Cancer 3 Flashcards
What is a carcinogen?
Any substance or agent directly involved in causing cancer
Name 2 ways a carcinogen may increase cancer risk
- Altering cellular metabolism
2. Directly damaging cellular DNA
Name 6 risk factors contributing to cancer
- Age
- Hormones
- Infections
- Radiation
- Lifestyle
- Genetics
What does the “Hit and Run” theory detail?
Causative agent not usually found in tumour as it is a multi step process so the causation of the first change is not likely to be found in eventual proliferation
Name 2 exceptions to the “Hit and Run” theory
- Viruses
2. Insoluble materials
Why are viruses exceptions to the “Hit and Run” theory?
The viral genome can often be found in the DNA of the tumour
Name 3 types of carcinogens
- Chemical substances
- Physical agents
- Biological agents
What 3 ways may carcinogens be taken into the body?
- Inhalation
- Absorption through the skin
- Ingestion
What is the major difference between direct-acting and indirect-acting chemical carcinogens?
- Direct acting carcinogens require no chemical transformation
- Indirect acting carcinogens require chemical transformation i.e. metabolism and it is a metabolite which is carcinogenic
Name a direct acting chemical carcinogen
Alkylating agents (cyclophosphamide)
Describe the carcinogenic properties of direct acting chemical carcinogens
- highly reactive
- Direct DNA damage leading to mutations
Name 3 examples of indirect acting chemical carcinogens
- Aromatic amines and azo dyes
- Beta-naphthylamine
- Polycyclic hydrocarbons
What are 3 stages of chemical carcinogenesis?
- Initiation
- Promotion
- Progression
Describe the initiation and promotion stages of chemical carcinogenesis
- Application of initiator
- Mutational activation of oncogene
- Application of promoters leads to clonal expansion of initiated cells
- Forced proliferation
- Clone of mutated cells accumulates additional mutations
What is the most common type of physical carcinogen?
Radiant energy
Name 3 types of skin cancers caused by UV light
- Melanoma
- Squamous cell carcinoma
- Basal cell carcinoma
Name a type of cancer caused by ionising radiation
Leukaemia
Name 4 work environments where exposure to radiation is possible
- Healthcare facilities
- Research institutions
- Nuclear reactors
- Nuclear weapon production facilities
_____ are the most prominent biological agent for the causation of cancer
Viruses
Name 4 cancers and viral infection associated with them
- Cervical Cancer (HPV)
- Burkitt’s Lymphoma (EBV)
- Nasopharyngeal Cancer (EBV)
- Hepatocellular Carcinoma (Hep B / Hep C)
Name 3 cancers and non-viral biological agents associated with them
- Hepatocellular Cancer (Aspergillus in grains)
- Gastric Cancer (Helicobacter pylori)
- Bladder Cancer (Schistosoma haematobium)
Name 5 ways carcinogens are identified
- Epidemiological studies
- Environmental linkage
- Direct exposure
- Laboratory tests
- Assessment of families
Name 2 complications in identifying carcinogens
- Cofactors
2. Latency between exposure and detection
What is the main body for carrying out epidemiological studies?
International Agency for Research on Cancer based in Lyon
Describe the function of epidemiological studies
- Association factors (casual / spurious)
- Population studies
- Identify precursor lesions
- Comparisons of lifestyle / diet / occupation
What is the criteria used to identify a true carcinogen?
Bradford Hill Criteria
Describe 4 environmental links with regards to cancer
- Lung carcinoma - Cigarette smokers
- Cervical carcinoma - Prostitutes (HPV infection)
- Bladder carcinoma - Dye (Beta-naphthylamine)
- Scrotal carcinoma - Chimney sweeps (polycyclic aromatic hydrocarbons in soot)
Name 3 types of laboratory tests carried out to identify carcinogens
- Cell culture studies
- Laboratory animal studies
- Tissue analyses
What is the function of cancer screening?
- Identification of potential signs for cancers developing
- Extend life expectancy
What is one caution of cancer screening?
Over-diagnosis
Why is over-diagnosis of cancers dangerous?
- Particular cancer may be very slow or non-progressive
- Person will die of other causes regardless of tumour
- Patient shouldn’t be treated as uneconomic and unnecessary
What does the “stage” of a tumour refer to?
Extent of spread of a tumour
Name 2 things which inform stage of a tumour
- Clinical and radiological assessment
2. Pathological examination of surgical specimens
Name the most common staging system
TMN (Tumour Node Metastases)
Name 4 staging systems which are organ specific
- Dukes
- Ann Arbor
- Breslow Depth
- Clarke Level
Name 5 benefits of a cancer staging system
- Determine treatment and prognosis
- Guide follow-ups
- Evaluate response to treatment
- Accurate communication between treatment centres
- Comparison between outcomes
What is the major difference between clinical and pathological staging?
Pathological is accurate as it is tests whereas clinical staging is simply guestimation
What is a positive tumour?
A tumour which moves beyond the surgical margins
What is the major complication of tumours in the head and neck?
Spread to lymph nodes and metastases
Name 2 clinical significances of staging
- Enable clinician to make some prediction of likely prognosis
- Essential information for the logical planning of treatment
What are 5 major modalities for cancer treatment?
- Surgery
- Radiation therapy
- Chemotherapy
- Hormonal therapy
- Immunotherapy
Why does hormonal therapy not tend to be used for tumours in the head and neck region?
Tissues in the head and neck region tend not to release hormones
What is a cancer biomarker?
A characteristic that is objectively measured and evaluated as an indicator of normal biological processes, pathogenic processes or pharmacologic response to a therapeutic intervention
Name 5 types of biomarkers found in cancer
- Genetic
- Epigenetic
- Proteomic
- Glycomic
- Imaging
Name 3 uses of cancer biomarkers
- Diagnosis
- Prognosis
- Epidemiology
What is precision medicine?
Personalised treatment so the right patient receives the right treatment at the right time
Name 3 typical modalities of treatment for head and neck cancer
- Surgery
- Surgery +/- radiotherapy
- Radiotherapy +/- chemotherapy
