Systemic chemotherapy is an approach to chemotherapy where the drugs are allowed to travel throughout the body to eradicate the cancer, rather than being applied directly to the cancer for the delivery of targeted therapy. The delivery method appropriate for a patient depends on the cancer and the situation. Patients with cancer will meet with oncologists to discuss treatment options and develop the most effective treatment plan. Treatment usually includes multiple forms of treatment to attack the cancer from several angles.
Physicians can deliver systemic chemotherapy intravenously or by mouth. Intravenous drugs go directly to the bloodstream and are often highly concentrated. Oral medications are absorbed through the patient's digestive tract, eventually reaching the blood. As the medications move through the body, they latch on to suspected cancer cells and destroy them or flag them for the body to destroy.
One problem with systemic chemotherapy is the high probability of collateral damage. These medications cannot distinguish between good, neutral, and bad cells, and may cause cell death in healthy cells as they attack cancerous cells. This can result in significant side effects for the patient, including disabling side effects like extreme fatigue, bone marrow depletion, and chronic nausea and vomiting. The medications are carefully calibrated to strike a balance between not getting enough cancer cells because the drugs are too weak, and taking out too many healthy cells because the drugs are too strong.
This type of chemotherapy may be recommended when a cancer has metastasized or there are concerns about metastasis and when it is impossible to deliver targeted medications directly to the tumor. The chemotherapy regimen can include a combination of drugs delivered in cycles, or a single drug, depending on the nature of the cancer. Surgical treatment to remove tumors and radiation to target tumors can also be included in cancer treatment.
Systemic chemotherapy can be very toxic. Patients are usually given treatments in a clinical environment in case they experience complications requiring medical intervention. When treatments are taken at home, patients are advised carefully about side effects and are encouraged to call a physician if they start to experience complications. The drugs are also carefully controlled, as they can be very dangerous for people who do not have cancer.
Success rates with systemic chemotherapy are highly variable. Some cancers respond very well to chemotherapy and the treatment may be curative in nature. Others are highly aggressive, and the chemotherapy may be intended primarily as a palliative measure to increase patient comfort without actually eradicating the cancer.