Chemotherapy is the most widely used and proven cancer treatment. Its effect is cytotoxic, which means that it targets and stops the cell multiplication cycle in a general manner.
Chemotherapy specifically concerns tumor cells, for which the cell growth is uncontrolled, but it also affects healthy cells whose division is rapid (e.g, mucous membranes, hair, etc.)
There are many chemotherapy treatments (often referred to as molecules) available in oncology /hematology
They are distinguished by the phase of the cell cycle during which they act.
The development of a cancerous tumor begins with the degeneration of a single cell.
That cell begins to proliferate in a uncontrolled and often rapid fashion. Each cell divides into two and then those two each dive again into four.
This can continue indefinitely, and to obvious great harm to the patient. This proliferation is divided into several phases :
These phases of cell activity are points of vulnerability that chemotherapy addresses to control or even stop the tumor growth. To enhance the effectiveness of treatment, chemotherapy molecules are combined in what is called a chemotherapy protocol. The various treatments are often named by the initials of the products includes in the mix.These drugs can be available in different forms: most often intravenous but also oral, intramuscular or subcutaneous. The treatment is provided in a series of cycles. Each cycle consists of one or more administrations of the chemotherapy treatment at regular intervals. The intervals between treatments are mainly determined by the foreseeable side effects of the treatment ( to give the body time to recover) but also by the mode of action of the molecule used. In some cases, chemotherapy is given orally in a series of regular doses. Overall treatment duration is determined by the indication but also the patient's response to the treatment. Your oncologist will carry out a complete assessment regularly with blood and imaging tests (typically every two or three cycles) to confirm treatment effectiveness.
Adverse effects from chemotherapy vary in frequency
and intensity depending on the molecules used.
Among the most common are :
Anemia : low hemoglobin levels (e.g. a low red blood cells count)
Leukopenia : a decrease in white blood cells,
and particularly polynuclear neutrophils (which protect against infections)
Thrombocytopenia : a decrease in platelets with risk of bleeding (most often minimal)
While some side effects are immediate, such as fatigue, nausea, and vomiting,
most will occur within 7-10 days of treatment.
In most cases, side effects can be minimized or even prevented
with specific treatments called pre-medications. Your oncologist will prescribe
these preventive measures in accordance with the treatment plan
and to the tolerance specific to each individual.
Chemotherapy is a systemic, or general, treatment that impacts cancer wherever it is present in the body.
It is therefore most often used in metastatic (spreading) cancers.
It can, however, be used effectively as a targeted therapy in at least two instances:
"adjuvant’ cases" :
After radical local treatment with the goal of completely removing the tumor (via surgery or radiation therapy) to minimize the risk of recurrence. It is well established that relapses after local treatment are possible as a result of microscopic cancer cells (those not visible on scans or MRI) passing into the bloodstream. These can, sometimes years later, colonize other organs. When this risk is considered significant, additional chemotherapy treatment may be offered 4 to 6 weeks after the operation.