Oncology Flashcards
Lymphoma, TCC, MGT, Hemangiosarcoma, Endocrine
Hematologic Malignancies
What is the common presentation of lymphoma in the canine?
presentation, stage and substage
What are the five stages and two substages?
Stage
1: Single enlarged lymph node (ln) or organ
2: Enlarged regional lymph nodes on one side of diaphragm
3: Generalized peripheral lymphadenopathy
4: Hepatosplenic involvement
5: Bone marrow involvement or extranodalsites (e.g. ocular, spinal, etc)
Substage
a: asymptomatic (feeling good) –80%
b: symptomatic (sick) –20% (more often T cell phenotype)
LEARNING OBJECTIVE: 80% of dogs are stage III or IV; most are substage a
What is the most common clinical presentation of canine lymphoma?
Multicentric lymphoma (~80% of cases) with generalized peripheral lymphadenopathy
Often asymptomatic in early stages (WHO substage A) and presents with non-specific systemic signs in later stages (substage B) such as lethargy, weight loss, and anorexia.
List five prognostic factors for canine lymphoma.
- Immunophenotype
- WHO Clinical Stage
- WHO Substage
- Response to Initial Chemotherapy
- Presence of Hypercalcemia
What is the prognosis for B-cell lymphoma compared to T-cell lymphoma in canine lymphoma?
B-cell lymphoma has a better prognosis and responds well to chemotherapy, while T-cell lymphoma has a worse prognosis and is often associated with hypercalcemia
A common mnemonic is ‘B is better, T is terrible.’
What are the distinguishing features between indolent and aggressive forms of lymphoma?
- Indolent lymphoma: Slow progression, minimal clinical signs, may not require chemotherapy
- Aggressive lymphoma: Rapid progression, systemic illness, standard treatment is CHOP chemotherapy
What characterizes large cell lymphoma (LCL) in cats?
- Acute, rapid progression
- Severe weight loss, vomiting, diarrhea
- Often presents with a palpable mass and significant lymphadenopathy
What characterizes small cell lymphoma (SCL) in cats?
- Chronic, slow progression
- Mild to moderate weight loss, intermittent GI signs
- Diffuse intestinal thickening without a palpable mass
What treatment is typically recommended for large cell lymphoma in cats?
CHOP chemotherapy (Cyclophosphamide, Doxorubicin, Vincristine, Prednisone) or COP (Cyclophosphamide, Vincristine, Prednisone)
Surgery may be performed for resectable masses.
What diagnostic tests are used to differentiate small cell gastrointestinal lymphoma from inflammatory bowel disease (IBD)?
- Abdominal Ultrasound
- Endoscopic Biopsy
- Full-thickness Biopsy
- Immunohistochemistry (IHC)
- PCR for Antigen Receptor Rearrangement (PARR)
Which canine breeds are most at risk for invasive urothelial carcinoma (iUC)?
- Scottish Terrier
- West Highland White Terrier
- Shetland Sheepdog
- wirehaired fox terrier
- Beagle
What is the BRAF mutation test useful for in clinical practice?
It detects the presence of the BRAF mutation in urine samples, aiding in early diagnosis of iUC, distinguishing iUC from benign conditions, and monitoring for recurrence
can use free catch
High specificity (100%) makes it a valuable diagnostic tool.
What are the MGT tumor types in canine and feline and percent malignancy?
what are the benign types? what are the malignant types?
Canine
50% benign
Adenoma
Fibroadenoma
Benign mixed tumor
Duct papilloma
50% malignant
Carcinoma
Sarcoma
Carcinosarcoma
Feline
10-15% benign
Hyperplasia
Adenoma
Fibroadenoma
85-90% malignant
Majority carcinoma
Sarcoma and carcinosarcoma rare
Dogs spayed before their first heat cycle have only a 0.5% risk of developing MGTs.
What are the key prognostic factors for canine mammary gland tumors?
- Tumor Size
- Lymph Node Status
- Histologic Grade
What is the difference in surgical approach to mammary tumors between dogs and cats?
Dogs typically undergo lumpectomy or mastectomy, while cats often require chain mastectomy due to the high malignancy rate of feline mammary tumors
80% to 90% of feline MGTs are malignant.
What is the median survival time for large cell lymphoma in cats with chemotherapy?
6-9 months with chemotherapy
Large cell Gastrointestinal
~75% response to chemo treatment
* 50% of responders have MST 6-8 months
* 25% of responders have MST 12 months or longer
~25% no response to chemo treatment
Prognosis is poor (<4-6 weeks)
What is the median survival time for small cell lymphoma in cats with treatment?
2-3 years with treatment
Feline Small Cell GI LSA prognosis:
90% response rate with chlorambucil/prednisolone therapy
Median survival time 2-3 years or more with treatment
Some cats may experience long remission and can taper off treatment after 1-2 years on continuous therapy
Some cats may go on to develop more aggressive form of lymphoma (e.g. large cell lymphoma)
What are the two main chemotherapeutic agents used for advanced disease in dogs and cats?
Doxorubicin and carboplatin
Why is hormonal therapy less effective for certain tumors?
Due to low hormone receptor expression
What are strong predictors of survival in tumors?
Tumor size and lymph node involvement
What histologic grade indicates a worse outcome?
Poorly differentiated tumors
What significantly reduces mammary tumor risk in dogs and cats?
Early spaying
What are critical prognostic factors for mammary gland tumors (MGTs)?
- Tumor size
- Lymph node involvement
- Histologic grade
What is the mainstay of treatment for MGTs?
Surgery
What type of carcinoma carries a poor prognosis and requires palliative care?
Inflammatory carcinoma
What are common presenting signs in dogs with visceral hemangiosarcoma?
- Acute lethargy
- Weakness
- Collapse
- Shock from internal hemorrhage
What steps are involved in stabilizing a dog with hemangiosarcoma?
- IV fluid resuscitation
- Oxygen supplementation
- Blood transfusion if severe anemia
- Analgesia and supportive care
What diagnostic tests are used for Cushing’s Syndrome?
- Low-dose dexamethasone suppression test (LDDS)
- Abdominal ultrasound
What is the preferred imaging method for assessing caval invasion in pheochromocytoma?
CT with contrast
What is the main surgical procedure for localized splenic hemangiosarcoma?
Splenectomy
What is the median survival time (MST) for splenic hemangiosarcoma with surgery alone?
19–86 days
What can increase the MST for splenic hemangiosarcoma when combined with surgery?
Chemotherapy
What is the prognosis for cardiac hemangiosarcoma?
Poor; MST ~1–3 months
What is the most common type of adrenal tumor?
Adrenocortical tumors
What syndrome is caused by functional adrenocortical tumors?
Cushing’s Syndrome
What is the classic triad of symptoms for insulinomas?
- Hypoglycemia
- Neuroglycopenic signs
- Resolution of signs with glucose supplementation
What is the preferred treatment for resectable thyroid tumors?
Surgical removal
What are common complications of thyroid tumor surgery?
- Hemorrhage
- Laryngeal paralysis
- Hypothyroidism
- Aspiration pneumonia
What is the median survival time for freely movable thyroid tumors?
Approximately 3 years
What is a common treatment for unresectable insulinomas?
Medical management with prednisone, diazoxide, and octreotide
What factor can significantly influence the prognosis of adrenal tumors?
Tumor invasiveness
What is the median survival time for insulinomas at Stage I?
Approximately 766 days
Fill in the blank: The mainstay of treatment for hemangiosarcoma is _______.
Surgery
True or False: Chemotherapy is the primary treatment for thyroid tumors.
False
What are the treatment options for thyroid tumors?
- Surgical removal
- Radiation therapy
- Iodine-131 (I-131) therapy
- Chemotherapy
