Term
| What 5 concepts make up the biologic basis of radiation therapy? |
|
Definition
Repair (of sublethal DNA damage)
Repopulation
Reassortment
Reoxygenation
Radiosensitivity |
|
|
Term
|
Definition
| stressed cells (normal and abnormal) increase proliferation |
|
|
Term
| Reassortment aka redistribution |
|
Definition
| cells in different phases of the cell cycle are more (ie. mitotis), or less (ie. G1), radiosensitive --> selective killing of sensitive cells --> synchronization of cell cycle in treated cell populations |
|
|
Term
|
Definition
| hypoxic cells are less radiosensitive. As cells adjacent to the blood supply are killed peripheral tissues enjoy increased vascularization and subsequent increased radiosensitivity (ie. kill the tumor from the inside out) |
|
|
Term
|
Definition
varying cell responses to radiation treatment (ex. apoptosis, interphase death, mitotic delay)
ie. how easily are cells killed by radiation, what is the response of the cells exposed to radiation |
|
|
Term
| What are the three types of radiation therapy |
|
Definition
Teletherapy (external beam radiotherapy)
Brachytherapy (application of radioactive materials to localized regions, interstitial, surface, or intracavitary)
Systemic (Oral or IV administration ex. I131 to tx hyperthyriodism) |
|
|
Term
| What is the only type of radiotherapy the results in a patient that is NOT radioactive following treatment? |
|
Definition
| teletherapy (external beam radiotherapy) |
|
|
Term
| What are the main differences in dose and protocol between curative and palliative external beam radiotherapy protocols? |
|
Definition
Curative: smaller doses(fractions) at increased frequency --> less damage to differentiated/late reacting tissues (ex. nerves, parenchymal organs etc.)
Palliative: higher doses less frequently administered (we don't need to worry about damaging late responding tissues because the patient will not live long enough for the negative impact to manifest) |
|
|
Term
|
Definition
| dose at which sing hit killing = multi hit killing |
|
|
Term
| What type of tissue have a high a/b ratio? Which have a low a/b ratio? |
|
Definition
acutely responding tissues have a high a/b (ex. gut, skin, hematopoetic)
Late responding tissue have a low a/b (ex. parenchymal organs) <-- in order to limit damage to these tissues give small frequent doses |
|
|
Term
| When would you use an electron beam for radiotherapy? |
|
Definition
| to treat external lesions, electon beams spare sensitive deeper structures |
|
|
Term
| When treating deep structures with radiotherapy what type of atomic particle should you choose? |
|
Definition
| Photon beam, more effective at penetrating to deeper structures than electron beams |
|
|
Term
| What type of radiotherapy protocol can be used as an adjuvant to chemotherapy in the treatment of lymphoma? |
|
Definition
| half body protocol (treat half the body, wait one month, treat the other half of the body) |
|
|
Term
| Increased cortisol --> catabolic state, impaired healing, altered fluid homeostasis, and adverse GI/pulmonary/cardiovascular/behavioral effects can all arise due to inadequate attention to which facet of cancer therapy? |
|
Definition
| inadequate pain management |
|
|
Term
| How can you minimize "wind up" or heightened sensitivity to pain? |
|
Definition
| treat early and give pre-emptive analgesia before a painful procedure (prevents sensitization and improves post-op analgesia) |
|
|
Term
| What are the types of adaptive pain? |
|
Definition
Nociceptive (transient, protect against environmental hazards)
Inflammatory (tissue damage -> release of inflammatory mediators -> sensitize neural pathways -> increased perception of pain) |
|
|
Term
| What are the types of maladaptive pain? |
|
Definition
functional (inappropriate management of functional pain -> hypersensitivity of neural pathways to pain "wind up" -> abnormal processing of normal sensory input)
neuropathic (damage to the nervous system -> spontaneous pain and hypersensitivity) |
|
|
Term
| Describe the origin and sensation of visceral pain |
|
Definition
| stretch, distention, or inflammation of the viscera --> poorly localized, deep/cramping/aching pain |
|
|
Term
| describe the origin and sensation of somatic pain |
|
Definition
| damage to the skin, muscles, bones, or joints --> localized, constant, sharp/aching/throbbing pain |
|
|
Term
| describe the origin and sensation of neuropathic pain |
|
Definition
| injury to PNS or CNS --> burning/shooting/tingling pain +/- motor, sensory, or autonomic deficits |
|
|
Term
| What are some behavioral signs indicative of pain? |
|
Definition
| decreased activity/lethargic attitude, decreased appetite, decreased grooming, restlessness, interrupted sleep, hiding, aggression, vocalization |
|
|
Term
| What are some physiologic signs indicative of pain? |
|
Definition
| tachycardia, tachypnea, hypertension, dilated pupils |
|
|
Term
| What are two examples of systemic radiation therapy? |
|
Definition
Iodine 131 -> tx thyroid cancer (i.e. hyperthyroid cats)
Samarium -> tx bone cancer |
|
|
Term
| what are some characteristics of an adjuvant analgesic? |
|
Definition
| weak solo analgesia however when used in combination with a traditional analgesic lower doses can be used to attain the same effect; therefore, side effects are lessened. |
|
|
Term
| T/F you can attain better client compliance if you instruct the client to provide pain control on an as-needed basis |
|
Definition
FALSE
this may result in delayed treatment of pain --> wind up and may necessitate higher doses |
|
|
Term
| What is the main biochemical mechanism of NSAIDs? |
|
Definition
| inhibition of cyclooxygenase |
|
|
Term
| What are four characteristics of cancer cell growth? |
|
Definition
| growth in the absence of stimulus, entire cell population arises from a single abnormal cell, retention or gaining capacity for self renewal, inability to fully differentiate |
|
|
Term
|
Definition
| oncogenes encode for proteins that can cause neoplastic cellular transformation (dominant effect [one hit] -> gain of function mutation) |
|
|
Term
|
Definition
| genes responsible for the control of cellular division and differentiation --> upon activation proto-oncogenes can be transformed into oncogenes |
|
|
Term
| define tumor-suppressor gene |
|
Definition
| tumor suppressor genes are cell proliferation inhibitors (recessive effect [2 hit] -> loss of function mutation) |
|
|
Term
| Why is cancer metastasis clinically significant? |
|
Definition
| metastasis is the cause of 90% of deaths from solid tumors |
|
|
Term
| What four features of tumors resemble non-healing wounds? |
|
Definition
| constitutively leaky capillaries -> clumps of fibrin in tumor associated stroma, high levels of PDGF, myofibroblasts in tumor associated stroma -> allow for mobilization of growth factors, agents that inhibit tumor associated angiogenesis also inhibit wound healing |
|
|
Term
| Describe the clonal evolution theory of tumor development |
|
Definition
| all of the cells in a tumor originate from a single cell that initially undergoes a neoplastic mutation |
|
|
Term
|
Definition
| cells within a tumor that possess the capacity to self renew and give rise to the heterogenous lineages that comprise the tumor. These cells retain multipotent capacity. |
|
|
Term
| T/F, both RNA and DNA viruses can cause tumors in domestic animals and humans |
|
Definition
|
|
Term
| What is most likely the causative agent of equine sarcoids? |
|
Definition
| bovine papillomaviruses (BPV) |
|
|
Term
| What is the major way that DNA viruses induce neoplastic transformation in host cells? |
|
Definition
| most DNA viruses carry genes that inactivate tumor suppressor pathways (ex. Rb or p53) --> cellular proliferation |
|
|
Term
| T/F most DNA viruses have lost their lytic capacity |
|
Definition
|
|
Term
| What is the hypothesis for the emergence of FeLV? |
|
Definition
| FeLV is a retrovirus with a high genetic similarity to MuLV (mouse virus). FeLV is thought to have arisen from cross-species (ie. mouse to cat) transmission of MuLV |
|
|
Term
| Which viral proteins protect FeLV RNA from enzymatic destruction in the host? |
|
Definition
|
|
Term
| Which viral protein binds to receptors on cat cells to initiate FeLV infection? |
|
Definition
| gp70 (there are three serotypes: A,B,C) type A is the dominant virus in nature, B and C arise from mutation and recombination of type A feLV with endogenous (inactive) retroviruses |
|
|
Term
| What percentage of cats infected with FeLV do NOT develop disease? |
|
Definition
| 60-65%, these animals will also have a negative ELISE |
|
|
Term
| What three tests can be used to diagnose FeLV? |
|
Definition
ELISA (whole blood or serum)
IFA (bone marrow)
PCR
Vaccination does NOT compromise dx |
|
|
Term
| You should recommend the FeLV vaccine for what population of cats? |
|
Definition
| multiple cat households, outdoor animals in endemic areas |
|
|
Term
| T/F Vaccinating FeLV infected cats is of no value |
|
Definition
| TRUE, cats should be tested before the initial vaccination and should be tested if there is a history of exposure |
|
|
Term
| Okay, your cat just tested positive for FeLV, what are five management practices you should adopt? |
|
Definition
Keep the cat indoors
Limit the cat's exposure to uninfected cats
Feed a balanced feline diet
Diligent parasite control
Semi-annual wellness exams |
|
|
Term
| 1/4 of all canine cancer is represented by which type? |
|
Definition
|
|
Term
| What is the most common manifestation of canine lymphoma? |
|
Definition
| multicentric with with generalized, painless, lymphadenopathy |
|
|
Term
| Which technique of collecting FNA is prepherable for diagnosing suspected neoplasia (if lesions are not hard, or very small)? |
|
Definition
| sewing needle/woodpecker is preferable for collection, neoplastic cells are fragile and syringe aspiration can cause them to rupture --> non-diagnostic; however, for poorly exfoliating tumors may be necessary to use negative pressure to collect a sample |
|
|
Term
| what is the ctyologic difference between a reactive lymph node and a lymph node with lymphoma? |
|
Definition
reactive -> 75-80% small lymphocytes, 0-25% plasama cells, lymphoblasts, neutrophils and macrophages
Lymphoma -> >50% lymphoblasts |
|
|
Term
| What are the two most common paraneoplastic syndromes associated with lymphoma? |
|
Definition
| mild anemia and hypercalcemia (often associated with T-cell lymphoma --> poorer prognosis) |
|
|
Term
| What are the two most common paraneoplastic syndromes associated with lymphoma? |
|
Definition
| mild anemia and hypercalcemia (often associated with T-cell lymphoma) |
|
|
Term
| What is the strongest single agent chemotherapy used against high grade (ie. lymphoblastic) lymphoma? |
|
Definition
| Doxorubicin --> 60-70% response rate with a remission duration of 6-7 months |
|
|
Term
| What is the most commonly used multiple agent chemotherapy protocol for high grade (ie. lymphoblastic) lymphoma? |
|
Definition
CHOP:
cyclophosphamide
hydrodoxydaunorubicin (doxorubicin)
oncovin (vincristine)
prednisone
80-90% respond, remission duration 9-12 months |
|
|
Term
| What is the most important element of novel therapy diets for the treatment of lymphoma in dogs? |
|
Definition
|
|
Term
| How frequently should you recheck patients in remission? |
|
Definition
|
|
Term
| How common is low grade (ie. small cell) lymphoma in canine patients and what therapy is indicated in these patients? |
|
Definition
<30% of canine lymphoma
histopath is often necessary for dx
most patients have NO clinical signs and therapy is often ineffective (few neoplastic cells in growth phase) |
|
|
Term
| What is the most important factor in prognosticating canine lymphoma? |
|
Definition
| histologic type (small cell (lymphocytic)/low grade -> good prognosis, vs. large cell (lymphoblastic)/high grade -> poorer prognosis) |
|
|
Term
| T/F Today most cats with lymphoma are FeLV or FIV positive |
|
Definition
| FALSE (<15% of all cases) |
|
|
Term
| What are the more common locations for lymphoma in cats that are FeLV negative? |
|
Definition
| alimentary (most common! 2/3 have palpable abdominal mass) and extranodal |
|
|
Term
| What signalment is most commonly associated with mediastinal lymphoma in cats? |
|
Definition
young siamese
also more common in young cats with FeLV (but FeLV is much less common now) |
|
|
Term
| lymphocytic (small cell/low grade) GI lymphoma can be challenging to differentiate from IBD, what is a more effective method than FNA or histopathology? |
|
Definition
| immunohistochemistry, will differentiate between monoclonal populations of lymphocytes (lymphoma) and mixed populations of lymphocytes (IBD) |
|
|
Term
| What is the treatment of choice for lymphocytic (small cell/low grade) lymphoma? |
|
Definition
| prednisone +/- chlorambucil |
|
|
Term
| T/F lymphoma of large granular lymphocytes (LGL) is poorly responsive to therapy, even multiagent treatment |
|
Definition
True
LGL thought to originate from NK cells or cytotoxic T cells |
|
|
Term
| What is the most important element of diet therapy for the treatment of GI lymphoma in cats? |
|
Definition
| hypoallergenic diet may be used given the association between IBD and GI lymphoma |
|
|
Term
| What cell type is most commonly implicated in leukemia? |
|
Definition
|
|
Term
| What is the most consistent clinical feature of acute lymphoblastic leukemia? |
|
Definition
| circulating lymphoblasts on CBC +/- peripheral cytopenias |
|
|
Term
| How is chronic lymphocytic leukemia differentiated diagnostically from acute lymphoblastic leukemia? |
|
Definition
| well differentiated lymphocytosis on CBC (vs. acute blastic leukemia --> peripheral lymphoblasts), dx with bone marrow biopsy |
|
|
Term
| what is the most common presentation and treatment for extramedullary plasma cell tumors? |
|
Definition
| dermal tumors are the most common presentation, metastasis rare so surgical excision is treatment of choice |
|
|
Term
| What type of hematapoetic neoplasia is common in young dogs (<3yrs) and is self limiting? |
|
Definition
| histiocytoma (present as benign dermal masses) |
|
|
Term
| Unlike histiocytoma histiocytic sarcoma is highly metastatic and carries a very poor prognosis. What breed is predisposed to this neoplasia and are are the two most common locations? |
|
Definition
Bernese Mountain Dogs
most often occur in skin/sq or spleen |
|
|
Term
| cancer staging involves ____ |
|
Definition
| diagnostic testing (PE, minimum database, regional LN aspirates, imaging) to determine local invasion or metastasis of a tumor |
|
|
Term
| What are some potential disadvantages to FNA aspirate in the workup of a cancer patient? |
|
Definition
| cannot grade (requires histopath), false negatives (cytologically benign but biologically aggressive - anal sac/thyroid) and false positives (reactive tissues - inflamed oral masses) |
|
|
Term
| What is the most important consideration before choosing a biopsy technique for histological grade? |
|
Definition
| consider to definitive surgical technique to ensure that the entire biopsy tract can be removed at this time. |
|
|
Term
| What is the definition of cancer grade? |
|
Definition
| a scoring of the histological features of the cancer (requires biopsy) |
|
|
Term
| What is the definition of cancer stage? |
|
Definition
| the physical extent of the tumor (ex. size of primary tumor, anatomic location of mets) |
|
|
Term
| Why is it important to collect a minimum database (CBC/Chem/UA) when staging cancer patients? |
|
Definition
| these results allow the clinician to identify and characterize any paraneoplastic syndromes, organ dysfunction (metastasis and/or help to guide treatment protocol decisions), concurrent unrelated disease that could affect overall prognosis |
|
|
Term
| T/F regional lymph nodes that palpate normally should still be sampled when staging a cancer patient |
|
Definition
| True! Normal LN may have mets, and enlarged LN may simply be reactive, esp. if tumor incites a strong inflammatory response |
|
|
Term
| What is the most likely route of metastasis for sarcomas? |
|
Definition
| hematologic (stage with thoracic rads and abdominal ultrasound) |
|
|
Term
| What is the most likely route of metastasis for carcinomas? |
|
Definition
| lymphatic (stage with regional LN FNA) |
|
|
Term
| What are satellite metastasis are where are they located in relation to the primary tumor? |
|
Definition
| Satellite mets are extravascular microextensions of the primary tumor located in the reactive zone just distal the the tumor pseudocapsule (compressed tumor cells) |
|
|
Term
| What are skip metastases and where are they located in relation to the primary tumor? |
|
Definition
| Skip mets are the result of intravascular micrometastasis are are located in normal tissue beyond the reactive zone but within the same tissue plane/compartment as the primary tumor |
|
|
Term
| What are the indications for an incisional (ie. take a piece) biopsy? |
|
Definition
| When the type of therapy or extent of resection is determined by tumor type, when tumor type and predicated behavior may affect owner's decision to treat |
|
|
Term
| What are some drawbacks to incisional biopsies? |
|
Definition
| requires repeated anesthesia, delays treatment, must include biopsy tract in definitive surgery (risk of tumor seeding) |
|
|
Term
| What are the three incisional biopsy techniques? |
|
Definition
| needle core, punch (best for superficial lesions like skin/oral/perianal), wedge (best for ulcerated an necrotic lesions) |
|
|
Term
| What location is best when collecting an incisional biopsy from a soft tissue tumor? |
|
Definition
| composite (ie. biopsy is taken from the junction of normal and abnormal tissue in one slice) --> doesn't contaminate uninvolved tissues that may be needed for reconstruction, doesn't compromise subsequent curative resection, helps pathologist determine degree of invasiveness |
|
|
Term
| What location is best when taking an incisional biopsy from a bony lesion? |
|
Definition
biopsy from the center of the lesion is best as a peripheral sample is more likely to represent reactive tissue rather than neoplastic cells
(remember: disect down to the bone before taking the biopsy unless there is a significant soft tissue component to the tumor) |
|
|
Term
| What are the five main principles of surgical oncology? |
|
Definition
1. Remove all biopsy or drain tracts
2. Early (esp. venous) vascular ligation
3. Appropriate resection margins (stay a tissue plane away from the mass!)
4. Minimal to no tumor handling
5. Change instruments and gloves if the tumor bed was entered or if there are multiple masses to be removed |
|
|
Term
| What are the indications for intracapsular excision? |
|
Definition
| cytoreduction (increase effectiveness of multimodal therapy, or decrease clinical signs associated with functional benign tumors <-- ex. thyroid adenoma in a hyperthroid cat) |
|
|
Term
| What are the indications for marginal excision? |
|
Definition
| just outside pseudocapsul, removal of a benign tumor (ex. lipoma), leaves microscopic disease |
|
|
Term
| What is radical excision? |
|
Definition
| entire compartment of a structure is removed (ie. amputation, removal of an entire muscle belly) --> NO local residual cancer |
|
|
Term
| What characteristics are necessary before considering limb spare procedures for osteosarcoma? |
|
Definition
lesion located at distal radius (best), or ulna, tibia
NO concurrent infection, pathologic fractures, extensive soft tissue involvement, >50% length of bone |
|
|
Term
| Chemotherapy is a good choice for the treatment of what kind of tumors? |
|
Definition
| hematapoietic and solid tumors with the presence, or a high likelihood of metastasis <-- adequate staging is ESSENTIAL |
|
|
Term
| Why is single agent chemotherapy rarely curative? |
|
Definition
| the smallest clinically detectable tumor contains 1 billion tumor cells, at this point it is likely that cancer cells have developed chemo resistant mutations, additionally by the time tumors are clinically detectable the growth rate of tumor cells is much slower and chemotherapy is more effective against rapidly dividing cells (these are all reasons to surgically debulk a tumor prior to chemotherapy) |
|
|
Term
| What are three important guidelines to keep in mind when choosing combination chemotherapy? |
|
Definition
1. All drugs should have some degree of efficacy as single agents
2. Avoid drugs with overlapping toxicities
3. Use drugs at the maximum tolerated doses |
|
|
Term
| T/F, chemotherapy toxicity is generally dose dependent |
|
Definition
|
|
Term
| What are the guidelines for prophylactic antibiotic treatment for patients with chemotherapy induced neutropenia? |
|
Definition
|
|
Term
| Below what number of platelets/uL are patients at increased risk of bleeding? |
|
Definition
|
|
Term
| What is phaseal? How does this relate to chemotherapy safety? |
|
Definition
| Phaseal is a method of dosing and administering chemotherapy through a closed system, this prevents hazardous aerosolization and/or spillage of chemo drugs |
|
|
Term
| What are some important client education points regarding chemotherapy safety in pets? |
|
Definition
| Most drugs are eliminated in the urine or feces, although the amount of drugs present in pet excriment is minimal, and the metabolites are often inactive, latex gloves should be used to clean urine/feces for optimum safety |
|
|
Term
| What are the classes of cell cycle independent chemotherapy agents? |
|
Definition
Alkylating agent (cyclophosphamide)
Antitumor antibiotics (doxorubicin)
Platnium agents (cisplatin) |
|
|
Term
| Other than BAG what toxicities can occur in 10% and 20 % of patients respectively, on cyclophosphamide (alkylating agent)? |
|
Definition
10%: sterile hemorrhagic cystitis (due to acrolein, an inactive metabolite of cyclophosphamide), give drug in AM with lots of fresh water.
20% hepatotoxicity: monitor liver enzymes, reversible if early detection, can use SAM-e and milk thistle (hepatoprotectants) |
|
|
Term
| Other than BAG what organ system can become compromised in canine patients receiving doxorubicin (anti tumor antibiotic)? |
|
Definition
| cardiotoxicity, occurs at a cumulative dose >180mg/m^2 (~6 doses), tx as for congestive heart failure |
|
|
Term
| Other than BAG what organ system can become compromised in feline patients receiving doxorubicin (anti tumor antibiotic)? |
|
Definition
|
|
Term
| What fatal idiosyncratic reaction can be seen in feline patients receiving cisplatin (platinum agents)? |
|
Definition
fatal idiosyncratic pulmonary edema
use carboplatin instead of cisplatin in cats |
|
|
Term
| What are the classes of cell cycle specific chemotherapy agents? |
|
Definition
antimetabolites (5-fluorouracil)
Spindle toxins (vinca alkaloids - vincristine/ taxanes - paclitaxel)
L-asparaginase |
|
|
Term
| Which chemotherapy agents can cause allergic reactions? |
|
Definition
doxorubicin (antibiotic, cycle independent)
Spindle toxins (vinca alkaloids and taxanes, cycle specific)
L-asparaginase (cycle specific) |
|
|
Term
| Which chemotherapy agents should not be used in cats? |
|
Definition
Cisplatin (platnum agent, cycle independent)
5-Fluorouacil (antimetabolite, s phase specific) |
|
|
Term
| Which chemotherapy agents can be nephrotoxic? |
|
Definition
doxorubicin (cats)
Platinum agents (cisplatin, carboplatin) |
|
|
Term
| Why should Vinca Alkaloids and doxorubicin not be used in Collie breeds of dogs? |
|
Definition
| Collies have an MDR-1 mutation that impairs their ability to clear drug from their tissues so drug acummulates causing toxicity |
|
|
Term
| What is the reasoning behind NSAID treatment for cancer in dogs? |
|
Definition
| some carcinomas overexpress cox II |
|
|
