What is chemotherapy? |

• First-line or standard chemotherapy: Given to destroy cancerous cells before disease progression or recurrence; first-line chemotherapy has been determined, through research studies and clinical trials, to have the best probability of treating a certain type of cancer





• Second-line chemotherapy: Given to destroy cancerous cells when the disease has not responded to first-line chemotherapy or has recurred after first-line chemotherapy





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  Adjuvant chemotherapy: Given to destroy cancerous cells that may remain after a known cancerous tumor has been surgically removed or after radiation therapy has been given





• Consolidation or intensification chemotherapy: Given once a remission is achieved, with the goal of sustaining a remission.





• Induction chemotherapy: Given to induce a remission





• Maintenance chemotherapy: Given in lower doses to help prolong a remission





• Palliative chemotherapy: Given to ease the symptoms of cancer and improve a patient’s quality of life

Cancers treated: All

Subclasses of this group:
Alkylating agents, anthracyclines, antimetabolites, corticosteroid hormones, mitotic inhibitors, nitrosoureas, topoisomerase inhibitors; some chemotherapy drugs do not fit into these classifications, including dactinomycin (Cosmegen), hydroxyurea (Droxia), L-asparaginase (Elspar), procarbazine (Matulane), and thalidomide (Thalomid)

Delivery routes: Chemotherapy drugs are most commonly administered intravenously (through an IV) or orally (by mouth) as pills, capsules, or liquid. They may also be administered topically (applied to the skin) as creams or lotions or injected directly into a tumor (intratumorally or intralesionally), into the muscle (intramuscularly), or under the skin (subcutaneously). The administration method is dependent on the drug’s specific action, dose, and potential side effects. In some cases, two or more administration methods may be used at once.

Intravenous chemotherapy medications may be infused through a peripheral central catheter (thin, flexible tube) inserted into a vein in the arm or hand; through a central venous catheter, also called a vascular access device; or through a port implanted into a large vein in the neck, chest, or arm. A central venous catheter is used to deliver chemotherapy when several drugs need to be administered at the same time, when continuous infusion chemotherapy is being given, or when long-term therapy is needed. A catheter may also be placed in an artery (intra-arterial), in the cerebrospinal fluid (intrathecal), in the chest (intrapleural), in the abdomen (intraperitoneal), or in the bladder (intravesical) to deliver the medication. A medication infusion pump is sometimes used with a catheter to deliver a preprogrammed dose of medication.

Chemotherapy can be administered on an inpatient, outpatient, or at-home basis, depending on the specific drug and the type of cancer, its location, and its aggressiveness. Where chemotherapy is administered may be dependent upon the patient’s insurance requirements, as well as the physician’s and patient’s personal preferences.

Chemotherapy drug dosages are based on a patient’s body weight in kilograms or a patient’s body surface area expressed in meters squared, which is calculated using the patient’s height and weight. Chemotherapy is given at regular intervals, or cycles, depending on the type and stage of cancer and how many chemotherapy drugs are being given at the same time. Rest periods between doses allow normal cells to recover from the effects of the medication. It is important for patients to receive the full recommended course of therapy to achieve the maximum therapeutic benefit. In some cases, the physician may adjust the course of treatment based on the incidence of certain side effects.

Liposomal therapy is a newer chemotherapy delivery method in which liposomes (microscopic synthetic capsules) are used to deliver chemotherapy drugs. The coating on the liposome capsules allows the medication to remain in the circulation for a longer period of time, so that the drugs selectively target cancer cells and decrease side effects on healthy tissue. Some liposomal medications currently available include doxorubicin liposomal (Doxil) and daunorubicin liposomal (DaunoXome).

How these drugs work: In the 1940s, nitrogen mustard became the first chemotherapy agent used to treat cancer. The use of chemotherapy for cancer treatment was discovered accidentally during World War II when a group of soldiers exposed to sulfur mustard gas, a chemical warfare agent, were later found to have very low white blood cell counts. Scientists hypothesized that this agent would have a similar effect on cancer. An IV injection of nitrogen mustard was given to several patients with advanced lymphomas and was successful in treating the cancer. In 2014 the American Society of Clinical Oncology reported that there were more than one hundred types of chemotherapy drugs are available, along with hormone therapies and targeted therapies, with many more being investigated.

Chemotherapy is a systemic treatment; the medicines travel through the whole body and are not confined to one specific treatment area. Chemotherapy drugs therefore can reach cancer cells that may have traveled from the main tumor through the blood or lymph systems to other parts of the body. Chemotherapy drugs may be given alone or in combination with other drugs or treatments, such as radiation therapy or surgery.

The chemical composition, action, and side effects of chemotherapy drugs vary. Chemotherapy drugs are classified according to how they affect cancer cells’ molecular context, cellular activities or processes, and specific phases of the cell cycle.

Targeted cancer therapies block the growth and spread of cancerous cells by interfering with cancer cell development, growth, and division. Some targeted therapies interfere with the proteins that are involved in the process that signals normal cells to turn into cancerous cells. In 2014 the National Cancer Institute reported that the FDA had approved targeted therapies for about two dozen types of cancer, including breast cancer, colorectal cancer, kidney cancer, leukemia, lung cancer, lymphoma, pancreatic cancer, prostate cancer, and soft tissue sarcoma. Some medications used for targeted therapy are FDA-approved to treat more than one cancer. For instance bevacizumab (Avastin) can be used in targeted therapies to treat brain cancer, cervical cancer, colorectal cancer, kidney cancer, and lung cancer.

Monoclonal antibodies are synthetic forms of protein that can help guide chemotherapy drugs directly into a tumor. Monoclonal antibodies are used only for certain types of cancer in which antigens and the respective antibodies have been identified, such as some types of breast cancer and lymphomas.

Angiogenesis inhibitor drugs may prevent the growth of blood vessels that supply oxygen from surrounding tissue to cancerous cells or tumors, thereby starving the cells of oxygen.

The type of chemotherapy prescribed is different for each patient and is based on the type of cancer, the stage of the disease, the patient’s age and overall health, the presence of coexisting medical conditions, and other cancer treatments that may have been given previously.

Side effects: Because chemotherapy drugs are systemic, they target cancerous as well as normal tissue and can have toxic side effects, depending on the specific drug, its dosage, the duration of administration, and the patient’s physical condition.

One of the most common side effects of chemotherapy is fatigue (tiredness), which may be the result of anemia (a decrease in oxygen-carrying red blood cells) or the result of the increased energy required to recover from the effects of the chemotherapy drugs. Other factors contributing to fatigue include poor appetite, lack of sleep, and emotional stress.

Depressed blood cell counts may increase the patient’s risk of infection and anemia. In addition, reduced platelets can cause easy bruising or bleeding including nosebleeds, bleeding gums, blood in the urine or stool, and unusually heavy menstrual flow.

Other common side effects include nausea and vomiting, loss of appetite, diarrhea, and fluid retention. A registered dietitian can provide nutritional therapy to help the patient develop an eating plan that meets dietary requirements but reduces these side effects and helps make treatment more tolerable. In some cases, antinausea or antidiarrheal medications may be prescribed to help prevent these troublesome side effects. It is important for patients to ask their physicians first before taking over-the-counter remedies for these side effects, as they could interfere with the action of the chemotherapy drug.

Since many chemotherapy drugs kill fast-growing cancer cells, they may also target fast-growing normal cells in the hair follicles, which can lead to alopecia (hair loss). Some chemotherapy drugs may cause only hair thinning, while others may cause complete hair loss, including loss of body hair and eyebrows. Hair loss is temporary, and hair will regrow after the cancer treatments are completed.

Emotional or mood changes, such as depression or anxiety, may occur. Patients should discuss their concerns about these side effects with their physician; support groups are available to help patients cope, and antidepressant medications can be prescribed when necessary.

In some cases, chemotherapy can cause certain side effects that are painful, such as burning or pain in the fingers or toes. Pain medications may be prescribed to reduce pain associated with cancer treatment.

Some chemotherapy drugs may lead to infertility (both amenorrhea in women and impaired spermatogenesis in men). In extreme cases, chemotherapy can lead to heart muscle damage (cardiotoxicity), which would mitigate the chemotherapy regimen.

There are several lifestyle changes a patient can make to manage certain side effects, such as fatigue and mouth, gum, and throat problems. The National Cancer Institute offers a publication, Chemotherapy and You, that provides several techniques for managing side effects.

The time it takes to recover from chemotherapy side effects varies, depending on the patient’s physical condition and the type of chemotherapy drug, dosage, and how long the medication was taken. Chemotherapy side effects are usually short term and often go away once treatment is finished. Patients should ask their doctor about the risk of side effects, both short term and long term, and the risk of serious side effects.

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