Lecture 13 2/24/25 Flashcards
What are the multifactorial components of canine lymphoma etiology?
-genetic
-epigenetic
-environmental
-immune-mediated
What are the three categories of lymphoma classifications?
-anatomic location
-histologic grade
-immunophenotype
What are the anatomic locations of lymphoma, from most to least common?
-multicentric/nodal (most common in dogs)
-alimentary
-cranial mediastinal
-atypical; cutaneous, CNS, ocular, etc.
Which lymph nodes can normally be palpated during exam?
-submandibular
-prescapular
-popliteal
Which lymph nodes can only be palpated with pathologic changes?
-axillary
-inguinal
What are the characteristics of multicentric/nodal lymphoma?
-non-painful, generalized lymphadenopathy
-often asymptomatic early on
-50% have liver and spleen involvement
-20% have cranial mediastinal lymph node involvement
-eventually infiltrates bone marrow
What are the clinical signs of alimentary lymphoma?
-vomiting
-diarrhea
-weight loss
-lethargy
What are the diagnostic findings in alimentary lymphoma?
-hypoproteinemia
-GI mass or diffuse intestinal thickening
-mesenteric lymphadenopathy
What are the clinical signs of mediastinal lymphoma?
-dyspnea
-cough
-exercise intolerance
What are the diagnostic findings in mediastinal lymphoma?
-cranial mediastinal mass
-possible pleural effusion
-hypercalcemia
What is the main differential for mediastinal lymphoma?
thymoma
What is the most common site for atypical lymphoma in dogs?
cutaneous
What are the clinical signs of cutaneous lymphoma?
-alopecia
-pruritus
-depigmentation
-scales/plaques/nodules
-ulceration
-possible peripheral lymphadenopathy
How is cutaneous lymphoma diagnosed?
-skin biopsy
-possible immunohistochemistry; always T cell lymphoma
What are the characteristics of intermediate/high grade lymphoma?
-more common
-aka large cell lymphoma
-involves immature cells/lymphoblasts
-shorter survival
What are the characteristics of low grade lymphoma?
-less common
-aka small cell lymphoma
-involves mature cells/lymphocytes
-longer survival
What is immunophenotype?
cell subtype based on surface markers/antigens
What are the lymphoma immunophenotypes in dogs?
-B cell; expresses CD21 and CD79a
-T cell; expresses CD3, CD4, and CD8
What are the characteristics of FNA cytology as a lymphoma diagnostic tool?
-100% sensitivity, 96% specificity for intermediate/large cell LSA
-quick
-cheap
-non-invasive
What are the characteristics of biopsy/histopath. as a lymphoma diagnostic tool?
-may be needed to diagnose small cell LSA
-can help to identify small cell LSA from reactive lymph nodes
Which tests are used to stage lymphoma?
-physical exam
-CBC/chem/lytes/UA
-thoracic rads
-abdominal rads/ultrasound
-bone marrow examination
-immunophenotyping
Which findings on physical exam indicate poorer lymphoma staging?
-peripheral lymphadenopathy
-organomegaly
Which findings on CBC indicate a poorer lymphoma staging?
-anemia
-thrombocytopenia
-neutrophilia
-lymphocytosis
Which findings on chem/lytes indicate a poorer lymphoma staging?
-hypercalcemia
-increased liver enzymes
-increased total bilirubin
What are the characteristics of urinalysis as a lymphoma staging tool?
-no lymphoma-specific abnormalities
-used to evaluate renal function and rule out UTI
What are the characteristics of thoracic rads as a lymphoma staging tool?
-will find abnormalities in 60-75% of cases
-20% will have cranial mediastinal masses; negative prognostic indicator
What are the characteristics of abdominal ultrasound as a lymphoma staging tool?
-50% of cases will have liver or spleen abnormalities
-no prognostic significance
When is bone marrow examination done on lymphoma patients?
when cytopenias are found on CBC
What are the characteristics of flow cytometry?
-identifies B vs T cell based on surface receptors
-requires many live cells
-detects CD3 on T cells
-detects CD21 and/or CD79a on B cells
What are the characteristics of PARR?
-identifies TCR or immunoglobulin receptors
-clonality indicates malignancy
-not as sensitive as immunophenotyping
-requires DNA samples
What are the WHO lymphoma stages?
1: one lymph node
2: multiple nodes on the same side of the diaphragm
3: generalized lymphadenopathy
4: liver and/or spleen involvement
5: bone marrow, peripheral blood, and/or atypical location
What are the two substages of WHO lymphoma stages?
a: healthy
b: sick
What are the treatment options for canine lymphoma?
-chemotherapy as the mainstay
-radiation therapy for localized lesions
-surgery for biopsy or to alleviate obstructions/single lesions
-supportive care; IV fluids, anti-nausea meds, antibiotics
What are the different categories of treatment response?
CR: complete remission
PR: partial remission; at least 30% reduction in lesion diameter sum
SD: stable disease
PD: progressive disease; at least 20% increase in lesion diameter sum
What are the characteristics of a frontline protocol?
-protocol of choice to induce remission
-finite number of treatments
-highest response rates and duration of remission
What are the frontline protocol options for lymphoma?
-CHOP (multi-drug)
-doxorubicin alone
-COP (CHOP minus doxorubicin)
What are the characteristics of CHOP?
-includes cytoxan, adriamycin, vincristine, and prednisone
-response rates of 85-95%
-MST of a year
What are the characteristics of single agent doxorubicin?
-response rates around 85%
-better response in B cell lymphoma
-MST around a year
-less frequent visits
-less expensive
What are the characteristics of COP?
-multiple schedule variations
-shorter survival time than protocols including doxorubicin
-less expensive
-less frequent visits after first month
What are the characteristics of a rescue chemo protocol?
-protocol used at time of relapse
-indefinite length of treatment
-lower response rates and durations
When is CCNU preferred?
-CNS lymphoma due to ability to cross BBB
-epitheliotrophic lymphoma
What are the characteristics of prednisone usage?
-used if chemo is out of question
-should not be given to asymptomatic/minimally symptomatic patients if owners are considering chemo
-does not prolong MST (2 months), just improves QOL
What are the three options in the event of relapse?
-re-induce with same protocol if dog has been in remission > 8 weeks
-rescue protocol if dog has been in remission < 8 weeks
-no additional chemo/prednisone only
What is the rule of thumb regarding remission?
second remissions last half as long as the first if re-inducing with a frontline protocol
What are the characteristics of tanovea?
-small molecule drug; not classic chemo
-inhibits DNA synthesis and proliferation to cause apoptosis
-mostly used as a rescue drug; inferior to CHOP
-causes derm. side effects and idiopathic pulmonary fibrosis
-not for use in westies; predisposed to lung side effects
What are the characteristics of laverdia?
-small molecule drug; not classic chemo
-mediocre response in patients
-common side effects of decreased appetite, anorexia, and vomiting
-can treat side effects with prednisone
What are the MSTs for various treatment options for canine LSA?
-12 months with multi-agent chemo protocol
-2 months with no treatment
-2 months with pred.; better QOL
What are the main prognostic indicators for canine LSA?
-clinical substage; “a” dogs do better
-immunophenotype; B cell has better prognosis
-histologic grade; small cell is better
What are the lesser prognostic indicators for canine LSA?
-hypercalcemia; neg. indicator
-cranial mediastinal mass; neg. indicator
-WHO stage; early stage better than late, but not strongly prognostic
-response to treatment; early response better
-treatment type; inclusion of doxorubicin is pos. indicator
-pre-treatment with pred.; neg. indicator
What are the characteristics of prednisone treatment as a negative prognostic indicator?
-induces the MDR-1 mediated resistance to chemotherapy; drugs are eliminated at faster rates
-should not be done in asymptomatic/minimally symptomatic dogs if owners are considering therapy
-can still be done for a few days in dogs that are symptomatic
