Anti-Cancer Medications

What genetic changes lead to malignant transformation?

Activation of oncogenes (cancer-causing genes) or inactivation of tumor suppressor genes (which prevent replication of abnormal cells)

What are the main drug classes used to treat cancer and what is used most often?

Cytotoxic agents (chemotherapy), Hormones and hormone antagonists, Targeted drugs; chemotherapy

What genetic changes lead to malignant transformation?

Activation of oncogenes (cancer-causing genes) or inactivation of tumor suppressor genes (which prevent replication of abnormal cells)

What are the main drug classes used to treat cancer and what is used most often?

Cytotoxic agents (chemotherapy), Hormones and hormone antagonists, Targeted drugs; chemotherapy

What are the four major phases of the cell cycle?

G1, S, G2, and Mitosis

G1 and S phase definition

G1- cell prepares to make the DNA; S- DNA is made

G2 and Mitosis phase definition

G2- preparing for cell division; Mitosis-actual division

What characterizes tissues with a high growth fraction?

Large percentage of proliferating (dividing) cells; few resting (non-dividing) cells

What characterizes tissues with a low growth fraction?

Mostly resting (non-dividing) cells

Mechanisms of drug resistance in chemotherapy?

Reduced drug uptake, Increased drug efflux, Reduced drug activation, Reduced target molecule sensitivity, Increased repair of drug-induced DNA damage

How does ongoing mutation affect chemotherapy success?

Cancer cells are not identical, Presence of a subpopulation of dissimilar cells increases resistance

How does limited drug access affect chemotherapy?

Difficult location and poor blood supply

What is the goal of intermittent chemotherapy?

Allow normal cells to repopulate faster than cancer cells between chemotherapy cycles

What is necessary for intermittent chemotherapy to be effective?

Normal cells must repopulate faster than cancer cells

What are the three types of bone marrow suppression caused by chemotherapy?

Neutropenia (↓ neutrophils), Thrombocytopenia (↓ platelets), Anemia (↓ red blood cells)

What is the normal neutrophil range and the danger point for neutropenia?

Normal: 2500–7000 cells/mm³; Danger: Absolute neutrophil count < 500/mm³

What is the normal platelet range?

150,000–450,000 per mcL

What causes nausea and vomiting during chemotherapy?

Direct stimulation of the chemoreceptor trigger zone (CTZ).

How can chemotherapy-induced nausea and vomiting be managed?

Premedicate with Ondansetron (Zofran) 8 mg PO twice on day 1

What are side effects of Ondansetron (Zofran)?

Headache (HA), Constipation, Diarrhea, Dizziness, QT prolongation

What are Alkylating Agents?

Cell cycle phase nonspecific (can react anytime), Kill cells by alkylation of DNA

Example of an Alkylating Agent

Cyclophosphamide

What are Platinum Compounds?

Cell cycle phase nonspecific, Kill cells by cross-linking DNA

Example of a platinum compound

cisplatin

What are Antimetabolites: Folic Acid Analogs?

Methotrexate: S-phase specific; Disrupts DNA synthesis

What are Antimetabolites: Pyrimidine Analogs?

Fluorouracil: S-phase specific; Inhibits DNA and RNA synthesis (kills dividing cells only)

What are Mitotic Inhibitors?

Act during M-phase to prevent cell division

Example of a mitotic inhibitor

Vincristine: Inhibits microtubule formation, stopping mitosis in metaphase

What are the basic benefits of chemotherapy?

Cure, Prolongation of life, Palliative treatment

What factors influence the decision to treat with chemotherapy?

General health of the patient, type of cancer and responsiveness to chemotherapy, Karnofsky Performance Scale

Karnofsky Performance Scale

less than 40 indicates patient unlikely to tolerate chemotherapy

How do Anti-estrogens work in breast cancer treatment?

Tamoxifen blocks estrogen receptors; Used for established breast cancer and reducing occurrence in high-risk patients

What are the adverse effects of Tamoxifen?

hot flashes, fluid retention, endometrial cancer

What does hormonal treatment like Leuprolide (Leupron) do?

Inhibits gonadotropin release, suppressing ovarian and testicular steroidogenesis

What are the side effects of Leuprolide (Leupron)?

Generally well tolerated, Hot flashes, Testosterone loss may aggravate bone pain