Adult Exam 4 Flashcards
Cancer
Group of more than 200 diseases
Characterized by uncontrolled and unregulated growth of cells
Biology of Cancer
Two major dysfunctions:
- Defective cell proliferation (growth)
- Defective cell differentiation
Defect in Cellular Proliferation
Characterized by loss of contact inhibition
No regard for cell boundaries, divide indiscriminately and haphazardly
Defect in Cellular Differentiation
Two types of genes that can be affected by mutation are protooncogenes and tumor suppressor genes
Protooncogenes
Regulate normal cellular processes such as promoting growth
Genetic locks that keep cells functioning normally
Mutations can activate them to work as oncogenes
Tumor Suppressor Genes
Function to regulate cell growth
Mutations make them inactive
Result in loss of suppression of tumor growth
Stages of Cancer Development
Initiation, Promotion, Progression
Initiation
Mutation of a cell’s genetic structure
Any change in the usual DNA sequence
May be inherited or acquired
Carcinogens
Cancer-causing agents capable of producing cell alterations
Many are detoxified by protective enzymes and are harmlessly excreted
May be chemical, radiation, or viral
Promotion
Characterized by reversible proliferation of altered cells
Activities of promotion are reversible (obesity, smoking, alcohol, dietary fat)
Latent Period of Cancer
May range from 1-40 years
Length of latent period associated with mitotic rate of tissue of origin and environmental factors
Progression
Characterized by increased growth rate of tumor, invasiveness, and metastasis
Main Sites of Metastasis
Lungs, brain, bone, liver, and adrenal glands
Role of Immune System in Cancer
Immune response is to reject or destroy cancer cells
Some cancer cells have changes on their surface antigens (Tumor-Associated Antigens, TAAs)
Immunologic surveillance (response to TAAs)
Immunologic Escape (mechanism by which cancer cells evade immune system)
Oncofetal antigens
Benign Neoplasms
Similar to tissue of origin
Well differentiated
Slow growth rate
No local invasion, often encapsulated
No metastasis
Malignant Neoplasms
Abnormal cells, poorly differentiated
Slow to rapid growth rate
Local invasion present, infiltrative growth, usually no capsule
Frequent metastasis
Significant harm to host
Tumors can be classified by…
Anatomic site
Histology (grading severity)
Extent of disease (staging)
Anatomic Site Classification
Carcinomas originate from embryonal ectoderm (skin, glands), endoderm (mucous membranes)
Sarcomas originate from embryonal mesoderm (connective tissue, muscle, bone, fat)
Lymphomas and leukemias originate from hematopoietic system
Histologic Classification
Appearance of cells and degree of differentiation are evaluated to determine how closely cells resemble tissue of origin
Grade I (cells differ slightly, well differentiated)
Grade II (cells are more abnormal, moderately differentiated)
Grade III (cells are very abnormal and poorly differentiated)
Grade IV (cells are immature and primitive and undifferentiated, cell of origin is difficult to determine)
Clinical Staging Classifications
0: Cancer in situ
I: tumor limited to tissue of origin, localized tumor growth
II: limited local spread
III: extensive local and regional spread
IV: Metastasis
TNM Classification System
Anatomic extent of disease based on three parameters:
Tumor size and invasiveness (T)
Spread to lymph nodes (N)
Metastasis (M)
Diagnoses of Cancer
Cytology studies Chest x-ray CBC, chemistry profile Liver function studies Endoscopic examinations Bone marrow examination Radiographic studies Radioisotope scans PET scan Tumor markers Genetic markers Molecular receptor status
Definitive Diagnostic Test
Biopsy
Tissue may be obtained by needle/aspiration, incisional procedure, excisional procedure
7 Warning Signs of Cancer
C: change in bowel/bladder function A: a sore that does not heal U: unusual bleeding or discharge T: thickening or lump I: indigestion or difficulty swallowing O: obvious change in wart/mole N: nagging cough or hoarseness
Primary Factors that Determine what Cancer Treatment Therapy Is Used…
Cell type
Location and size of tumor
Extent of disease
Physiologic and psychologic status
Role of Surgery in Cancer Treatment
Consideration of surgical intervention involves assessment of tumor stage, technical feasibility of surgical resection, co-morbidities that may influence surgical risk, and expected postoperative functional outcomes
Objective is to remove all or as much resectable tumor as possible while sparing normal tissue
Goals of Chemotherapy
Can offer cure for some cancers, control other cancers for long periods of time, and in some instances offer palliative relief of symptoms
Chemotherapy Effect on Cells
Effective against dividing cells, so cancer cells escape death by staying in G0 phase
Problem: presence of drug-resistant resting and noncycling cells
As tumors get bigger, more cells become inactive and convert to G0
Classification of Chemotherapy Drugs
Classified by molecular structure and mechanism of action
Two major categories: Nonspecific and cell cycle phase-specific drugs
Typically given in combination
Cell Cycle Phase Nonspecific Drugs
Alkylating agents Nitrosoureas Platinum drugs Antitumor antibiotics Corticosteroids Hormone therapy
Cell Cycle Phase Specific Drugs
Antimetabolites
Mitotic inhibitors
Topoisomerase inhibitors
Chemotherapy Methods of Administration
Oral IM IV (most common) Intracavitary (intravesical, intraperitoneal) Intrathecal/Intraventricular Intraarterial
Preparation and Handling of Chemotherapy Agents
May pose an occupational hazard
Drugs may be absorbed through skin or inhalation
Only properly trained personnel should handle drugs
Chemotherapy Effects on Normal Tissue
Chemotherapy agents cannot distinguish between normal and cancer cells
Side effects are the result of the destruction of normal cells
General and drug-specific adverse effects are classified as acute, delayed, and chronic
Acute Toxicity of Chemotherapy
Occurs during and immediately after drug administration and includes anaphylactic and hypersensitivity reactions, extravasation or a flare reaction, anticipatory nausea and vomiting, and cardiac dysrhythmias
Delayed Effects of Chemotherapy
Include delayed nausea and vomiting, mucositis, alopecia, skin rashes, bone marrow suppression, and altered bowel function
Chronic Toxicities of Chemotherapy
Involve damage to organs such as the heart, liver, kidneys, and lungs
Radiation Therapy
Emission of energy from a source and travels through space or some material
Different types of ionizing radiation are used to treat cancer
Typically delivered once a day for 5 days a week for 2 to 8 weeks
Low-Energy Beams
Expend energy quickly
Penetrate a short distance
Useful for skin lesions
High-Energy Beams
Greater depth of penetration
Suitable for optimal dosing of internal targets while sparing the skin