Oncology Flashcards
How can you define cancer for your client?
Disease where a group of abnormal cells grow uncontrollably be disregarding the normal rules of cell division
Normal cells = subject to signals that dictate whether the cell should divide, differentiate into another cell or die
Cancer cells develop a degree of autonomy from these signals
- > equals uncontrolled growth and proliferation
- > if malignant eventually metastasis and death
What causes cancer?
DNA mutations -defect in regulatory circuits of a cell
—> disruption of normal cell proliferation and behaviour
LIFESTYE AND ENVIRONMENT
Diet - high fat, low fiber diets linked to bowel, pancreatic, breast, and prostate cancers
Exposure - carcinogens, mutagens (UV, cigarette smoke, and alcohol)
Viruses -HepB, FeLV, FIV
Age- alterations in the immune system (accumulation of random genetic mutations or lifetime carcinogen exposure; hormonal alterations or exposure
What is the mechanism of cancer development?
Initiation (rapid): carcinogens induce DNA damage but not enough to induce neoplastic transformation
Promotion: original carcinogens or normal growth promoters cause reversible tissue and cellular changes
Progression (slow): processing agents are able to irreversibly convert an initiated cell into a cell exhibiting malignancy
What are the 6 hallmarks of cancer?
Self-sufficiency in growth signals Insensitivity to anti-growth signals Tissue invasion and metastasis Limitless replicative potential Sustained angiogenesis Evading apoptosis
A dog comes in with a mass on its limb, suspecting cancer, what is the first thing you should do?
Comprehensive history
- rapid vs slow growth
- tease out extent of involvement
- co-morbidities
Signalment assessment
-breed specific neoplasms
Complete PE
DIAGNOSTIC CYTOLOGY —> establish a tissue diagnosis
When doing a cytopatholgoy, all (most) cancer comes from what three distinct cell types?
Round cell
Mesenchymal cell
Epithelial cell
Best to worst, when doing cytopathology, which cell type has the best yield(exfoliation)?
Round > epithelial > mesenchymal
What is the cell type?
Individualized round cells arranged in a monolayer
Round cells
What is the cell type?
Spindle-shaped, stellate or oval shaped cells arranged individually or in non-cohesive aggregates
Mesenchymal
What type of cells?
Round, cuboidal, columnar, or polygonal cells arranged in cohesive sheets or clusters
Epithelial
Round, cuboidal, columnar, or polygonal cells arranged in cohesive sheets or clusters
DDX?
Carconoma
Eg squamous cell, adenocarcinoma, undifferentiated
Spindle-shaped, stellate or oval shaped cells arranged individually or in non-cohesive aggregates
DDX?
Sarcoma
Eg osteo, chondro, fibro, hemangiosarcoma
Individualized round cells arranged in a monolayer
DDX?
Lymphoma Mast cells Plasmacytoma Histiocytoma TVT
Melanoma (sometimes)
What are characteristics of malignancy?
Homogenous (cancer cell) vs heterogenous (inflamm)
Monomorphic (single lineage with uniform appearance) vs pleomorphic (malignant)
Cellular/cytoplasmic criteria - anisocytoisis (var in size), hyperchromasia, variable N:C ratio
Nuclear criteria - anisokaryosis (var in size), multiple nucleoli, increased mitosis
What are the advantages to cytopathology?
Non-invasive, low risk Low cost Rapid turnover of results Ability to evaluate morphological appearance of individual cells Highly specific
What are the disadvantages of cytopathology?
Low sensitivity (false -)
Poor sample quality
Small sample size
Inability to evaluate tissue architecture
In what cases can cytopathology not give you a diagnosis?
Oral and splenic tumors —> bleed a lot, may not get a good tissue spample
Feline mammary gland tumors -> may inflammatory cells (carcinomas generally have a lot of inflammation)
Mesenchymal tumors dont exfoliate well —> not always found with cytology
T/F: there is a high rate of needle tract implantation of neoplasms
False
Very low incidence
**except in urogenital neoplasms
What is the clinical techniques used for FNA?
Needle off (coring) —> mass is grasped and stabilized in non-dominant hand between thumb and index finger
—> needle is advanced through the mass and is redirected several times to dislodge cells
—>coring diminishes blood contamination of the specimen in vascular tissues
Needle on (suction)
What type of tumor is Alkaline Phosphate staining used??
Osteosarcoma
ALP is required for bone mineralization
Marker of osterobastic lineage
What is the difference between staging and grading ?
Staging = is the tumor localized/spread OR is there any evidence of advanced stage disease
Grading= establishes aggressiveness of tumor
T/F: cytology is used for grading tumors
False
Requires biopsy
What are tests used for staging a tumor?
MDB (CBC/chem/T4/UA/FeL/FIV) Regional LN cytology Three-view thoracic metastasis check (ie radiographs) Abdominal ultrasound (+/- FNA) Cross sectional imaging (CT/MRI)
When doing lymphnode cytology to stage cancer, you should be sampling the _______ node
Sentinel node -> not always the anatomic drainage pathway
