The Case of the Efficacy Explanation
Jenni is an oncology nurse practitioner in an outpatient medical oncology clinic. She is meeting with 70-year-old Don after his first cycle of cabozantinib for treatment of metastatic medullary thyroid carcinoma when he asks why the oncologist put him on a pill instead of using IV chemotherapy. “Is it because I don’t have long to live?” Don wonders.
What Would You Do?
Oncology nurses need an understanding of the different types of oral anticancer medications (OAMs) and how they affect cancer cells (see sidebar) so they can answer questions related to their efficacy.
OAMs are categorized in two main classes: cytotoxic therapy and targeted therapy. Cytotoxic therapy is typically given via IV; however, several oral versions of cytotoxic drugs are as equally effective as their IV counterparts. Cytotoxic drugs affect DNA replication and mitotic rates (https://doi.org/10.1186/s12918-017-0464-7) in rapidly dividing cancer cells, leading to cell death.
Targeted therapies offer a more individualized approach to cancer treatments because the choice of therapy is based on mutations in and around a cancer cell. Small molecule inhibitors (SMIs) block processes in the cellular environment (https://doi.org/10.1186/s12918-017-0464-7), thereby halting the growth, progression, and spread of a cancer. Because SMIs are taken daily, tumor cells and their microenvironment are continuously exposed to the drug’s effects (https://www.nccn.org/JNCCN/PDF/JNSU3_combined_Oral_Chemo_2008.pdf). Monoclonal antibodies affect proteins on the outside of cells and can send toxic chemicals directly into the intracellular environment.
Jenni explains the use of SMIs in treating Dan’s cancer, including the continual exposure of the cancer cells to the oral therapeutic agent. She reiterates that his current treatment is standard of care for his specific disease and based on how the thyroid cancer cells reproduce in the body. Jenni reviews the side effects associated with cabozantinib (e.g., diarrhea, mouth sores, hand and foot syndrome), reminding Don that just because his treatment is in a pill form, it is not less potent than IV forms of cytotoxic therapy.