The method of administration of chemo treatments along with the dose is determined by rigorous testing called clinical trials, which are done prior to the specific chemo drug being available for commercial use with patients. During this testing process, scientists and doctors determine how specific chemo drugs are absorbed in the body and how they work. Sometimes stomach juices can destroy different chemicals, making some medications impossible to give as a pill. Other substances are found to have better anti-cancer action if given intravenously (needle in the vein). Some medications can be given as an injection into the muscle and still others are absorbed when given directly into the bladder or the abdominal cavity.
Oral Chemotherapy Medications (Taken by Mouth)
Oral chemotherapy medications – those that can be swallowed – come in a variety of oral forms (pills, tablets, capsules, liquid), all of which can be absorbed by the stomach or under the tongue.
- Oral chemo medications that are swallowed are encased in a protective coating that is broken down by the digestive juices in the stomach. The stomach acids dissolve the coating releasing the medication, which is then absorbed through the lining of the stomach.
- Some therapy medications can be encased in different protective coatings which are released at different times in the system allowing for a time delay, called an extended release. This method allows longer periods of time between doses.
- Sub-lingual chemo medications are adsorbed under the tongue are referred to as sub-lingual. These medications are placed under the tongue where they dissolve and quickly absorb into the circulation of the body. This is a rapid way to have medication introduced into the body. Anti-nausea medications are particularly effective when given in this manner, as they will not be lost if the patient vomits.
- Why can’t all medications come in oral form? Some medications cannot be given orally because the stomach acids destroy them. Other medications cannot absorbed into the patient’s body through the lining of the stomach or intestines. If the drug cannot be absorbed it is passed through the stool or urine and is ineffective. Other medications may be too harsh and could cause damage to the stomach lining.
- Some chemotherapy can be given by multiple methods such as oral or intravenous depending on the strength, convenience, and regimen that has been prescribed.
Subcutaneous Injection of Chemotherapy Treatments
- Subcutaneous injections (sub-q) involve the use of a short needle such as those used by diabetics for the injection of insulin.
- With subcutaneous injection of chemo treatment, the needle goes into the space between the skin and muscle but does not enter as far the muscle layer.
- Subcutaneous chemo injections are commonly used for some types of biologic response modifiers and chemotherapy support drugs.
- If a patient’s platelet count is low subcutaneous injections are less likely to cause bleeding than intra- muscular injections.
Intra-Muscular Chemotherapy Injections
- Intra-muscular injections are given through the skin into the muscle layer. This involves the use of a larger needle with deeper penetration than the subcutaneous injection. The medication is deposited in the muscle tissue.
- Absorption of the medication is more rapid then the oral form but slower then sub lingual , subcutaneous injection and intravenous administration.
- Intra-muscular injection is a popular method for anti- nausea medications because it bypasses an already irritated stomach.
- Most chemotherapy cannot be given intra-muscularly because of the harshness of the chemical.
- Intra-muscular injection is avoided when possible in patients with low platelets, as bleeding within the muscle can be a complication.
Intravenous Chemotherapy Treatments
Intravenous administration of therapy medication allows for rapid entry into the body’s circulation, where it is carried throughout the body in the blood stream. This is the most common method of chemotherapy administration, since most chemo drugs are easily absorbed through the blood stream. Intravenous administration offers the most rapid absorption time of all currently available methods and the most versatile. IV methods also enable more flexibility with drug dosing. Doses can be given as an IV bolus lasting from a few minutes to a few hours. Continuous infusions can be given over a few days or for weeks at a time. Portable pumps allow medication to be given at a slow continuous rate allowing for on going IV absorption of the medication. Intravenous medications are given directly into the blood stream through a variety of methods.
- An angiocatheter may be placed in a vein in the arm or hand and then removed after the chemo medication is given. This is a temporary venous-access device inserted by a nurse prior to treatment then removed after treatment has been completed. The in-use time of angiocatheters generally ranges from a few minutes to a few days.
- PICC line. Although still considered temporary, a PICC line can be inserted and used for six weeks to a few months before it is discontinued. PICC line insertion involves the placement of a long plastic catheter into one of the larger veins of the arm. This procedure is a non-surgical outpatient procedure. A special x-ray, called fluoroscopy will confirm that the PICC line catheter is in the right place. This option is ideal for multiple short infusions or continuous infusions given in a hospital or at home with a portable pump.
- Non-tunneled catheters. Non-tunneled catheters are inserted directly through the skin into the jugular or subclavian vein and travel through the vessel to the superior vena cava vessel at entrance of the right atrium of the heart. These can be inserted at the bedside, in a non-surgical setting. A special x-ray, called fluoroscopy, must be done to be sure the catheter is in the right place. These are used most commonly short term or in emergency situations since long-term use is associated with the potential for infection along the catheter. Most refer to these catheters as “jugular” or “subclavian” for the vein in which it is inserted. These catheters require dressing changes and careful maintenance.
- Tunneled Catheters. Tunneled catheters are placed through the skin in the middle of the chest. They are tunneled through the subcutaneous tissue (the layer of tissue between the skin and muscle) and inserted into the superior vena cava vessel at entrance of the right atrium of the heart. There is a dacron cuff about two inches from the part of the catheter that exits the skin in the chest. Scar tissue forms around the cuff to hold the catheter in place. These catheters are inserted in an outpatient surgical procedure and a special x-ray, called fluoroscopy, must be done to be sure the catheter is in the right place. These catheters can be left in place for months or years with low incidence of infection. Dressing changes and maintenance is required. These catheters can have multiple lumens (entrances) for medications to be infused or for blood to be drawn. A single lumen has one entrance for medications, a double lumen has two entrances and a triple lumen (the most available) has three entrances. These catheters are most often used for extensive chemotherapy regimens such as bone marrow transplant procedures. Tunneled catheters are usually called by their brand names: Broviac, Groshong, and Hickman. The Hickman catheter, like the Broviac cathether, has an open-ended line inside the vein. In contrast, the Groshong catheter has small, valve-like openings in the line’s tip.
- Port-a-cath. A more permanent option involves the placement of a port-a-cath. The port-a-cath is placed under the skin on the chest. The catheter is then inserted into the superior vena cava vessel at entrance of the right atrium of the heart. This catheter can be placed in radiology by an interventional radiologist or by a surgeon in the operating room. It is approximately a one-hour procedure. The useful lifetime of a port-a-cath can be as long as three to five years. The port-a-cath can be felt under the skin and the nurse can find the entrance by locating the edges of the port-a-cath and inserting (cannulating) a special needle (called a Huber needle) into the soft middle section. Medications can be given through the port-a-cath and blood can be drawn from it eliminating the need for a blood draw from the arm. The use of a portable pump and port-a-cath allows the medication to be given over several days in the home setting rather then as a patient in the hospital. There are no dressing changes required but there is some maintenance involved.
Intraventricular/Intrathecal Chemotherapy Treatments
Intraventricular or intrathecal chemotherapy is used when drugs need to reach the cerebrospinal fluid (CSF), the fluid that is in the brain and spinal cord. The body’s blood-brain barrier does not allow many chemotherapy drugs given systemically (through the whole body) to get to the CSF. There are two ways chemotherapy can be given to the CSF:
- Lumbar puncture (Intrathecal). Chemotherapy can be given through a lumbar puncture (spinal tap). In this case a small amount of chemotherapy is injected during the lumbar puncture, directly into the CSF. Once the drug is administered the catheter is removed.
- Ommaya reservoir (Intraventricular). The ommaya reservoir is a small dome-shaped device with an attached catheter. It is placed into the subcutaneous tissue (the layer of tissue between the skin and the muscle) on the scalp. The catheter is threaded into the lateral (outer) ventricle of the brain. The nurse or doctor, who is specially trained on this method of giving chemotherapy, will insert a small needle through the skin on the scalp into the ommaya reservoir to inject the chemotherapy.
- This procedure is used most commonly in acute leukemias but can be used in other situations as well.
Intraperitoneal Chemotherapy Treatments
Some chemotherapy medications can be given directly into the abdominal cavity. A catheter is placed through the abdominal wall with the catheter draining into the abdominal cavity. It drains into the cavity that surrounds the organs, not into the stomach or any of the other organs. Chemotherapy is then infused directly into this cavity. The patent is encouraged to change positions from side to side and lying on the back to facilitate the movement of the medication. In some cases the medication is drained out after a few hours. In other instances it is left inside where it is gradually absorbed. This method allows the organs to be bathed in the medication, which is then slowly absorbed into the tumor site. The rationale for this type of chemotherapy is that the tumor will be exposed to higher concentrations of medications without exposing the rest of the body to the toxicity. This type of treatment is somewhat controversial because even though the tumor concentrations of the medication are higher, the decrease in cancer has not been demonstrated. There are three ways to deliver intraperitoneal chemotherapy:
- Temporary single-use catheters are inserted through the abdominal wall and removed after the chemotherapy treatment.
- Tenckhoff catheters are soft, flexible, silicone tubes with one or two dacron cuffs. This catheter is placed in a surgical procedure with the tip of the catheter placed near the tumor, the dacron cuffs tunneled and placed into subcutaneous tissue (the layer of tissue between the skin and muscle). Then the end of the catheter is brought out of the abdomen through a puncture. The Tenckhoff catheter may be selected for cyclic chemotherapy. There are some complications associated with the Tenckhoff catheters, namely microbial peritonitis (infection in the peritoneum) and occlusion (blocking) of the catheter so that chemotherapy cannot be infused.
- Port-a-cath. A more permanent option involves the placement of a port-a-cath. The port-o-cath is placed under the skin on the abdominal wall. The catheter with multiple holes at the inserted end is then tunneled through the subcutaneous tissue (the layer between the skin and the muscle) into the peritoneum. This catheter can be placed in radiology by an interventional radiologist or by a surgeon in the operating room. It is approximately a one-hour procedure. The useful lifetime of a port-a-cath can be as long as three to five years. The port-a-cath can be felt under the skin and the nurse can find the entrance by locating the edges of the port-o-cath and inserting (cannulating) a special needle (called a Huber needle) into the soft middle section. Medications can be given through the port-a-cath and, although it can be difficult, peritoneal fluid samples and drainage can be accomplished through a port-o-cath.
Intra-Arterial Chemotherapy Treatments
Intra-arterial drugs are given into the artery that is supplying the blood to the tumor. Angiography, a special x-ray that uses dye so that the blood vessels can be seen, is used to locate the arteries that supply blood to the tumor. There are two ways of giving medications intra-arterially:
- Temporary external catheter. A radiologist can insert a temporary catheter into the artery. The catheter is removed once the medication is given. The insertion site must be monitored carefully for bleeding.
- Implanted pump. A pump can be implanted surgically into the subcutaneous tissue (the layer between the skin and the muscle) with the catheter threaded into the artery. The pump can be removed once therapy is complete.
- This type of therapy has been used most commonly for colon cancer that has spread to the liver. However, it has also been used in cancers of the head and neck, limb sarcoma, limb melanoma, gastric cancer , pancreatic cancer, and others.
- The rationale for this type of treatment is that the tumor will have high exposure to the drug without the associated toxicity of these doses given systemically (throughout the whole body). Although the local tumor responses have been better with this therapy, there has been no survival benefit to date.
Intravesicular Chemotherapy Treatments
Intravesicular medications are given with the use of a urinary catheter directly into the bladder.
- A urinary catheter is placed. The medication is injected into the catheter, which is then clamped. Clamping the catheter allows the medication to remain in the bladder.
- The patient is encouraged to roll form side to side and to lie on their backs to help the medication reaching all areas of the bladder.
- After a predetermined time the catheter is unclamped and the fluid is drained. The catheter is then removed.
- This method is used frequently for people with superficially invasive (cancer on the surface of the bladder that cannot be removed) bladder cancer.
Intrapleural Chemotherapy Treatments
Chemotherapy can be given into the pleural cavity (the space between the lung and the lining of the lung). Intrapleural chemotherapy is used to control malignant pleural effusions. A malignant pleural effusion is an accumulation of cancerous fluid in the pleural space. The fluid may cause the lung to collapse, making breathing more difficult. Draining the fluid will help, but the fluid will usually come back unless intrapleural chemotherapy is given. This procedure is also known as sclerosis or pleurodesis.
- A chest tube is inserted into the pleural space. Any fluid is drained (this may take several days). The chemotherapy is inserted into the chest tube.
- The chemotherapy causes the lung to stick to the pleural lining, allowing the lung to re-expand and stay expanded.
- Intrapleural chemotherapy is used primarily for symptom relief.
Implantable Chemotherapy Treatments
Gliadel wafer is a form of the chemotherapy medication carmustine that can be placed and left in the cavity after surgical removal of a brain tumor, specifically glioblastoma multiforme. This formulation of the carmustine wafer allows the drug to be delivered directly to the site of the brain tumor. After a surgeon operates to remove the cancerous tissue in the brain, he or she implants up to eight dime-sized wafers in the space where the tumor once was. Over the following 2 to 3 weeks, the wafers slowly dissolve, bathing the surrounding cells with the chemo medication. The goal of this method of treatment is to kill tumor cells left behind after surgery.
Topical Chemotherapy Treatments
Some chemotherapy creams are applied directly to the skin in certain cases of skin cancer. The cream is then absorbed through the skin directly into the cancerous lesion. The use of topical preparations is very limited in cancer treatments.