19 – Oncology 1 Flashcards
Is cancer common?
- Yes
- 1 in 4
- Fatal and difficult to treat
What are the 3 parts of cancer diagnostics?
- Diagnosis
- Staging
- Treatment
What are some tools used to make a cancer diagnosis?
- FNA
- Biopsy
- Bone marrow sampling
- Clonality test
- Flow cytometry
FNA technique
- Use 22-23G needles
o Look in hub to see if you are getting anything - Ultrasound guidance
- *Mast cells tumors release histamines=can get ulcer, allergic reaction, bruising
o Give ANTI-HISTAMINES immediately (might have a suspicion, but hard to know)
What are some cytology tips/questions you can ‘ask’?
- Are there nucleated cells?
- Is the population uniform?
- **What types of cells are they?
a. Epithelial
b. Mesenchymal
c. round - Malignancy criteria?
Epithelial cells
- Coming from surface (ex. skin, organs, glands)
- They are ‘good friends’, want to be close together=CLUSTERED
Mesenchymal cells
- Spread out, no tight connections
- Unique feature of having a spindle shaped tail
- Ex. sarcomas
Round cells
- Cancer of BLOOD=round, individualized
What cell type?
-mesenchymal
What cell type?
-round cell
>mast cell tumor (histamine inside=dots)
What cell type?
-round cell
>lymphoma
What are the DDx of round cell tumors?
- Lymphoma
- Mast cell tumor
- Histiocytic sarcoma
- Histiocytoma
- Plasma cell tumor (B-cells, clear around nucleus=antibodies)
- Melanoma
Histology
- Look at invasiveness
- Adenoma: clear border, encapsulated=benign
- Adenocarcinoma: invasive=malignant
What are some types of tissue biopsy?
- Tru-Cut: usually so it doesn’t bleed right away
- Punch: superficial, easy to handle
- Wedge: if can’t safely do punch or mass is bigger
- Excisional: when a mass is small, wont get great margins but will use to get a diagnosis
When to biopsy?
- What are your differential diagnosis?
- Does the result change my CASE MANAGEMENT?
a. If DDx: plasma cell tumor or histiocytoma=will excise either way
b. If histiocytic sarcoma, soft tissue sarcoma or hemangiosarcoma=will treat DIFFERENTLY
What is included in the histopathology report?
- Diagnosis
- Grade and mitotic count (# of cells in mitosis)
- Margins
What do you do if histo does not fit with the clinical picture?
- Get a second opinion
- Clinical decision change:
o Major: 17-39%
o Minor: 14-21%
What do you use immunohistochemistry (IHC) for?
- Diagnostic confirmation
a. Ex. undifferentiated cancer
b. Figured out it was histiocytic sarcoma - Prognosis
a. Ex. mast cell tumor
b. Figured out: high metastatic risk/poor prognosis
*use specific antibodies to stain specific proteins
Some cancers may not form a mass: what might be seen on the blood work?
- Cytopenia
- Increased cell count
- Circulating atypical cells
- Monoclonal gammopathy
- *can do bone marrow testing
Bone marrow sampling:
- Sedation or GA
- Use bone marrow needles (bigger than FNA needles) to get core of bone marrow and aspirate
- Ex: sternal with 22G needle
- Spots: ilial wing, proximal humerus, femur
*What tests can be done if you are unsure if it is neoplastic or reactive lymphocytes?
- PCR for antigen receptor rearrangement (PARR) (ex. B-cell vs. T-cell)
o Lymphoma: monoclonal
o Reactive lymphocytes: polyclonal
o *gene test: so cells can be dead - Flow cytometry for lymphocytes
o Lymphocytes in fluid: passed through and laser gathers information (ex. T-cell vs. B-cell, size, what they are expressing)
o *cells NEED to be ALIVE
Liquid biopsy: cancer screening example
- IDEXX cancer Dx testing
- *not tested that well
