Intro to Oncology Flashcards
Objectives
1
Q
What is Cancer?
A
- A disease of uncontrolled growth of abnormal cells in the body
- A disease of aging
- 70% of cancer cases occur >50
- 65% of cancer deaths occur after 65
2
Q
Cancer Incidence in 2018
A
- 1.7 million new cases diagnosed
- Lung, colorectal, breast, and prostate
- 50 to 55% of all new cancers
- 50% of cancer deaths
3
Q
most common cancer in men
A
Prostate cancer
4
Q
most common cancer in women
A
Breast cancer
5
Q
2nd and 3rd most common cancer in both sexes
A
- 2nd= lung cancer
- 3rd= colorectal cancer
6
Q
What is normal cellular growth
A
- All growing cells go through a cycle, during which there are checkpoints – opportunities for growth/the cell cycle to be stopped if necessary
7
Q
Two types of genes involved in the cellular growth process
A
- Genes that are needed for the normal functioning of the cell
- Genes that determine the differentiating characteristics of the particular cell type
8
Q
Cell Cycle
A
9
Q
What is a cellular adaptation?
A
- Normal cellular adaptation occurs in response to a stimulus, or stress, and *usually* ceases once the need for adaptation has ceased.
- Cells are able to adapt to increased work demands or threats to survival by changing their size, number, or sometimes function.
10
Q
Types of cellular adaptations chart
A
11
Q
Hypertrophy
A
- Increase in cell size with an increase in the amount of function in tissue mass.
- Is the result of an increased workload
- Commonly in cardiac and skeletal muscles
12
Q
Hyperplasia
A
- Increase in the number of cells in an organ or tissue
- Tissues that are capable of mitotic division
- The epidermis, intestinal epithelium, and glandular tissue
- Hormonal and compensatory
- Breast and uterine enlargement due to pregnancy
13
Q
Dysplasia
A
- Faulty/abnormal cell formation in size, shape, or arrangement of cells.
- REVERSIBLE change in mature cells to an atypical or disorderly appearance
14
Q
Metaplasia
A
- Change of cells from a normal type for a certain tissue to that of an abnormal type
- Could develop into cancer
- Metaplasia is a REVERSIBLE change of one mature cell type to another cell type
15
Q
Neoplasia
A
- Abnormal tissue that forms tumors (neoplasms)
- Loss of differentiation and reversion to a more primitive form and is IRREVERSIBLE
16
Q
How does neoplasia differ from normal cellular growth
A
- Neoplasias lack the normal regulatory control over cell growth and division
- Neoplasms are classified into benign and malignant
17
Q
benign neoplasms
A
- composed of well-differentiated cells that retain original structure and function but have lost the ability to control cell proliferation
18
Q
Malignant neoplasms
A
- less differentiated and have the lost the ability to control both cell differentiation and proliferation
19
Q
Cell Proliferation
A
- Cell division
- Adaptive response for when cells old cells need replacement or when more cell are needed
20
Q
In all neoplasms, the genetic changes that allow excessive and uncontrolled proliferation is..?
A
- unregulated by the normal growth stimuli
21
Q
Cell Differentiation
A
- The process of specialization whereby new cells acquire the specific structural and functional characteristics of the cells they replace
22
Q
Cell differentiation in benign neoplasms
A
- composed of well differentiated cells
23
Q
Cell differentiation in malignant neoplasms
A
- less differentiated or undifferentiated
24
Q
Benign neoplasm characteristics
A
- Usually grow slowly but progressively
- Well differentiated
- Usually well-demarcated masses that do not invade
- Do not metastasize
- Usually non-life threatening
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Benign tumor example
* Spherical
* Compresses/pushes normal structures
* Well-organized capsule
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Malignant tumor characteristics
* Erratic rate of growth but tend to grow rapidly
* Poorly differentiated or undifferentiated
* Locally invasive/infiltrate surrounding tissues
* Metastasizes
* Great vascularity
* High mitotic rate – cell production greater than cell loss
* Atypical tissue structure / irregular in shape
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Progression of Malignancy
* invasion
* metastasis
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For invasion of tumor to occur
* Cell adhesion to the basement membrane
* Local proteolysis of the membrane
* Movement of cell through the membrane
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Metastasis occurs when
* Cells gain access to circulation and repeat above at remote sites
* Tumor cells then generate blood vessels to support local growth (angiogenesis)
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Metastatic cancer
* development of a secondary tumor in a site distant from the primary location
* Spreads by direct invasion, lymphatics, or bloodstream
* Metastatic cancer has the same name and same type of cancer cells as the primary (original) cancer
* ex: Colon cancer with metastatic liver disease
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Cancer as a Genetic Disease occurs via...
* Alterations in specific genes causes unrestrained cellular growth
* Damage to DNA can arise as result of:
* Exposure to carcinogen
* Exposure to certain viruses
* Inherited damage (inherited allele)
* Spontaneous errors
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Genes Associated with Cancer
* Mutated proto-oncogenes, i.e. oncogenes
* Mutated Tumor-suppressor genes
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Proto-oncogenes
* Code for normal proteins involved in a cell’s normal growth control pathway
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Oncogenes
* Arise from the mutation of proto-oncogenes
* Oncogenes code for a mutated version and/or excessive quantities of various growth proteins
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causes of oncogenes
* increased cell division
* decreased cell differentiation
* inhibition of cell death
* cell’s growth pathway to become hyperactive
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Examples of Oncogenes Found in Cancer
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Tumor Suppressor Genes (TSG)
* Normal cells have regulatory mechanisms that protect them against activated oncogenes
* TSGs produce proteins that restrain cell growth and division
* When TSGs are mutated/inactivated, the signal that usually inhibits cell proliferation is removed resulting in unregulated cell growth
* Mutations in TSGs are generally recessive
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Hereditary Breast Cancer
* Mutation in Breast Cancer Susceptibility Gene 1 or 2, which are TSGs
* These mutations result in inc breast Cancer in females and males
* BRCA-1
* BRCA-2
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BRCA-1
* maps to chromosome 17q21
* inc in Ashkenazi Jewish women
* inc risk of ovarian cancer in females and prostate cancer in males
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BRCA-2
* on chromosome 13
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More hereditary cancer chart
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Non-genetic cancer risk factors
* Tobacco products
* Chemicals
* Benzene, nickel, asbestos, petroleum products
* Aging
* Ultraviolet exposure
* Ionizing radiation
* Viral infections
* Excessive Alcohol
* Sedentary lifestyle, poor diet, obesity
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Tobacco as risk factor for cancer
* The most common, preventable cause of cancer
* ~ 30% of all cancer deaths in US are directly linked to tobacco
* 171,000 deaths in US
* 1.42 million deaths world wide
* 85-90% of lung cancer cases occur in smokers
* Tobacco smoke contains over 4000 chemicals
* 70 of which are known carcinogens
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Ingredients in Cigarettes
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Tobacco causing cancer pathophys
* Tobacco delivers carcinogens directly to the tissues \>\>Tissue exposure to carcinogens \>\>formation of covalent bonds between the carcinogens and DNA (DNA adduct formation) \>\>resulting accumulation of permanent mutations in critical genes
46
cancers associated w/ tobacco
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radiation as risk factor for cancer
* Ionizing radiation
* Gamma rays, X-rays, CT scans
* Nonionizing radiation
* Microwaves, cell phones, UV light
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viral infection as a risk factor for cancer
* Growing evidence that some cancers are associated with viral infection
* Some viruses carry an oncogene and incorporate it into human DNA when the virus infects the cell
* Some can turn on a human oncogene when the virus infects the cell
* All oncogenic viruses have the ability to stimulate unlimited cell growth
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Oncogenic Viruses Examples
* EBV
* Burkitt’s lymphoma
* HPV, types 16 and 18
* cervical cancer
* Hepatitis B and C
* hepatic carcinoma
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For nonsmokers, the biggest modifiable risk factors are ...?
* are nutrition and physical activity
* Decreased physical activity is associated with an increased risk of cancer
* Obesity linked to breast, uterine, colon cancers
* High intake of processed meat is associated with an increased risk of colon cancer
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Excess alcohol as risk factor for cancer
* Linked to inc risk of
* Head & neck cancers
* Esophageal cancers
* Liver cancers
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Physical activity associated with a decreased risk of
* Breast cancer
* Colon cancer
* Prostate cancer
* Endometrial cancer
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Diets high in fruits and veggies may decrease risk of
* Esophageal cancer
* Colon cancer
* Stomach cancer
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Cancer Prevention Strategies
* Detecting precancerous lesions
* Ex: Routine Pap smears, mammograms
* Modifying risk factors
* Ex: Smoking cessation, moderation of alcohol intake, increase physical activity
* Immunization
* Ex: HPV vaccine (cervical cancer)
* Chemoprophylaxis
* Tamoxifen has been shown to reduce the incidence of breast CA by 50% in high-risk women
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Clinical manifestations of cancer result from
* Pressure from local tumor growth
* Infiltration or metastatic invasion of tumor cells in other organs
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Warning signs of cancer
* Unusual bleeding or discharge
* Thickening, swelling, or lump in the breast or elsewhere in the body
* Persistent indigestion /difficulty swallowing
* Obvious change in a skin lesion
* Persistent new cough or hoarseness
* Unexplained weight loss
* New, persistent pain
* Blood in the urine
* Recurrent nausea & vomiting
* Recurrent fevers
* Enlarged lymph nodes
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Paraneoplastic Syndrome
* another clinical manifestation of cancer caused by the presence of tumor cells in the body
* Hormones or cytokines excreted by tumor cells exert unusual hormonal or metabolic effects
* More common with cancers of the lung, breast, ovaries or lymphatic system
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Paraneoplastic effects of tumor are...
* remote effects that are not related to the direct invasion, obstruction, or metastasis
* Effects can be metabolic, hematologic, neurologic, etc
* Divided into which system they effect
* Effects/findings can appear similar to those of primary endocrine, hematologic, neurologic, or neuromuscular disorders
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Paraneoplastic Syndromes are clinically important b/c..
* They may provide early clues to the presence of some cancers
* The metabolic or toxic effects of the syndrome may create a more urgent situation than cancer itself
* Hypercalcemia, hyponatremia
* Once the tumor has been treated and resolved, the paraneoplastic syndrome resolves as well
* Return of sxs may signify recurrence of the cancer
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Paraneoplastic Endocrine Syndromes
* The tumor tissue itself secretes the hormone that produces the syndrome (ectopic hormone production)
* Ectopic hormones are usually pro-hormones of higher molecular weight than those secreted by the normal, differentiated endocrine cell
* Believed to result from activation of oncogenes in the tumor
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Types of Paraneoplastic Endocrine Syndromes
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Paraneoplastic Neurologic Syndromes
* Paraneoplastic neurologic disorders occur in 2-3% of patients with small cell lung cancer
* In 60% of patients the neurologic symptoms precede the cancer diagnosis
* Most are induced by the patient’s immune system in response to the tumor
* Immunologic response (antibodies, WBCs) directed against neuronal proteins/antigens that are expressed by the tumor, but antigens are also predominantly expressed by the nervous system
* Antibodies may be detected in the CSF and serum
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Surgical Biopsy Cancer Dx
* Requires surgery where an external incision is made and mass(es) or piece of mass is removed / organ or piece of organ could be removed
* Fluid can also be aspirated for diagnostic purposes
* Small amount of tissue may be left behind to monitor response to chemo, ex: lymphomas
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Needle Biopsy cancer Dx
* Needle is injected into the area of concern for diagnosis
* Several passes of needle is made into mass
* Pathology is often on hand to give preliminary diagnosis
* Ex: FNA (fine needle aspiration); core biopsy as in stereotactic breast biopsy, ultrasound/CT guided needle biopsy
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Endoscopic Biopsy with or without Ultrasound Dx of cancer
* Endoscopy allows the direct visualization and biopsy of small masses/areas of concern, especially hard-to-reach/visualize organs like the pancreas
* Fiberoptic scope and lens is used to directly view an organ
* If a mass is visualized with the camera, ultrasound is used to guide fine needle aspiration/biopsy
* Often done under sedation
* No external incisions are made
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Types of Endoscopic Biopsy
* colonoscopy
* esophagogastroduodenoscopy
* endoscopic retrograde cholangiopancreatography
* endoscopic ultrasound
* cystoscopy
* colposcopy
* bronchoscopy
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Frozen Section Biopsy cancer Dx
* During surgery, a specimen/piece of tissue is removed, quick-frozen in a cryostat machine, cut by microtome, and stained immediately for examination by a pathologist
* Takes less than 30 minutes
* Allows for rapid diagnosis of possible malignant lesions during surgery
* If the **tissue is determined to be cancerous** and is amenable to surgery, the mass can be removed at that time
* If the **tissue is determined to be benign**, then the mass may not always need to be removed and the surgery can end
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Exfoliative Cytology Cancer Dx
* Microscopic examination of cells desquamated from a body surface or lesion as a means of detecting malignancy and microbiologic changes, to measure hormonal levels, etc.
* Such cells are obtained by aspiration, washing, scraping, brushing, etc
* Ex: Pap Smear for cervical cancer/changes
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Bone Marrow Biopsy cancer Dx
* Bone marrow biopsy provides a definitive diagnosis for hematologic malignancies
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Clinical Laboratory Tests for cancer Dx
* The following may detect the possibility that a cancer is present:
* Fecal occult blood test
* Ex: Colorectal cancer
* CBC (complete blood count) with Differential
* Ex: Leukemia
* Urinalysis
* Ex: renal tubular epithelial casts, high amounts of protein
* Serum protein electrophoresis
* Ex: Bence Jones protein
* Papanicolaou (Pap) test
* Ex: Cervical cancer
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