ONCOLOGY Flashcards
Differentiation
Each cell types differentiates and carries out particular functions.
The structure reflects the function of the tissue.
Mitosis
Part of the cell cycle
Requires genetic control—DNA and RNA
Mutation
If DNA in parent cell is altered and passed on, offspring cells will carry the mutation
Apoptosis
Programmed cell death
Controlled by genetic elements
Neoplasm or tumor
Cellular growth that no longer responds to normal genetic controls
Cell continues to reproduce, without need for them to reproduce
Deprives other cells of nutrition
Neoplasms may consist of atypical or immature cells.
Characteristics of each tumor depend on:
• Type of cell from which the tumor arises
• Unique structure and growth pattern
Defect in Cellular Proliferation
Most human tissues contain predetermined, undifferentiated stem cells.
Predetermined stem cells give rise to mature cells of the type of tissue where they reside.
All cells are controlled by an intracellular mechanism that determines proliferation.
Cancer cells grown in culture are characterized by loss of contact inhibition.
Grow on top of one another and on top of or between normal cells
Cancer cells respond differently from normal cells to intracellular signals regulating equilibrium.
Divide indiscriminately
Stem cell theory
Loss of intracellular control of proliferation results from mutation of stem cells.
DNA is substituted or permanently rearranged.
Once mutated
Cells can die from damage or by initiating programmed cellular suicide (apoptosis).
Can recognize damage and repair itself
Surviving mutated cells have potential to become malignant.
Two types of genes that can be affected by mutation are
1.Proto-oncogenes
Regulate normal cellular processes such as promoting growth
2.Tumour suppressor genes
Suppress growth of tumours
Function to regulate cell growth
Nomenclature
Benign tumors have tissue name plus the suffix -oma (e.g., adenoma)
Malignant tumors (cancers) have the tissue name plus the suffix -carcinoma (e.g., adenocarcinoma)
Tumors of connective tissue are usually termed sarcomas and are often malignant.
Several malignant tumors have unique names:
Hodgkin’s disease
Wilms’ tumor
Leukemia
Benign tumors
Usually differentiated cells that reproduce at a higher rate than normal
Encapsulated
Tissue damage
This is a result of compression of adjacent structures.
It can be life-threatening in the brain.
Malignant tumors
Undifferentiated, nonfunctional cells
Rapid reproduction—abnormal mitotic figures
Infiltrate or spread into surrounding tissue
Spread to distant sites
Malignant Tumors: Cancer
Lack control of mitosis and do not undergo apoptosis
No normal organization or differentiation
No contact inhibition
Abnormal cell membranes
Altered surface antigens
Do not adhere to each other
–Often break loose from mass
–Invade other tissues and may spread to distant sites
Mass compresses blood vessels.
—Leads to necrosis and inflammation around tumor
Tumor cells may secrete enzymes or hormones.
–Break down of proteins and cells
–Systemic effects, such as altered calcium levels
Inflammation and loss of normal cells
–Lead to progressive reduction in organ integrity and function
Angiogenesis
–Some tumor cells secrete growth factors.
• Stimulate the development of new capillaries in the tumor
Carcinogenesis
Process whereby normal cells are transformed into cancer cells
Process varies greatly with respect to time
Cancer is thought to be a multifactorial disease because of :
–Environmental effects
–Change in gene expression (heredity)
–Infection in some cases (e.g., cervical and hepatic cancers)
Some cancers have well-established risk factors.
Development of Cancer
Likely to be multifactorial
Origin of cancer may be: Genetic Chemical Environmental Viral or immunological From causes not yet identified
Development of Cancer (Cont.): initiation
Mutation of cell’s genetic structure
• From inherited mutation (an error during DNA replication)
• From exposure to a chemical, radiation, or viral agent
Mutated cell has the potential to develop into clone of neoplastic cells
Once initiated, mutation is irreversible.
Not all mutated cells form a tumour.
Mutated cells become tumours only when they establish the ability to self-replicate and grow.
Carcinogens may be:
- Chemical
- Radiation
- Viral
Carcinogens can be:
- Detoxified (by protective enzymes)
- Harmlessly excreted
Cells damaged by carcinogens may:
- Self-repair
- Die
- Replicate into daughter cells with same genetic alteration
Development of Cancer
1. Chemical carcinogens
- -Long latency period makes identification of carcinogens difficult.
- -Animal studies may not apply to humans.
- -Certain drugs have been identified as carcinogens.
Development of Cancer
2.Radiation
- -Ionizing radiation can cause cancer in almost any human tissue.
- -Dose of radiation needed to cause cancer is unknown.
- –Ultraviolet radiation is associated with melanoma and squamous and basal cell carcinoma.
Development of Cancer (Cont.)
3. viral carcinogens
ie. Epstein-Barr virus (EBV)= Burkitt’s lymphoma
Development of Cancer (Cont.)
PROMOTION
Process leads to tumor development Activities of promotion are reversible: • Obesity • Smoking • Alcohol • Dietary fat • Hormones • environmental chemicals Cause further changes in DNA Less differentiation and increased rate of mitosis and/or lack of apoptosis Dysplasia or anaplasia may be evident.
Development of Cancer (Cont.)
LATENT PERIOD
- -May range from 1 to 40 years
- -Length of latent period associated with mitotic rate of tissue of origin and environmental factors
- -For disease to be clinically evident, tumour must reach a critical mass that can be detected.
Development of Cancer (Cont.)
PROGRESSION
Characterized by • Increased growth rate of tumour • Invasiveness • Metastasis Most frequent sites of metastasis are lungs, brain, bone, liver, and adrenal glands.
Metastasis process begins with rapid growth of primary tumour
• Develops its own blood supply
—-Critical for survival and growth of tumour
• Tumour angiogenesis is formation of blood vessels within tumour
• Certain segments of primary tumour can detach and invade surrounding tissues
• Detached cells can invade lymph nodes and vascular vessels to travel to distant sites.
• Most mobile tumour cells do not survive.
• Surviving tumour cells must create an environment conducive to growth and development.
Immunity and Cancer Risk
—Cell-mediated immunity recognizes some tumor cells and destroys them.
—Immunization for cervical cancer and hepatitis is recommended to reduce cancer risk from infection.
Risk Factors
Genetic factors
–Oncogenes that regulate all growth
Viruses
–Oncoviruses alter host cell’s DNA.
Radiation
–Ultraviolet rays, X-rays and gamma rays, Radioactive isotopes, Risk is increased with higher cumulative dosage.
Chemicals (check health and safety information)
–Organic solvents, Asbestos, Heavy metals, Formaldehyde, Chemotherapy agents
Biological factors
–Chronic irritation and inflammation, Age, Diet,, Hormones
Risk Reduction
Limit UV exposure from sun or tanning booths.
Regular medical and dental examinations
Self-examination
Diet:
- Increased fiber content
- Reduced fats
- Five to ten servings of fresh fruits and vegetable daily. These foods contain antioxidants, which reduce changes in DNA.
Warning Signs of Cancer
- anemia
- change in bowel movements
- a sore that does not heal
- weight loss
- cough
Local Effects of Tumors
—-Pain
May be absent until very late stages
Occurs when tumor is well advanced
Severity depends on the type of tumor
—-Obstruction
Occurs wen tumor compresses a duct or passageway
Blood supply or lymphatic flow may be restricted
Digestive tract
Airflow in bronchi
——Tissue necrosis and ulceration
May lead to bleeding or infection around the tumor
Systemic Effects of Malignant Tumors
Weight loss and cachexia (ca-KeK-Sia): Anorexia, fatigue, pain, stress. Increased demands on the body from tumor cells
Anemia: Caused by blood loss at tumor site,Nutritional deficits may reduce hemoglobin synthesis.
Severe fatigue: Caused by inflammatory changes, cachexia, anemia, Stress of treatment schedule, Psychological factors
Effusions : Inflammation causes fluid buildup in body cavities.
Infections: Occur frequently as resistance declines
Bleeding: Tumor cells may erode the blood vessels.
Paraneoplastic syndrome: Associated with certain tumor types, Tumor cells release substances that affect neurological function and may have hormonal effects.
Diagnostic Tests
–Routine screening
Essential for early detection
Following treatment to detect any further tumors
–Self-examination
Early detection if done consistently
Breast, testicular, and skin examinations are important.
–Blood tests
Measure blood cell levels during treatment
May detect tumor markers (e.g., PSA test)
–Radiographic, ultrasound, MRI, CT
–Methods of visualizing changes in tissues or organs
–Cytological tests require biopsy or cell sample
Histological and cytological examinations to determine degree of differentiation and tumor type
May be tested for growth promoter sensitivities, (e.g., estrogen-dependent tumors)
Most dependable confirmation of malignancy
Spread of Malignant Tumors
INVASION
Local spread
Tumor cells grow into adjacent tissues
Example: Uterine carcinoma invades the vagina
Spread of Malignant Tumors
METASTASIS
Spread to distant sites
Via blood or lymph or other body fluids
Example: Carcinoma of the colon spreads to the liver.
Staging Cancer
Essential to standardize comparative studies of treatments and outcomes
Used to estimate prognosis
Most common system used is the TMN system:
- -Size of primary tumor (T)
- -Involvement of regional lymph nodes (N)
- -Spread (metastasis) of tumor (M)
Treatment
Depends on specific cancer
- Surgery, chemotherapy, immunotherapy, radiation
- Combination of the above
Surgery
Removal of tumor and surrounding tissue
May be done with laparoscope and several small incisions
—Minimizes tissue damage
—Improves recovery time
Removal of adequate surrounding tissue may result in changes in function.
Radiofrequency ablation (RFA)
—Alternative surgery for small single tumors in solid or fluid-filled organs, but not the lungs
Radiation Therapy
May be used alone or combined with other therapies
Causes mutations or alterations in target DNA
Most effective in rapidly dividing cells
Some types of cancers are radioresistant.
May be used as an adjuvant therapy prior to surgery to shrink tumor
Radiation Therapy (Cont’d) METHODS OF ADMIN
External sources—cobalt machine
• Radiation for a short time to specific site in the body
• Requires multiple treatments
Internal Insertion of radioactive material at the tumor site
• Treat specific cancers (e.g., cervical or oral tumors).
Instill radioisotope in a solution into a body cavity.
• Monitor to ensure that there is no leakage
• Radioisotopes may be given by injection for specific tumors.
Adverse Effects of Radiation
Bone marrow depression
- Decreased leukocytes—increase risk of infection
- Decreased erythrocytes—fatigue, tissue breakdown
- Decreased platelets—excessive bleeding
Epithelial cell damage
-Damage to blood vessels and skin, hair loss
Infertility
-Caused by abdominal radiation
Nonspecific fatigue and lethargy
-Can lead to mental depression
Chemotherapy
Antineoplastic drugs
Can be used alone or in combination with surgery or radiation
Usually combination of two to four drugs -Given at periodic intervals -Classifications include: • Antimitotics • Antimetabolites • Alkylating agents • Antibiotics -Drugs interfere with protein synthesis and/or DNA replication.
Adverse Effects of Chemotherapy
—Bone marrow depression
Limiting factor with chemotherapy
Blood test taken before each treatment
Nadir is point of lowest cell count—different points in cycle
—Nausea
May occur prior to, during, or shortly after treatment
Antiemetic drugs helpful for decreasing nausea
—Epithelial cell damage
Occurs easily
Hair loss
Breakdown of skin and mucosa
----Damage to specific areas With some antineoplastic drugs Fibrosis in the lungs Damage to myocardial cells Kidney damage
Other Drugs
Blocking agents: Act to block receptors for growth promoters on cancer cells
Biological response modifiers (BRMs): Augment the natural immune response
Angiogenesis inhibitors: Inhibit the stimulus for growth of blood vessels
Analgesics: Prescribed to alleviate pain AND May be used in high dosages
Nutrition
Patients with advanced cancer are often malnourished.
Contributing factors: Change in taste sensation Anorexia Vomiting and/or diarrhea from treatments Sore mouth or loss of teeth Pain and fatigue Malabsorption caused by inflammation in the digestive tract
Complementary Therapies
--May include: Massage Meditation Counseling Exercise Therapeutic touch Research-based evidence has not been published for: Raw food macrobiotic diet Use of insulin and glucose with chemotherapy
–Health care workers need to be aware of these different types of therapies to advise patients.
Prognosis
–Cancer-free state generally defined as 5-year survival without recurrence
–Some cancers such as childhood leukemias can be considered cured after a 10-year, cancer-free period.
–Remission—no clinical signs of cancer
Client may experience several remissions
–Life expectancy and death rates for specific cancers vary.
Examples of Malignant Tumors
–Skin cancer
Visible, easily diagnosed and treated
Excellent prognosis, with exception of malignant melanoma
–Ovarian cancer
Poor prognosis because of hidden nature of cancer
High mortality rates
–Brain tumors
Both benign or malignant tumors are life-threatening because of compression of brain tissue.
Primary tumor usually fatal; thus, no metastasis
Cancer Incidence
Most common in men
- Prostate cancer
- Lung cancer
- Colorectal cancer
Most common in women
- Breast cancer
- Lung cancer
- Colorectal cancer
Lung Cancer
About 90% of cases are related to smoking.
Bronchogenic carcinoma
-Most common type of primary malignant lung tumor
-Arises from bronchial epithelium
Squamous cell carcinoma
-Usually develops from epithelial lining of a bronchus
Adenocarcinomas and bronchoalveolar cell carcinomas
-Usually found on periphery of lung
Lung tumor effects
Obstruction of airflow into a bronchus
• Causes abnormal breath sounds and dyspnea
Inflammation and bleeding surrounding the tumor
• Cough, hemoptysis, and secondary infections
Pleural effusion, hemothorax, pneumothorax
Paraneoplastic syndrome - altered immune response to a neoplasm
• Occurs wen tumor cell secretes hormones or hormone-like substances
Usual systemic effects of cancer
Early signs OF LUNG CANCER
Persistent productive cough Detection on radiograph Hemoptysis Pleural involvement Chest pain Hoarseness, facial or arm edema, headache, dysphagia, or atelectasis
Systemic signs
–Weight loss, anemia, fatigue
Paraneoplastic syndrome
- -Indicated by signs of an endocrine disorder
- -Related to the specific hormone secreted
Signs of metastases
- -Bone pain
- -Cognitive deficits, motor deficits
LUNG CANCER DIAGNOSTIC TESTS AND TREATMENT
Diagnostic tests: Specialized helical CT scans and MRI Chest radiography Bronchoscopy Biopsy and mediastinoscopy
Treatment:
Surgical resection or lobectomy
Chemotherapy and radiation
Photodynamic therapy
Colorectal Cancer
Most malignancies develop from adenomatous polyps. Early diagnosis is essential. Cancer occurs primarily in persons older than 50 years. Risk factors -Familial multiple polyposis -Long-term ulcerative colitis -Genetic factors -Environmental factors • Diet low in fiber
COLORECTAL CANCER SIGNS AND SYMPTOMS
Initial signs depend largely on the location of the growth.
General signs: Change in bowel habits Alternating diarrhea and constipation Bleeding Fatigue, weight loss, anemia
COLORECTAL TREATMENT
Surgical removal with radiation and/or chemotherapy
Carcinoma of the breast
MALIGNANT CANCER
Incidence increases after age 20 years
• Most cases in women between ages 50 and 69 years
Most tumors are unilateral
Earlier onset associated with more aggressive growth
Different types
• Most arise from ductal epithelial cells
Metastasis occurs via lymph nodes early in the course of the disease.
Presence of estrogen or progesterone receptors on tumor cells influences treatment
Carcinoma of the Breast
Predisposing factors
First-degree relative with the disease Strong genetic predisposition (BRCA1 and BRCA2) Longer and higher exposure to estrogen Nulliparous or late first pregnancy Lack of exercise Smoking High-fat diet Radiation therapy to the chest Cancer of the uterus, ovaries, or pancreas
Carcinoma of the Breast (Cont.) SIGNS AND SYMPTOMS
Change on mammogram
Initial sign—single, small, hard, painless nodule
Later—distortion of breast tissue, dimpled skin, discharge from nipple
Ultrasound or needle biopsy confirms diagnosis.
CARCINOMA OF THE BREAST
Course of breast cancer
Metastasis occurs by the time the tumor is 1 to 2 cm in diameter. Axillary lymph node involvement Secondary tumors in: • Bone • Lung • Brain • Liver
Carcinoma of the Breast (Cont.)
TREATMENT
- -Surgery may be a lumpectomy or removal of the breast.
- -Lymph nodes may be removed, depending on the stage of the disease.
- -Tissue biopsy will determine the presence of specific growth factors to design drug treatment and chemotherapy.
- -Radiation therapy may be done before or after surgery.
Carcinoma of the Breast
STAGING
Staging is based on the TMN system and the presence of receptors for specific growth accelerators in the tumor.
Carcinoma of the Cervix
Most cases of cervical cancer are caused by human papillomavirus (HPV) infection, a sexually transmitted virus.
Vaccines now exist against the causative strains of HPV.
Routine Pap smears of cervical cells are important in identifying early, treatable stages of the disease:
-By age 20 years or in the year that sexual intercourse begins
-At intervals, as advised by health care worker
Carcinoma of the Cervix (Cont.)
COURSE OF DISEASE
Early dysplasia of cells; abnormal cells showing less differentiation
In situ tumor is located on the mucosal surface.
Invasion to submucosa
Invasion and spread to adjacent organs
Late metastasis
Carcinoma of the Cervix (Cont.)
RISK FACTORS
Age < 40 years
Strongly linked to HPV viral infection (STD)
Multiple partners
Sexual intercourse beginning in early teenage years
Smoking
History of prior STDs
LEEP-
(loop electrosurgical excision procedure) — removes abnormal tissue by cutting it away using a thin wire loop that carries an electrical current.
The Leukemias
Group of neoplastic disorders involving white blood cells
Uncontrolled WBC production in bone or lymph nodes
Other hemopoietic tissues are reduced.
One or more types of leukocytes are undifferentiated, immature, and nonfunctional.
Large numbers released into general circulation
Infiltrate lymph nodes, spleen, liver, brain, other organs
Acute leukemias (ALL and AML)
High proportion of immature nonfunctional cells in bone marrow and peripheral circulation
Onset usually abrupt , marked signs of complications
Occurs primarily in children and younger adults
Chronic leukemias (CLL and CML)
Higher proportion of mature cells
Insidious onset
Mild signs and better prognosis
Common in older adults
Signs and Symptoms of Acute Leukemia
Usual signs at onset -Frequent or uncontrolled infections -Petechiae and purpura -Signs of anemia Severe and steady bone pain Weight loss, fatigue, possible fever Enlarged lymph nodes, spleen, liver Headache, visual disturbances, drowsiness, vomiting
The Leukemias (Cont.) Diagnostic tests
Peripheral blood smears
• Immature leukocytes and altered numbers of WBCs
• Numbers of RBCs and platelets decreased
• Bone marrow biopsy for confirmation
The Leukemias (Cont.) Treatment
Chemotherapy
ALL in young children responds well to drugs
Biological therapy (interferon)
May be used to stimulate the immune system
Complications of Leukemia
Opportunistic infections, including pneumonia Sepsis Congestive heart failure Hemorrhage Liver failure Renal failure CNS depression and coma
