Understanding Cancer
Terms
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- Incidence and Epidemiology
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-Major health problem in US: More than 8 million Americans are living with cancer
-Incidence rises with age. Most cases affect adults in mid-life and beyond with 77% Dx. after age 55.
-Second most common cause of death with half occurring before 65 - Epidemiology
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-2004 data shows:
Mortality rates for the 4 most common cancers: lung, breast, prostate and colorectal have decreased.
-Reasons for decrease:
Better methods of detection and increased knowledge of prevention
Effective treatment approaches - Cost
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-NIH Estimate: 171.6 billion in 2002
-17% of Americans under 65 years have no health insurance
-27% of Americans over 65 have only Medicare coverage (not enough to cover cancer pt.) - What is Cancer?
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-More than 200 diseases characterized by unregulated cell growth.
-Cellular proliferation may be defective
-Cellular differentiation may be defective - Normal Cellular Proliferation
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-Population of predetermined undifferentiated cells
-Characterized by programmed cell death
-The number of cells proliferating equals the number of cells dying - Cellular Differentiation
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-Protooncogenes: normal cellular genes promote and regulate cell
-Tumor suppressor genes: suppress cellular growth
-Mutations may alter these genes and influence the development of cancer - Characteristics of Normal Cells
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-Have limited cell division
-Specific morphology (shape and look)
-Small nuclear cytoplasmic ratio
-Perform specific differentiated functions
-Adhere tightly together
-Are non-migratory
-Grow in orderly, regulated manner
-Are contact inhibited - Characteristics of Benign Cells
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-Continuous/inappropriate cell growth
-Specific morphology
-Small nuclear cytoplasmic ratio
-Perform differentiated functions
-Adhere tightly together
-Are non-migratory
-Grow in orderly manner - Characteristics of Malignant Cells
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-Rapid or continuous cell division
-Anaplastic morphology (don't look normal)
-Large nuclear cytoplasmic ratio
-Lose some or all diff. functions
-Adhere loosely together
-Are able to migrate
-Grow by invasion
-Are not contact inhibited - Cancer Cell Characteristics
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-Immortal
-Able to divide without anchorage
-Capable of angiogenesis
-Accelerated use of nutrients
-Able to invade other tissues - Histological Analysis Classification: Grading
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Grade I -- Cells differ slightly from normal cells and are well differentiated: Mild dysplasia
Grade II -- Cells are more abnormal and moderately differentiated: Moderate dysplasia
Grade III -- Cells are very abnormal and poorly differentiated: Severe dysplasia
Grade IV -- Cells are immature and primitive and undifferentiated: Anaplasia -
Basic Clinical Staging
(How much cancer does this person have?) -
Stage 0 -- Carcinoma insitu
Stage I -- Localized tumor growth, limited to tissue of origin (clear, clean margins)
Stage II -- Limited local spread
Stage III -- Extensive local and regional spread (spread to lymph nodes)
Stage IV -- Metastatic disease, distant spread - "TNM" Classification
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T = tumor size
N = degree of regional spread or lymph nodal status
M = metastatic spread - Staging
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T1 N2 M0 = small tumor, 2 lymph nodes, no metastasis
T2 N0 Mx = larger tumor, no lymph nodes, unknown metastasis
T2 N2 M1 = large tumor, 2 lymph nodes, metastasis - Cancer Development
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Carcinogenesis/oncogenesis
Malignant transformation - Biology of Cancer
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-Metastasis can occur early or late
-follows a somewhat predictable pattern (example: lung cancer check bone and brain for site of metastasis)
-Angiogenesis: the ability to establish a blood supply and directly invade tissues. - Extrinsic Factors
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-Environmental carcinogens
-Chemical
-Physical
-Viral
-Dietary - Intrinsic Factors (Non-Modifiable)
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-Immune function
-Age
-Genetic predisposition
-Geographic location
-Stress
-Gender - Warning Signs of Cancer
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C-change in bowel/bladder habits
A-sore that doesn't heal
U-unusual bleeding or discharge
T-thickening or lump in breast
I-indigestion or difficulty swallowing
O-obvious change in wart or mole
N-nagging cough or hoarseness
Unintentional weight loss - Role of the Immune System
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-Initiate a response to foreign substances
-Respond to Tumor Associated Antigens
-Immune surveillance - Escape Mechanisms
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-Cell surface antigens are weak
-Overwhelming antigen exposure
-Blocking factors - Oncofetal Antigens
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-Type of tumor antigen found on the surfaces and inside cancer cells and fetal cells
-These antigens have been the focus of recent cancer therapies -
Tumor Surface Antigens
(measures how active cancer is, also called Tumor Markers) -
-Alpha-fetoprotein (AFP)
-CA-125
-CA-15-3
-Human chorionic Gonadotropin (HCG)
-Carcinoembryonic Antigen (CEA) colon cancer
-Prostate Specific Antigen (PSA) - Different Kinds of Cancer
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Some common carcinomas
-Lung
-Breast
-Colon
-Bladder
-Prostate
Leukemias
-Bloodstream
Lymphomas
-Lymph nodes
Some common sarcomas
-Fat
-Bone
-Muscle -
Naming Cancers
Prefix: adeno - gland
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Naming Cancers
Prefix: chondro- - cartilage
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Naming Cancers
Prefix: erythro- - red blood cell
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Naming Cancers
Prefix: hemangio- - blood vessels
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Naming Cancers
Prefix: hepato- - liver
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Naming Cancers
Prefix: lipo- - fat
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Naming Cancers
Prefix: lympho- - lymphocyte
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Naming Cancers
Prefix: melano- - pigment cell
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Naming Cancers
Prefix: myelo- - bone marrow
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Naming Cancers
Prefix: myo- - muscle
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Naming Cancers
Prefix: osteo- - bone
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Naming Cancers
Tissue of Origin: Epithelium - Malignancy: Adenocarcinoma
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Naming Cancers
Tissue of Origin:
Connective Tissue - Malignancy: Sarcoma
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Naming Cancers
Tissue of Origin:
Endothelial Tissue - Malignancy: Hemangiosarcoma
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Naming Cancers
Tissue of Origin: Neural Tissue - Malignancy: Glioblastoma, Medulloblastoma
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Naming Cancers
Origin of Tumor: Bone - Name: -sarcoma
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Naming Cancers
Origin of tumor: Cartilage - Name: Chondro
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Naming Cancers
Origin of tumor: Fat - Name: Lipo
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Naming Cancers
Origin of tumor: Skeletal Muscle - Name: Rhabo
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Naming Cancers
Origin of tumor: Smooth Muscle - Name: Leiomyo
- Goals and Principals of Cancer Therapies
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-Cure: A complete response that is durable
-Control: An extension of life when we do not expect cure
-Palliation: Comfort and reduction in tumor burden that may be causing symptoms - Adjuvant Therapy
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-"Added therapy" usually follows definitive treatment
-Therapy may be chemotherapy, radiation therapy, hormonal therapy or immunotherapy
-Requires careful evaluation of risk vs benefit.
-"Added therapy" usually follows definitive therapy - Treatment Modalities: Surgery
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-Preventive: removal of precancerous lesion or suspicious area with cells that are likely to become cancer
Examples: suspicious moles, prophylactic mastectomy, colon polypectomy - Surgery
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-Cytoreductive Surgery
a.k.a. debulking
Remove as much of a cancer as possible, then treat with chemotherapy or radiation therapy
-Undertaken when there is a good chance radiation and chemo will be able to destroy residual cancer - Surgery: Diagnostic and staging
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-Biopsy
-Staging
-Endoscopic
"second look" - make sure we removed all the cancer - Radiation Therapy a.k.a. XRT
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-Radiation disrupts the replication process of dividing cells
-The goals of radiation therapy are similar to those of surgery or chemotherapy
-Kills cancer cells and non-cancer (healthy) cells - Radiation
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-1895-First discovered by Wm. Roentgen
-1896-Radium discovered by Madame Marie Curie and Pierre Curie
-1960's-Beginning of research/improved technology and equipment
-Today approx. 60% of cancer patients will receive radiation therapy to treat their disease - Goals of Radiation Therapy
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-Achieve maximum tumor kill while minimizing injury to surrounding tissue
*Cure
*Control
*Palliation
*Adjuvant - Types of Radiation Therapy
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-External beam: radiation is directed from an outside source into the body also referred to as teletherapy (given in divided doses)
-Brachytherapy: could also be called internal therapy, the radioactive source is placed inside the body, near the cancer. - Radiation Therapy
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-Usually daily treatment over 2-8 weeks depending on total dose = fractionalization
-Curative course longer than palliative
-Given by Fractionalization-goal to give large dose over time, decreasing toxicity, increasing cell kill
-Requires simulation = CT Scans (mark field with skin markers or tatoos. Nurse must know not to remove). - Simulation
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-Meeting with radiation oncologist and physicist to determine dose, location and methods to be used.
-Client is positioned where mock treatment is to be performed
-Skin markings used to mark treatment field-DO NOT WASH OFF! (May even be a tattoo). - Brachytherapy
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-Radiation delivered directly by implant or insertion of radioactive source directly into tumor or nearby the tumor
-Treatment usually over short period
-Maximum effect to local area with minimal damage to surrounding area
Example: Brachytherapy for Prostate Cancer - Brachytherapy-Sealed Sources
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-Placed into tumor (interstitial) or body cavity (intracavity)
-Body fluids not contaminated
-Notify Radiation Oncologist if dislodged, never touch with bare hands!
-Need lead container/forceps in room for accidental dislodgement - Brachytherapy-Sealed Sources (cont)
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-Safety issues: private room, usually lead-lined walls
-Caregivers wear dosimeter to monitor radiation exposure
-Minimal contact with client
-Follow agency protocol re: linens, dressings and dispose of accordingly - Brachytherapy, Unsealed source
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-Systemic radioisotope that concentrates in high activity area (ie, the tumor), given IV or PO
-Safety issues: client and potentially body fluids are radioactive up to 3-4 days
-Excreted in saliva, sweat, urine, emesis, stool - Brachytherapy, Unsealed source (cont)
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-Due to contamination issues, attention must be given to avoiding oral contact with others, wash eating utensils/dishes separately.
-Flush toilet twice, reduces contamination.
-Practice good hand hygiene.
-Wash clothes separately
-Know your agency protocol - Time, Distance, Shielding
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-Time: Dose of radiation received based on time near source
-Nursing Implication: Cluster care, organize supplies prior to entering room
-Health care provider: 1/2 hour in 8 hour shift
-Visitor: no more then 1/2 hour per day
-No pregnant persons - either visitors or staff - Time, Distance, Shielding (cont)
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-Shielding: involves placing protective device between source and caregiver.
-Most often used is lead, ie. lead-lined walls or containers
-Note: lead aprons NOT advised as don't shield all rays. - Will I be radioactive?
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-External Beam: there is NO potential radiation exposure to caregivers or families.
-Internal Radiation: when the source of radiation is an enclosed implant patients are hospitalized in a lead-shielded room to protect others from exposure to the minimal amounts of radiation emitting. - Will I be radioactive? (cont)
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-Prostate implants: the amount of radiation to the patient and others is considered safe. Answer: NO
-Radioactive Iodine: patients are isolated from children and from physical contact with others until the iodine is flushed from the body. Answer: YES, need instruction when they leave hospital - Radiation Side Effects
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-Fatigue (3-4 weeks into treatment)
-GI symptoms-nausea, vomiting, anorexia, altered taste, diarrhea
-Alteration in skin integrity
-Bone marrow suppression
-Genitourinary tract - cystitis, nephrotoxicity, reproductive dysfunction
-Pneumonitis-acute and delayed (pleural effusion need to think about what's in the field) - Radiation Side Effects (cont)
- -Local effects will be noted as a result of exposure of the tissues to the radiation. An example would be, pneumonitis (SOB), diarrhea or xerostomia (dry mouth)
- Xerostomia and Mucositis
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-May be related to radiation or chemotherapy
-May compromise nutritional status
-Mucositis may involve the entire GI tract
Treatment for mucositis: saliva substitutes, vitamin E tablets