oncology 5 Flashcards
blood tests for cancer that have some use in dogs?
- cell-free DNA
- nucleosomes
> small fragments of DNA wrapped around a histone
what is a cell free DNA test? what can it detect? what types of cancer is it useful for and what information does it give us?
- apoptosis and necrosis of tumour cells releases cfDNA into blood
- detect mutations from 30 types of cancer
- most mutations cannot be confidently linked to a specific cancer yet
- only report the suspected cancer type for some instances of canine lymphoma, for which the assocaited mutations are well-defined
> otherwise, the results will only indicate whether cancer-related mutations were found or not found - “cancer signal detected”
()
results in trial: - Sn 54.7%
- Sp 98.5%
what are nucleosomes and what is their use in cancer detection? limitations?
- small fragments of DNA wrapped around a histone octamer core
- nucleosome quantiffication can identify patients who may have a cancer
> must then be confirmed by follow up procedures
> will not differentiate between systemic inflammatory illness and cancer
nucelosome blood test is best at detecting what type of cancers? Sn and Sp?
- best detects systemic cancers with a high cellular turnover rate
> identified 82% of hemangiosarcoma & 77% of lymphomas
> detected 49.8% of all cancers in dogs with specificity of 97%
how to biopsy a urothelial carcinoma and why?
- ultrasound-guided traumatic catheterization biopsy, biopsy via cystoscopy, or surgical
biopsy (change gloves & equipment) - spreads easily by seeding, therefor not aspirated through unaffected areas
molecular (gene) testing is useful for what type of cancer (at least in people)? what type of test for dogs? how good is it?
urothelial carcinoma
> looks for gene mutations
* CADET® BRAF for Diagnosis & Monitoring of
Canine TCC/UC
* evaluates urine for cells with the BRAF mutation or specific copy number variations
(CNV) associated with TCC/UC
* identify 95% of TCC/UC cases
* extremelylowlimitofdetectionof10
mutation‐bearing cells allows early diagnosis
what is fidocure?
Precision Medicine
* DNA sequencing of tumour >. allow targetted therapies
what is vidium animal health and its use?
- SearchLight DNA
- next generation diagnostic test that identifies mutations in 120 cancer genes
- “identifies drug therapies that target those
specific mutations as well as therapies that are unlikely to be effective or may even result in accelerated tumor growth”
() - in human oncology, “precision therapies” exist that are directed against a cancer’s specific mutations
- fewer precision therapies exist in veterinary medicine > will become increasingly available as we increase our understanding
hemangiosarcoma clinical signs depend on
- anatomic site
– +/‐ metastases
– tumour size
– tumour rupture - coagulopathies
hemangiosarcoma clinical signs / presenting complaints, depending on their underlying cause:
- Anatomic site
> muffled heart sounds
> weak femoral pulses - tumour size
> abdominal distension
> noticeable subcutaneous mass - coagulopathies
> bruising
> pale mucous membranes - tumour rupture
> collapse
> lethargy (sometimes repeated episodes)
> pale mucous membranes
> abdominal distension - cardiac arrhythmias
> lethargy
> collapse
how often are splenic masses neoplastic? how many of these are HSA vs other possibilites? what increases this likelihood?
- 2/3 are neoplastic
> 2/3 of these are hemangiosarcoma
> increased likelihood of HSA if hemoabdomen - other neoplasms:
> lymphoma
> MCT
> malignant histocytosis
> soft tissue sarcoma
non-neoplastic splenic mass possibilities
- hematoma
- hemangiosarcoma
- extra-medullary hematopoiesis (EMH)
options for splenic mass diagnosis, and how good they are:
– Abdominal ultrasound (US)
> visualize mass - cavitated vs. solid, solitary vs. multiple?
> abdominal effusion?
– Fine needle aspirate (FNA) + cytology of mass
> low yield for HSA
> may not be low yield for other splenic tumour types
– Diagnostic abdominocentesis + cytology
> low yield for diagnosis
> characterize effusion
» Does the peripheral PCV = effusion PCV?
- Excisional biopsy
> splenectomy
> often only way to diagnose HSA - Immunohistochemistry (IHC)
> may be needed for diagnosis
> Von Willebrand factor antigen, CD31
3 common primary sites for hemangiosarcoma
- spleen (28-50%)
- right atrium and auricle (3-50%)
- skin or subcutaneous (13%)
Other sites:
- liver, kidney, bladder, prostate, lung, etc.
cardiac mass differential diagnoses
– Neoplasia
* Hemangiosarcoma*
* Chemodectoma (heart base mass)
* Ectopic thyroid carcinoma
* Lymphoma
