5.2.2 Cancer

Pathophysiology of Cancer and the Cell Cycle

  • Cell Cycle and Cancer Development     * Normal cells follow a tightly controlled life cycle.     * Mutation in DNA occurs when anti-tumor suppression genes inactivate.     * Oncogenes become overactive, leading to unregulated cell growth and survival.     * Cell cycle checkpoints often fail in cancerous states, allowing abnormal cells to bypass apoptosis (programmed cell death).     * Steps of Cellular Dysfunction:         1. DNA damage occurs.         2. Cell cycle checkpoints fail.         3. Abnormal cells are not stopped.         4. Apoptosis is disabled.         5. Damaged cells survive.         6. Rapid proliferation occurs.         7. A tumor forms.         8. Cancer cells invade close tissue.         9. Metastasis occurs via blood and lymph.

  • Normal Cell Cycle Phases:     * G1: Cell prepares to make DNA.     * S Phase: Cell makes DNA.     * G2: Preparation for mitosis.     * Mitosis: The cell divides.     * Apoptosis: Programmed cell death to make room for healthy cells.

  • Key Definitions and Classification:     * Carcinoma: Covers all epithelial surfaces.     * Sarcoma: Originates in bone/connective tissue.     * Blastoma: Derived from immature cells.     * Malignant: Denotes the ability to metastasize (spread) throughout the body.     * Angiogenesis: The process by which tumors create their own blood supply.     * Primary Tumor: The original site of cancer.     * Subsequent Sites: Locations where cancer spreads after the primary site.     * Carcinogen: A cancer trigger.

  • Stages of Cellular Change:     1. Hyperplasia: Cells look normal but there are more of them.     2. Dysplasia: Cells look abnormal.     3. Carcinoma in situ: Abnormal cells stay in one place where they first formed.     4. Malignancy: Cells metastasize to other areas.

Antineoplastic Medications: Alkylating Agents, Antibiotics, Antimitotics, and Antimetabolites

  • Alkylating Agent (Nitrogen Mustard): Cyclophosphamide (Cytoxan)     * Mode of Action: Cross-links DNA strands; damages DNA to prevent cell division.     * Indications: Leukemia, lymphomas, Hodgkin's disease, breast/ovarian cancer, multiple myeloma.     * Contraindications: Pregnancy/lactation, bone marrow suppression, severe infection.     * Side Effects: Alopecia, nausea, vomiting (N/V), bone marrow suppression.     * Adverse Reactions: Hemorrhagic cystitis, liver damage, teratogenic effects.     * Nursing Considerations: Monitor CBC, infection, and bleeding; monitor liver function and IV site; stop if infiltration occurs.     * Education: Report fever, sore throat, or mouth sores; report N/V, hematuria, or dysuria; void before dose; increase fluids; use contraception; avoid breastfeeding.     * Dose/Route: Oral, SubQ, IM, IV; typical dose is 1−5 mg/kg/day1-5\,mg/kg/day.

  • Antitumor Antibiotic (Anthracycline): Doxorubicin (Adriamycin)     * Mode of Action: Intercalates into DNA and inhibits topoisomerase II; prevents DNA repair, causing cell death.     * Indications: Leukemia, lymphoma, Wilms tumor, neuroblastoma, sarcomas, breast/ovarian, thyroid/lung cancer.     * Contraindications: Pregnancy, cardiac disease, live vaccines.     * Side Effects: Alopecia, stomatitis, red urine/tears, bone marrow suppression.     * Adverse Reactions: Severe bone marrow suppression, cardiotoxicity, extravasation/tissue damage.     * Nursing Considerations: Monitor CBC, cardiac function, liver function, and IV site; central line placement preferred; antidote = dexrazoxane.     * Education: Red urine is expected for 1-2 days; report shortness of breath (SOB), chest pain, or jaundice; hand hygiene/food safety is critical.     * Dose/Route: IV; dose recorded as 60-70 or n0-10 mg/m2mg/m^2 q21 days.

  • Antimitotic (Vinca Alkaloid/Natural Product): Vincristine (Oncovin)     * Mode of Action: Inhibits mitosis (M phase) by disrupting microtubules, preventing cell division.     * Indications: Acute lymphocytic leukemia, lymphomas, leukemia, Wilms tumor, neuroblastoma, sarcomas.     * Contraindications: Pregnancy, intestinal ileus, radiation history, neurologic disorders.     * Side Effects: Alopecia, constipation, fatigue.     * Adverse Reactions: Low White Blood Cell (WBC) count, platelets (PLT), and Red Blood Cell (RBC) count; peripheral neuropathy; tissue damage if extravasated.     * Nursing Considerations: Monitor CBC, bowel movements, respiratory status, and IV site; antidote = hyaluronidase.     * Education: Report numbness, tingling, or weakness; increase fiber and fluids; bleeding precautions; avoid pregnancy.     * Dose/Route: IV; dose is 1.4 mg/m21.4\,mg/m^2 qwk.

  • Antimetabolite: Methotrexate     * Mode of Action: Inhibits dihydrofolate reductase, which blocks folic acid activation, disrupting DNA synthesis during the S phase.     * Indications: Leukemia, Choriocarcinoma, uterine cancer, breast/lung cancer, Osteosarcoma.     * Contraindications: Pregnancy, renal damage, fluid volume deficit, GI ulceration.     * Side Effects: Stomatitis, N/V, bone marrow suppression.     * Adverse Reactions: Electrolyte imbalance (Low K+K+, Low Na+Na+), hepatotoxicity, pulmonary fibrosis.     * Nursing Considerations: Monitor CBC to reflect neutropenia, liver function, and electrolytes; give Leucovorin with high doses.     * Education: Avoid alcohol; use contraception; avoid pregnancy; Ivy pain; use IV monitoring.     * Dose/Route: Oral, SubQ, IM, IV; dose is 7.5−10 mg7.5-10\,mg IV per week.

Hormone Therapy and Biologic Response Modifiers

  • Selective Estrogen Receptor Blocker (SERM): Tamoxifen (Soltamox)     * Mode of Action: Blocks estrogen receptors in breast tissue, preventing tumor growth in estrogen-sensitive cancers.     * Indications: Estrogen receptor positive breast cancer.     * Contraindications: Pregnancy, lactation, history of anticoagulant therapy.     * Side Effects: N/V, hot flashes, blurred vision, anorexia, weight loss.     * Adverse Reactions: Endometrial hyperplasia, endometrial cancer, depression, thromboembolism.     * Nursing Considerations: Monitor vision, signs/symptoms of clots, bone density, and endometrial biopsy results.     * Education: Report abnormal vaginal bleeding or leg swelling; get regular eye exams; caution with driving.     * Dose/Route: Oral; 10−20 mg10-20\,mg.

  • Biologic Response Modifiers: Interferon alfa (2A, 2B)     * Mode of Action: Naturally occurring protein that stimulates the immune system to keep cancer cells in the G0 phase, preventing cell division and slowing tumor growth.     * Indications: Kaposi's sarcoma, hairy cell leukemia, multiple myeloma, Hepatitis B and C.     * Contraindications: Allergy, suicidal ideation, colitis.     * Side Effects: Fever, chills, fatigue, muscle aches, dizziness, insomnia (flu-like symptoms).     * Adverse Reactions: Bone marrow suppression.     * Nursing Considerations: Monitor CBC, infection, bleeding, hydration, and neurologic status; interferons are NOT interchangeable; do not shake the vial.     * Education: Report fever, depression, or bleeding; take acetaminophen before the dose to mitigate flu-like symptoms.     * Dose/Route: SubQ, IM, IV.

Cancer Clinical Manifestations and Triggers

  • Systemic Clinical Cues:     * Unexplained weight loss.     * Fatigue/Chronic fatigue.     * Anemia.     * Night sweats.     * Fever.     * Mass or lump.     * Pain.     * Organ dysfunction.     * Bleeding.     * Enlarged lymph nodes.     * Neutropenia (leading to sepsis).     * Nausea, Vomiting, Diarrhea (N/V/D).     * Taste changes.     * Oral ulcers (stomatitis).     * Peripheral neuropathy.     * Lymphedema (interstitial fluid buildup via lymph nodes).

  • Cancer Triggers (Carcinogens):     * Genetics (e.g., BRCA1 mutation).     * Environment: Smoking/Tobacco, UV light.     * Age: Increased risk due to toxin accumulation and decreased immunity.     * Alcohol.     * Air pollution.     * Obesity/Sedentary lifestyle/Poor diet.     * Contaminants: Arsenic, aflatoxin, pesticides.

Treatment Modalities: Radiation and Surgery

  • Radiation Therapy:     * Goal: Disrupts DNA in cancer cells but also kills good cells.     * Types:         * External Beam Radiation: Delivered from outside the body.         * Internal (Brachytherapy): Radioactive seeds or implants placed locally.         * Systemic: Radiopharmaceuticals like iodine pellets.     * Safety (ALARA - As Low As Reasonably Achievable):         * Distance: Increase space between yourself and the source.         * Shielding: Protection to decrease exposure.         * Time: Limit exposure duration.         * Dosimeter: Device that measures the amount of radiation exposure.     * Side Effects: Fatigue, skin changes (radiation dermatitis), alopecia, low blood counts, mouth sores, taste changes, N/V, tooth decay.     * Nursing Care: Energy conservation; skin care (avoid irritants); oral care for mucousa; separate patient's belongings (radioactive precautions); increase fluids.

  • Surgery and Biologic Therapy:     * Surgery: Physical removal of tumors.     * Biologic Therapy: Uses the patient's own immune system to attack cancer (Immunotherapy).

Chemotherapy Safety and Emergencies

  • Safety Protocols:     * Chemotherapy handling requires specialized kits.     * Spills: Use kits and provide immediate cleaning.     * Extravasation: Leads to severe tissue damage. Response includes stopping the infusion, potentially giving an antidote (hyaluronidase for Vincristine, dexrazoxane for Doxorubicin), and tagging materials as radioactive if applicable.

  • Oncologic Emergencies:     * Hypercalcemia.     * Spinal Cord Compression.     * Superior Vena Cava Syndrome (SVCS).     * Tumor Lysis Syndrome: Occurs when cancer cells are destroyed and release their contents into the bloodstream. Characterized by:         * ↓Ca\downarrow Ca (Low Calcium)         * ↑Phos\uparrow Phos (High Phosphorus)         * ↑K+\uparrow K+ (High Potassium)         * ↑Uric\uparrow Uric (High Uric Acid)         * ↑Cr\uparrow Cr (High Creatinine)

  • Nursing Support for Chemotherapy:     * Neutropenia precautions: No crowds, strict hand hygiene.     * Report fever > 100.4\,^{\circ}F, uncontrolled pain, or neuro changes.     * Do not stop medications abruptly.     * Psychological support for anxiety, depression, or financial stress.     * High-calorie, high-protein meals for malnutrition.     * Antiemetics for N/V.     * Fall/seizure precautions.

Diagnosing and Staging Cancer

  • PET Scan (Positron Emission Tomography):     * Imaging test showing cellular metabolic activity.     * Uses radioactive glucose (FDG).     * Cancer cells absorb glucose at higher rates than normal tissue.     * Standard Uptake Volume (SUV): 0−20-2 is normal. High FDG uptake signals cancer, infection, or healing tissue. Low FDG uptake signals necrotic tissue or ischemia.

  • Tumor Staging (TNM System):     * T (Tumor): Size and extent of the primary tumor.     * N (Node): Number of nearby lymph nodes that show cancer.     * M (Metastasized): Whether cancer has moved to distant organs.

  • Stage Classifications:     * Stage 0: Abnormal cells are present but stay in situ (where they first formed).     * Stage I: Cancer is localized.     * Stage II: Cancer has spread to relatively close tissues.     * Stage III: Regional spread to lymph nodes.     * Stage IV: Distant spread/metastasized across the body.

Cancer Screenings and Early Detection

  • Breast Cancer:     * Mammogram and clinical breast exams.     * Self-exams monthly; look for lumps or changes.     * Genetic testing for BRCA1 and BRCA2 mutations.

  • Lung Cancer:     * Low Dose CT scan for high-risk populations.

  • Prostate Cancer:     * PSA Blood Test.     * Digital Rectal Exam (DRE) to check for enlargement.

  • Colorectal Cancer:     * Colonoscopy every 10 years or as recommended.

  • Cervical Cancer:     * Pap smear starting at age 21, every 3-5 years.     * HPV testing.

  • Skin Cancer:     * Yearly skin exams and monthly self-exams.     * Look for ABCDE: Asymmetry, Border (irregular), Color (changing), Diameter (> 6\,mm), Evolving.