Introduction. Oncologyin general. Most common neoplasms

Question 1

Tumours

Answer 1

Not unknown problems–many details are known,
•Not one type of disease–many forms,
•Not the more expensive treatment possibilities–many options with different expenses,
•Not one form of death
–manyarecurable.

Question 2

Therapy

Answer 2

Primary aim of therapy for cancer patients is improving the life quality.
Secondary aim can be the increase of lifespan

Question 3

Tumours are

Answer 3

Genetic changes which cause increase proliferation and altered differentiation, as the cells escape from the regulatory mechanisms

Therefore uncontrolled proliferation & eternal life + youth gained.=> mass of cells or leukemia. develop

An estimated 5-6 mutations is the minimum number that can provide a cell & its progeny with the 6 hallmarks of cancer.

Rarely inheritable except RCND-gene=> renal carcinoma & nodular dermatofibrosis- german shepherd

Question 4

6 Hallmarks of cancer

Answer 4

1. Evading apoptosis
2. Self-sufficiency in growth signals
3. Insensitivity to anti-growth signals
4. Tissue invasion and metastasis
5. Limitless replicative potential
6. Sustained angiogenesis

Question 5

Steps

Answer 5

1. Initiation: Some cells gain a progress & primacy compared to other cells
2. Progression:
   - angiogenesis
   - Invasiveness, metastasis (malignancy)- selective non-random process
   - bypassing immune system

Tumour growth is exponential slower (plateau), till 0.5-1 cm diameter or 1g (10^8 cells–are visible on x-ray and 10^9 cells are palpable).

Question 6

Tumour growth

Answer 6

In theory, one sub-clone could secrete angiogenic factors to enhance blood vessel formation & thereby bring in nutrients + O2 to facilitate growth, while its partner could produce proteinases that degrade the surrounding extracellular matrix allowing invasion + dissemination.
When present together, 2 distinct populations of cancer cells transplanted together can lead to disease progression + liver metastasis, but are unable to do so when transplanted individually.

Question 7

Types of tumour

Answer 7

Benign tumours
Proliferating(growing), but non-invasive, non-metastatic

Malignant tumours
Proliferating(growing), and invasive and/or metastatic

Blood cell tumours: leukemia=/= leucocytosis

Question 8

Epithelial cells (tumors)

Answer 8

Characteristic features: cell to cell bridges,
exfoliate clumps of cells (some individual cells), ductal or acinar arrangements may be identified

• Large to very large size,
• moderate to abundant cytoplasm,
• round to oval nuclei w/ smooth to coarse chromatin pattern coarser & ropy in malign. cases,

Nuclei contain one or more prominent nucleoli that become lager or irregular in malign. cases
Malign. tumors show marked variation in cellular, nuclear and nucleolar size and shape, increase in nucleus: cytoplasm ratio

Question 9

Common skin lesions

Answer 9

Discrete round cell tumors

• Individual small-medium round cells
• moderate to abundant cytoplasm,
• sometime typical IC granules/ particles,
• round to oval nuclei w/ smooth to coarse chromatin pattern coarser & ropy in malign. cases,
• nuclei contain 1+ prominent nucleoli that become lager / irregular in malign. cases

Malign. tumors show marked variation in cellular, nuclear and nucleolar size and shape, increase in nucleus: cytoplasm ratio.

Question 10

Cells of mesenchymal origin (spindle-cell tumors)

Answer 10

Yield individual cells instead of groups,

• clumps or sheets occasionally,
• moderate to abundant azurophilic inter cellular material,
• fusiform or spindle appearance
• varying numbers of cells may show, cytoplasmic tails, trailing away from nucleus in 1-2 directions,
• small-medium, moderately light to medium blue cytoplasm,
• round-oval nucleus with smooth to fine lacy chromatin pattern, nucleoli aren’t usually visible in non-neoplastic spindle cells, except fibroblasts.

Note: spindle cell tumors are often impossible to name cytologically,
-granulation tissue produces plum, young fibroblasts that may have prominent criteria of malignancy

Malignant cases
-nucleoli become prominent,
-spindle shape becomes less prominent,
-cell, nuclear & nucleolar size + shape vary markedly,
-chromatin pattern becomes coarser, -
-cytoplasmic basophilic ,
-increase in nucleus: cytoplasm ratio.
hemangiosarcoma

Question 11

Prevalence

Answer 11

number of cases of a disease at one particular point in time
-proportion of individuals who have the disease
prevalence %= (no. of ppl w/ disease)/(no. of ppl in the pop) x100

Question 12

Incidence

Answer 12

two definitions
-incidence proportion
= (no. of new cases)/(pop without disease at baseline)x100

-incidence ratee (aka. incidence density)= (no. of new cases)/(person-time at risk)

Question 13

Cancer Statistics

Answer 13

Cancer is the major cause of death in pets greater than 10 years old
45% of all dogs older than 10 years of age die of cancer 23% of all dogs die of cancer

Question 14

Tumour staging

Answer 14

After tumour typing, the next step is staging.
Staging= evaluation of the patient’s tumour spreading.
Staging contains a description of the localisation of the tumour in respect of the surrounding tissues, presence of clinical demonstrable metastases in the regional lymph nodes / further distance, and paraneoplastic syndromes.
TNM system adapted from human oncology.
T : primary tumour
N : regional lymph node metastasis
M : distant metastasis