Lecture 4 - Cancer Flashcards
Most common types of cancer in males (Aus)?
- prostate
- colorectal
- melanoma
- lung
Most common types of cancer in females (Aus)?
- breast
- colorectal
- melanoma
- lung
~how many cases of cancer annually, worldwide?
> 14 million
~how many people die of cancer annually, worldwide?
8.2 million
~how many people living with cancer in the world today?
21 million
describe the difference between cancer and neoplasia?
neoplasia = ‘new growth’, these new growths may be benign or malignant. Cancer implies malignancy, so cancer is a type of neoplasm
define neoplasia?
- disorder of cell growth leading to excessive proliferation of a single cell and its clonal progeny
- occurs independently of physiologic growth-regulatory stimuli
- may be benign or malignant
- due to a series of acquired mutations
explain the 3 key characteristics of a neoplastic growth?
- Unregulated by normal physiologic mechanisms
- Irreversible
- Monoclonal (arises from singular abnormal cell)
A neoplasm is colloquially known as?
A tumor
State the principle fighter of a bacterial infection in the human body?
Neutrophils
What is the fundamental difference between a cancer cell, and a normal cell?
Normal cells send, receive and interpret signals which solve as SOCIAL CONTROLS: cells behave responsibly with resting, dividing, dying etc.
Cancer cells do not abide by social controls, they divide without normal constraints and invade territories belonging to other cells
why do cancer cells divide so uncontrollably?
due to a mutation in the neoplastic cells giving them a survival and growth advantage
t/f: cancerous growths are always homogenous (all same type of cancer)
false - often heterogenous, this is why chemotherapy isn’t always effective and immunotherapy is a better approach
t/f: cancer can be caused by a singular mutation
false - needs to be a series of mutations, not just one
define hyperplasia?
increased proliferation of cells which is ‘occurring normally’ (observing social controls)
compare or contrast hyperplasia and neoplasia?
Main difference = neoplasia involves mutated cell, hyperplasia involves non-mutated cell
- in hyperplasia growth occurrs normally (social controls) whereas in neoplasia it is abnormal
- hyperplasia is reversible whereas neoplasia is not
- neoplasia originates from a single cell, whereas hyperplasia may originate from one or many cells
describe whats meant by the ‘degree of differentiation’ of tumor cells?
the extent to which the tumor cells resemble the normal tissue of origin, structurally and functionally
well differentiated= close resemblance to tissue of origin, likely benign
poorly differentiated= minimal resemblance to tissue of origin, likely malignant
(note: normal healthy tissue contains a variety of healthy cells, so the normal cells are well differentiated into their roles, whereas cancerous cells aren’t differentiated into their roles)
explain what’s meant by an ‘anaplastic’ tumor?
The worst!
One which is poorly differentiated - so it doesn’t resemble the tissue of origin to the point where it cannot be determined what the tissue of origin is, and is likely malignant
if a tumour is well differentiated, what does this mean in terms of its appearance and apparent threat level?
it appears normal - same as original tissue, likely benign
if a tumor is poorly differentiated, what does this mean in terms of its structure and apparent threat level?
it appears different to original tissue from which it came, the cells are poorly differentiated meaning they haven’t taken up their normal roles - this is likely a malignant tumor
All neoplasms have 2 components - what are they?
- Parenchyma - proliferating cells of the tumor, defines the behavior
- Supportive stroma - CT, BV, framework from which parenchyma grows
(note: this doesn’t only apply to tumors - parenchyma always means function portion of tissue etc)
Contrast features of benign and malignant neoplasms?
- benign margins are well defined, malignant are poorly defined and locally invasive
- benign growths don’t invade surrounding tissue whereas malignant does, destroying it and spreading (metastasizing)
- benign prognosis good (death unlikely), malignant is poor
t/f: benign tumors do not have major abnormalities in the regulation of growth
true
t/f: benign tumors grow locally and rapidly
false - locally and slowly
can benign tumors cause significant clinical symptoms?
yes - ie. thru compression of adjacent structures (meningioma)
can benign tumors be fatal?
yes
how can benign tumors affect hormone levels?
tumor within endocrine cells –> excessive levels of hormone secretion
t/f: malignant tumors are always poorly differentiated (ie. do not resemble tissue of origin)`
false - malignant tumours can be well differentiated, however they are often poorly differentiated
the spread of malignant neoplasms is also known as?
metastasis
Describe the mechanisms of metastasis?
- Direct invasion (into adjacent organs or thru nerves)
- Spead by lymphatics (to lymph nodes)
- Haematogenous spread (by blood to distant sites such as liver, lungs, brain, bones, adrenal)
- Transceolomic spread (abdominal cavity tumors which spread directly across peritoneal spaces by seeding cells which migrate to the surfaces of other organs)
note: 4 is technically not considered metastasis
what’re the most common mechanisms of metastasis?
lymphatic spread & haematogenous
t/f: some tumors show a mix of benign and malignant characteristics, and are difficult to classify accordingly
true
Basal cell carcinoma:
a. ) Risk of metastasis?
b. ) Cured by?
c. ) If not completely excised, likely activity?
a. ) <0.1%
b. ) simple excision
c. ) becomes highly invasive and locally destructive
A categorically malignant tumor is one which has all 3 malignant qualities of a cancer - what are they?
- Unlimitied/ uncontrolled growth
- Invasion of surrounding tissue (direct invasion)
- Potential for distant spread (metastasis)
(note: think of cancer qualities as the things determining cancer movements, this IS different to the 3 characteristics of a neoplasm)
A ‘categorically benign tumor’ is defined as?
lacking all 3 qualities of a categorically malignant tumor (growth, metastasis, invasion)
What are tumors which possess 1 or 2 of the 3 qualities of a benign tumor?
May be classified as either malignant or benign depending, often disagreement occurs
Breast fibroadenoma:
a. ) Growth unlimited?
b. ) Invasion?
c. ) Metastasis?
No to all 3; categorically benign
Breast carcinoma:
a. ) Growth unlimited?
b. ) Invasion?
c. ) Metastasis?
Yes to all 3; categorically malignant
Colonic polyp (tubular adenoma):
a. ) Growth unlimited?
b. ) Invasion?
c. ) Metastasis?
a. ) Growth unlimited
b. ) Invasion occurrs
c. ) No metastasis
classified as benign!
explain suffix -oma?
benign neoplasm
ie. gland with benign neoplasm becomes adenoma