How does chemotherapy work?
Chemotherapy is the treatment of cancer with cytostatic drugs. It is used either as a sole therapy or in combination with other treatments. Read everything about the course of chemotherapy, what it is used for and what kind of risks it entails.
Chemotherapy is the treatment of malignant tumors with drugs called cytotoxic drugs. The term cytostasis means “cell arrest”. This means that the cytostatic agents intervene in the cancer cell proliferation cycle, thereby inhibiting tumor growth.
Since cancer cells have a particularly high rate of division, they are particularly susceptible to the cytostatic agents. However, there are other cell types in our body that multiply rapidly, such as those of the hematopoietic bone marrow or mucosa.
Since the cytostatics usually make no difference between healthy and diseased cells, there are often numerous side effects.
Chemotherapy can be carried out as part of a hospital stay or as an outpatient. The patient receives the outpatient chemotherapy either in an oncology practice or in outpatient clinic.
- Induction phase: intensive chemotherapy until the tumor regresses
- Consolidation phase: Reduced dose chemotherapy to stabilize the tumor decline
- Maintenance phase: less aggressive therapy administered over a longer period of time to prevent a resurgence of the tumor cells
Neoadjuvant chemotherapy and adjuvant chemotherapy
Cancer is often treated not only with chemo alone but with, for example, radiotherapy or surgical removal of the tumor.
Neoadjuvant chemotherapy is a chemotherapy that is performed before a surgical tumor removal. The aim is usually to reduce the size of the tumor and counteract early spread of tumor cells (metastasis).
This is to ensure that the procedure itself no longer has to be so radical. In international usage, one often speaks of a “primary chemotherapy”.
Adjuvant chemotherapy means that the cytostatics are used after another cancer treatment. It should be prevented after a healing tumor therapy, for example, an operation, that again a tumor (recurrence) arises.
For example, adjuvant chemotherapy is currently being administered at certain stages of breast, colon or testicular cancer.
Curative or palliative chemotherapy?
When the goal of chemotherapy is to cure the patient of their cancer, it is called a curative intention. Unfortunately, there are also situations in which a cure is no longer possible, for example, if the tumor has already spread to other organs: then the doctor can use the so-called palliative chemotherapy.
Their goal is to relieve discomfort and prolong the patient’s survival. It is important to provide the patient with detailed information about palliative chemotherapy.
Life expectancy and prognosis must be explained clearly and comprehensibly to the patient; that no cure is possible, the doctor must communicate clearly. Then it often makes sense to include psychological care in palliative chemotherapy.
How long does chemotherapy last?
The duration of chemotherapy depends on the cancer, the general health of the patient and the chosen drug combination. Basically, one speaks of a chemotherapy of treatment cycles.
When do you have chemotherapy?
Chemotherapy is used to treat malignant tumors. The cytostatics are supposed to destroy the cancer cells. Applications include leukemia, lymphoma, lung cancer, colon or stomach cancer, breast cancer and soft tissue tumors.
Chemotherapy for lung cancer
Especially in so-called small cell lung cancer, the most important treatment is currently chemotherapy. Lung cancer of the non-small cell type is rather removed surgically, the treatment with platinum-containing cytostatics is used here in addition, if at all.
Chemotherapy in breast cancer
Chemotherapy is also used in patients or patients with breast cancer. In particular, the following patients with these tumors can benefit from adjuvant chemotherapy:
- Hormone-sensitive tumors
- Tumors with HER2-positivity
- Tumors that have spread to the lymph nodes
- Tumors with a high risk of recurrence
Even patients who have breast cancer before the age of 35 will usually receive chemotherapy. Breast cancer preparations are mostly the so-called taxanes and anthracyclines. Standard chemotherapy lasts 18 to 24 weeks.
Neoadjuvant chemotherapy prior to surgical removal of the tumor may provide the option of a breast conserving procedure, depending on tumor size and location. Preoperatively, six to eight cycles are given.
Chemotherapy for gastric cancer
Even with advanced tumors of the stomach and the transition of the esophagus to the stomach, chemotherapy is used. Frequently perioperative, that means both before and after surgical removal of the tumor. Cisplatin chemotherapy is often administered in combination with epirubicin and 5FU (ECF protocol).
Easier to use is the so-called PLF protocol, in which epirubicin is replaced by leucovorin. In patients with advanced gastric carcinoma, taxane-containing combinations are increasingly being used, but they have more side effects. More gentle is the so-called FLOT chemotherapy (fluorouracil, leucovorin, ocaliplatin and docetaxel).
Chemotherapy for colon cancer
Adjuvant chemotherapy for colorectal cancer is only useful if the tumor has previously been surgically removed as a whole. The products oxaliplatin and 5FU / folinic acid, which are used in combination. This scheme refers to the oncologist as FOLFOX. Alternatively, the patient may receive a so-called fluoropyrimidine as a single therapy.
Chemotherapy for leukemia
In acute leukemias, the rapid initiation of intensive chemotherapy (high-dose chemotherapy) is important. Acute leukemia is treated with chemotherapy for five weeks during the induction phase, followed by a four-week consolidation period.
The maintenance therapy should be continued until two years after diagnosis, for example, methotrexate is used. Because high-dose chemotherapy, because of its intensity, has more side effects than standard chemotherapy, careful clinical monitoring is necessary.
What do you do with chemotherapy?
In chemotherapy, the doctor gives the patient cytostatic drugs that attack the tumor cells and thus shrink or inhibit the growth of the tumor.
The typical chemotherapy procedure takes place in cycles. This means that the patient receives cytostatics on a regular basis. The periods between cycles are well defined.
How many such cycles are to be performed, the doctor decides together with the patient. If the patient tolerates chemotherapy poorly, the intervals between cycles may be extended or chemotherapy may be discontinued.
Between cycles, the doctor will check if the cancer responds to chemotherapy. He recognizes this by whether the tumor has become smaller or whether cancer cells have receded. If the treatment has no effect, it makes no sense to continue the chemotherapy according to the previous scheme.
Chemotherapy tablets or infusion?
Only a few chemotherapeutic agents can be taken as a tablet. They often consist of a precursor of the actual active ingredient. This is then metabolized in the liver, which releases the actual active ingredient and passes into the blood.
One difficulty with oral cytostatics is the dosability: Since each patient has an individual metabolism and their own eating habits, the drugs are absorbed at different rates through the stomach or intestine. This complicates a precise dosage.
Usually the doctor gives the patient the cytostatics as an infusion into a vein, through which they reach the heart. This then pumps the medication into the whole body (systemic effect).
On the other hand, if chemotherapy does not act systemically, but only on the tumor-affected organ, this is called regional chemotherapy. The cytostatics are injected into an artery instead of a vein.
In cerebral or spinal cord tumors, however, the cytostatics are given directly into the nerve water, which is called intrathecal administration.
What are the risks of chemotherapy?
Most cytostatics can not differentiate between diseased cancer cells and healthy body cells and attack primarily cell clusters with a high rate of division. That’s why there are some side effects. These can be partially well with supportive measures under control, in the worst case, but they are even life threatening. Typical side effects are:
- Increased risk of infection
- Bleeding disorder
- Performance reduction and fatigue
- Nausea and vomiting
- Urinary tract infections
- Hair loss from eyelashes, eyebrows and head hair
- Organ damage to liver, heart, kidney and nerve tissue
What do I have to consider after chemotherapy?
After your chemotherapy, it is important that you have your family doctor or general oncologist perform regular blood counts. In this way, he can detect in good time whether the number of blood cells is normalizing and the risk of infections and bleeding is reduced.
Until then, try to reduce your individual risk of infection by avoiding large crowds (subway, concerts, and others) and carrying a small hand sanitizer if necessary.
Tell your doctor immediately if you notice any symptoms, especially:
- Bleeding (gum or nose bleeding, blood in the stool or urine)
- Shortness of breath
Nutrition in chemotherapy
Many patients suffer from lack of appetite during treatment, because of the numerous side effects. To keep your weight, you should take several small meals a day. Full or light food is allowed, adapted to your individual preferences. If necessary, you can get advice from a specially trained dietician.
Late effects of chemotherapy
Most of the side effects that you experience during chemotherapy will disappear after the treatment is over. Nevertheless, there are some long-term consequences that can occur long after the therapy:
- Secondary tumors (years or decades later)
- Damage to nerves (disturbance of fine motor skills, the sense of touch)
- Premature menopause in women
- Exhaustion states (fatigue)
Also, keep in mind that once a chemotherapy has survived, it will not protect you from developing another, independent tumor throughout your life. Therefore, continue to take regular screening for cancer screening.