Methods for Administering Chemotherapy

Some chemotherapy agents are available in liquid, tablet or capsule form. An advantage of oral administration is that it involves no needles (and most people find needles unpleasant). Another benefit is that this is easiest method of administering chemotherapy and patients can take the medicine at home. A disadvantage is that the medicine may irritate the digestive system.   Other disadvantages that may occur in oral chemotherapy are side effects including nausea, vomiting, diarrhea, mouth sore, hair loss and low white blood cell counts, although these side effects happen with other methods of administering chemotherapy, too.

Peripheral Intravenous Chemotherapy

An intravenous (IV) tube is inserted via needle into a blood vessel in the hand or arm in this method of chemotherapy. The medicine (or medicines) goes straight into the circulatory system through a vein. One advantage of this type of treatment is that the medicine enters the body quickly. Peripheral intravenous chemotherapy can also be administered in the home with the proper set-up and a visiting nurse. Disadvantages can include extravasation which is when the medicine leaks out of the vein which, in turn, causes the skin to burn and blister. It is also uncomfortable to insert the needle and the whole process is scary for some patients, at least when they start

Topical Chemotherapy

Anticancer drugs are applied to the skin as a lotion, cream or ointment. The advantages are that it is easy (the patient can apply medicine), quick and can be done at home. Disadvantages can include sensitive and red skin and skin that burns, discharges fluid, itches and changes color.

Intramuscular Chemotherapy

The chemotherapy is injected into a muscle in the arm, thigh or buttock. Although the shot may hurt for a bit, this is a quick way to administer chemo medicine. This type of chemotherapy can be given in the home by a healthcare professional.

Subcutaneous Chemotherapy

This type of treatment, also known as sub-q, uses a small needle that is similar to ones used by diabetics for administering insulin. The needle is inserted into the space between the skin and the muscle. An advantage to this method is that the chemotherapy medicine enters the circulatory system at a slower rate; therefore, the chances of systemic toxicity are lowered. Disadvantages can include irritation, damage to muscles, and damage to skin tissue.

Intra-arterial Chemotherapy

Medicine is injected straight into an artery (through a catheter), usually to treat a single area. (See page on regional chemotherapy.)  The catheter is placed directly into the artery that feeds the tumor. Because the chemotherapy agent is directed only to a specific area, the side effects of the drug are limited in other parts of the body. When used in brain cancer treatment, this method requires brain scans, arteriograms, anesthesia, seizure drugs and blood thinners. There is potential for hemorrhage or stroke following the procedure.

Other Forms of Chemotherapy Administration

Intrathecal Chemotherapy – medicine is infused into the nervous system via the cerebrospinal fluid.

Intrapleural Chemotherapy – medicine is infused into the chest cavity.  A form of regional chemotherapy.

Intraperitoneal Chemotherapy – medicine is infused into the abdominal cavity.  Another form of regional chemotherapy.

Intravesical Chemotherapy – medicine is infused straight into the bladder.

Intralesion or Intratumoral – medicine is injected right into the tumor.

Metronomic Chemotherapy – continuous low doses

Dose-dense Chemotherapy – a regimen in which the time between administrations of drugs is shortened

Once the Drug is in the Body

The therapeutic window refers to the dosage that doctors administer in an attempt to make the treatment both safe and effective.  Too low a dose is not effective in treating the disease.  Too high a dose and the side effects of the drug become detrimental or dangerous.  One challenge with chemotherapy is that the therapeutic windows tend to be narrow.  The toxic dose isn’t too much higher than the effective dose.  More on dosing.

One advantage of targeted therapies is that the therapeutic window may be wider.

See page on pharmacokinetics.

Chemo Parity

The high cost of oral chemotherapy agents means some insurers won’t pay for them because conventional IV drugs are available.  Some states have adopted “chemo parity” laws which require equal treatment of drugs regardless of how they are administered.