Chemotherapy, next to immunotherapy, radiotherapy, targeted therapies and surgical treatment, is one of the methods of treating neoplastic diseases. Unfortunately, due to its low specificity, it often has a very destructive effect on the patient's body. What types of chemotherapy can we distinguish and what side effects should we take into account? Find out how chemotherapy works and what drugs are used in chemotherapy.

Chemotherapyin the treatment of malignant neoplasms is designed to destroy neoplastic cells. At the same time, however, chemotherapy also destroys he althy cells. However, it is used because of the effectiveness of the treatment of neoplastic diseases. For many people, a diagnosis of cancer becomes a death sentence. Fortunately, advances in medicine make it possible to fight cancer, and in many cases it is successful. Properly selected and early actions make it possible to slow down the growth and division rate of cancer cells or even to eliminate them.

Chemotherapy: how does it work?

Chemotherapy is based on the action of the so-called cytostatics, i.e. drugs that are toxic to rapidly dividing cancer cells.

Depending on the stage of the disease, the implementation of chemotherapy may lead to the complete destruction of cancer cells in the body or at least limit the progression of the cancer.

Properly selected therapy causes:

  • tumor volume reduction
  • destruction of cancer cells (also in case of remission or metastasis)
  • supplementing and enhancing the effects of other therapeutic methods, e.g. hormone therapy, radiotherapy or surgery.

Chemotherapy: methods of administering chemotherapy

Depending on the adopted method, the manner of administering chemicals may also differ . This is most often done by:

  • injection
  • intra-arterial or intravenous infusions
  • skin application
  • oral administration of the preparation.

Chemotherapy: types

Chemical treatments for cancer can be classified in many different ways. One of the breakdown systems can be the division in terms of the number of active substances used:

  • monotherapy- includes treatment with one cytostat
  • polychemotherapy- involves the use of several drugs in a specific treatment regimen.

Individual types of chemotherapy are used at different stages of disease treatment. Assuming the purpose of the activity as the division criterion, we can distinguish the following types:

Radical chemotherapy

Assumes complete elimination of neoplastic cells from the body. It is most often used in the treatment of hematological neoplasms, but also solid tumors (e.g. in testicular cancer).

Complementary (adjuvant) chemotherapy

Used to remove cancer cell micrometastases. The selection of adjuvant therapy is always determined by prognostic factors (relating to the tumor location) and predictive factors (determining tumor sensitivity).

Initial (neoadjuvant) chemotherapy

Performed before the planned tumor removal surgery. Its task is to reduce the size of the tumor (shrink it) and eliminate metastases that may not be visible during the procedure. Neoadjuvant therapy increases the chances of successful surgery.

Synchronous chemotherapy

Used simultaneously with concurrent radiotherapy for the best possible treatment results. Some cytostatic substances may "sensitize" cancer cells to ionizing radiation, while slowing down their repair capacity.

Thanks to this double-strike, tumor cells become more susceptible to treatment.

Anti-angiogenic chemotherapy

The compounds used destroy the network of blood vessels - surrounding and supplying the tumor with oxygen and nutrients, and at the same time carrying away metabolites.

What drugs are used in chemotherapy?

Cytostatic drugs used in chemotherapy inhibit cell division, usually in a specific phase of the cell cycle.

The type of selected drugs depends on the type of cancer, its stage of development and the patient's he alth condition. The most frequently selected groups of substances are:

  • alkylating drugs(e.g. cisplatin, oxaliplatin, cyclophosphamide) - their mechanism is to create chemical bonds with functional groups of other molecules, e.g. DNA, RNA or enzymes, inhibiting their functions . They work independently of the phase of the cell cycle.
  • mitotic spindle inhibitors(e.g. vincristine, vinblastine, paclitaxel) - disrupt the division of the cell nucleus during mitosis.
  • topoisomerase II inhibitors(e.g. etoposide, teniposide) - disturb the normalDNA replication in a cancer cell
  • antimetabolites(e.g. methotrexate, 5-fluorouracil) - "impersonate" compounds physiologically used in the life cycle of a cancer cell, impeding its division.
  • cytostatic antibiotics(e.g. doxorubicin, daunorubicin, mitoxantrone) - they work in many ways, e.g. create free radicals, damaging the structure of DNA and cell membranes.

Chemotherapy: side effects

Potentialundesirable effects of chemotherapyare strongly associated with the group of cytotoxic substances used. By design, cytostatics destroy dividing cells. Therefore, they will have a negative impact on all tissues of the body, including he althy body tissues, where there are frequent cell divisions (such as skin, mucous membranes, bone marrow or reproductive cells).

The best results are most often brought by polychemotherapy, i.e. the use of a mixture of preparations (so-called cocktails) with a synergistic or additive effect.

It may be difficult to isolate symptoms characteristic for the use of one ingredient in such a situation.

The side effects that accompany virtually all the cytostatic drugs used are:

  • nausea and vomiting
  • hair loss
  • bone marrow damage
  • immune disorders

However, with reference to the above-mentioned groups of cytostatics, additional side effects can be distinguished.

Side effects of alkylating drugs

Alkylating drugs often lead to blood clotting disorders, pulmonary fibrosis, and damage to the kidneys and urinary tract.

Older generations of platinum analogues, classified as drugs with an alkylating effect, often caused hearing damage, disorders of the nervous system (including movement and sensation) or flu-like symptoms.

Medicines, the so-called second-generation drugs such as carboplatin and oxaliplatin show slightly fewer side effects.

Side effects of mitotic spindle inhibitors

In the case of mitotic spindle inhibitors, the effects may be more severe. Patient case reports mention, inter alia, permanent damage to the bone marrow and inflammation of peripheral nerves and veins.

Side effects of topoisomerase inhibitors

The popular effects of topoisomerase inhibitors include, among others. heart damage and thrombocytopenia.

Side effects of antimetabolites

In turn, the use of antimetabolites in chemotherapy may lead to hyperkalemia (pathological, increased concentration of potassium ionsin the blood), anemia, inflammation of the nerves or the cornea.

Chemotherapy: what determines the occurrence of side effects?

Unfortunately, you should be aware that any chemotherapy is associated with a high risk of side effects. Complications may also appear at different times, both directly during therapy, after several weeks or even years.

The worst complications are certainly those that areirreversible . While inflammation or hair loss is generally a temporary problem, permanent damage to internal organs or the nervous system is difficult to ignore.

In extreme cases (e.g. when the germ cells are damaged), the so-calledlate toxicity , when the effects of cytostatics are revealed in future generations.

The cytotoxicity of chemical therapies does not mean, however, that every patient will experience all the inconveniences of the same severity. Often, how a patient responds to a given type of chemotherapy depends on individual characteristics.

When selecting the ingredients of chemotherapy, the patient is always assessed first. The dosage and concentration of the substance are modified so that the treatment regimen brings the lowest risk of complications.

In order to reduce the symptoms, several substances are often associated with inhibiting individual symptoms, and they modify the patient's diet and lifestyle.

Chemotherapy: is it effective?

An ideal anti-cancer therapy should "attack" selectively previously identified cancer cells without adversely affecting he althy body tissues. This type of treatment is called targeted therapy.

Due to the advancement of medicine, many drugs and molecules (such as monoclonal antibodies) have been created that can specifically block specific metabolic pathways or receptors on the surface of selected cells.

Unfortunately, not all tumors have specific places on their surface that enable their identification and targeting such a molecular "projectile". This is when chemotherapy comes to the rescue, which, acting systemically, gives hope to control the progression of the disease.

There is also ongoing research on the synthesis of newer cytostatics, which will be more specific and less toxic than the older generation of drugs.

The effectiveness of the treatment taken depends on many factors . The most important prognostic and predictive indications include:

  • type of cancer,
  • phase of its development
  • and grade.
  • The key isalso the general he alth of the patient (especially age and coexisting diseases).

When fighting cancer with chemotherapy, we must be prepared for a long and strenuous treatment process. Considering the above-mentioned wide spectrum of side effects, concerning all groups of cytostatics, it is difficult to clearly indicate one type of chemotherapy with the worst complications.

Probably they will depend on the number of cycles required and the individual concentration of each drug in the administered mixture.

A given patient may also subjectively feel the power of selected anticancer drugs. Undoubtedly, however, taking appropriately selected chemotherapy in many cases gives a good chance of complete recovery and enjoying life.

  • Chemotherapy: types. How does chemotherapy work?
  • How to prepare for chemotherapy - practical advice
  • Diet during and after chemotherapy - menu and rules
  • Cancer classification

Category:

Oncology