherapy can also be used if there is metastasis, which is when cancer cells have grown in areas other than the original cancer. This is called metastatic chemotherapy.

Chemotherapy can be used alongside radiotherapy, and for certain types of cancer, immunotherapy, a major therapeutic advance in recent years in the fight against cancer.

The molecules used in chemotherapy also act on the healthy cells of the body, in particular those which multiply rapidly (those of the bone marrow, hair, skin, etc.), which causes various side effects:

• a decrease in certain white blood cells and therefore a weakening of immunity;
• low platelets and red blood cells;
• nausea and vomiting which may appear immediately after the chemotherapy session and in the following 5 days;
• diarrhea;
• inflammation of the mouth (mucositis);
• hair loss;
• skin and nail changes;
• venous fragility;
• great fatigue.

Adverse effects vary depending on the molecules used but also on the patient, because each organism reacts differently.

Medicines can limit these side effects, as do some alternative medicines, such as auriculotherapy or acupuncuture, used in some hospitals. This care, called “supportive care”, is essential for the patient’s quality of life, since cancer management cannot stop at the sole treatment of the disease. Psychological support is also important, as is maintaining a good image of care, through workshops or beauty treatments for example.