Oncology Patho Flashcards
Cancer the number 1 cause of death in SG. True or false?
True.
What are the top 5 leading cancers for both genders in SG?
Female:
1. Breast
2. Colo-rectum
3. Corpus uteri
4. Lung
5. Ovary
Male:
1. Colo-rectum
2. Lung
3. Prostate
4. Lymphoid neoplasms
5. Liver
What is the most common cancer in males?
Prostate cancer
What is the most common cancer in females?
Breast cancer
What is a tumour?
Abnormal mass of tissue
The growth is autonomous, exceeds that of normal tissue and persists after cessation of the stimuli that initiated it.
What are the 2 types of tumours?
Benign & malignant
Histology of benign tumour vs malignant tumour:
Benign: typical of tissue of origin, few mitoses
Malignant: anaplastic, with abnormal cell size and shape, many mitoses
Growth rate of benign tumour vs malignant tumour:
Benign: slow
Malignant: fast
Localization of benign tumour vs malignant tumour:
Benign: strictly local, often encapsulated/no metastasis
Malignant: infiltrative/frequent metastasis
Recurrence after treatment of benign tumour vs malignant tumour:
Benign: Rare
Malignant: Common
Local invasion of benign tumour vs malignant tumour:
Benign: cohesive growth, capsule & basement membrane not touched
Malignant: poorly cohesive and infiltrative, capsule & basement membrane breached
Tumour necrosis of benign tumour vs malignant tumour:
Benign: Rare
Malignant: Common
Prognosis of benign tumour vs malignant tumour:
Benign: good, unless in critical area
Malignant: poor if untreated
What are the 4 phases of tumour development & growth?
- Transformation
- Growth of transformed cells
- Invasion of tumour cells into the surrounding tissues
- Metastasis of tumour cells to distant sites
What occurs in phase 1 (transformation) of tumour development for benign & malignant tumours?
Benign: mostly well differentiated, resemble the cell from which they originated
Malignant: transformation - ANAPLASIA!!
- nuclear and cellular pleoporphism (size & shape changes)
- abnormal nuclear morphology (hyperchromasia, high nuclear cytoplasmic ratio, chromatin clumping, prominent nucleoli)
- loss of polarity
- abundant mitoses
What is hypoplasia?
Fewer cells than what is deemed a normal amount (usually BENIGN) - underdevelopment of tissue
Shrinking of cells
What is hyperplasia?
Increased cell number, under control of normal proliferation regulatory mechanism
A result of external stimuli (trauma, pressure etc.)
What is neoplasia?
Similar to hyperplasia but denotes abnormal multiplication due to loss of normal proliferation regulation and absence of stimuli
AKA cells manifesting hyperplasia with atypia
What is dysplasia?
A change in the normal shape, size and organisation , usually a response to chronic irritation (eg. cigarette smoke or inflammation) within a tissue
NOT YET MALIGNANT: Changes are reversible if stimulus is removed, otherwise cells with become metaplastic
What is metaplasia?
A reversible change of one cell type to another. (NOT YET MALIGNANT)
eg. ciliated columnar epithelium of the respiratory surface becoming stratified squamous epithelium after prolonged irritation from smoking
Changes are reversible if the stimulus is removed, otherwise the cells become anaplastic
What is anaplasia?
A reversal in differentiation (dedifferentiation) OR loss of structural & functional differentiation of normal cells.
Not reversible, high grade malignant tumour, very poor prognosis
A characteristic of cancerous tumours (MALIGNANT)
What occurs in phase 2 (rate of growth) of tumour development?
Grading of the tumour by how differentiated the cells are.
What are the levels of differentiation?
- Well differentiated neoplasm
- Poorly differentiated neoplasm
- Undifferentiated or “anaplastic” tumour
What will well differentiated neoplasm look like?
It will resemble mature cells of the tissue of origin.
What will poorly differentiated neoplasm look like?
Composed of primitive cells with little differentiation
What occurs in phase 3 (local invasion) of tumour development of benign tumours?
Benign: cohesive cells, have a rim of condensed connective tissue - capsule
What occurs in phase 3 (local invasion) of tumour development of malignant tumours
Malignant: invade locally
- detachment “loosening up” of the tumour cells from each other
- attachment to matrix components
- degradation of matrix components (eg. using collegenase)
- migration of tumour cells
What occurs in phase 4 (metastasis) of tumour development?
Unequivocal sign of malignancy
- Lymphatic
- Hematogenous
- Seeding of body cavities
What is the significance of nodal metastasis?
Prognostic is an important component of TNM staging system
T: Tumour
N: Nodes
M: Metastasis
T1N0M0 vs T4N1M1, what do these mean and which has a better prognosis?
T1 - small
T4 - large
N0 - no spread to regional lymph nodes
N1 - spread to regional lymph nodes
M0 - no metastasis
M1 - metastasised to other organs
T1N0M0 - stage I
T4N1M1 - stage IV
What are the steps of metastasis?
- Intravasation
- tumour cells pass through basement membrane, penetrate a nearby artery/blood vessel - Embolization
- tumour cells get attached to e.g. a platelet, forms an embolus - Adhesion
- more platelets will gather and stick to the existing platelet embolus, this is called adhesion - Extravasation
- adhere to a cell wall and exit - Metastatic Growth
- tumour cells could go to another organ
What are the nomenclature for neoplasms (benign & malignant)?
Benign:
-oma (eg. lipoma, fibroma, osteoma etc.)
Malignant:
- carcinoma - epithelial cells (eg. squamous cell carcinoma, adenocarcinoma)
- sarcoma - mesenchymal cells (eg. liposarcoma, fibrosarcoma, osteosarcoma etc.)
What are the predisposing factors for cancer?
- Age
- Body Mass (obesity increases cancer risk by 50%)
- Chronic inflammation
- Precancerous conditions
What are common childhood cancers?
- Leukemias & CNS neoplasms
- Wilms tumour
- Retinoblastoma
- Bone and skeletal muscle tumours
Why are elderly predisposed to cancer?
Older persons have a greater propensity to develop neoplasms from lack of effective control mechanisms.
What are some precancerous conditions that predispose people to cancer?
- Chronic ulcerative colitis
- Atrophic gastritis of pernicious anemia
- Leukoplakia of mucous membranes
What is the etiology of cancer?
90-95% Environmental factors
5-10% Genetic factors
What are the environmental factors that can lead to cancer?
- Chemicals
- UV light/ionizing radiation
- Viral infections
- Smoking and alcohol abuse