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Study Notes on Cancer Treatment Drugs

CHAPTER 17: Drugs for Cancer Treatment

OVERVIEW

  • Overview of cancer treatment.
    • Traditional chemotherapy.
    • Hormone therapy for cancer treatment.

OVERVIEW OF CANCER

  • Cancer is characterized by abnormal cell growth resulting from:
    • Changes to the normal DNA, leading to damage or alterations in gene expression.
    • Loss of normal growth control mechanisms.
  • Cancer cells grow uncontrollably.
  • Refer to Table 17.1 on Page 333 for characteristics of normal vs. cancer cells.

CANCER CELL BIOLOGY

  • Mitosis: Process of cell division.
  • Neoplasia: Abnormal cell growth not necessary for normal development or tissue replacement.
  • Benign tumors: Grow by expansion without invasion and do not metastasize.
  • Loss of gene expression processes controlling normal cell growth and function.

CANCER CELLS

  • Cancer cells have distinct characteristics:
    • Continuous cell division.
    • Faster division rate compared to normal cells.
    • Unlimited lifespan; can overgrow and metastasize by invading other parts of the body.

CANCER DEVELOPMENT

  • Malignant transformation (carcinogenesis): Multistep process converting normal cells into cancer cells.
  • Carcinogens: Substances or events that damage normal cell DNA, leading to cancer.
  • Primary tumor: Original site of cancerous growth.
  • Metastasis: Movement of cancer cells from primary tumor to establish new tumors via hematologic or lymphatic spread.

CAUSES OF CANCER

  • Three interacting factors influencing cancer development:
    • Carcinogen exposure: Environmental or chemical agents that may lead to cancer.
    • Genetic predisposition: Genetic factors contributing to cancer risk.
    • Immune function: Impaired immune responses may allow for cancer development.

PERSONAL AND ENVIRONMENTAL CAUSES

  • Environmental carcinogens:
    • Chemicals, physical agents, and certain viruses (oncoviruses).
  • Personal factors:
    • Immune function, age, and genetic risk factors.

CANCER TREATMENT APPROACHES

  • Local treatments:
    • Surgery and radiation therapy, most effective for localized tumors.
  • Systemic treatments:
    • Traditional chemotherapy, hormone therapy, biologics or targeted therapies.
    • Aim to kill cancer cells throughout the body and often used in combination to enhance effectiveness.

CANCER DRUG NOMENCLATURE

  • Malignant neoplasm: Technical term for cancer.
  • Antineoplastic drugs: Used specifically to treat cancer, also known as cancer drugs, anticancer drugs, cytotoxic chemotherapy, or simply chemotherapy.

TRADITIONAL CHEMOTHERAPY

  • Utilizes cytotoxic drugs to destroy cancer cells:
    • Drugs damage cancer cell DNA and disrupt cell division.
    • Categories vary, but outcomes are similar: limiting cancer cell division leading to cell death.
    • Both normal and cancer cells may be affected.
    • Can be cell-cycle specific or nonspecific.

CAUTIONS IN CHEMOTHERAPY

  • Dosing based on patient’s body surface area (BSA).
  • Monitor absolute neutrophil count (ANC):
    • Normal range: 2,500 – 6,000 neutrophils.
  • All chemotherapy drugs classified as high-alert drugs due to potential for serious harm from incorrect dosing.
  • Only certified chemotherapy nurses may administer these drugs.

CHEMOTHERAPY TERMS

  • Dose-limiting adverse effects: Common in gastrointestinal tract and bone marrow.
  • Other terms:
    • Alopecia (hair loss), emetic potential, myelosuppression (bone marrow suppression), extravasation, targeted drug therapy.

CATEGORIES OF CHEMOTHERAPY DRUGS

  • Alkylating agents:
  • Antimetabolites:
  • Antitumor antibiotics:
  • Topoisomerase inhibitors:
  • Mitotic inhibitors: also known as antimitotic agents.
  • Combination therapy: Use of multiple drugs for increased efficacy.

CHEMOTHERAPY DRUGS

  • Each drug category has:
    • Action: Mechanism of effect.
    • Uses: Indications for treatment.
    • Expected Side Effects: Reactions commonly observed.
    • Adverse Reactions: More serious effects requiring close monitoring.
    • Nursing Implications: Important considerations for patient care and education.

ALKYLATING AGENTS

  • Action: Prevent cell division by damaging DNA.
  • Uses: Effective against various cancers:
    • Lung, breast, ovary, leukemia, lymphoma, Hodgkin disease, multiple myeloma, and sarcoma.
  • Expected Side Effects: Nausea, vomiting, alopecia.
  • Adverse Reactions: Bone marrow toxicity, suppression of granulocytes and platelets, GI toxicities, pulmonary damage, renal toxicity.
  • Monitor for signs of low platelet counts (bruising, petechiae, or ecchymosis).

EXAMPLES OF ALKYLATING AGENTS

  • Common agents include:
    • Cisplatin (Platinol): Treats solid tumors.
    • Cyclophosphamide (Cytoxan): Effective for bone tumors, lymph, blood cancers, and solid tumors.
    • Mechlorethamine (Mustargen): Used for Hodgkin's lymphoma.

ANTIMETABOLITES

  • Action: Considered cell-cycle-specific drugs; interfere with DNA synthesis.
  • Uses: Leukemias and various cancers:
    • Breast, ovary, head and neck, GI system including colorectal, rectal, stomach, lung, and pancreatic cancers.
  • Contraindication: Not to be used during pregnancy or breast-feeding (teratogenic effects).

INDICATIONS AND ADVERSE EFFECTS

  • Used in combination therapies for solid and some hematologic cancers:
    • May be given in oral/topical forms for maintenance and palliative care.
  • Expected Side Effects: Also include nausea, vomiting, loss of appetite, diarrhea, fatigue, headaches, and hair loss.
  • Adverse Reactions: Liver damage, severe GI effects, one may observe systemic toxicities including neurological issues and tumor lysis syndrome.
  • Stevens-Johnson syndrome and toxic epidermal necrolysis as severe reactions.
TUMOR LYSIS SYNDROME
  • Risk Factors:
    • Large tumor burden, aggressive treatment, pre-existing renal conditions.
  • Clinical criteria: Presence of at least one clinical symptom confirmed by laboratory diagnosis.
  • Management: Requires careful hydration, monitoring of electrolytes, and medications like allopurinol or rasburicase.

EXAMPLES OF ANTIMETABOLITES

  • Folate antagonists: Methotrexate, pemetrexed, pralatrexate.
  • Purine antagonists: Fludarabine, mercaptopurine, thioguanine.
  • Pyrimidine antagonists: Fluorouracil, cytarabine, capecitabine.

ANTITUMOR (CYTOTOXIC) ANTIBIOTICS OVERVIEW

  • Action: Cell-cycle nonspecific; bind to DNA to prevent RNA synthesis.
  • Subcategories:
    • Anthracycline antibiotics (associated with heart toxicity).
    • Nonanthracycline antibiotics.

USES AND ADVERSE EFFECTS

  • Effective against a variety of cancers, both solid and hematologic.
  • Common adverse effects: Heart issues, bone marrow suppression, and pulmonary complications (especially with Bleomycin).
  • Close monitoring of cardiac function recommended due to potential cardiotoxicity from high cumulative doses of certain drugs (e.g., Doxorubicin).

TOPOISOMERASE INHIBITORS OVERVIEW

  • Mechanism: Cell-cycle-specific; affect S and early G2 phases by disrupting topoisomerase enzymes.
  • Subcategories:
    • Topoisomerase I inhibitors.
    • Topoisomerase II inhibitors.

ACTION AND INDICATIONS

  • Indications for colorectal, lung, pancreatic, ovarian, breast, cervical, and hematological cancers.
  • Common side effects: Include alopecia, nausea, fatigue, GI disturbances.
  • Adverse reactions: Bone marrow suppression, allergies, organ impairment.

EXAMPLES OF TOPOISOMERASE INHIBITORS

  • Topoisomerase I inhibitors: Irinotecan, topotecan.
  • Topoisomerase II inhibitors: Etoposide, mitoxantrone, teniposide.

MITOTIC INHIBITORS OVERVIEW

  • Type: Antimitotic agents affecting microtubule function.
  • Subcategories:
    • Taxanes.
    • Vinca alkaloids.
  • Noted for causing severe peripheral neuropathy potentially leading to permanent nerve damage.

ACTION, USES, AND ADVERSE EFFECTS

  • Interfere with microtubule formation, hindering cell division.
  • Used for cancers such as breast, lung, ovary, lymphoma, and leukemia.
  • Common side effects: Nausea, vomiting, peripheral neuropathy, bradycardia, bone marrow suppression.

COMBINATION CHEMOTHERAPY

  • Comprises multiple chemotherapy drugs targeting cancers throughout the cell cycle.
  • Combining specific and nonspecific drugs enhances efficacy but increases normal tissue damage and side effects.

MISCELLANEOUS ANTINEOPLASTICS

  • Bevacizumab (Avastin): An angiogenesis inhibitor.
  • Hydroxyurea: Similar action to antimetabolites; treats specific cancers and has various side effects.
  • Imatinib (Gleevec): Treats chronic myeloid leukemia (CML) and has numerous drug interactions.
  • Mitotane (Lysodren): Adrenal cytotoxic drug for adrenal carcinoma with CNS side effects.
  • Octreotide (Sandostatin): Manages carcinoid crisis-associated diarrhea.

HORMONE THERAPY

  • Targeted at hormone-sensitive cancers (e.g., prostate, breast cancer).
  • Reduces hormone levels or antagonizes hormone receptors to slow cancer growth without resulting in a curative effect.

HORMONE THERAPY FOR BREAST CANCER

  • Focused on estrogen's role in breast cancer progression.
  • Therapy methods aim to reduce estrogen levels, thus inhibiting tumor growth:
    • With a recommended duration of at least 5 years unless disease progression occurs.
  • **Drug categories: **
    • Aromatase inhibitors (AIs), SERMs, ERAs, LHRH agonists.

COMMON HORMONE THERAPY SIDE EFFECTS FOR BREAST CANCER

  • Return of perimenopausal symptoms, weight gain, fluid retention, and increased risk for blood clots.

HORMONE THERAPY FOR PROSTATE CANCER

  • Targeted at reducing androgen (testosterone) levels/inhibition to manage cancer growth.
  • Drug categories: Include androgen receptor antagonists, LHRH agonists, and antagonists.

SIDE EFFECTS OF PROSTATE CANCER HORMONE THERAPY

  • Related to decreased testosterone levels and may include gynecomastia, reduced sex drive, fatigue, and hot flashes.

NURSING IMPLICATIONS

ASSESSMENT

  • Understand the specific cancer type and prescribed chemotherapy drugs; anticipate their side effects.
  • Monitor vital signs and laboratory values closely, especially temperature and blood cell counts.

PLANNING AND IMPLEMENTATION

  • Ensure adequate hydration to reduce renal impact, utilize antiemetics, and manage patient exposure to infectious agents post-chemotherapy due to potential bone marrow suppression.

EVALUATION

  • Assess patient response to treatment and side effects, perform thorough evaluations of IV sites, and ensure understanding of post-operative instructions regarding care.

EXTRAVASATION

  • Define as leakage of chemotherapy agent into surrounding tissues during IV administration.
  • Potential consequences are serious including nerve and muscle damage, with prevention of extravasation being crucial.

PATIENT TEACHING

  • Instruct patients on the importance of reporting elevated temperatures, adhering to antiemetic schedules, maintaining hydration, and practicing good oral hygiene to prevent mucositis.