Chapter 14: Antineoplastic Agents

The underlying nature of cancer involves a single abnormal cell that multiplies, developing characteristics such as anaplasia (loss of normal cellular differentiation), autonomy (uncontrolled growth), metastasis (the ability to spread to other tissues), and angiogenesis (the formation of new blood vessels to feed the tumor). The therapeutic goal of traditional antineoplastic therapy is to significantly reduce the size of the tumor mass so that the host's immune system can effectively eliminate the remaining abnormal cells. The efficacy of these agents often relies on their ability to target rapidly dividing cells, which leads to unavoidable toxicity in normal body systems, including the GI tract, hair follicles, and especially the bone marrow. The chapter systematically covers several major drug classes: Alkylating Agents are non–cell cycle specific, achieving cytotoxicity by reacting chemically with DNA and RNA, making them effective against slow-growing cancers. Antimetabolites are S phase specific, inhibiting DNA production by acting as false building blocks, and are primarily used for rapidly dividing hematological malignancies and some solid tumors. Antineoplastic Antibiotics interfere with cellular DNA synthesis, but carry specific risks of organ toxicity, such as cardiotoxicity requiring cardioprotective adjuncts like dexrazoxane. Mitotic Inhibitors halt cell division during the M phase and pose a significant risk of tissue damage from extravasation. Hormones and Hormone Modulators are used for hormone-sensitive tumors by blocking specific receptor sites, resulting in adverse effects that mimic menopause, hypercalcemia, and increased cardiovascular risk. A major focus is placed on the emerging class of Cancer Cell–Specific Agents, including protein tyrosine kinase inhibitors (like imatinib) and proteasome inhibitors, which target enzyme systems unique to cancer cells, leading to decreased systemic toxicity compared to older drugs. Nursing considerations across the lifespan are critical, demanding careful monitoring of bone marrow suppression (leukopenia, anemia, thrombocytopenia), hepatic and renal function, and diligent management of GI effects (nausea and vomiting) often utilizing adjunctive antiemetic therapies. Patient teaching must emphasize infection avoidance, proper hydration, nutrition maintenance, and the mandatory use of barrier contraceptives due to the severe teratogenic risks associated with these powerful drugs.