Lecture 4 Flashcards
What does carcinogenic mean
Agent that causes mutations resulting in tumor formation
What is oncology
The study of neoplasia (diagnosis, treatment)
What are the characteristics of benign neoplasm
Well differentiated The cells resemble closely the parent tissue Little or no anaplasia Slow growth No basement membrane invasion Do not metastasize Often encapsulated
How can a benign neoplasm cause disease
By compressing sensitive tissues
By being metabolically active
By malignant transformation
What are the characteristics of malignant neoplasm
Some lack of differentiation Anaplasia Rapid Growth Many mitotic figures Abnormal mitotic figures Locally invasive Infiltrative growth Frequent metastasis Usually no capsule
What are some names of epithelial tumors
Adenoma
Papilloma
Carcinoma
Adenocarcinoma
What are some names of mesenchymal tumors
Tissue -oma
Tissue -sarc0ma
How does a tumor metastasise
Invasion of host tissue
Dissemination through vascular system
Implantation on new surfaces
What are some diagnostic methods for neoplasm
radiology computed tomography ultrasound MRI Nuclear Medicine cytology DNA, RNA analysis
What do you do radiography for
screening test
why do you use computed tomography
to characterize and localize lesion
identify metastasis
surgery and radiotheraphy planning
Why do we use ultrasound
Abdomen: internal structure of organs and to image body cavities when effusion
Assess vasculature
Ultrasound-guided sampling
Why do we use nuclear medicine
administration of radioisotopes
What are the advantages to cytology
Relatively low risk of procedures to the animal
Lower cost compared with biopsy
Speed with which results can be obtained
Best to evaluate cellular criteria (ex lymphoma)
what are the disadvantages to cytology
Small sample (may not be representative) No tissue architecture
Why do we do DNA and RNA analysis
Study mutations to help classify tumors Diagnostic utility (lymphocytosis) Can help guide therapy
Why do we do grading
Done to predict/classify the behavior of the tumor.
Different criteria depending on tumor type.
Done by pathologist
Why do we do staging
Describing or classifying a cancer based on the extent of cancer in the body.
Often based on the size of the tumour, presence of metastasis
Stages are based on specific factors for each type of cancer
What are some clinical effects of neoplasm
The pressure exerted by the neoplasm on the surrounding tissues will cause the following effects: Pain Vessels blockage Dyspnea, hypoxia Compromise organ function
What is cachexia
Weakness and wasting of the body due to severe chronic illness
that cannot be reversed nutritionally
Inflammatory cytokines involved
What causes anemia
Suppression of erythropoietin synthesis in kidneys
Hemorrhages
Decreased erythropoiesis
Erythrocyte fragmentation
What causes hypercalcemia
Tumor cell secretions
Osteolytic metastases of neoplasms
What are some causes of cancer
Genetic Immunosuppression Chemical carcinogens Viral carcinogens Physical carcinogens Chronic tissue injury
What are some environmental factors that cause cancer
Cigarette smoke
Ultraviolet irradiation
Urbanization
Diet
What are the intrinsic factor that cause cancer
Oxygen free radicals that result from chronic inflammation
Intrinsic errors in DNA replication
every time a cell divides, each daughter cell is likely to carry at least a few hundred mutations in its DNA
Most are silent, but accumulate
describe heritable cancer syndromes
Cancers with clear heritable basis
Not many described in veterinary literature
Describe genetic Influence in Sporadic Cancers
It is Why not all smokers get lung cancer
Describe Presence of distinct heritable traits that segregate with common cancer phenotypes in dogs (animals)
Will not cause cancer directly (unlike heritable syndrome)
Histiocytic sarcoma in Bernese Mountain dogs
What are the characteristics of the chemical extrinsic factors
Very wide variety Most bind covalently to DNA Direct carcinogen Indirect: Require metabolic activation
what are the characteristics of the physical extrinsic factors
Sunlight facial, aural, and nasal planum SCC in white or partially white cats and may also play a similar role in some cutaneous SCC lesions in dog Trauma/Inflammation Chronic keratitis Feline vaccine associated sarcoma Radiation At site of radiation therapy Surgery/Implants Anecdotal reports
what are the characteristics of the hormonal extrinsic factors
Canine mammary cancer
most common neoplasm of female intact dogs
Similar in cats, but not as well documented
Perianal adenoma
occurs primarily in intact male dogs, whereas perianal adenocarcinoma occurs in both intact and castrated males
Resolves after castration
Prostate cancer
neutered dogs have been shown to be at increased risk
Describe the papilloma virus
Usually multiple lesions affecting young dogs
Most regress without txt
Describe the feline leukaemia virus
Still much to discover
Only 20% of cats persistently infected with FeLV develop lymphoid cancer
Twenty years ago, 70% of lymphomas in cats were believed to be caused by FeLV
describe the FIV virus
neoplasms most commonly linked to FIV infection
Lymphomas and myeloid tumors (myelogenous leukemia, myeloproliferative disease)
few carcinomas and sarcomas
Lentiviruses such as FIV not oncogenic in themselves
markedly immunosuppressive
affect normal immunosurveillance of cancerous cells
Describe canine hemangiosarcoma
Highly malignant neoplasm that originates from vascular endothelium
Affects middle-age to older dogs, large breed
Primary tumor site:
Spleen
Heart (right atrium)
Subcutis
Liver
Metastasis:
lungs, liver, mesentery, and omentum (hematogenous)
Direct spread
Features helpful for diagnosis (pertinent staging/grading, etc):
Often morphologically altered RBCs are present, such as schistocytes, acanthocytes, and poikilocytes
Can present as acute abdomen or cardiac tamponade
Other (complications, prognosis, etc)
Highly metastatic
Watch for DIC
If Splenic, need to remove spleen, but prognosis still poor (better with chemo - 141–179 days)
