Clinical Oncology Flashcards
What is cancer staging? Why is it used? What are the key factors involved in staging?
- Describes the severity of a patient’s cancer based on the size and/or extent (reach) or the original (primary) tumour and whether or not cancer has spread in the body
- Helps to plan the appropriate treatment
- Can be used to determine prognosis
- Helps veterinarians and researchers exchange information about patients
- Elements of staging
- Site of primary tumour and the cell type
- Tumour size and/or extent
- Lymph node involvement
- Presence of metastasis
- Tumour grading
Describe the TNM staging system for oncology.
- T- size and invasiveness of primary tumour
- Size, shape, consistency
- Should be measured with calipers
- Imaging
- Cytological/histological diagnosis
- Biopsy procedure can be used
- N-status of regional lymph node metastasis
- Palpation
- Size, consistency
- Biopsy
- Care in interpretation
- Grade
- NX: Regional lymph nodes cannot be evaluated
- N0: No regional lymph node involvement
- N1, N2, N3: Degree of regional lymph node involvement
- M- Status of distant metastasis
- Clinical examination
- Clinical imaging
- Biopsy
What is cancer screening? How is it done?
- Cancer Screening
- a means of detecting disease early in asymptomatic individuals
- Positive results are usually not diagnostic but identify an individual at increased risk for the presence of cancer who warrant further evaluation
- Diagnosis is confirmation of disease by biopsy or tissue examination in the work-up following positive screening tests
- Types
- Physical screening
- Annual checkups
- Chemical screening
- None available for dogs at the moment
- Genetic screening
- Through the canine genome project, for example
- Physical screening
What is positron emission tomography (PET)?
- A nuclear medicine, functional imaging technique that produces a three-dimensional image of functional processes in the body
- A PET scan uses a small amount of radioactive material (tracer). The tracer is given through a vein (IV), travels through your blood and collects in organs and tissues.
How are oncolgy biopsies to be preserved/stored.
- Samples should be stored in formalin with tumour margins and body orientation marked
What are the clinical signs of hypercalcaemia? What type of cancer would cause hypercalcaemia?
- Clinical signs of hypercalcaemia
- Polyuria/Polydipsia (PU/PD)
- Vomiting, constipation
- Depression, weakness
- Hypertension, bradycardia
- Hyperparathyroid, with an excess production of PTH, would cause hypercalcaemia
What are bisphosphonates?
- Analogue of pyrophosphates
- Inhibit osteoclasts through interrupted metabolism (perhaps osteoclast apoptosis)
What neoplasic conditon causes hyperglycemia?
- Insulinoma: Islet β cell malignancy
What is polycythemia?
An abnormally increased concentration of haemoglobin in the blood, either through reduction of plasma volume or increase in red cell numbers. It may be a primary disease of unknown cause, or a secondary condition linked to respiratory or circulatory disorder or cancer.
Define the possible intents of tumour surgery.
- Prophylactic surgery
- Surgery that results in a reduction of future tumours, rate of recurrence of neoplastic disease
- Palliative surgery
- Surgery aims to improve quality of life (QOL)
- Generally performed without intent for long term survival
- Cytoreductive surgery
- Performed where definitive intent surgery not possible
- Improves utility of radiation therapy and/or chemotherapy as reduces # of malignant cells remaining
- Must be aware of scar orientation- should be longitudinal to avoid subsequent lymphatic radiation
- Definitive intent
- Goal is for surgery to be the sole treatment without need for adjunct therapy
What is the definition of the radiation dose? What are the units of radiation dosage?
Amount of radiation absorbed by the patient. Measured in Gray= Gy= 1 joule/kg
Describe acute toxicity in radiation therapy.
- Occurs during or shortly after therapy
- Generally are ‘reversible’ changes
- Severity increases with increased dose, dose rate, and dose per fraction
- Onset of clinical signs is dose independent
- Discomfort and pan are expected short term
Describe late toxicity of radiation therapy.
- Occurs >=3-6 months after radiation therapy (RT)
- Dose limiting
- Severity dependent on dose per fraction
- Bigger doses are more likely to cause toxicity
- Secondary to vascular damage, fibrosis, and/or loss of parenchymal cells
- Progressive and irreparable
Describe definitive radiation therapy.
- Generally large # of fractions but low dose/fraction
- Intent is long term control
- Acute side effects are expected
- Goal to limit late toxicity
Describe palliative (course fraction) radiation therapy.
- Fewer # of fractions but higher dose/fraction
- Palliative- improve quality of life (QOL) or function, decrease pain
- Few acute side effects
- Higher risk of clinically significant late toxicity
