Side effects due to chemotherapy (cancer treatment)
What is chemotherapy?In the body, cells are constantly being replaced by a process of sharing and growing. When cancer occurs, cells reproduce in an uncontrolled manner. More and more malignant cells are produced in this way and then take up more and more space. In this way they displace the space of the healthy cells. Chemotherapy drugs interfere with the ability of a cancer cell to divide and reproduce. The doctor uses a single medication or a combination of medication. This is administered directly by the doctor into the bloodstream to attack cancer cells throughout the body, or else he directs chemotherapy to specific cancer sites.
Purpose of cancer treatmentThe purpose of chemotherapy depends on the type of cancer and how advanced it is.
HealingIn some cases, the treatment destroys the cancer cells and they are no longer present in the body. After that, in the best case they don't grow back, but sometimes the cancer returns.
ControlIt is sometimes possible to prevent cancer from spreading to other parts of the body through chemotherapy, or else it is possible with these drugs to slow down the growth of malignant tumors.
LightingChemotherapy can sometimes be used to reduce tumors or relieve the pain or pressure caused by certain tumors. These tumors often start to grow again and cause symptoms.
Administration of drugs for the treatment of cancerThe medicines can be administered in different ways:
- topical: via cream form on the skin
- an injection: directly into the muscles of the hip, thigh or arm, or into the fatty part of the arm, leg or stomach, just below the skin.
- intra-arterial: directly to the artery that feeds the cancer, via a needle or a soft, thin tube (catheter)
- intraperitoneal: in the peritoneal cavity (contains organs such as the liver, intestines, stomach and ovaries); happens during surgery or through a tube with a special port that the doctor places
- intravenous: through a vein
- oral: take a pill or liquid through the mouth
Chemotherapy may cause fatigue / Source: Concord90, Pixabay
Examples of side effects and reactionsChemotherapy causes numerous possible side effects and reactions such as:
- thinking and memory changes
- an infection
- low blood cell count
- a sore mouth
- a loss of appetite
- hearing problems
- flu-like symptoms
- hair loss
- skin changes
- nausea and vomiting
- inflamed veins
- inflamed mucous membranes (mucositis: oral mucosa)
- organ damage
- pain at the injection site
- sexual and fertility problems
- second cancers
- changes in vision
- changes in taste (taste disturbances) and odor (reduced sense of smell)
- fluid retention
Flooding (extravasation) of intravenous medicinesOnly professionally trained personnel administer cytotoxic drugs (drugs that are toxic to cells) intravenously (through a vein) to the patient. These medicines cause severe local tissue necrosis if medication leaks outside the vein. The caregiver must then immediately stop the infusion and set up local measures. For example, he must aspirate (aspirate) as much of the drug from the cannula, then introduce a saline solution into the area and finally apply warm compresses. Antihistamines (medicines for the treatment of an allergic reaction) and corticosteroids (powerful anti-inflammatory drugs) provide symptomatic relief for the extravasation of intravenous medicines. Dexrazoxane can be used as an antidote when anthracycline causes a flood of drugs.
Low blood cell countChemotherapy has reduced the production of red blood cells, white blood cells and platelets. A decrease in red blood cells leads to anemia (anemia) with symptoms such as shortness of breath, fatigue and palpitations. A reduced number of white blood cells (neutropenia) leads to a weaker immune system with a higher risk of infection. Antibiotics reduce the chance of developing infections. With a low number of platelets (thrombocytopenia), a patient runs the risk of blood clotting problems, bleeding (such as bleeding gums or nose), bruising and bruising. The reduced number of blood cells occurs with most cytotoxic drugs and is a dose related phenomenon. Very aggressive myelosuppressive chemotherapy (chemotherapy that suppresses bone marrow action) may be needed if the doctor starts treatment with the aim of healing the patient, despite the fact that in rare cases these drugs lead to a fatal infection or bleeding. Anemia (anemia) and a reduced number of platelets (thrombocytopenia) can be treated by transfusions of red blood cells or platelets.
Immediate intervention is certainly essential for bone marrow suppression. Patients with neutropenia (reduced number of neutrophils (type of white blood cells) run a high risk of bacterial and fungal infections, often from the intestinal flora. Patients with fever> 37.5 ° C and less than 0.5 x 109 neutrophils / L get a immediate intravenous treatment with broad-spectrum antibiotics for the treatment of the infection, the doctor may adjust the type of antibiotic based on the microbiological results obtained from a blood test, and hemopoietic growth factors such as G-CSF and peripheral blood stem cells shorten the duration of neutropenia, benefits patients at high risk of infectious complications.
Hair lossMany but not all cytotoxic drugs cause hair loss. Cooling the scalp is sometimes useful to reduce hair loss, but in general this side effect can only be reduced by not using these drugs. The hair always grows back after completing chemotherapy.
Nausea and vomitingThe severity of this common side effect varies with the cytotoxic drug that the doctor administers. In 75% of patients nausea and vomiting can be eliminated thanks to the use of modern anti-emetics (medicines for nausea and vomiting). Nausea and vomiting occur mainly with platinum compounds (inhibiting tumor growth) and with the drug doxorubicin. The doctor then uses a step-by-step policy with multiple anti-emetics. In the case of persistent nausea, the doctor uses drugs such as cyclizine, haloperidol and levomepromazine, and benzodiazepines.
Mucositis (mucosal infection)Mucositis is a common side effect of chemotherapy. The condition reflects the sensitivity of the mucosa to antimitotic agents (these substances inhibit cell division = mitosis). The patient experiences severe pain in the mouth and throat area and has swallowing and feeding problems due to the mucous membrane infection of the mouth area (stomatitis). Sometimes the mucous membrane inflammation occurs in the entire intestinal tract which then results in life-threatening diarrhea. The treatment of the mucous membrane inflammation is done with antiseptic and anti-candidiasis mouthwash. If the patient experiences severe symptoms due to mucositis, the doctor will initiate supportive treatment via intravenous fluid administration and antibiotics, because the mucous membrane is a gateway to intestinal organisms.
Loss of appetiteEither chemotherapy or the cancer itself may affect the body's metabolism, leading to a loss of appetite and weight loss until the cancer is in remission or until treatment is terminated. The severity of loss of appetite depends on the cancer type of cancer and the chosen chemotherapy treatment. Eating smaller, more frequent meals is usually recommended so that patients retain more nutrition. Patients should also drink fluids through a straw to maintain fluid intake. A nasogastric probe is needed to feed the patient through a tube (goes directly through the nose to the stomach).
FatigueFatigue is a common side effect of chemotherapy. This is often present most of the time or sometimes only after certain activities. Adequate rest is needed and patients also avoid strenuous activities. The patient should report serious fatigue to the doctor as this may indicate a significant decrease in red blood cells, leading to anemia (anemia).
Medication-specific side effects
Cardiotoxicity (toxic for the heart)Cardiotoxicity is a rare side effect of chemotherapy, usually associated with anthracyclines such as doxorubicin. It is dose related and can be largely prevented by limiting the cumulative total dose of anthracyclines within the safe range (equivalent to 450 mg / m2 body surface cumulative dose of doxorubicin). It is also possible to reduce the risks by:
- the use of analogue epirubicin or
- reducing peak drug concentrations via sustained-release preparations (such as liposomal doxorubicin or fractional administration schedules)
Hearing damageThe toxic effects of chemotherapy in some patients lead to temporary or permanent hearing loss.
Skin problemsThrough chemotherapy, and especially through 5-fluorouracil, a patient is more likely to experience plantar dermatitis (rash on the sole of the foot) or palmar dermatitis (rash on the palm of the hand).
Nephrotoxicity (toxic to the kidneys)Cisplatin (but not oxaliplatin or carboplatin), methotrexate and ifosfamide may cause kidney damage. This can be prevented by ensuring that the patient pees enough during treatment to reduce the drug concentration in the kidney tubules (as well as by carefully monitoring renal function).
Neurotoxicity (toxic to the brain)Neurotoxicity mainly occurs with the use of vinca alkaloids, taxanes and platinum compounds (but not with carboplatin). It is dose dependent and accumulates. In most cases, the doctor will stop chemotherapy before the patient develops a significant polyneuropathy (disorder of multiple peripheral nerves) that, once diagnosed, is only partially reversible. Vinca alkaloids such as vincristine should never be administered intrathecally (within the brain or spinal cord) by the doctor, because the neurological damage is progressive and fatal.
Infertility and early menopauseSome anticancer medicines cause damage to the sex glands. This is especially true for alkylating substances, but also anthracyclines and docetaxel. This results in infertility and in the loss of ovarian estrogen production (premature menopause) in women, which may be irreversible. In men, the doctor must offer the patient the storage of sperm prior to chemotherapy when chemotherapy with curative (healing) intention is given. In women, it is possible to collect ova that are fertilized in vitro and frozen as embryos for subsequent implantation. The recovery of the gonadal function (function of the sex glands) depends on the status before treatment. In women, this is usually related to the age at which women younger than forty years have significantly more ovarian reserves.
Pulmonary toxicity (toxic to the lungs)Some chemotherapeutic agents such as bleomycin, for example, affect the lungs. For example, they cause inflammation in the lung cells that result in pneumonia. The drugs sometimes also lead to scarring in the lungs (lung fibrosis), which means that lung function is limited. Known lung-related symptoms that occur during or a few months after chemotherapy treatment are dry cough, shortness of breath (especially during exercise), wheezing and tiredness. The doctor lowers or stops the medication and supports the lung problems.
Secondary malignancyAnti-cancer drugs have a mutagenic potential (chance of making genetic changes). The development of secondary malignancies, mainly acute leukemia, is an unusual but especially undesirable and long-term side effect in patients who are cured of the primary cancer form. In particular, alkylating agents (a group of cancer agents that inhibit cell division) are involved in this complication.
Drug resistanceDrug resistance is one of the biggest obstacles to cancer cure with chemotherapy. Some tumors have a low degree of resistance to the available treatment and are often curable. This is especially true for gonadal germ cell tumors, Hodgkin's lymphoma and acute leukemia in children. Solid tumors such as small cell lung cancer (bronchial carcinoma), breast cancer and ovarian cancer are initially chemically sensitive, with the majority of patients responding, but most patients end up with a resistant disease. With esophageal, gastric and colon cancer, there is an average degree of sensitivity, while with other tumors, such as pancreatic cancer (pancreatic cancer with jaundice), non-small cell lung cancer and a melanoma (skin cancer), the disease is largely chemoresistant from the outset.
Most resistance occurs as a result of a genetic mutation (modification) and becomes more likely as the number of tumor cells increases. Anti-cancer drugs are also capable of increasing the rate from mutation to resistance. Resistance to cytotoxic drugs is often multiple and is then known as multidrug resistance (MDR). For example, resistance to doxorubicin is often associated with resistance to vinca alkaloids and epipodophyllotoxins. Many other mechanisms are also involved in resistance to chemotherapy.