How Is Chemotherapy Administered?
Chemotherapy is usually given in cycles, with each cycle involving a treatment session followed by a rest period. Several cycles ordinarily make up a course of treatment (Chemocare 2017; ACS 2015; CRUK 2015).
Chemotherapy can be administered by various strategies with differing intent, depending on each patient’s unique situation (Baszkowsky 2012; SHCI 2014; Attarian 2011):
- Neoadjuvant chemotherapy, sometimes called induction chemotherapy, is given prior to surgery or radiotherapy in order to shrink the original (primary) tumor.
- Adjuvant chemotherapy is given after surgery or radiation if there is high risk of recurrence or metastasis (the spread of cancer from the primary site to other parts of the body).
- Palliative chemotherapy is administered without curative intent, but rather to prolong life and/or relieve symptoms.
- Consolidation chemotherapy, or post-remission chemotherapy, is sometimes part of treatment for leukemias and a small number of other types of cancer. It involves multiple treatment cycles over several months in order to sustain remission.
- Maintenance chemotherapy generally refers to long-term low-dose treatment to maintain or prolong tumor control.
- Combination chemotherapy refers to the use of several drugs that have different mechanisms of action and different toxicities. It is typically used to prevent or overcome resistance during neoadjuvant or adjuvant chemotherapy; and
- Combined modality therapy, which refers to the use of classical cytotoxic chemotherapy drugs along with other cancer treatments, including surgery, radiation therapy, or newer classes of anticancer drugs such as molecularly targeted agents, monoclonal antibodies, hormonal treatments, or immunotherapy.
Chemotherapy can be administered by different routes, including (NCI 2014a; SHCI 2017):
- Intravenous (IV): injection into a vein
- Chemotherapy and other necessary medications (eg, fluids, antibiotics) can be administered intravenously. While in some cases these are injected into veins in an arm or hand, sometimes it is necessary to inject into a larger vein. This requires the use of a central venous catheter. Another method is an implantable venous access port, sometimes referred to by brand names including Port-a-Cath and Medi-port. The catheter is inserted into a vein, and the access port is surgically placed under the skin, typically resulting in a small lump where the port is located. Other types of catheters accessed without an implanted port may also be used. In these cases, the end of the catheter into which medicine is injected is visible outside the body. These types of catheters include the peripherally inserted central catheter, or PICC line, and the Hickman catheter. Catheters and ports allow administration of more than one IV chemotherapy drug; blood draws for tests, and/or blood transfusions, all on more than one occasion, without having to use multiple needle punctures or insert new IV lines (ACS 2017b; ASCO 2013).
- Oral: administration by mouth
- Intrathecal: infusion into the fluid surrounding the brain and spinal cord
- Intra-arterial (IA): injection into an artery
- Intraperitoneal (IP): injection into the abdominal cavity
- Intravesical: administration directly into the urinary bladder through a catheter
- Intramuscular: injection into a muscle
- Topical: application to the skin
- Subcutaneous: injection under the skin