Chemotherapy

21.03.2024

CHEMOTHERAPY DRUGS IN CANCER TREATMENT

Chemotherapy is a commonly used method of treating cancer and includes drugs designed to kill cancer cells or slow their growth. These drugs can reach cancer cells that have spread to various parts of the body, so chemotherapy is often preferred for metastatic or advanced-stage cancers. Chemotherapy can be used alone or in combination with other treatment methods such as surgery and radiotherapy. When administered before surgery (neoadjuvant chemotherapy), it can shrink the tumor and make the operation easier and more effective. When used after surgery (adjuvant chemotherapy), it aims to destroy remaining cancer cells and prevent recurrence of the disease. Chemotherapy is applied with different drug combinations depending on the type and stage of the disease. Chemotherapy may have side effects; These side effects include nausea, vomiting, hair loss, fatigue, and increased risk of infection. Therefore, close follow-up and supportive care of patients during and after treatment is important. The chemotherapy regimen is customized for each patient and is determined based on the patient's overall health, type of cancer, and other treatment history.

Image 1: Although chemotherapy is often administered intravenously as serum, it can also be administered as oral tablets or intra-abdominal hot chemotherapy.

Chemotherapy drugs used in cancer treatment work in various types and by different mechanisms. Some of these drugs include:

Alkylating Agents: These drugs prevent cancer cells from multiplying by changing their DNA. Examples include cisplatin, cyclophosphamide and melphalan.

Nitrosoureas: They work by damaging the DNA of cancer cells. This category includes carmustine and lomustine.

Antimetabolites: They prevent cancer cells from making the genetic material needed to create new cells. Drugs in this group include 5-fluorouracil, capecitabine and methotrexate.

Topoisomerase Inhibitors: These drugs prevent cancer cells from multiplying by preventing the topoisomerase enzyme from copying the DNA itself. Etoposide and Topotecan can be given as examples of this group.

Mitotic Inhibitors (Vinca Alkaloids): They prevent cancer cells from dividing and forming new cells. Paclitaxel, Vinblastine and Vincristine are in this category.

Antitumor Antibiotics: They prevent the DNA inside cancer cells from copying and sometimes damage the DNA. Anthracyclines such as Dokorubicin and Epirubicin are included in this group.

Other Chemotherapy Drugs: Not all chemotherapy drugs fit into the main categories. This group includes drugs such as Arsenic trioxide, Asparaginase and Procarbazine.

Corticosteroids: They are prescribed to help manage side effects during chemotherapy treatments. Dexamethasone and Prednisone are examples of this group.

These medications are selected depending on the type and stage of the cancer and the patient's general health condition and can be given through a variety of methods - intravenous infusion, pills, injections, skin creams, or applied directly to the area where the cancer is located. The selection and application of chemotherapy drugs is determined by the doctor according to the patient's cancer type, stage of cancer, general health, previous cancer treatments and personal preferences.

Image 2: Cancer patients receive treatments such as chemotherapy or immunotherapy in chemotherapy units.

FOR WHAT PURPOSE IS CHEMOTHERAPY USED?

Chemotherapy drugs are used for various purposes in cancer treatment.

These purposes and functions of drugs can be summarized as follows:

Killing Cancer Cells: Chemotherapy drugs kill cancer cells by preventing them from growing and multiplying. These drugs work by damaging DNA during cell division or disrupting the vital functions of the cell.

Ensuring Tumor Shrinkage: Chemotherapy (neoadjuvant chemotherapy) administered before surgery or radiation therapy shrinks the tumor, making other treatment methods more effective.

Preventing the Spread of Cancer: Chemotherapy is used to prevent cancer from spreading to other parts of the body. This is especially important in metastatic cancers.

Destroying Remnants of Cancer Cells: Chemotherapy administered after surgery (adjuvant chemotherapy) helps prevent recurrence of the disease by destroying the remaining remnants of cancer cells removed by surgery.

Alleviating Cancer Symptoms: In advanced stage cancers, chemotherapy can be used as palliative treatment to relieve symptoms and improve the patient's quality of life.

Being Effective on the Immune System: Some chemotherapy drugs modulate the immune system, helping it fight cancer cells. These drugs are often used together with immunotherapy.

Direct Targeted Therapy: Some chemotherapy drugs target specific genetic changes or proteins in cancer cells with antibodies in their composition. These drugs act more specifically on cancer cells that have a specific molecular target. Example: Trastuzumab emtansine

The selection of chemotherapy drugs is based on the type and stage of cancer, the patient's general health condition and previous treatment history. Each drug has a different mechanism of action and side effects may vary. For this reason, chemotherapy treatment is planned individually and the patient must be closely monitored during the treatment process.

Image 3: Some chemotherapy-related side effects may occur. It is organized by oncology physicians regarding side effect treatments.

WHAT ARE THE SIDE EFFECTS?

Side effects of chemotherapy drugs may vary depending on the drug used, the dosage and duration of treatment, as well as the general health condition of the patient.

Common side effects of chemotherapy drugs include:

Tiredness: Patients often feel tired during and after treatment.

Nausea and Vomiting: These side effects are common, especially in the first days of treatment, and can usually be controlled with medications.

Hair Loss (Alopecia): Some chemotherapy drugs can damage hair follicles, which can lead to temporary hair loss.

Decrease in Blood Cells: Chemotherapy can damage the bone marrow, which produces blood cells, which can lead to an increased risk of infection, a tendency to bleed, and fatigue.

Inflammation in the Mucous Membrane (Mucositis): Inflammation of the mucosa of the mouth, throat and digestive tract is a common side effect.

Loss of appetite: Decreased appetite or changes in taste are common side effects.

Skin and Nail Changes: Some chemotherapy drugs can cause skin rash, itching, or discoloration; Color and texture changes may be observed in the nails.

Nervous System Effects: Some medications can cause side effects on the nervous system, such as drowsiness, tingling, or pain.

Effects on the Reproductive System and Sexuality: Chemotherapy can cause temporary or permanent infertility and may have effects on sexual function.

Cognitive Changes: Some patients may experience concentration and memory problems, a condition sometimes referred to as "chemo brain".

The severity and duration of these side effects vary depending on the type and dose of chemotherapy. Supportive treatments and medications are available to help patients cope with these side effects. During the treatment process, it is important to maintain regular communication with doctors to manage these side effects. Side effects usually decrease or disappear over time as chemotherapy treatment ends.

Chemotherapy is now considered one of the cornerstones of cancer treatment. This treatment method can be effective in the treatment of various types of cancer and extends the lifespan of patients and improves their quality of life. Chemotherapy drugs work by preventing cancer cells from growing and multiplying or by directly killing them. These drugs can be used in the treatment of local and metastatic cancers, and in some cases they are preferred together with or as an alternative to surgery or radiotherapy.

Chemotherapy can prevent the spread of disease, especially in early-stage cancers, and help relieve symptoms in some advanced-stage cancers. New chemotherapy drugs and targeted therapies in development are designed to be more specific and have fewer side effects. Additionally, chemotherapy plays an important role in personalized cancer therapy and can be customized for individual patients based on genetic and molecular analyses.

Advances in managing and reducing the side effects of chemotherapy are improving the tolerability and effectiveness of the treatment. All these developments strengthen the importance and effect of chemotherapy in cancer treatment, and research in this field focuses on the development of more effective and less toxic treatment options. Therefore, chemotherapy remains an integral part of modern cancer treatment.