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Practical OncologyWendy Blount, DVM

1DefinitionsCancerThe state in which normal growth controlling mechanisms are permanently impaired, permitting progressive growth of cells without reaching growth equilibriumGrowth EquilibriumProduction of new cells = cell deathNo net gain of tissue (liver) (heart)

DefinitionsHyperplasiaNormal tissue response to noxious stimuliReversible when regeneration is completeNeoplasiaCell replication never turns offAnaplasiaLack of cell differentiaion

DefinitionsMalignantpropensity to spread by recurring locally and/or metastasizingMitotic IndexNumber of mitotic figures per high power field

DefinitionsCarcinomaCancer arising from ectodermal or endodermal tissuesSarcomaCancer arising from mesodermal tissues

DefinitionsGrade (based on histopathology)Grade I behaves most benignlyGrade III behaves most malignantlyStage (based on tests to determine extent of tumor invasion)Stage I is the least invasiveStage 4-5+ are most invasive, and often carry poor prognosis for cure

What Causes Cancer?Genetic derangement of the things that normally eventually turn cell replication offFaulty differentiation of pluripotent stem cellsNOT anaplasia of differentiated cellsExcept in rare circumstancesCancer most often arises from cells that continually replicate

What Causes Cancer?Cancer is a disease of agingodds of aberrant cell division increasesImmune surveillance weakensCell repair mechanisms failGenetic injury by exposure becomes more likelyExposure to carcinogensInfection by viruses carrying oncogenesPhysical damage by trauma or irritationWhat Causes Cancer?OncogenesVirus RNA that causes cancer when incorporated into host genesOncogenes make growth factors that are most often kinasesBasis of the new TKI anticancer drugsWhat Causes Cancer?Lost Tumor Suppressor genesNormal people and animals have theseThe are lost in some individuals that will have genetic tendencies to particular pediatric cancersRetinoblastomaOsteosarcoma What Causes Cancer?Cancer Cell ImmortalizationNormally a cell line eventually dies out because the telomeres required for cell division are used upTelomerase allows extension of the telomeres for cell division ad infinitumTelomerase products are sold as health food supplements to combat agingWhat Causes Cancer?Apoptosis defectsApoptosis programmed cell deathImportant to growth equilibriumSome genetic mutations eliminate apoptosisWhat Causes Cancer?It can take many years for a malignant cell to produce a detectable tumorWith senescence, odds of aberrant cell division increasesExposure to carcinogensInfection by viruses carrying oncogenesPhysical damage by trauma or irritationWhat Causes Cancer?Biology of metastasisCancer cells shed into blood or lymphaticsEvade immune surveillanceCome to rest in capillary or lymphatic vessel bedsDisrupt the basement membrane (proteases, metalloproteinases) New blood supply grows (angiogenesis)Treatment ModalitiesSurgery and RadiationLocal controlException whole body radiation for lymphomaChemotherapyTo manage widespread disease that is chemo responsiveTo slow progression of metastatic disease

Treatment ModalitiesMetronomic ChemotherapyLow dose, long term chemoGenerally well toleratedFor less aggressive tumorsFor palliation for advanced tumor stages

Cytology BasicsIs cellularity adequate? are there plenty of cells?Are the cells those you intended to sample?Are there cells other than RBC?If there are few cells, is it possibly a cyst or hematoma?Are the nucleated cells WBC or other cells?If WBC, are they lymphoid cells?

Cytology BasicsAre the lymphoid cells uniform or of various stages?Various stages indicates inflammatory lymphoid responseAll lymphoblasts large cell lympomaAll plasma cells plasmacytoma, myelomaAll lymphocytes can be normal in lymph node or spleenLymphocytic tumors can require histopathology

Cytology Basics6. If non-lymphoid WBC, what kind?Neutrophils suppurativeDegenerate toxic neutrophils septicNeutrophils + macrophages pyogranulomatousMacrophages granulomatousEosinophils, basophils allergic, parasiticMott cells, plasma cells chronic antigenic stimulationFibroblasts can accompany chronic inflammation

Cytology BasicsAre cells round, epithelial or mesenchymal?Nuclei round - round cells and epithelial cellsNuclei and cytoplasm oblong with mesenchymal cellsClustering Epithelial cells are clustered look for cell-to-cell adhesionsNo cell-to-cell adhesion with round cells or mesenchymal cellsCytoplasmic borders are distinct for round cells and epithelial cellsAll three cell types present anaplastic sarcoma

Cytology Basics

Julie Bradford Tyler TXMelissa Riley Houston TXRosalie Cooper-Chase Crockett TXCytology Basics

Round CellsCytology Basics

Mesenchymal CellsCytology Basics

Epithelial CellsCytology Basics

Anaplastic melanomaCytology Basics8. Are there characteristics of malignancy?Cells arent normally found thereIncreased blast cellsChanges in nucleusIncreased, abnormal mitotic figuresEspecially odd number of poles Hyperchromatic nucleusProminent or abnormal nucleoliUnexpected multinucleationEspecially different sizes

Cytology Basics8. Are there characteristics of malignancy?Changes in cytoplasmLoss of differentiation Changes in CellIncreased N:C ratio (nucleus takes over the cell)Cell polymorphism variation in size and shape

Cytology Basics9. Is sufficient inflammation present to explain dysplasia?No strong characteristic of malignancyMesothelial cells, macrophages and fibroblasts can look very dysplastic in response to severe inflammation

Cytology Basics

Cytology Basics

Cytology Basics

Cytology Basics

Cytology Basics

Cytology BasicsBarton Cytologic RubricIs it inflammatory or non-inflammatory?Is it round cell, epithelial cell, or mesenchymal cell?Are there characteristics of malignancy?Are they weak or strong?

Cytology BasicsTechnique TipsTry coring with needle only prior to attaching a syringe for aspirationStart with a 22 or 25 gauge needleIf inadequate cellularity, try a bigger needle and/or aspirationUse a 10-12cc syringe to spray the sample quickly onto a slideSmear gently vertical for lymph nodes and testicles

Cytology BasicsMalignant is a reasonable cytologic diagnosisBenign is almost never a cytologic diagnosisCytology can not distinguish malignancy from wicked inflammationIf the lump changes, aspirate it again