Neoplasia 4 Flashcards
What are the most common cancers? (4)
Breast carcinoma
Lung carcinoma
Prostate carcinoma
Bowel carcinoma
What proportion of cancer do breast, lung, prostate and bowel carcinomas account for?
Over half of all cancers
Why are carcinomas more common than other types of cancers?
Epithelia is a labile tissue
epithelial cells proliferate a lot
more opportunity to accumulate mutations
Cancer is most common in what age range?
65+ years
Cancers in children younger than 14 tend to be…? (3)
Leukaemias
Lymphomas
CNS tumours
How is the aggression of cancer measured?
By looking at 5 year survival rates
proportion of people with the cancer that are still alive after 5 years
What are some examples of cancers that have a high 5 year survival rate? (4)
Testicular
Prostate
Breast
Malignant melanoma
What are some examples of cancers that have low 5 year survival rates?
Brain
Lung
Stomach
Oesophagus
Pancreas
Which cancer gives the biggest number of deaths?
Lung - high incidence and aggressive
Which cancer gives a low number of deaths?
Stomach - aggressive but low incidence
What factors are considered when predicting the outcome of cancer?
Age
General health status
Tumour site
Tumour type
Tumour grade
Tumour stage
Availability of effective treatments
What is tumour stage?
Measure of neoplasm’s overall burden, including
- size
- how far it’s spread
What is the commonest method for assessing stage of tumour?
TNM staging system
What does TNM stand for?
T - size of tumour
N - regional node metastasis
M - distant metastatic spread
What are the ranges of T?
T1 - T4
tumour gets bigger from T1 —–> T4
What are the ranges of N?
N0 - N3
no regional node metases in N0
more regional node metastases from N0 —–> N3
What are the ranges of M?
M0 - M1
no distant metastases in M0, but are in M1
How does the TNM system give us the stage of the tumour? What does each stage mean?
T1, T2 = stage 1 - early local cancer
T3, T4 = stage 2 - locally advanced
N1, N2, N3 = stage 3 - regional metastasis
M1 = stage 4 - distant metastasis
What are two examples of cancers that have their own unique staging system?
Lymphoma
Colorectal cancer
What is the unique staging system for lymphoma?
Ann Arbor system
What is the Ann Arbor staging system for lymphoma?
Stage 1 - lymphoma in a single node region
Stage 2 - lymphoma in two separate regions, one side of diaphragm
Stage 3 - lymphoma in two separate regions, both sides of diaphragm
Stage 4 - involvement of extra-lymphatic organ e.g. bone marrow
What is the unique staging system for colorectal cancer?
Dukes staging system
What is the Dukes staging system for colorectal cancer?
Stage A - invasion into but not through bowel wall
Stage B - invasion through bowel wall
Stage C - involvement of lymph nodes
Stage D - distant metastases
How does the stage of a cancer relate to the outcome?
Stage correlates with outcome
higher stage means poorer outcome - more deaths, earlier on
What is the difference between regional and distal metastases?
Local involves lymphatics only
Distant also involves blood circulation
more severe
What is the grade of a tumour based on?
The degree of differentiation of the neoplasm
What are the different grades of a tumour? What do they each mean?
G1 - well-differentiated
G2 - moderately differentiated
G3 - poorly differentiated
G4 - undifferentiated, anaplastic - doesn’t resemble any tissue
Which cancers is the G1 - G4 grading system used for?
Squamous cell carcinoma
Colorectal carcinoma
Which type of cancer has its own unique grading system? What is the grading system called?
Breast cancer
Blood-richardson system
What is the Bloom-richardson grading system for cancer?
Give points based on presence of
- tubules
- mitotic figures
- nuclear pleomorphism
How does tumour grading correlate with outcome?
The worse a grade of tumour i.e. the more undifferentiated it is
the poorer the outcome - reduced survival
Tumour grading is particularly important in which types of cancer?
Breast cancer
Prostate cancer
Primary brain tumour
Lymphomas
How is cancer treated?
Surgery
Radiotherapy
Chemotherapy
Hormone therapy
Treatment targeted to specific molecule alterations
Therapies targeting immune system
What is the MAIN treatment for cancer?
Surgery
What is adjuvant treatment?
Treatment given after surgical removal of primary tumour
to eliminate any micrometastases
What is neoadjuvant treatment?
Treatment given to reduce size of tumour
in order to allow for removal by surgery
How does radiation kill cancer cells?
Direct DNA damage
or produces free radicals
which then damage DNA - so is indirectly done
DNA damage means cell is stopped at checkpoint of cell cycle
undergoes apoptosis
How is normal tissue protected from radiation?
Shield normal tissue
Give radiation in fractionated doses to minimise normal tissue damage
What type of radiation is used in radiotherapy?
X-rays
Radiation kills cancer cells when they are in what phase of the cell cycle?
Mostly G2 phase
What are the different types of drugs given in chemotherapy?
Antimetabolites
Alkylating agents
Antibiotics
Plant-derived drugs
How do antimetabolites kill cancer cells?
Mimic substrates involved in DNA replication
so DNA replication doesn’t occur
What is an example of an antimetabolite?
Fluorouracil
How do alkylating agents work?
Form cross-links between the two strands of DNA
so it can’t replicate
What is an example of an alkylating agent?
Cisplatin
How do antibiotics kill cancer cells?
Damage DNA of the cancer cells
induces apoptosis of the cell
What are some examples of antibiotics used to treat cancer? How do they each work?
Doxyrubicin - inhibits DNA topoisomerase
Bleomycin - causes double-stranded breaks in DNA
How do plant-derived drugs kill cancer cells?
Block microtubule assembly
interferes with mitotic spindle formation
What is an example of a plant-derived drug used to kill cancer cells?
Vincristine
What is a disadvantage of chemotherapy?
Damages healthy cells that proliferate a lot
e.g. epithelia, bone marrow, hair follicles
What is an example of a hormone therapy used to treat breast cancer? What does it do?
Tamoxifen - binds to oestreogen receptors and blocks them so oestreogn can’t bind
When is tamoxifen ideal for treatment of breast cancer?
If breast cancer is oestrogen receptor positive
What do oestrogen receptors look like under the microscope?
Appear brown
What is a gene that’s commonly over-expressed in breast cancer?
HER-2 gene
Which drug is used to block her-2 signalling in breast cancer?
Herceptin
Which is the genetic alteration that has occurred in chronic myeloid leukaemia?
Translocation between chromosomes 9 and 22
creating abnormal fusion protein BCR-ABL
causes excessive cell proliferation
How is chronic myeloid leukaemia treated?
Imatinib - inhibits the abnormal fusion protein BCR-ABL
How do therapies targeting the immune system work?
Block immune checkpoints
How are tumour markers used clinically?
Monitor tumour burden
during treatment
for follow-up
What are some of the different types of tumour markers?
Hormones
Oncofoetal antigens
Specific proteins
Glycoproteins
What is the aim of cancer screening and why?
Detect cancers as early as possible
chance of cure is highest earlier on
What are some of the disadvantages of screening?
Lead time bias
Length bias
Overdiagnosis
What is lead time bias?
Person gets cancer and dies by cancer at same time
but if diagnosed earlier, seems like they’ve lived longer
but they actually haven’t
What is length bias?
Slow growing tumours are diagnosed more by screening than rapidly growing tumours
are less aggressive, better outcome to begin with
makes screening seem more effective than it is
What is overdiagnosis?
Seems that cancer rates are increasing rapidly
but are actually just diagnosing benign tumours
that may not have presented clinically otherwise
because are asymptomatic
